Relative biological effectiveness if alpha radiation for human lung exposure

International Nuclear Information System (INIS)

Yarmoshenko, I.; Kirdin, I.; Zhukovsky, M.

2006-01-01

estimates for cases of indoor radon alpha exposure and exposure to implanted plutonium can be seen. Difference in biological effectiveness of inhaled radon and implanted plutonium may appear due to different distribution of short-lived radon progeny and long lived plutonium within lung tissues. Low RBE value for alpha particle exposures of human lung tissues may be a reason of known inconsistency of dose conversion factors for radon estimates based on dosimetric and epidemiologic approaches. (authors)

UV radiation: sources, effects and risks of human and environmental exposure

International Nuclear Information System (INIS)

Eggink, G.J.; Slaper, H.

1992-01-01

This paper summarizes the principal results of a review study on UV- -exposure and UV related risks in the Netherlands. Both the present state of affairs and future developments are discussed, the latter partly based on model calculations. The sun is the main UV source to which the whole population is exposed. Solar exposure is estimated to amount at least 90% of the annual UV burden for the Dutch population. For certain groups in the population man made sources are estimated to contribute considerably to the yearly UV dose. Ozone depletion as a result of human activities, growing use of tungsten halogen lamps and increasing application of UV-sources in industry and medicine all tend to increase UV exposure. UV exposure can lead to a wide variety of health effects, among which the induction of skin cancer, skin aging, cataract formation and suppression of immune responses. Risk estimates of these health effects are available for skin cancer and to a lesser extend for cataracts. The estimated UV related skin cancer incidence rate in the Netherlands is 10 -3 per year (15 000 cases), and the associated mortality rate amounts to 6-25·10 -6 per year (90-400 deaths). The ozone depletion presently observed over the past decade (5% in the Netherlands), is expected to lead to an increased annual mortality rate due to skin cancer of 1,3·10 -6 per year. Environmental exposure can influence plant physiology and lead to a decrease of biomass in aquatic as well as terrestrial ecosystems. This may result in adverse effects on the foodweb and biodiversity of ecosystems. Quantitative risk estimates for these effects are very uncertain or lacking. (author)

Human Health Effects Associated with Exposure to Cyanobacteria and Cyanotoxins: What Do We Know?

Science.gov (United States)

The study of environmental health typically focuses on human populations. However, companion animals, livestock and wildlife also experience adverse health effects from environmental pollutants. Animals may experience direct exposure to pollutants unlike people in most ambient ex...

Human exposure to aluminium.

Science.gov (United States)

Exley, Christopher

2013-10-01

Human activities have circumvented the efficient geochemical cycling of aluminium within the lithosphere and therewith opened a door, which was previously only ajar, onto the biotic cycle to instigate and promote the accumulation of aluminium in biota and especially humans. Neither these relatively recent activities nor the entry of aluminium into the living cycle are showing any signs of abating and it is thus now imperative that we understand as fully as possible how humans are exposed to aluminium and the future consequences of a burgeoning exposure and body burden. The aluminium age is upon us and there is now an urgent need to understand how to live safely and effectively with aluminium.

The Adverse Effects of Heavy Metals with and without Noise Exposure on the Human Peripheral and Central Auditory System: A Literature Review

Directory of Open Access Journals (Sweden)

Marie-Josée Castellanos

2016-12-01

Full Text Available Exposure to some chemicals in the workplace can lead to occupational chemical-induced hearing loss. Attention has mainly focused on the adverse auditory effects of solvents. However, other chemicals such as heavy metals have been also identified as ototoxic agents. The aim of this work was to review the current scientific knowledge about the adverse auditory effects of heavy metal exposure with and without co-exposure to noise in humans. PubMed and Medline were accessed to find suitable articles. A total of 49 articles met the inclusion criteria. Results from the review showed that no evidence about the ototoxic effects in humans of manganese is available. Contradictory results have been found for arsenic, lead and mercury as well as for the possible interaction between heavy metals and noise. All studies found in this review have found that exposure to cadmium and mixtures of heavy metals induce auditory dysfunction. Most of the studies investigating the adverse auditory effects of heavy metals in humans have investigated human populations exposed to lead. Some of these studies suggest peripheral and central auditory dysfunction induced by lead exposure. It is concluded that further evidence from human studies about the adverse auditory effects of heavy metal exposure is still required. Despite this issue, audiologists and other hearing health care professionals should be aware of the possible auditory effects of heavy metals.

Variation in calculated human exposure. Comparison of calculations with seven European human exposure models

NARCIS (Netherlands)

Swartjes F; ECO

2003-01-01

Twenty scenarios, differing with respect to land use, soil type and contaminant, formed the basis for calculating human exposure from soil contaminants with the use of models contributed by seven European countries (one model per country). Here, the human exposures to children and children

Assessment of human exposures

Energy Technology Data Exchange (ETDEWEB)

Lebret, E. [RIVM-National Inst. of Public Health and Environmental Protection (Netherlands)

1995-12-31

This article describes some of the features of the assessment of human exposure to environmental pollutants in epidemiological studies. Since exposure assessment in air pollution epidemiology studies typically involve professionals from various backgrounds, interpretation of a concepts like `exposure` may vary. A brief descriptions is therefore given by way of introduction

Assessment of human exposures

Energy Technology Data Exchange (ETDEWEB)

Lebret, E [RIVM-National Inst. of Public Health and Environmental Protection (Netherlands)

1996-12-31

This article describes some of the features of the assessment of human exposure to environmental pollutants in epidemiological studies. Since exposure assessment in air pollution epidemiology studies typically involve professionals from various backgrounds, interpretation of a concepts like `exposure` may vary. A brief descriptions is therefore given by way of introduction

Relative significance of natural irradiation vs all human exposures

International Nuclear Information System (INIS)

Jammet, H.

1985-01-01

A review is made of the fundamentals allowing to quantitatively express the importance of the various sources of human exposure by an individual or collective approach. Following a summary of the components of normal exposure to natural sources, the various human actions at the origin of enhanced exposure are studied: 1) those modifying the relationship between natural sources and man (dwelling conditions, coal burning, geothermal energy production, exploitation of phosphate rock); 2) those creating new artificial sources (nuclear explosions in the atmosphere, nuclear power production, medical use of radiation and radionuclides). The effective dose equivalent commitments for these sources are compared with those necessarily involved by continuous normal exposure to the natural sources of exposure [fr

Human exposure to cyanotoxins and their effects on health.

Science.gov (United States)

Drobac, Damjana; Tokodi, Nada; Simeunović, Jelica; Baltić, Vladimir; Stanić, Dina; Svirčev, Zorica

2013-06-01

Cyanotoxins are secondary metabolites produced by cyanobacteria. They pose a threat to human health and the environment. This review summarises the existing data on human exposure to cyanotoxins through drinking water, recreational activities (e.g., swimming, canoeing or bathing), the aquatic food web, terrestrial plants, food supplements, and haemodialysis. Furthermore, it discusses the tolerable daily intake and guideline values for cyanotoxins (especially microcystins) as well as the need to implement risk management measures via national and international legislation.

Effect of nickel and iron co-exposure on human lung cells

International Nuclear Information System (INIS)

Salnikow, Konstantin; Li Xiaomei; Lippmann, Morton

2004-01-01

Exposure to ambient air particulate matter (PM) is associated with increased mortality and morbidity in susceptible populations. The epidemiological data also suggest a relationship between PM air pollution and impairment of cardiopulmonary function. The mechanisms that may be responsible for these effects are not fully understood and are likely related to perturbations of cellular and molecular functions. One type of PM, residual oil fly ash (ROFA), is of particular interest. ROFA does not contain much organic material, but does contain relatively high quantities of transition metals, predominantly nickel, vanadium, and iron, as well as black carbon and sulfates. In this study, we investigated the effect of two metals (iron and nickel) on the induction of 'hypoxia-like' stress and the production of interleukins (ILs) in minimally transformed human airway epithelial cells (1HAEo - ). We found that exposure to soluble nickel sulfate results in the induction of hypoxia-inducible genes and IL-8 production by the 1HAEo - cells. The simultaneous addition of iron in either ferric or ferrous form and nickel completely inhibited IL-8 production and had no effect on 'hypoxia-like' stress caused by nickel, suggesting the existence of two different pathways for the induction 'hypoxia-like' stress and IL-8 production. The effect of nickel was not related to the blocking of iron entry into cells since the level of intracellular iron was not affected by co-exposure with nickel. The obtained data indicate that nickel can induce different signaling pathways with or without interference with iron metabolism. Our observations suggest that in some cases the excess of iron in PM can cancel the effects of nickel

Cadmium osteotoxicity in experimental animals: Mechanisms and relationship to human exposures

International Nuclear Information System (INIS)

Bhattacharyya, Maryka H.

2009-01-01

Extensive epidemiological studies have recently demonstrated increased cadmium exposure correlating significantly with decreased bone mineral density and increased fracture incidence in humans at lower exposure levels than ever before evaluated. Studies in experimental animals have addressed whether very low concentrations of dietary cadmium can negatively impact the skeleton. This overview evaluates results in experimental animals regarding mechanisms of action on bone and the application of these results to humans. Results demonstrate that long-term dietary exposures in rats, at levels corresponding to environmental exposures in humans, result in increased skeletal fragility and decreased mineral density. Cadmium-induced demineralization begins soon after exposure, within 24 h of an oral dose to mice. In bone culture systems, cadmium at low concentrations acts directly on bone cells to cause both decreases in bone formation and increases in bone resorption, independent of its effects on kidney, intestine, or circulating hormone concentrations. Results from gene expression microarray and gene knock-out mouse models provide insight into mechanisms by which cadmium may affect bone. Application of the results to humans is considered with respect to cigarette smoke exposure pathways and direct vs. indirect effects of cadmium. Clearly, understanding the mechanism(s) by which cadmium causes bone loss in experimental animals will provide insight into its diverse effects in humans. Preventing bone loss is critical to maintaining an active, independent lifestyle, particularly among elderly persons. Identifying environmental factors such as cadmium that contribute to increased fractures in humans is an important undertaking and a first step to prevention.

High Throughput Heuristics for Prioritizing Human Exposure to ...

Science.gov (United States)

The risk posed to human health by any of the thousands of untested anthropogenic chemicals in our environment is a function of both the potential hazard presented by the chemical, and the possibility of being exposed. Without the capacity to make quantitative, albeit uncertain, forecasts of exposure, the putative risk of adverse health effect from a chemical cannot be evaluated. We used Bayesian methodology to infer ranges of exposure intakes that are consistent with biomarkers of chemical exposures identified in urine samples from the U.S. population by the National Health and Nutrition Examination Survey (NHANES). We perform linear regression on inferred exposure for demographic subsets of NHANES demarked by age, gender, and weight using high throughput chemical descriptors gleaned from databases and chemical structure-based calculators. We find that five of these descriptors are capable of explaining roughly 50% of the variability across chemicals for all the demographic groups examined, including children aged 6-11. For the thousands of chemicals with no other source of information, this approach allows rapid and efficient prediction of average exposure intake of environmental chemicals. The methods described by this manuscript provide a highly improved methodology for HTS of human exposure to environmental chemicals. The manuscript includes a ranking of 7785 environmental chemicals with respect to potential human exposure, including most of the Tox21 in vit

Cumulative effects of prenatal-exposure to exogenous chemicals and psychosocial stress on fetal growth: Systematic-review of the human and animal evidence.

Science.gov (United States)

Vesterinen, Hanna M; Morello-Frosch, Rachel; Sen, Saunak; Zeise, Lauren; Woodruff, Tracey J

2017-01-01

Adverse effects of prenatal stress or environmental chemical exposures on fetal growth are well described, yet their combined effect remains unclear. To conduct a systematic review on the combined impact and interaction of prenatal exposure to stress and chemicals on developmental outcomes. We used the first three steps of the Navigation Guide systematic review. We wrote a protocol, performed a robust literature search to identify relevant animal and human studies and extracted data on developmental outcomes. For the most common outcome (fetal growth), we evaluated risk of bias, calculated effect sizes for main effects of individual and combined exposures, and performed a random effects meta-analysis of those studies reporting on odds of low birthweight (LBW) by smoking and socioeconomic status (SES). We identified 17 human- and 22 animal-studies of combined chemical and stress exposures and fetal growth. Human studies tended to have a lower risk of bias across nine domains. Generally, we found stronger effects for chemicals than stress, and these exposures were associated with reduced fetal growth in the low-stress group and the association was often greater in high stress groups, with limited evidence of effect modification. We found smoking associated with significantly increased odds of LBW, with a greater effect for high stress (low SES; OR 4.75 (2.46-9.16)) compared to low stress (high SES; OR 1.95 (95% CI 1.53-2.48)). Animal studies generally had a high risk of bias with no significant combined effect or effect modification. We found that despite concern for the combined effects of environmental chemicals and stress, this is still an under-studied topic, though limited available human studies indicate chemical exposures exert stronger effects than stress, and this effect is generally larger in the presence of stress.

Naphthalene distributions and human exposure in Southern California

Science.gov (United States)

Lu, Rong; Wu, Jun; Turco, Richard P.; Winer, Arthur M.; Atkinson, Roger; Arey, Janet; Paulson, Suzanne E.; Lurmann, Fred W.; Miguel, Antonio H.; Eiguren-Fernandez, Arantzazu

The regional distribution of, and human exposure to, naphthalene are investigated for Southern California. A comprehensive approach is taken in which advanced models are linked for the first time to quantify population exposure to the emissions of naphthalene throughout Southern California. Naphthalene is the simplest and most abundant of the polycyclic aromatic hydrocarbons found in polluted urban environments, and has been detected in both outdoor and indoor air samples. Exposure to high concentrations of naphthalene may have adverse health effects, possibly causing cancer in humans. Among the significant emission sources are volatilization from naphthalene-containing products, petroleum refining, and combustion of fossil fuels and wood. Gasoline and diesel engine exhaust, with related vaporization from fuels, are found to contribute roughly half of the daily total naphthalene burden in Southern California. As part of this study, the emission inventory for naphthalene has been verified against new field measurements of the naphthalene-to-benzene ratio in a busy traffic tunnel in Los Angeles, supporting the modeling work carried out here. The Surface Meteorology and Ozone Generation (SMOG) airshed model is used to compute the spatial and temporal distributions of naphthalene and its photooxidation products in Southern California. The present simulations reveal a high degree of spatial variability in the concentrations of naphthalene-related species, with large diurnal and seasonal variations as well. Peak naphthalene concentrations are estimated to occur in the early morning hours in the winter season. The naphthalene concentration estimates obtained from the SMOG model are employed in the Regional Human Exposure (REHEX) model to calculate population exposure statistics. Results show average hourly naphthalene exposures in Southern California under summer and winter conditions of 270 and 430 ng m -3, respectively. Exposure to significantly higher concentrations

High-resolution simulations of the thermophysiological effects of human exposure to 100 MHz RF energy

International Nuclear Information System (INIS)

Nelson, David A; Curran, Allen R; Nyberg, Hans A; Marttila, Eric A; Mason, Patrick A; Ziriax, John M

2013-01-01

Human exposure to radio frequency (RF) electromagnetic energy is known to result in tissue heating and can raise temperatures substantially in some situations. Standards for safe exposure to RF do not reflect bio-heat transfer considerations however. Thermoregulatory function (vasodilation, sweating) may mitigate RF heating effects in some environments and exposure scenarios. Conversely, a combination of an extreme environment (high temperature, high humidity), high activity levels and thermally insulating garments may exacerbate RF exposure and pose a risk of unsafe temperature elevation, even for power densities which might be acceptable in a normothermic environment. A high-resolution thermophysiological model, incorporating a heterogeneous tissue model of a seated adult has been developed and used to replicate a series of whole-body exposures at a frequency (100 MHz) which approximates that of human whole-body resonance. Exposures were simulated at three power densities (4, 6 and 8 mW cm −2 ) plus a sham exposure and at three different ambient temperatures (24, 28 and 31 °C). The maximum hypothalamic temperature increase over the course of a 45 min exposure was 0.28 °C and occurred in the most extreme conditions (T amb = 31 °C, PD = 8 mW cm −2 ). Skin temperature increases attributable to RF exposure were modest, with the exception of a ‘hot spot’ in the vicinity of the ankle where skin temperatures exceeded 39 °C. Temperature increases in internal organs and tissues were small, except for connective tissue and bone in the lower leg and foot. Temperature elevation also was noted in the spinal cord, consistent with a hot spot previously identified in the literature. (paper)

Toxicity levels to humans during acute exposure to hydrogen fluoride

International Nuclear Information System (INIS)

Halton, D.M.; Dranitsaris, P.; Baynes, C.J.

1984-11-01

A literature review was conducted of the acute toxicity of hydrogen fluoride (HF) with emphasis on the effects of inhalation of gaseous HF. The data and findings of the relevant references were summarized under four categories: animal studies, controlled human studies, community exposure and industrial exposure. These were critically reviewed and then lethal concentration-time relationships were developed for humans, corresponding to LCsub(LO), LCsub(10) and LCsub(50) levels. The effects of age, health and other physiological variables on the sensitivity to HF were discussed, as well as antagonistic and synergistic effects with other substances

Human Exposure and Health

Science.gov (United States)

The ROE is divided into 5 themes: Air, Water, Land, Human Exposure and Health and Ecological Condition. From these themes, the report indicators address fundamental questions that the ROE attempts to answer. For human health there are 3 questions.

Effects of artificial light at night on human health: A literature review of observational and experimental studies applied to exposure assessment.

Science.gov (United States)

Cho, YongMin; Ryu, Seung-Hun; Lee, Byeo Ri; Kim, Kyung Hee; Lee, Eunil; Choi, Jaewook

2015-01-01

It has frequently been reported that exposure to artificial light at night (ALAN) may cause negative health effects, such as breast cancer, circadian phase disruption and sleep disorders. Here, we reviewed the literature assessing the effects of human exposure to ALAN in order to list the health effects of various aspects of ALAN. Several electronic databases were searched for articles, published through August 2014, related to assessing the effects of exposure to ALAN on human health; these also included the details of experiments on such exposure. A total of 85 articles were included in the review. Several observational studies showed that outdoor ALAN levels are a risk factor for breast cancer and reported that indoor light intensity and individual lighting habits were relevant to this risk. Exposure to artificial bright light during the nighttime suppresses melatonin secretion, increases sleep onset latency (SOL) and increases alertness. Circadian misalignment caused by chronic ALAN exposure may have negative effects on the psychological, cardiovascular and/or metabolic functions. ALAN also causes circadian phase disruption, which increases with longer duration of exposure and with exposure later in the evening. It has also been reported that shorter wavelengths of light preferentially disturb melatonin secretion and cause circadian phase shifts, even if the light is not bright. This literature review may be helpful to understand the health effects of ALAN exposure and suggests that it is necessary to consider various characteristics of artificial light, beyond mere intensity.

Assessment of indirect human exposure to environmental sources of nickel: oral exposure and risk characterization for systemic effects.

Science.gov (United States)

De Brouwere, Katleen; Buekers, Jurgen; Cornelis, Christa; Schlekat, Christian E; Oller, Adriana R

2012-03-01

This paper describes the indirect human exposure to Ni via the oral route for the regional scale in the EU, together with a method to assess additional local exposure from industrial emissions. The approach fills a gap in the generic REACH guidance which is inadequate for assessing indirect environmental exposure of metals. Estimates of regional scale Ni dietary intake were derived from Ni dietary studies performed in the EU. Typical and Reasonable Worst Case dietary Ni intakes for the general population in the EU were below the oral Derived No Effect Level (DNEL) of Ni sulfate for systemic effects. Estimates for the Ni dietary intake at the local scale take into account the influence of aerial Ni deposition and transfer from soil to crops grown near industrial plants emitting Ni. The additional dietary exposure via this local contribution was small. Despite the use of conservative parameters for these processes, this method may underestimate dietary exposure around older industrial sites because REACH guidance does not account for historical soil contamination. Nevertheless, the method developed here can also be used as a screening tool for community-based risk assessment, as it accounts for historical soil pollution. Nickel exposure via drinking water was derived from databases on Ni tap water quality. A small proportion of the EU population (<5%) is likely to be exposed to tap water exceeding the EU standard (20 μg Ni/l). Taking into account the relative gastrointestinal absorption of Ni from water (30%) versus from solid matrices (5%), water intake constitutes, after dietary intake, the second most important pathway for oral Ni intake. Incidental ingestion of Ni from soil/dust at the regional scale, and also at the local scale, was low in comparison with dietary intake. Copyright © 2011 Elsevier B.V. All rights reserved.

Sun Exposure and Its Effects on Human Health: Mechanisms through Which Sun Exposure Could Reduce the Risk of Developing Obesity and Cardiometabolic Dysfunction

Science.gov (United States)

Fleury, Naomi; Geldenhuys, Sian; Gorman, Shelley

2016-01-01

Obesity is a significant burden on global healthcare due to its high prevalence and associations with chronic health conditions. In our animal studies, ongoing exposure to low dose ultraviolet radiation (UVR, found in sunlight) reduced weight gain and the development of signs of cardiometabolic dysfunction in mice fed a high fat diet. These observations suggest that regular exposure to safe levels of sunlight could be an effective means of reducing the burden of obesity. However, there is limited knowledge around the nature of associations between sun exposure and the development of obesity and cardiometabolic dysfunction, and we do not know if sun exposure (independent of outdoor activity) affects the metabolic processes that determine obesity in humans. In addition, excessive sun exposure has strong associations with a number of negative health consequences such as skin cancer. This means it is very important to “get the balance right” to ensure that we receive benefits without increasing harm. In this review, we detail the evidence around the cardiometabolic protective effects of UVR and suggest mechanistic pathways through which UVR could be beneficial. PMID:27727191

Wood smoke in a controlled exposure experiment with human volunteers

DEFF Research Database (Denmark)

Riddervold, Ingunn Skogstad; Bønløkke, Jakob Hjort; Mølhave, Lars

2011-01-01

Exposure to wood smoke in the general population is increasing and concurrently, also our awareness. This article describes a wood-smoke generating system for studying human exposure to wood smoke and symptoms related to this exposure. Twenty nonsmoking atopic human participants with normal lung...... function and normal bronchial reactivity were randomly exposed for 3h at three different exposure conditions; clean filtered air (control exposure) and wood smoke with a characteristic particulate matter (PM) concentration of 200 µg/m3 (low) and 400 µg/m3 (high) under controlled environmental conditions.......0007), “irritative body perceptions” (p = 0.0127), “psychological/neurological effects” (p = 0.0075) and “weak inflammatory responses” (p = 0.0003). Furthermore, significant effects (p = 0.0192) on self-reported general mucosa irritation were found. In conclusion, exposure to wood smoke affected symptom rating...

Effects of environmental Bisphenol A exposures on germ cell development and Leydig cell function in the human fetal testis.

Directory of Open Access Journals (Sweden)

Soria Eladak

Full Text Available Using an organotypic culture system termed human Fetal Testis Assay (hFeTA we previously showed that 0.01 μM BPA decreases basal, but not LH-stimulated, testosterone secreted by the first trimester human fetal testis. The present study was conducted to determine the potential for a long-term antiandrogenic effect of BPA using a xenograft model, and also to study the effect of BPA on germ cell development using both the hFETA and xenograft models.Using the hFeTA system, first trimester testes were cultured for 3 days with 0.01 to 10 μM BPA. For xenografts, adult castrate male nude mice were injected with hCG and grafted with first trimester testes. Host mice received 10 μM BPA (~ 500 μg/kg/day in their drinking water for 5 weeks. Plasma levels of total and unconjugated BPA were 0.10 μM and 0.038 μM respectively. Mice grafted with second trimester testes received 0.5 and 50 μg/kg/day BPA by oral gavage for 5 weeks.With first trimester human testes, using the hFeTA model, 10 μM BPA increased germ cell apoptosis. In xenografts, germ cell density was also reduced by BPA exposure. Importantly, BPA exposure significantly decreased the percentage of germ cells expressing the pluripotency marker AP-2γ, whilst the percentage of those expressing the pre-spermatogonial marker MAGE-A4 significantly increased. BPA exposure did not affect hCG-stimulated androgen production in first and second trimester xenografts as evaluated by both plasma testosterone level and seminal vesicle weight in host mice.Exposure to BPA at environmentally relevant concentrations impairs germ cell development in first trimester human fetal testis, whilst gonadotrophin-stimulated testosterone production was unaffected in both first and second trimester testis. Studies using first trimester human fetal testis demonstrate the complementarity of the FeTA and xenograft models for determining the respective short-term and long term effects of environmental exposures.

Virus load in chimpanzees infected with human immunodeficiency virus type 1: effect of pre-exposure vaccination

NARCIS (Netherlands)

ten Haaft, P.; Cornelissen, M.; Goudsmit, J.; Koornstra, W.; Dubbes, R.; Niphuis, H.; Peeters, M.; Thiriart, C.; Bruck, C.; Heeney, J. L.

1995-01-01

Many reports indicate that a long-term asymptomatic state following human immunodeficiency virus type 1 (HIV-1) infection is associated with a low amount of circulating virus. To evaluate the possible effect of stabilizing a low virus load by non-sterilizing pre-exposure vaccination, a quantitative

Exposure to Hedione Increases Reciprocity in Humans

Directory of Open Access Journals (Sweden)

Sebastian Berger

2017-05-01

Full Text Available Cooperation among unrelated humans is frequently regarded as a defining feature in the evolutionary success of our species. Whereas, much research has addressed the strategic and cognitive mechanisms that underlie cooperation, investigations into chemosensory processes have received very limited research attention. To bridge that gap, we build on recent research that has identified the chemically synthesized odorant Hedione (HED as a ligand for the putative human pheromone receptor (VN1R1 expressed in the olfactory mucosa, and hypothesize that exposure to HED may increase reciprocity. Applying behavioral economics paradigms, the present research shows that exposure to the ligand causes differentiated behavioral effects in reciprocal punishments (Study 1 as well as rewards (Study 2, two types of behaviors that are frequently regarded as essential for the development and maintenance of cooperation.

Exposure to Hedione Increases Reciprocity in Humans

Science.gov (United States)

Berger, Sebastian; Hatt, Hanns; Ockenfels, Axel

2017-01-01

Cooperation among unrelated humans is frequently regarded as a defining feature in the evolutionary success of our species. Whereas, much research has addressed the strategic and cognitive mechanisms that underlie cooperation, investigations into chemosensory processes have received very limited research attention. To bridge that gap, we build on recent research that has identified the chemically synthesized odorant Hedione (HED) as a ligand for the putative human pheromone receptor (VN1R1) expressed in the olfactory mucosa, and hypothesize that exposure to HED may increase reciprocity. Applying behavioral economics paradigms, the present research shows that exposure to the ligand causes differentiated behavioral effects in reciprocal punishments (Study 1) as well as rewards (Study 2), two types of behaviors that are frequently regarded as essential for the development and maintenance of cooperation. PMID:28512400

Exposure to UV radiation and human health

Science.gov (United States)

Kimlin, Michael G.

2005-08-01

This paper will overview the significant issues facing researchers in relating the impact of exposure to sunlight and human health. Exposure to solar ultraviolet radiation is the major causative factor in most sun-related skin and eye disorders, however, very little is known quantitatively about human UV exposures. Interestingly, human exposure to sunlight also has a nutritional impact, namely the development of pre-Vitamin D, which is an important nutrient in bone health. New research suggest that low vitamin D status may be a causative factor in the development of selective types of cancer and autoimminue diseases, as well as a contributing factor in bone health. The 'health duality' aspect of sunlight exposure is an interesting and controversial topic that is a research focus of Kimlin's research group.

Human Exposure and Health Effects of Inorganic and Elemental Mercury

Science.gov (United States)

Zheng, Wei

2012-01-01

Mercury is a toxic and non-essential metal in the human body. Mercury is ubiquitously distributed in the environment, present in natural products, and exists extensively in items encountered in daily life. There are three forms of mercury, i.e., elemental (or metallic) mercury, inorganic mercury compounds, and organic mercury compounds. This review examines the toxicity of elemental mercury and inorganic mercury compounds. Inorganic mercury compounds are water soluble with a bioavailability of 7% to 15% after ingestion; they are also irritants and cause gastrointestinal symptoms. Upon entering the body, inorganic mercury compounds are accumulated mainly in the kidneys and produce kidney damage. In contrast, human exposure to elemental mercury is mainly by inhalation, followed by rapid absorption and distribution in all major organs. Elemental mercury from ingestion is poorly absorbed with a bioavailability of less than 0.01%. The primary target organs of elemental mercury are the brain and kidney. Elemental mercury is lipid soluble and can cross the blood-brain barrier, while inorganic mercury compounds are not lipid soluble, rendering them unable to cross the blood-brain barrier. Elemental mercury may also enter the brain from the nasal cavity through the olfactory pathway. The blood mercury is a useful biomarker after short-term and high-level exposure, whereas the urine mercury is the ideal biomarker for long-term exposure to both elemental and inorganic mercury, and also as a good indicator of body burden. This review discusses the common sources of mercury exposure, skin lightening products containing mercury and mercury release from dental amalgam filling, two issues that happen in daily life, bear significant public health importance, and yet undergo extensive debate on their safety. PMID:23230464

Human Bisphenol A Exposure and the “Diabesity Phenotype”

Science.gov (United States)

Leone, Alessandro; Battezzati, Alberto

2015-01-01

Bisphenol A (BPA), a known endocrine disruptor, is a food contaminant suspected of being a contributing factor to the present-day increase in obesity, diabetes, and cardiovascular disease. This issue is of increasing interest in the field of diabetes research and has become a matter of concern for regulatory agencies and food industries. Recently, the number of studies involving BPA has increased exponentially, but there are still many gaps in the knowledge of the relationship between actual BPA exposure and cardiometabolic risk and of the modalities of food intake exposure, all of which prevents sound judgments concerning the risks to human health. This review focuses on the association between human exposure to BPA and obesity, thyroid function, diabetes, insulin resistance, metabolic syndrome, cardiovascular diseases, and BPA content in food. Many cross-sectional studies support, sometimes contradictorily, an adverse effect of BPA exposure on obesity, diabetes, and cardiovascular diseases. Few prospective studies support an adverse effect of BPA exposure on such pathologies. Moreover, no intervention studies have been conducted to evaluate the causality of such associations. This is mainly due to lack of an appropriate database of BPA content in foods, thus hindering any estimation of the usual dietary BPA intake. PMID:26858585

Human exposure to low level ionising radiation

International Nuclear Information System (INIS)

Paix, David

1988-01-01

This paper describes the low-level radiation sources and their effects on human populations, from a global perspective. 'Low-level' means exposures in the range of the natural background to which everybody is exposed. The quoted values are whole-world averages, but individual variations are mentioned in a few cases. (author). 22 refs

[Effects of lead exposure on the human body and health implications].

Science.gov (United States)

Moreira, Fátima Ramos; Moreira, Josino Costa

2004-02-01

To review the literature concerning the risks associated with exposure to lead and lead compounds, especially in children and in populations that are occupationally exposed. Using "chumbo" [lead] and "efeitos" [effects] as search terms, two large databases, namely PubMed (United States National Library of Medicine) and LILACS (Literatura Latino-Americana e do Caribe em Ciências da Saúde [Latin American and Caribbean Literature in the Health Sciences]), were searched for studies on lead toxicity from 1988 to 2002. Other sources used to conduct the search include the web page of the United States Agency for Toxic Substances and Disease Registry, in Atlanta, Georgia, and the library of the Toxicology Laboratory of the Center for Workers' Health and Human Ecology at the National School of Public Health [Centro de Estudos da Saúde de Trabalhador e Ecologia Humana, Escola Nacional de Saúde Pública], Fundação Oswaldo Cruz, Rio de Janeiro, Brazil. The toxic effects of lead and lead compounds have been extensively studied for over a century. In recent years, epidemiologic studies have focused primarily on the neurotoxic effects of lead on children, particularly in terms of impaired intellectual ability and behavioral problems. However, there is still insufficient information on the mechanisms of action that account for such toxicity. More in-depth studies are also needed on the effects of lead exposure on bone, the central nervous system, the cardiovascular system, the kidneys, the liver, the male and female reproductive systems, and the endocrine system. The potential teratogenicity and carcinogenicity of lead, as well as its effect on pregnancy outcomes and neonatal growth and development, also require further study.

Individual differences in the effects of mobile phone exposure on human sleep: rethinking the problem.

Science.gov (United States)

Loughran, Sarah P; McKenzie, Raymond J; Jackson, Melinda L; Howard, Mark E; Croft, Rodney J

2012-01-01

Mobile phone exposure-related effects on the human electroencephalogram (EEG) have been shown during both waking and sleep states, albeit with slight differences in the frequency affected. This discrepancy, combined with studies that failed to find effects, has led many to conclude that no consistent effects exist. We hypothesised that these differences might partly be due to individual variability in response, and that mobile phone emissions may in fact have large but differential effects on human brain activity. Twenty volunteers from our previous study underwent an adaptation night followed by two experimental nights in which they were randomly exposed to two conditions (Active and Sham), followed by a full-night sleep episode. The EEG spectral power was increased in the sleep spindle frequency range in the first 30 min of non-rapid eye movement (non-REM) sleep following Active exposure. This increase was more prominent in the participants that showed an increase in the original study. These results confirm previous findings of mobile phone-like emissions affecting the EEG during non-REM sleep. Importantly, this low-level effect was also shown to be sensitive to individual variability. Furthermore, this indicates that previous negative results are not strong evidence for a lack of an effect and, given the far-reaching implications of mobile phone research, we may need to rethink the interpretation of results and the manner in which research is conducted in this field. Copyright © 2011 Wiley Periodicals, Inc.

Naphthalene and Naphthoquinone: Distributions and Human Exposure in the Los Angeles Basin

Science.gov (United States)

Lu, R.; Wu, J.; Turco, R.; Winer, A. M.; Atkinson, R.; Paulson, S.; Arey, J.; Lurmann, F.

2003-12-01

Naphthalene is the simplest and most abundant of the polycyclic aromatic hydrocarbons (PAHs). Naphthalene is found primarily in the gas-phase and has been detected in both outdoor and indoor samples. Evaporation from naphthalene-containing products (including gasoline), and during refining operations, are important sources of naphthalene in air. Naphthalene is also emitted during the combustion of fossil fuels and wood, and is a component of vehicle exhaust. Exposure to high concentrations of naphthalene can damage or destroy red blood cells, causing hemolytic anemia. If inhaled over a long period of time, naphthalene may cause kidney and liver damage, skin allergy and dermatitis, cataracts and retinal damage, as well as attack the central nervous system. Naphthalene has been found to cause cancer as a result of inhalation in animal tests. Naphthoquinones are photooxidation products of naphthalene and the potential health effects of exposure to these quinones are a current focus of research. We are developing and applying models that can be used to assess human exposure to naphthalene and its photooxidation products in major air basins such as California South Coast Air Basin (SoCAB). The work utilizes the Surface Meteorology and Ozone Generation (SMOG) airshed model, and the REgional Human EXposure (REHEX) model, including an analysis of individual exposure. We will present and discuss simulations of basin-wide distributions of, and human exposures to, naphthalene and naphthoquinone, with emphasis on the uncertainties in these estimates of atmospheric concentrations and human exposure. Regional modeling of pollutant sources and exposures can lead to cost-effective and optimally health-protective emission control strategies.

A systematic review of the human body burden of e-waste exposure in China.

Science.gov (United States)

Song, Qingbin; Li, Jinhui

2014-07-01

As China is one of the countries facing the most serious pollution and human exposure effects of e-waste in the world, much of the population there is exposed to potentially hazardous substances due to informal e-waste recycling processes. This report reviews recent studies on human exposure to e-waste in China, with particular focus on exposure routes (e.g. dietary intake, inhalation, and soil/dust ingestion) and human body burden markers (e.g. placenta, umbilical cord blood, breast milk, blood, hair, and urine) and assesses the evidence for the association between such e-waste exposure and the human body burden in China. The results suggest that residents in the e-waste exposure areas, located mainly in the three traditional e-waste recycling sites (Taizhou, Guiyu, and Qingyuan), are faced with a potential higher daily intake of these pollutants than residents in the control areas, especially via food ingestion. Moreover, pollutants (PBBs, PBDEs, PCBs, PCDD/Fs, and heavy metals) from the e-waste recycling processes were all detectable in the tissue samples at high levels, showing that they had entered residents' bodies through the environment and dietary exposure. Children and neonates are the groups most sensitive to the human body effects of e-waste exposure. We also recorded plausible outcomes associated with exposure to e-waste, including 7 types of human body burden. Although the data suggest that exposure to e-waste is harmful to health, better designed epidemiological investigations in vulnerable populations, especially neonates and children, are needed to confirm these associations. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of gasoline and ethanol-gasoline exhaust exposure on human bronchial epithelial and natural killer cells in vitro.

Science.gov (United States)

Roth, Michèle; Usemann, Jakob; Bisig, Christoph; Comte, Pierre; Czerwinski, Jan; Mayer, Andreas C R; Beier, Konstantin; Rothen-Rutishauser, Barbara; Latzin, Philipp; Müller, Loretta

2017-12-01

Air pollution exposure, including passenger car emissions, may cause substantial respiratory health effects and cancer death. In western countries, the majority of passenger cars are driven by gasoline fuel. Recently, new motor technologies and ethanol fuels have been introduced to the market, but potential health effects have not been thoroughly investigated. We developed and verified a coculture model composed of bronchial epithelial cells (ECs) and natural killer cells (NKs) mimicking the human airways to compare toxic effects between pure gasoline (E0) and ethanol-gasoline-blend (E85, 85% ethanol, 15% gasoline) exhaust emitted from a flexfuel gasoline car. We drove a steady state cycle, exposed ECs for 6h and added NKs. We assessed exhaust effects in ECs alone and in cocultures by RT-PCR, flow cytometry, and oxidative stress assay. We found no toxic effects after exposure to E0 or E85 compared to air controls. Comparison between E0 and E85 exposure showed a weak association for less oxidative DNA damage after E85 exposure compared to E0. Our results indicate that short-term exposure to gasoline exhaust may have no major toxic effects in ECs and NKs and that ethanol as part of fuel for gasoline cars may be favorable. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mobile phone radiofrequency exposure has no effect on DNA double strand breaks (DSB) in human lymphocytes.

Science.gov (United States)

Danese, Elisa; Lippi, Giuseppe; Buonocore, Ruggero; Benati, Marco; Bovo, Chiara; Bonaguri, Chiara; Salvagno, Gian Luca; Brocco, Giorgio; Roggenbuck, Dirk; Montagnana, Martina

2017-07-01

The use of mobile phones has been associated with an increased risk of developing certain type of cancer, especially in long term users. Therefore, this study was aimed to investigate the potential genotoxic effect of mobile phone radiofrequency exposure on human peripheral blood mononuclear cells in vitro. The study population consisted in 14 healthy volunteers. After collection of two whole blood samples, the former was placed in a plastic rack, 1 cm from the chassis of a commercial mobile phone (900 MHz carrier frequency), which was activated by a 30-min call. The second blood sample was instead maintained far from mobile phones or other RF sources. The influence of mobile phone RF on DNA integrity was assessed by analyzing γ-H2AX foci in lymphocytes using immunofluorescence staining kit on AKLIDES. No measure of γ-H2AX foci was significantly influenced by mobile phone RF exposure, nor mobile phone exposure was associated with significant risk of genetic damages in vitro (odds ratio comprised between 0.27 and 1.00). The results of this experimental study demonstrate that exposure of human lymphocytes to a conventional 900 MHz RF emitted by a commercial mobile phone for 30 min does not significantly impact DNA integrity.

Exposure is not enough: suppressing stimuli from awareness can abolish the mere exposure effect.

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Daniel de Zilva

Full Text Available Passive exposure to neutral stimuli increases subsequent liking of those stimuli--the mere exposure effect. Because of the broad implications for understanding and controlling human preferences, the role of conscious awareness in mere exposure has received much attention. Previous studies have claimed that the mere exposure effect can occur without conscious awareness of the stimuli. In two experiments, we applied a technique new to the mere exposure literature, called continuous flash suppression, to expose stimuli for a controlled duration with and without awareness. To ensure the reliability of the awareness manipulation, awareness was monitored on a trial-by-trial basis. Our results show that under these conditions the mere exposure effect does not occur without conscious awareness. In contrast, only when participants were aware of the stimuli did exposure increase liking and recognition. Together these data are consistent with the idea that the mere exposure effect requires conscious awareness and has important implications for theories of memory and affect.

Exposure is not enough: suppressing stimuli from awareness can abolish the mere exposure effect.

Science.gov (United States)

de Zilva, Daniel; Vu, Luke; Newell, Ben R; Pearson, Joel

2013-01-01

Passive exposure to neutral stimuli increases subsequent liking of those stimuli--the mere exposure effect. Because of the broad implications for understanding and controlling human preferences, the role of conscious awareness in mere exposure has received much attention. Previous studies have claimed that the mere exposure effect can occur without conscious awareness of the stimuli. In two experiments, we applied a technique new to the mere exposure literature, called continuous flash suppression, to expose stimuli for a controlled duration with and without awareness. To ensure the reliability of the awareness manipulation, awareness was monitored on a trial-by-trial basis. Our results show that under these conditions the mere exposure effect does not occur without conscious awareness. In contrast, only when participants were aware of the stimuli did exposure increase liking and recognition. Together these data are consistent with the idea that the mere exposure effect requires conscious awareness and has important implications for theories of memory and affect.

Negative Effects of High Glucose Exposure in Human Gonadotropin-Releasing Hormone Neurons

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Annamaria Morelli

2013-01-01

Full Text Available Metabolic disorders are often associated with male hypogonadotropic hypogonadism, suggesting that hypothalamic defects involving GnRH neurons may impair the reproductive function. Among metabolic factors hyperglycemia has been implicated in the control of the reproductive axis at central level, both in humans and in animal models. To date, little is known about the direct effects of pathological high glucose concentrations on human GnRH neurons. In this study, we investigated the high glucose effects in the human GnRH-secreting FNC-B4 cells. Gene expression profiling by qRT-PCR, confirmed that FNC-B4 cells express GnRH and several genes relevant for GnRH neuron function (KISS1R, KISS1, sex steroid and leptin receptors, FGFR1, neuropilin 2, and semaphorins, along with glucose transporters (GLUT1, GLUT3, and GLUT4. High glucose exposure (22 mM; 40 mM significantly reduced gene and protein expression of GnRH, KISS1R, KISS1, and leptin receptor, as compared to normal glucose (5 mM. Consistent with previous studies, leptin treatment significantly induced GnRH mRNA expression at 5 mM glucose, but not in the presence of high glucose concentrations. In conclusion, our findings demonstrate a deleterious direct contribution of high glucose on human GnRH neurons, thus providing new insights into pathogenic mechanisms linking metabolic disorders to reproductive dysfunctions.

Human response to combined indoor environment exposures

DEFF Research Database (Denmark)

Toftum, Jørn

2002-01-01

Most thermal comfort standards and guidelines presume sedentary, light activity and a neutral overall thermal sensation when predicting local thermal discomfort. In addition, current standards specify criteria for separate aspects of the indoor environment, e.g. thermal climate, air quality...... or noise, with only little consideration of possible interactions between the different types of exposure. The studies summarized in this article found a clear impact of activity and overall thermal sensation on human sensitivity to air movement, whereas no interaction effects of exposure to several local...... thermal discomfort factors were observed. Limited evidence was found of significant interactions between different aspects of the indoor environment. Only for the effect of air temperature and air humidity on sensory air quality were well-estabished relationships available....

Human bromethalin exposures reported to a U.S. Statewide Poison Control System.

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Huntington, Serena; Fenik, Yelena; Vohra, Rais; Geller, Richard J

2016-03-01

Bromethalin is an increasingly used alternative to long-acting anticoagulant and cholecalciferol rodenticides. There are few reports of human exposures, and no existing professional society guidelines on medical management of bromethalin ingestions. The aim of this retrospective data review is to characterize bromethalin exposures reported to the California Poison Control System (CPCS) between 1997 and 2014. This is an observational retrospective case review of our statewide poison control system's electronic medical records. Following Institutional Board Review and Research Committee approvals, poison center exposures related to bromethalin were extracted using substance code and free text search strategies. Case notes of bromethalin exposures were reviewed for demographic, clinical, laboratory, and outcome information; inclusion criteria for the study was single-substance, human exposure to bromethalin. There were 129 calls related to human bromethalin exposures (three cases met exclusion criteria). The age range of cases was 7 months-90 years old, with the majority of exposures (89 cases; 70.6%), occurring in children younger than 5 years of age (median age of 2 years). Most exposures occurred in the pediatric population as a result of exploratory oral exposure. One hundred and thirteen patients (89.7%) had no effects post exposure, while 10 patients (7.9%) had a minor outcome. Adverse effects were minor, self-limited, and mostly gastrointestinal upset. There were no moderate, major, or fatal effects in our study population. The approximate ingested dose, available in six cases, ranged from 0.067 mg/kg to 0.3 mg/kg (milligrams of bromethalin ingested per kilogram of body weight), and no dose-symptom threshold could be established from this series. Exposures were not confirmed through urine or serum laboratory testing. The prognosis for most accidental ingestions appears to be excellent. However, bromethalin exposures may result in a higher number of

Pre-exposure to 50 Hz magnetic fields modifies menadione-induced genotoxic effects in human SH-SY5Y neuroblastoma cells.

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Jukka Luukkonen

Full Text Available BACKGROUND: Extremely low frequency (ELF magnetic fields (MF are generated by power lines and various electric appliances. They have been classified as possibly carcinogenic by the International Agency for Research on Cancer, but a mechanistic explanation for carcinogenic effects is lacking. A previous study in our laboratory showed that pre-exposure to ELF MF altered cancer-relevant cellular responses (cell cycle arrest, apoptosis to menadione-induced DNA damage, but it did not include endpoints measuring actual genetic damage. In the present study, we examined whether pre-exposure to ELF MF affects chemically induced DNA damage level, DNA repair rate, or micronucleus frequency in human SH-SY5Y neuroblastoma cells. METHODOLOGY/PRINCIPAL FINDINGS: Exposure to 50 Hz MF was conducted at 100 µT for 24 hours, followed by chemical exposure for 3 hours. The chemicals used for inducing DNA damage and subsequent micronucleus formation were menadione and methyl methanesulphonate (MMS. Pre-treatment with MF enhanced menadione-induced DNA damage, DNA repair rate, and micronucleus formation in human SH-SY5Y neuroblastoma cells. Although the results with MMS indicated similar effects, the differences were not statistically significant. No effects were observed after MF exposure alone. CONCLUSIONS: The results confirm our previous findings showing that pre-exposure to MFs as low as 100 µT alters cellular responses to menadione, and show that increased genotoxicity results from such interaction. The present findings also indicate that complementary data at several chronological points may be critical for understanding the MF effects on DNA damage, repair, and post-repair integrity of the genome.

Pre-exposure to 50 Hz magnetic fields modifies menadione-induced genotoxic effects in human SH-SY5Y neuroblastoma cells.

Science.gov (United States)

Luukkonen, Jukka; Liimatainen, Anu; Höytö, Anne; Juutilainen, Jukka; Naarala, Jonne

2011-03-23

Extremely low frequency (ELF) magnetic fields (MF) are generated by power lines and various electric appliances. They have been classified as possibly carcinogenic by the International Agency for Research on Cancer, but a mechanistic explanation for carcinogenic effects is lacking. A previous study in our laboratory showed that pre-exposure to ELF MF altered cancer-relevant cellular responses (cell cycle arrest, apoptosis) to menadione-induced DNA damage, but it did not include endpoints measuring actual genetic damage. In the present study, we examined whether pre-exposure to ELF MF affects chemically induced DNA damage level, DNA repair rate, or micronucleus frequency in human SH-SY5Y neuroblastoma cells. Exposure to 50 Hz MF was conducted at 100 µT for 24 hours, followed by chemical exposure for 3 hours. The chemicals used for inducing DNA damage and subsequent micronucleus formation were menadione and methyl methanesulphonate (MMS). Pre-treatment with MF enhanced menadione-induced DNA damage, DNA repair rate, and micronucleus formation in human SH-SY5Y neuroblastoma cells. Although the results with MMS indicated similar effects, the differences were not statistically significant. No effects were observed after MF exposure alone. The results confirm our previous findings showing that pre-exposure to MFs as low as 100 µT alters cellular responses to menadione, and show that increased genotoxicity results from such interaction. The present findings also indicate that complementary data at several chronological points may be critical for understanding the MF effects on DNA damage, repair, and post-repair integrity of the genome.

Pulmonary Inflammatory Responses to Acute Meteorite Dust Exposures - Implications for Human Space Exploration

Science.gov (United States)

Harrington, A. D.; McCubbin, F. M.; Vander Kaaden, K. E.; Kaur, J.; Smirnov, A.; Galdanes, K.; Schoonen, M. A. A.; Chen, L. C.; Tsirka, S. E.; Gordon, T.

2018-01-01

New initiatives to send humans to Mars within the next few decades are illustrative of the resurgence of interest in space travel. However, as with all exploration, there are risks. The Human Research Roadmap developed by NASA identifies the Risk of Adverse Health and Performance Effects of Celestial Dust Exposure as an area of concern. Extended human exploration will further increase the probability of inadvertent and repeated exposures to celestial dusts.

Human exposure assessment to antibiotic-resistant Escherichia coli through drinking water.

Science.gov (United States)

O'Flaherty, E; Borrego, C M; Balcázar, J L; Cummins, E

2018-03-01

Antibiotic-resistant bacteria (ARB) are a potential threat to human health through drinking water with strong evidence of ARB presence in post treated tap water around the world. This study examines potential human exposure to antibiotic-resistant (AR) Escherichia coli (E. coli) through drinking water, the effect of different drinking water treatments on AR E. coli and the concentration of AR E. coli required in the source water for the EU Drinking Water Directive (DWD) (Council Directive 98/83/EC, 0CFU/100ml of E. coli in drinking water) to be exceeded. A number of scenarios were evaluated to examine different water treatment combinations and to reflect site specific conditions at a study site in Europe. A literature search was carried out to collate data on the effect of environmental conditions on AR E. coli, the effect of different water treatments on AR E. coli and typical human consumption levels of tap water. A human exposure assessment model was developed with probability distributions used to characterise uncertainty and variability in the input data. Overall results show the mean adult human exposure to AR E. coli from tap water consumption ranged between 3.44×10 -7 and 2.95×10 -1 cfu/day for the scenarios tested and varied depending on the water treatments used. The level of AR E. coli required in the source water pre-treatment to exceed the DWD varied between 1 and 5logcfu/ml, depending on the water treatments used. This can be used to set possible monitoring criteria in pre-treated water for potential ARB exposure in drinking water. Copyright © 2017 Elsevier B.V. All rights reserved.

A translatable predictor of human radiation exposure.

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Lucas, Joseph; Dressman, Holly K; Suchindran, Sunil; Nakamura, Mai; Chao, Nelson J; Himburg, Heather; Minor, Kerry; Phillips, Gary; Ross, Joel; Abedi, Majid; Terbrueggen, Robert; Chute, John P

2014-01-01

Terrorism using radiological dirty bombs or improvised nuclear devices is recognized as a major threat to both public health and national security. In the event of a radiological or nuclear disaster, rapid and accurate biodosimetry of thousands of potentially affected individuals will be essential for effective medical management to occur. Currently, health care providers lack an accurate, high-throughput biodosimetric assay which is suitable for the triage of large numbers of radiation injury victims. Here, we describe the development of a biodosimetric assay based on the analysis of irradiated mice, ex vivo-irradiated human peripheral blood (PB) and humans treated with total body irradiation (TBI). Interestingly, a gene expression profile developed via analysis of murine PB radiation response alone was inaccurate in predicting human radiation injury. In contrast, generation of a gene expression profile which incorporated data from ex vivo irradiated human PB and human TBI patients yielded an 18-gene radiation classifier which was highly accurate at predicting human radiation status and discriminating medically relevant radiation dose levels in human samples. Although the patient population was relatively small, the accuracy of this classifier in discriminating radiation dose levels in human TBI patients was not substantially confounded by gender, diagnosis or prior exposure to chemotherapy. We have further incorporated genes from this human radiation signature into a rapid and high-throughput chemical ligation-dependent probe amplification assay (CLPA) which was able to discriminate radiation dose levels in a pilot study of ex vivo irradiated human blood and samples from human TBI patients. Our results illustrate the potential for translation of a human genetic signature for the diagnosis of human radiation exposure and suggest the basis for further testing of CLPA as a candidate biodosimetric assay.

A translatable predictor of human radiation exposure.

Directory of Open Access Journals (Sweden)

Joseph Lucas

Full Text Available Terrorism using radiological dirty bombs or improvised nuclear devices is recognized as a major threat to both public health and national security. In the event of a radiological or nuclear disaster, rapid and accurate biodosimetry of thousands of potentially affected individuals will be essential for effective medical management to occur. Currently, health care providers lack an accurate, high-throughput biodosimetric assay which is suitable for the triage of large numbers of radiation injury victims. Here, we describe the development of a biodosimetric assay based on the analysis of irradiated mice, ex vivo-irradiated human peripheral blood (PB and humans treated with total body irradiation (TBI. Interestingly, a gene expression profile developed via analysis of murine PB radiation response alone was inaccurate in predicting human radiation injury. In contrast, generation of a gene expression profile which incorporated data from ex vivo irradiated human PB and human TBI patients yielded an 18-gene radiation classifier which was highly accurate at predicting human radiation status and discriminating medically relevant radiation dose levels in human samples. Although the patient population was relatively small, the accuracy of this classifier in discriminating radiation dose levels in human TBI patients was not substantially confounded by gender, diagnosis or prior exposure to chemotherapy. We have further incorporated genes from this human radiation signature into a rapid and high-throughput chemical ligation-dependent probe amplification assay (CLPA which was able to discriminate radiation dose levels in a pilot study of ex vivo irradiated human blood and samples from human TBI patients. Our results illustrate the potential for translation of a human genetic signature for the diagnosis of human radiation exposure and suggest the basis for further testing of CLPA as a candidate biodosimetric assay.

Pharmacological and toxicological effects of co-exposure of human gingival fibroblasts to silver nanoparticles and sodium fluoride

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Inkielewicz-Stepniak I

2014-04-01

Full Text Available Iwona Inkielewicz-Stepniak,1,* Maria Jose Santos-Martinez,2–4,* Carlos Medina,2,4 Marek W Radomski2,41Department of Medicinal Chemistry, Medical University Gdansk, Debinki, Poland; 2The School of Pharmacy and Pharmaceutical Sciences, Panoz Institute, Trinity College Dublin, Dublin, Ireland; 3School of Medicine, Trinity College Dublin, Dublin, Ireland; 4Trinity Biomedical Sciences Institute, Trinity College, Dublin, Ireland*These authors contributed equally to this workBackground: Silver nanoparticles (AgNPs and fluoride (F are pharmacological agents widely used in oral medicine and dental practice due to their anti-microbial/anti-cavity properties. However, risks associated with the co-exposure of local cells and tissues to these xenobiotics are not clear. Therefore, we have evaluated the effects of AgNPs and F co-exposure on human gingival fibroblast cells.Methods: Human gingival fibroblast cells (CRL-2014 were exposed to AgNPs and/or F at different concentrations for up to 24 hours. Cellular uptake of AgNPs was examined by transmission electron microscopy. Downstream inflammatory effects and oxidative stress were measured by real-time quantitative polymerase chain reaction (PCR and reactive oxygen species (ROS generation. Cytotoxicity and apoptosis were measured by 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assay and real-time quantitative PCR and flow cytometry, respectively. Finally, the involvement of mitogen-activated protein kinases (MAPK was studied using Western blot.Results: We found that AgNPs penetrated the cell membrane and localized inside the mitochondria. Co-incubation experiments resulted in increased oxidative stress, inflammation, and apoptosis. In addition, we found that co-exposure to both xenobiotics phosphorylated MAPK, particularly p42/44 MAPK.Conclusion: A combined exposure of human fibroblasts to AgNPs and F results in increased cellular damage. Further studies are needed in order to evaluate

Carcinogen biomonitoring in human exposures and laboratory research: validation and application to human occupational exposures.

Science.gov (United States)

Talaska, Glenn; Maier, Andrew; Henn, Scott; Booth-Jones, Angela; Tsuneoka, Yutaka; Vermeulen, Roel; Schumann, Brenda L

2002-08-05

A multiple biomarker approach is required to integrate for metabolism, temporal response and exposure-response kinetics, biological relevance, and positive predictive value. Carcinogen DNA adduct analysis can be used in animal and in vitro studies to detect absorption permutations caused by mixture interactions, and to control metabolic variation when specific CYP450 genes (1A1 or 1A2) are knocked out. These enzymes are not critical to the metabolic activation of model Polycyclic Aromatic Compounds (PAC) and aromatic amines, respectively, as suggested by in vitro analysis. Several human studies have been carried out where multiple biomarkers have been measured. In a study of benzidine workers, the similarities in elimination kinetics between urinary metabolites and mutagenicity is likely responsible for a better correlation between these markers than to BZ-DNA adducts in exfoliated cells. In a study of rubber workers, the relationship between specific departments, urinary 1 HP and DNA adducts in exfoliated cells coincided with the historical urinary bladder cancer risk in these departments; the same relationship did not hold for urinary mutagenicity. In a study of automotive mechanics, biomarkers were used to monitor the effectiveness of exposure interventions. These data reinforce the notion that carcinogen biomarkers are useful to monitor exposure, but that a complementary approaches involving effect and perhaps susceptibility biomarkers is necessary to obtain the necessary information.

Immunomodulatory effects of the herbicide propanil on cytokine production in humans: In vivo and in vitro exposure

International Nuclear Information System (INIS)

Corsini, Emanuela; Codeca, Ilaria; Mangiaratti, Simona; Birindelli, Sarah; Minoia, Claudio; Turci, Roberta; Viviani, Barbara; Facchi, Alessandra; Vitelli, Nora; Lucchi, Laura; Galli, Corrado L.; Marinovich, Marina; Colosio, Claudio

2007-01-01

Propanil, 3,4-dichloropropionanilide, a commonly used herbicide, has been shown to induce effects on the mouse immune system. The aim of this study was to assess the immunotoxicity of propanil in occupationally exposed agricultural workers and to characterize its molecular mechanism of action. Seven agricultural workers intermittently exposed to propanil and 7 healthy matched controls entered the study. Data were collected through physical examination, and laboratory investigations addressed at the main serum, cellular, and functional immune parameters. The levels of exposure were assessed by determining the urine concentration of the major propanil metabolite, 3,4-dichloroaniline. The investigation of serum, cellular, and functional immune parameters suggested that propanil exposure results in a modest immunomodulatory effect, characterized by an increase in the plasma level of IgG 1 and in LPS-induced IL-6 release and, by a reduction in PHA-induced IL-10 and IFN release, associated with a reduced IFN/IL-4 ratio. As observed, following in vivo exposure, in vitro treatment of human peripheral blood leukocytes with propanil resulted in a dose-dependent reduction in PHA-induced IFN-gamma and IL-10 production, while LPS-induced TNF-α production was not affected indicating a direct effect of propanil on selected immune parameters. We demonstrated that propanil interfering with PHA-induced intracellular calcium increase modulated IL-10 and IFN-gamma transcription and translation, which indicates that propanil acts on early events triggered by PHA. Overall, our results suggest that human exposure to propanil has slight immunomodulatory effects, and point out that the inhibition of the PHA-induced intracellular calcium rise is an important target of propanil. These findings improve our understanding of the mechanism underlying propanil-induced immunotoxicity

Effects of 3G cell phone exposure on the structure and function of the human cytochrome P450 reductase.

Science.gov (United States)

Tanvir, Shazia; Thuróczy, György; Selmaoui, Brahim; Silva Pires Antonietti, Viviane; Sonnet, Pascal; Arnaud-Cormos, Delia; Lévêque, Philippe; Pulvin, Sylviane; de Seze, René

2016-10-01

Cell phones increase exposure to radiofrequency (RF) electromagnetic fields (EMFs). Whether EMFs exert specific effects on biological systems remains debatable. This study investigated the effect of cell phone exposure on the structure and function of human NADPH-cytochrome P450 reductase (CPR). CPR plays a key role in the electron transfer to cytochrome P450, which takes part in a wide range of oxidative metabolic reactions in various organisms from microbes to humans. Human CPR was exposed for 60min to 1966-MHz RF inside a transverse electromagnetic cell (TEM-cell) placed in an incubator. The specific absorption rate (SAR) was 5W·kg(-1). Conformation changes have been detected through fluorescent spectroscopy of flavin and tryptophan residues, and investigated through circular dichroism, dynamic light scattering and microelectrophoresis. These showed that CPR was narrowed. By using cytochrome C reductase activity to assess the electron flux through the CPR, the Michaelis Menten constant (Km) and the maximum initial velocity (Vmax) decreased by 22% as compared with controls. This change was due to small changes in the tertiary and secondary structures of the protein at 37°C. The relevance of these findings to an actual RF exposure scenario demands further biochemical and in-vivo confirmation. Copyright © 2016 Elsevier B.V. All rights reserved.

Health Effects of Chronic Arsenic Exposure

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Young-Seoub Hong

2014-09-01

Full Text Available Arsenic is a unique element with distinct physical characteristics and toxicity whose importance in public health is well recognized. The toxicity of arsenic varies across its different forms. While the carcinogenicity of arsenic has been confirmed, the mechanisms behind the diseases occurring after acute or chronic exposure to arsenic are not well understood. Inorganic arsenic has been confirmed as a human carcinogen that can induce skin, lung, and bladder cancer. There are also reports of its significant association to liver, prostate, and bladder cancer. Recent studies have also suggested a relationship with diabetes, neurological effects, cardiac disorders, and reproductive organs, but further studies are required to confirm these associations. The majority of research to date has examined cancer incidence after a high exposure to high concentrations of arsenic. However, numerous studies have reported various health effects caused by chronic exposure to low concentrations of arsenic. An assessment of the health effects to arsenic exposure has never been performed in the South Korean population; thus, objective estimates of exposure levels are needed. Data should be collected on the biological exposure level for the total arsenic concentration, and individual arsenic concentration by species. In South Korea, we believe that biological exposure assessment should be the first step, followed by regular health effect assessments.

Deleterious Effects From Occupational Exposure to Ethylene Thiourea in Pregnant Women.

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Mutic, Abby D; Baker, Brenda J; McCauley, Linda A

2017-12-01

Human exposure to endocrine disrupting chemicals (EDCs) has become common as a result of widespread application of these chemicals to the food supply, environmental contamination, and occupational exposures (Caserta et al., 2011). However, relatively little is known about the effects of EDCs such as ethylene thiourea (ETU) in developing fetuses and the lasting implications of this disruption on human development from birth through adulthood. Of highest concern are chronic, low-dose exposures among industrial and agricultural workers. Current knowledge regarding the significance of endocrine thyroid signaling on normal human development raises serious concerns about the possible deleterious effects of EDCs in the developing fetus, children, and mature adults. Occupational health nurses are critical in identifying women and families at increased risk of ETU exposure and mitigating early exposures in pregnancy.

ASSESSMENT OF HUMAN EXPOSURE TO TOLUENE DIISOCYANATE

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OLIVIA ANCA RUSU

2011-03-01

Full Text Available Assessment of human exposure to toluene diisocyanate. Toluene diisocyanate (TDI, an aromatic compound, may be dangerous for human health. Diisocyanates have wide industrial use in the fabrication of flexible and rigid foams, fibers, elastomers, and coatings such as paints and varnishes. Isocyanates are known skin and respiratory sensitizers, and proper engineering controls should be in place to prevent exposure to isocyanate liquid and vapor; exposure to TDI vapors is well documented to increase asthma risk. The study focused on the exposure of workers and nearby populations to toluene diisocyanate in a Polyurethane Foam Factory located in Baia Mare, Romania. Workplace air measurements were performed in different departments of the plant, after sampling either in fixed points or as personal monitoring. Sampling in four different locations of Baia Mare town was carried out, - during and after the foaming process. TDI sampling was performed on silica cartridge followed by GC-MS analysis. TDI concentration at workplace was lower than 0,035 mg/m³, which represents the permissible exposure limit, while in the city the TDI concentration had shown values below 0,20 μg/m³. Health assessment of a group of 49 workers was based on questionnaire interview, determination of TDI antibodies and lung function tests. Data collected until this stage do not show any negative effects of TDI on the employees health. Since this plant had only recently begun operating, continuous workplace and ambient air TDI monitoring, along with workers health surveillance, is deemed necessary.

Human exposure to bisphenol A by biomonitoring: Methods, results and assessment of environmental exposures

International Nuclear Information System (INIS)

Dekant, Wolfgang; Voelkel, Wolfgang

2008-01-01

Human exposure to bisphenol A is controversially discussed. This review critically assesses methods for biomonitoring of bisphenol A exposures and reported concentrations of bisphenol A in blood and urine of non-occupationally ('environmentally') exposed humans. From the many methods published to assess bisphenol A concentrations in biological media, mass spectrometry-based methods are considered most appropriate due to high sensitivity, selectivity and precision. In human blood, based on the known toxicokinetics of bisphenol A in humans, the expected very low concentrations of bisphenol A due to rapid biotransformation and the very rapid excretion result in severe limitations in the use of reported blood levels of bisphenol A for exposure assessment. Due to the rapid and complete excretion of orally administered bisphenol A, urine samples are considered as the appropriate body fluid for bisphenol A exposure assessment. In urine samples from several cohorts, bisphenol A (as glucuronide) was present in average concentrations in the range of 1-3 μg/L suggesting that daily human exposure to bisphenol A is below 6 μg per person (< 0.1 μg/kg bw/day) for the majority of the population

Atmospheric Ionizing Radiation and Human Exposure

Science.gov (United States)

Wilson, John W.; Mertens, Christopher J.; Goldhagen, Paul; Friedberg, W.; DeAngelis, G.; Clem, J. M.; Copeland, K.; Bidasaria, H. B.

2005-01-01

Atmospheric ionizing radiation is of interest, apart from its main concern of aircraft exposures, because it is a principal source of human exposure to radiations with high linear energy transfer (LET). The ionizing radiations of the lower atmosphere near the Earth s surface tend to be dominated by the terrestrial radioisotopes. especially along the coastal plain and interior low lands, and have only minor contributions from neutrons (11 percent). The world average is substantially larger but the high altitude cities especially have substantial contributions from neutrons (25 to 45 percent). Understanding the world distribution of neutron exposures requires an improved understanding of the latitudinal, longitudinal, altitude and spectral distribution that depends on local terrain and time. These issues are being investigated in a combined experimental and theoretical program. This paper will give an overview of human exposures and describe the development of improved environmental models.

Atmospheric Ionizing Radiation and Human Exposure

Science.gov (United States)

Wilson, J. W.; Goldhagen, P.; Friedberg, W.; DeAngelis, G.; Clem, J. M.; Copeland, K.; Bidasaria, H. B.

2004-01-01

Atmospheric ionizing radiation is of interest, apart from its main concern of aircraft exposures, because it is a principal source of human exposure to radiations with high linear energy transfer (LET). The ionizing radiations of the lower atmosphere near the Earth s surface tend to be dominated by the terrestrial radioisotopes especially along the coastal plain and interior low lands and have only minor contributions from neutrons (11 percent). The world average is substantially larger but the high altitude cities especially have substantial contributions from neutrons (25 to 45 percent). Understanding the world distribution of neutron exposures requires an improved understanding of the latitudinal, longitudinal, altitude and spectral distribution that depends on local terrain and time. These issues are being investigated in a combined experimental and theoretical program. This paper will give an overview of human exposures and describe the development of improved environmental models.

Human health and exposure to electromagnetic radiation

International Nuclear Information System (INIS)

Dennis, J.A.; Muirhead, C.R.; Ennis, J.R.

1992-07-01

This review consists of three main parts. In the first the general features of electromagnetic fields and their interactions with the human body are described. The second part deals with the epidemiological evidence for effects on general health and birth outcome. The third part describes the epidemiological evidence from occupational and residential studies of a possible association between electromagnetic field exposures and cancer. (author)

Human exposure to nickel

Energy Technology Data Exchange (ETDEWEB)

Grandjean, P

1984-01-01

In order of abundance in the earth's crust, nickel ranks as the 24th element and has been detected in different media in all parts of the biosphere. Thus, humans are constantly exposed to this ubiquitous element, though in variable amounts. Occupational exposures may lead to the retention of 100 micrograms of nickel per day. Environmental nickel levels depend particularly on natural sources, pollution from nickel-manufacturing industries and airborne particles from combustion of fossil fuels. Absorption from atmospheric nickel pollution is of minor concern. Vegetables usually contain more nickel than do other food items. Certain products, such as baking powder and cocoa powder, have been found to contain excessive amounts of nickel, perhaps related to nickel leaching during the manufacturing process. Soft drinking-water and acid beverages may dissolve nickel from pipes and containers. Scattered studies indicate a highly variable dietary intake of nickel, but most averages are about 200-300 micrograms/day. In addition, skin contact to a multitude of metal objects may be of significance to the large number of individuals suffering from contact dermatitis and nickel allergy. Finally, nickel alloys are often used in nails and prostheses for orthopaedic surgery, and various sources may contaminate intravenous fluids. Thus, human nickel exposure originates from a variety of sources and is highly variable. Occupational nickel exposure is of major significance, and leaching of nickel may add to dietary intakes and to cutaneous exposures. 79 references.

Human exposure to a 60 Hz, 1800 micro tesla magnetic field: a neuro behavioral study

International Nuclear Information System (INIS)

Legros, A.; Corbacio, M.; Prato, F.S.; Thomas, A.W.; Beuter, A.; Goulet, D.; Lambrozo, J.; Souques, M.; Plante, M.

2010-01-01

The effects of time-varying magnetic fields (MF) on humans have been actively investigated for the past three decades. One important unanswered question that scientists continue to investigate is the potential for MF exposure to have acute effects on human biology. Different strategies have been used to tackle this question using various physiological, neuro-physiological and behavioral indicators. For example, researchers investigating electro-encephalography (EEG) have reported that Extremely Low Frequency (ELF, < 300 Hz) MF can increase the resting occipital alpha rhythm (8-12 Hz) [1, 2]. Interestingly, other studies have demonstrated that human motor behavior can be modulated by ELF MF exposure, reporting that such an exposure can reduce anteroposterior standing balance oscillations [3, 4] or decrease physiological tremor intensity [5]. However, the main limitation in this domain is the difficulty of reproducing the results. A possible reason for this is the large variety of experimental approaches employed. Therefore, the aim of this project is to investigate the effects of a 60 Hz, 1800 μT MF exposure on physiological (i.e. heart rate and peripheral blood perfusion), neuro-physiological (brain electrical activity), and behavioral (postural oscillations, voluntary motor functions, and physiological tremor) aspects in humans using a single experimental procedure.Though the results from this study suggest a subtle reduction of human standing balance as well as a subtle increase of physiological tremor amplitude with MF exposure, no effect appeared on other investigated parameters, suggesting that one hour of 60 Hz, 1800 μT MF exposure may modulate human involuntary motor control without being detected in the electrical activity of the brain. (authors)

Effects of Ambient Air Pollution Exposure on Olfaction: A Review.

Science.gov (United States)

Ajmani, Gaurav S; Suh, Helen H; Pinto, Jayant M

2016-11-01

Olfactory dysfunction affects millions of people worldwide. This sensory impairment is associated with neurodegenerative disease and significantly decreased quality of life. Exposure to airborne pollutants has been implicated in olfactory decline, likely due to the anatomic susceptibility of the olfactory nerve to the environment. Historically, studies have focused on occupational exposures, but more recent studies have considered effects from exposure to ambient air pollutants. To examine all relevant human data evaluating a link between ambient pollution exposure and olfaction and to review supporting animal data in order to examine potential mechanisms for pollution-associated olfactory loss. We identified and reviewed relevant articles from 1950 to 2015 using PubMed and Web of Science and focusing on human epidemiologic and pathophysiologic studies. Animal studies were included only to support pertinent data on humans. We reviewed findings from these studies evaluating a relationship between environmental pollutant exposure and olfactory function. We identified and reviewed 17 articles, with 1 additional article added from a bibliography search, for a total of 18 human studies. There is evidence in human epidemiologic and pathologic studies that increased exposure to ambient air pollutants is associated with olfactory dysfunction. However, most studies have used proxies for pollution exposure in small samples of convenience. Human pathologic studies, with supporting animal work, have also shown that air pollution can contact the olfactory epithelium, translocate to the olfactory bulb, and migrate to the olfactory cortex. Pollutants can deposit at each location, causing direct damage and disruption of tissue morphology or inducing local inflammation and cellular stress responses. Ambient air pollution may impact human olfactory function. Additional studies are needed to examine air pollution-related olfactory impacts on the general population using measured

Effects of Long-Term Dust Exposure on Human Respiratory System Health in Minqin County, China.

Science.gov (United States)

Wang, Jinyu; Li, Sheng; Wang, Shigong; Shang, Kezheng

2015-01-01

The aim of this study was to assess the effects of long-term sand dust exposure on human respiratory health. Dust events break out frequently in Minqin County, northwest China, whereas Pingliang City, northwest China, is rarely influenced by dust events. Therefore, Minqin and Pingliang were selected as sand dust exposure region and control area, respectively. The incidence of respiratory system diseases and symptoms was determined through a structured respiratory health questionnaire (ATS-DLD-78-A) and personal interviews. The subjects comprised 728 farmers (Minqin, 424; Pingliang, 304) aged 40 years or older, who had nondocumented occupational history to industrial dust exposure. Prevalences (odds ratio [OR], 95% confidence interval [CI]) of chronic rhinitis, chronic bronchitis, and chronic cough increased 9.6% (3.141, 1.776-5.555), 7.5% (2.468, 1.421-4.286), and 10.2% (1.787, 1.246-2.563) in Minqin comparison with Pingliang, respectively, and the differences were significant (p <.01).

Probabilistic integrated risk assessment of human exposure risk to environmental bisphenol A pollution sources.

Science.gov (United States)

Fu, Keng-Yen; Cheng, Yi-Hsien; Chio, Chia-Pin; Liao, Chung-Min

2016-10-01

Environmental bisphenol A (BPA) exposure has been linked to a variety of adverse health effects such as developmental and reproductive issues. However, establishing a clear association between BPA and the likelihood of human health is complex yet fundamentally uncertain. The purpose of this study was to assess the potential exposure risks from environmental BPA among Chinese population based on five human health outcomes, namely immune response, uterotrophic assay, cardiovascular disease (CVD), diabetes, and behavior change. We addressed these health concerns by using a stochastic integrated risk assessment approach. The BPA dose-dependent likelihood of effects was reconstructed by a series of Hill models based on animal models or epidemiological data. We developed a physiologically based pharmacokinetic (PBPK) model that allows estimation of urinary BPA concentration from external exposures. Here we showed that the daily average exposure concentrations of BPA and urinary BPA estimates were consistent with the published data. We found that BPA exposures were less likely to pose significant risks for infants (0-1 year) and adults (male and female >20 years) with human long-term BPA susceptibility in relation to multiple exposure pathways, and for informing the public of the negligible magnitude of environmental BPA pollution impacts on human health.

Human exposure to dioxin from combustion sources

International Nuclear Information System (INIS)

Hattemer-Frey, H.A.; Travis, C.C.

1988-01-01

Because of their extreme toxicity, much concern and debate has arisen about the nature and extent of human exposure to dioxin. Since municipal solid waste (MSW) incinerators are known to emit polychorinated dibenzo-p-dioxins (PCDDs) and polycholorinated dibenzofurnas (PCDFs) many people who live near MSW incinerators fear that they will be exposed to high levels of dioxin and subsequently develop cancer. What is often overlooked in this debate, however, is the fact that the general population is continuously being exposed to trace amounts of dioxin as exemplified by the fact that virtually all human adipose tissue samples contain dioxin at levels of 3 parts per trillion (ppt) or greater. This paper provides a perspective on MSW incineration as a source of human exposure to dioxin by comparing this exposure source with exposure to background environmental contamination and evaluates some of the potential key sources of PCDD/PCDF input into the enviroment. 32 refs., 3 tabs

Acute effects of acrolein in human volunteers during controlled exposure.

Science.gov (United States)

Dwivedi, Aishwarya M; Johanson, Gunnar; Lorentzen, Johnny C; Palmberg, Lena; Sjögren, Bengt; Ernstgård, Lena

2015-01-01

Acrolein is a reactive aldehyde mainly formed by combustion. The critical effect is considered to be irritation of the eyes and airways; however, the scarce data available make it difficult to assess effect levels. The aim of the study was to determine thresholds for acute irritation for acrolein. Nine healthy volunteers of each sex were exposed at six occasions for 2 h at rest to: clean air, 15 ppm ethyl acetate (EA), and 0.05 ppm and 0.1 ppm acrolein with and without EA (15 ppm) to mask the potential influence of odor. Symptoms related to irritation and central nervous system effects were rated on 100-mm Visual Analogue Scales. The ratings of eye irritation were slightly but significantly increased during exposure to acrolein in a dose-dependent manner (p acrolein alone but not during any of the other five exposure conditions. Based on subjective ratings, the present study showed minor eye irritation by exposure to 0.1 ppm acrolein.

Role of H2O2 in the Oxidative Effects of Zinc Exposure in Human Airway Epithelial Cells

Science.gov (United States)

Human exposure to particulate matter (PM) is a global environmental health concern. Zinc (Zn(2+)) is a ubiquitous respiratory toxicant that has been associated with PM health effects. However, the molecular mechanism of Zn(2+) toxicity is not fully understood. H202 and Zn(2+) hav...

Effect of physical exertion on the biological monitoring of exposure of various solvents following exposure by inhalation in human volunteers: I. Toluene.

Science.gov (United States)

Nadeau, Véronique; Truchon, Ginette; Brochu, Martin; Tardif, Robert

2006-09-01

Physical exertion (work load) has been recognized as one of several factors that can influence the kinetics of xenobiotics within the human body. This study was undertaken to evaluate the impact of physical exertion on two exposure indicators of toluene (TOL) in human volunteers exposed under controlled conditions in an inhalation chamber. A group of four volunteers (one woman, three men) were exposed to TOL (50 ppm) according to the following scenarios involving several periods during which volunteers were asked to perform either aerobic (AERO), muscular (MUSC), or both (AERO/MUSC) types of physical exercise (exercise bicycle, treadmills, pulleys). The target intensities (W) for each exercising period of 30 min--interspaced with 15 min at rest--were the following: REST, 50 W AERO (time-weighted average intensity [TWAI]: 46 watts); 50 W AERO/MUSC (TWAI: 38 watts) and 100 W AERO (TWAI: 71 watts) for 7 hours and 50 W MUSC for 3 hours (TWAI: 29 watts). Alveolar air and urine samples were collected at different time intervals before, during, and after exposure for the measurement of unchanged TOL in expired air (TOL-A) and urinary o-cresol (o-CR). Overall, the results showed that TOL-A measured during and after all scenarios involving physical activities were higher (approximately 1.4-2.0 fold) compared with exposures at rest. All scenarios involving physical exertion also resulted in increased end-of-exposure urinary o-CR (mean +/- SD): 0.9 +/- 0.1 mg/L (REST) vs. 2.0 +/- 0.1 mg/L (TWAI 46 watts). However, exposure at a TWAI of 71 watts did not further increase o-CR excretion (1.7 +/- 0.2 mg/L). This study confirms the significant effect of work load on TOL kinetics and showed that o-CR excretion increased proportionally with work load expressed as TWAI or with the estimated mean pulmonary ventilation during the period of exposure. This study also shows that exposure to TOL (50 ppm) involving a work load of around 50 W (light intensity) or lower is likely to produce

Sensory and Physiological Effects on Humans of Combined Exposures to Air Temperatures and Volatile Organic Compounds

DEFF Research Database (Denmark)

Mølhave, Lars; Liu, Zunyong; Jørgensen, Anne Hempel

1993-01-01

Ten healthy humans were exposed to combinations of volatile organic compounds (VOCs) and air temperature (0 mg/m3 and 10 mg/m3 of a mixture of 22 volatile organic compounds and 18, 22 and 26° C). Previously demonstrated effects of VOCs and thermal exposures were replicated. For the first time nasal...... cross-sectional areas and nasal volumes, as measured by acoustic rhinometry, were shown to decrease with decreasing temperature and increasing VOC exposure. Temperature and pollutant exposures affected air quality, the need for more ventilation, skin humidity on the forehead, sweating, acute sensory...... irritation and possibly watering eyes in an additive way. Interactions were found for odor intensity (p = 0.1), perceived facial skin temperature and dryness, general well-being, tear film stability, and nasal cavity dimension. The presence of interactions implies that in the future guidelines for acceptable...

Molecular effects of 1-naphthyl-methylcarbamate and solar radiation exposures on human melanocytes.

Science.gov (United States)

Ferrucio, Bianca; Tiago, Manoela; Fannin, Richard D; Liu, Liwen; Gerrish, Kevin; Maria-Engler, Silvya Stuchi; Paules, Richard S; Barros, Silvia Berlanga de Moraes

2017-02-01

Carbaryl (1-naphthyl-methylcarbamate), a broad-spectrum insecticide, has recently been associated with the development of cutaneous melanoma in an epidemiological cohort study with U.S. farm workers also exposed to ultraviolet radiation, the main etiologic factor for skin carcinogenesis. We hypothesized that carbaryl exposure may increase deleterious effects of UV solar radiation on skin melanocytes. This study aimed to characterize human melanocytes after individual or combined exposure to carbaryl (100μM) and solar radiation (375mJ/cm 2 ). In a microarray analysis, carbaryl, but not solar radiation, induced an oxidative stress response, evidenced by the upregulation of antioxidant genes, such as Hemeoxygenase-1 (HMOX1), and downregulation of Microphtalmia-associated Transcription Factor (MITF), the main regulator of melanocytic activity; results were confirmed by qRT-PCR. Carbaryl and solar radiation induced a gene response suggestive of DNA damage and cell cycle alteration. The expression of CDKN1A, BRCA1/2 and MDM2 genes was notably more intense in the combined treatment group, in a synergistic manner. Flow cytometry assays demonstrated S-phase cell cycle arrest, reduced apoptosis levels and faster induction of cyclobutane pyrimidine dimers (CPD) lesions in carbaryl treated groups. Our data suggests that carbaryl is genotoxic to human melanocytes, especially when associated with solar radiation. Copyright © 2016 Elsevier B.V. All rights reserved.

Gene expression signatures that predict radiation exposure in mice and humans.

Directory of Open Access Journals (Sweden)

Holly K Dressman

2007-04-01

Full Text Available The capacity to assess environmental inputs to biological phenotypes is limited by methods that can accurately and quantitatively measure these contributions. One such example can be seen in the context of exposure to ionizing radiation.We have made use of gene expression analysis of peripheral blood (PB mononuclear cells to develop expression profiles that accurately reflect prior radiation exposure. We demonstrate that expression profiles can be developed that not only predict radiation exposure in mice but also distinguish the level of radiation exposure, ranging from 50 cGy to 1,000 cGy. Likewise, a molecular signature of radiation response developed solely from irradiated human patient samples can predict and distinguish irradiated human PB samples from nonirradiated samples with an accuracy of 90%, sensitivity of 85%, and specificity of 94%. We further demonstrate that a radiation profile developed in the mouse can correctly distinguish PB samples from irradiated and nonirradiated human patients with an accuracy of 77%, sensitivity of 82%, and specificity of 75%. Taken together, these data demonstrate that molecular profiles can be generated that are highly predictive of different levels of radiation exposure in mice and humans.We suggest that this approach, with additional refinement, could provide a method to assess the effects of various environmental inputs into biological phenotypes as well as providing a more practical application of a rapid molecular screening test for the diagnosis of radiation exposure.

Human reproductive system disturbances and pesticide exposure in Brazil

Directory of Open Access Journals (Sweden)

Koifman Sergio

2002-01-01

Full Text Available The observation of reproductive disturbances in humans and in the wildlife has been reported in the last decade in different countries. Exposure to different chemicals possibly acting in the endocrine system or endocrine disruptors, including pesticides, has been a hypothesis raised to explain the observed changes. This paper aimed to present results of an epidemiological ecologic study carried out to explore population data on pesticides exposure in selected Brazilian states in the eighties and human reproductive outcomes in the nineties. Pearson correlation coefficients were ascertained between available data pesticides sales in eleven states in Brazil in 1985 and selected further reproductive outcomes or their surrogates. Moderate to high correlations were observed to infertility, testis, breast, prostate and ovarian cancer mortality. Despite the restrains of ecologic studies to establish cause-effect relationships, the observed results are in agreement with evidence supporting a possible association between pesticides exposure and the analyzed reproductive outcomes.

Quantifying human exposure to air pollution - moving from static monitoring to spatio-temporally resolved personal exposure assessment

DEFF Research Database (Denmark)

Steinle, Susanne; Reis, Stefan; Sabel, Clive E

2013-01-01

exposure studies to accurately assess human health risks. ? We discuss potential and shortcomings of methods and tools with a focus on how their development influences study design. ? We propose a novel conceptual model for integrated health impact assessment of human exposure to air pollutants. ? We......Quantifying human exposure to air pollutants is a challenging task. Ambient concentrations of air pollutants at potentially harmful levels are ubiquitous in urban areas and subject to high spatial and temporal variability. At the same time, every individual has unique activity-patterns. Exposure...... results from multifaceted relationships and interactions between environmental and human systems, adding complexity to the assessment process. Traditionally, approaches to quantify human exposure have relied on pollutant concentrations from fixed air quality network sites and static population...

The Progression of Circadian Phase during Light Exposure in Animals and Humans

NARCIS (Netherlands)

Beersma, Domien G. M.; Comas, Marian; Hut, Roelof A.; Gordijn, Marijke C. M.; Rueger, Melanie; Daan, Serge

Studies in humans and mice revealed that circadian phase shifting effects of light are larger at the beginning of a light exposure interval than during subsequent exposure. Little is known about the dynamics of this response reduction phenomenon. Here the authors propose a method to obtain

Progress in human exposure assessment for biocidal products

NARCIS (Netherlands)

Hemmen, J.J. van

2004-01-01

An important shortcoming in our present knowledge required for risk assessment of biocidal products is the assessment of human exposure. This knowledge gap has been filled in a preliminary fashion with the TNsG on human exposure to biocidal products (available from the ECB website). Explicit User

Forecasting human exposure to atmospheric pollutants in Portugal - A modelling approach

Science.gov (United States)

Borrego, C.; Sá, E.; Monteiro, A.; Ferreira, J.; Miranda, A. I.

2009-12-01

indoors (leisure activities like shopping areas, gym, theatre/cinema and restaurants). The results show how this developed modelling system can be useful to anticipate air pollution episodes and to estimate their effects on human health on a long-term basis. The two metropolitan areas of Porto and Lisbon are identified as the most critical ones in terms of air pollution effects on human health over Portugal in a long-term as well as in a short-term perspective. The coexistence of high concentration values and high population density is the key factor for these stressed areas. Regarding the 50% emission reduction scenario, the model results are significantly different for both pollutants: there is a small overall reduction in the individual exposure values of PM 10 (<10 μg m -3 h), but for O 3, in contrast, there is an extended area where exposure values increase with emission reduction. This detailed knowledge is a prerequisite for the development of effective policies to reduce the foreseen adverse impact of air pollution on human health and to act on time.

Exposure of sea bream (Sparus aurata) to toxic concentrations of benzo[a]pyrene: possible human health effect.

Science.gov (United States)

Zena, R; Speciale, A; Calabrò, C; Calò, M; Palombieri, D; Saija, A; Cimino, F; Trombetta, D; Lo Cascio, P

2015-12-01

Polycyclic aromatic hydrocarbons (PAHs) can accumulate in the food chain, due to their lipophilic properties. Fish can accumulate contaminants including PAHs and frequent consumption of such contaminated fish can pose risk to human health. The aim of this study was to clarify if acute exposure of sea bream (Sparus aurata, a fish species of great economic importance in the Atlantic and Mediterranean areas) to a PAH, benzo[a]pyrene (B[a]P), at a dose that can induce CYP1A and pathological changes in fish gills, liver and muscle, can induce accumulation in muscle. We investigated the cytotoxic effects (as changes in cell viability, DNA laddering and glutathione content) of in vitro exposure of human peripheral blood mononuclear cells (PBMCs) to organic extracts obtained from muscle of sea breams previously exposed via water to B[a]P (2mg/l, for 12, 24 and 72 h). At this level of exposure, B[a]P caused morphological changes, inflammatory response and CYP1A induction not only in sea bream gills and liver but also in muscle; furthermore, in fish muscle we observed a substantial B[a]P accumulation, which may be associated with the increased CYP1A activity in liver and especially in muscle. However, when PBMCs were exposed to organic extracts obtained from sea bream muscle contaminated with B[a]P, a toxic, although modest effect was revealed, consisting in a significant decrease in cell glutathione levels without alterations in cell viability and DNA laddering. This suggests that consumption of sea breams from B[a]P contaminated waters might represent a risk for human health. Copyright © 2015 Elsevier Inc. All rights reserved.

Acute Exposure to Electronic and Combustible Cigarette Aerosols: Effects in an Animal Model and in Human Alveolar Cells.

Science.gov (United States)

Husari, Ahmad; Shihadeh, Alan; Talih, Soha; Hashem, Yasmine; El Sabban, Marwan; Zaatari, Ghazi

2016-05-01

Smoking electronic cigarettes (ECIG) is promoted as a safer alternative to smoking combustible cigarettes. This study investigates the effects of ECIG aerosol and cigarette smoke (CS) in an animal model and in human alveolar cell cultures (A549). Mice were divided into Control, ECIG, and CS. Animals were exposed for 6h/d to either lab air, ECIG or CS, for of 3 days. Total particulate matter exposure for the ECIG was set at higher levels compared to CS. Lung injury was determined by: (1) measurement of wet-to-dry ratio; (2) albumin concentration in the bronchoalveolar lavage fluid; (3) transcriptional expression of inflammatory mediators IL-1β, IL-6, TNF-α; (4) oxidative stress; (5) assessment of cell death; and (6) lung histopathology. Human alveolar cell cultures were treated with various concentrations of ECIG and CS aerosol extracts and the effects on cell proliferation were evaluated. Wet-to-dry ratio was higher in CS when compared to ECIG. Albumin leak in bronchoalveolar lavage fluid was evident in CS but not in ECIG. ECIG exposure was only associated with a significant increase in IL-1β. In contrast, CS exposure resulted in significant increases in IL-1β, IL-6, TNF-α expression, and oxidative stress. TUNEL staining demonstrated significant cell death in CS but not in ECIG. At the cellular level, ECIG and CS extracts reduced cell proliferation, however, CS exhibited effects at lower concentrations. Despite higher exposure conditions, ECIG exhibited less toxic effects on lungs of experimental animals and on A549 cell cultures when compared to CS. © The Author 2015. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Effects of butyltin exposures on MAP kinase dependent transcription regulators in human natural killer cells

Science.gov (United States)

Person, Rachel J.; Whalen, Margaret M.

2010-01-01

Natural Killer (NK) cells are a major immune defense mechanism against cancer development and viral infection. The butyltins (BTs), tributyltin (TBT) and dibutyltin (DBT) have been widely used in industrial and other applications and significantly contaminate the environment. Both TBT and DBT have been detected in human blood. These compounds inhibit the lytic and binding function of human NK cells and thus could increase the incidence of cancer and viral infections. Butyltin (BT)-induced loss of NK function is accompanied by activation of mitogen activated protein kinases (MAPKs) and decreases in expression of cell-surface and cytolytic proteins. MAPKs activate components of the transcription regulator AP-1 and activate the transcription regulator Elk-1. Based on the fact that BTs activate MAPKs and alter protein expression, the current study examined the effect of BT exposures on the levels and phosphorylation states of the components of AP-1 and the phosphorylation state of Elk-1. Exposure to 300 nM TBT for 10 min increased the phosphorylation of c-Jun in NK cells. 1 h exposures to 300 nM and 200 nM TBT increased the phosphorylation and overall level of c-Jun. During a 300 nM treatment with TBT for 1 h the binding activity of AP-1 was significantly decreased. There were no significant alterations of AP-1 components or of Elk-1 with DBT exposures. Thus, it appears that TBT-induced alterations on phosphorylation, total levels and binding activity of c-Jun might contribute to, but are not fully responsible for, TBT-induced alterations of NK protein expression. PMID:20370538

Assessment of genetic risk for human exposure to radiation

International Nuclear Information System (INIS)

Sevcenko, V.A.; Rubanovic, A.V.

2002-01-01

Full text: The methodology of assessing the genetic risk of radiation exposure is based on the concept of 'hitting the target' in development of which N.V. Timofeeff-Ressovsky has played and important role. To predict genetic risk posed by irradiation, the U N Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) has worked out direct and indirect methods of assessment, extrapolation, integral and palpitation criteria of risk analysis that together permit calculating the risk from human exposure on the basis of data obtained for mice. Based on the reports of UNSCEAR for the period from 1958 to 2001 the paper presents a retrospective analysis of the use of direct methods and the doubling dose method for quantitative determination of the genetic risk of human exposure expressed as different hereditary diseases. As early as 1962 UNSCEAR estimated the doubling dose (a dose causing as many mutations as those occurring spontaneously during one generation) at 1 Gy for cases of exposure to ionizing radiations with low LET at a low dose rate and this value was confirmed in the next UNSCEAR reports up to now. For cases of acute irradiation the doubling dose was estimated at 0,3-0,4 Gy for the period under review. The paper considers the evolution of the concepts of human natural hereditary variability which is a basis for assessing the risk of exposure by the doubling dose method. The level of human natural genetic variability per 1 000 000 newborns is estimated at 738 000 hereditary diseases including mendelian, chromosomal and multifactorial ones. The greatest difficulties in assessing the doubling dose value were found to occur in the case of multifactorial diseases the pheno typical expression of which depends on mutational events in polygenic systems and on numerous environmental factors. The introduction in calculations of the potential recoverability correction factor (RPCF) made it possible to assess the genetic risk taking into account this class of

Elevated personal exposure to particulate matter from human activities in a residence.

Science.gov (United States)

Ferro, Andrea R; Kopperud, Royal J; Hildemann, Lynn M

2004-01-01

Continuous laser particle counters collocated with time-integrated filter samplers were used to measure personal, indoor, and outdoor particulate matter (PM) concentrations for a variety of prescribed human activities during a 5-day experimental period in a home in Redwood City, CA, USA. The mean daytime personal exposures to PM(2.5) and PM(5) during prescribed activities were 6 and 17 times, respectively, as high as the pre-activity indoor background concentration. Activities that resulted in the highest exposures of PM(2.5), PM(5), and PM(10) were those that disturbed dust reservoirs on furniture and textiles, such as dry dusting, folding clothes and blankets, and making a bed. The vigor of activity and type of flooring were also important factors for dust resuspension. Personal exposures to PM(2.5) and PM(5) were 1.4 and 1.6 times, respectively, as high as the indoor concentration as measured by a stationary monitor. The ratio of personal exposure to the indoor concentration was a function of both particle size and the distance of the human activity from the stationary indoor monitor. The results demonstrate that a wide variety of indoor human resuspension activities increase human exposure to PM and contribute to the "personal cloud" effect.

Histone Deacetylase Inhibitor Induced Radiation Sensitization Effects on Human Cancer Cells after Photon and Hadron Radiation Exposure

Directory of Open Access Journals (Sweden)

Ariungerel Gerelchuluun

2018-02-01

Full Text Available Suberoylanilide hydroxamic acid (SAHA is a histone deacetylase inhibitor, which has been widely utilized throughout the cancer research field. SAHA-induced radiosensitization in normal human fibroblasts AG1522 and lung carcinoma cells A549 were evaluated with a combination of γ-rays, proton, and carbon ion exposure. Growth delay was observed in both cell lines during SAHA treatment; 2 μM SAHA treatment decreased clonogenicity and induced cell cycle block in G1 phase but 0.2 μM SAHA treatment did not show either of them. Low LET (Linear Energy Transfer irradiated A549 cells showed radiosensitization effects on cell killing in cycling and G1 phase with 0.2 or 2 μM SAHA pretreatment. In contrast, minimal sensitization was observed in normal human cells after low and high LET radiation exposure. The potentially lethal damage repair was not affected by SAHA treatment. SAHA treatment reduced the rate of γ-H2AX foci disappearance and suppressed RAD51 and RPA (Replication Protein A focus formation. Suppression of DNA double strand break repair by SAHA did not result in the differences of SAHA-induced radiosensitization between human cancer cells and normal cells. In conclusion, our results suggest SAHA treatment will sensitize cancer cells to low and high LET radiation with minimum effects to normal cells.

Effect of a single 3-hour exposure to bright light on core body temperature and sleep in humans.

Science.gov (United States)

Dijk, D J; Cajochen, C; Borbély, A A

1991-01-02

Seven human subjects were exposed to bright light (BL, approx. 2500 lux) and dim light (DL, approx. 6 lux) during 3 h prior to nocturnal sleep, in a cross-over design. At the end of the BL exposure period core body temperature was significantly higher than at the end of the DL exposure period. The difference in core body temperature persisted during the first 4 h of sleep. The latency to sleep onset was increased after BL exposure. Rapid-eye movement sleep (REMS) and slow-wave sleep (SWS; stage 3 + 4 of non-REMS) were not significantly changed. Eight subjects were exposed to BL from 20.30 to 23.30 h while their eyes were covered or uncovered. During BL exposure with uncovered eyes, core body temperature decreased significantly less than during exposure with covered eyes. We conclude that bright light immediately affects core body temperature and that this effect is mediated via the eyes.

Effects of prenatal exposure to ionizing radiation

International Nuclear Information System (INIS)

Miller, R.W.

1990-01-01

Prenatal exposure to ionizing radiation induces some effects that are seen at birth and others that cannot be detected until later in life. Data from A-bomb survivors in Hiroshima and Nagasaki show a diminished number of births after exposure under 4 wk of gestational age. Although a wide array of congenital malformations has been found in animal experimentation after such exposure to x rays, in humans only small head size (exposure at 4-17 wk) and mental retardation (exposure primarily at 8-15 wk) have been observed. In Hiroshima, small head size occurred after doses of 0.10-0.19 Gy or more, and an excess of mental retardation at 0.2-0.4 Gy or more. Intelligence test scores were reduced among A-bomb survivors exposed at 8-15 wk of gestational age by 21-29 IQ points per Gy. Other effects of in-utero exposure to atomic radiation include long-lasting complex chromosome abnormalities

Effects of prenatal exposure to ionizing radiation

Energy Technology Data Exchange (ETDEWEB)

Miller, R.W. (National Cancer Institute, Bethesda, MD (USA))

1990-07-01

Prenatal exposure to ionizing radiation induces some effects that are seen at birth and others that cannot be detected until later in life. Data from A-bomb survivors in Hiroshima and Nagasaki show a diminished number of births after exposure under 4 wk of gestational age. Although a wide array of congenital malformations has been found in animal experimentation after such exposure to x rays, in humans only small head size (exposure at 4-17 wk) and mental retardation (exposure primarily at 8-15 wk) have been observed. In Hiroshima, small head size occurred after doses of 0.10-0.19 Gy or more, and an excess of mental retardation at 0.2-0.4 Gy or more. Intelligence test scores were reduced among A-bomb survivors exposed at 8-15 wk of gestational age by 21-29 IQ points per Gy. Other effects of in-utero exposure to atomic radiation include long-lasting complex chromosome abnormalities.

Toxicology and human health effects following exposure to oxygenated or reformulated gasoline.

Science.gov (United States)

Ahmed, F E

2001-09-15

In order to replace antiknock leaded derivatives in gasoline, legislations were enacted in the United States and other countries to find safer additives and to reduce CO, O3, and volatile organic compounds (VOCs) in non-attainment areas. Oxygenates commonly used include various alcohols and aliphatic ethers. Methyl tert-butyl ether (MTBE) is the most widely used and studied ether oxygenate and is added to gasoline at concentrations up to 15% by volume. Inhalation of fumes while fueling automobiles is the main source of human exposure to MTBE. Humans are also exposed when drinking water contaminated with MTBE. Epidemiological, clinical, animal, metabolic and kinetic studies have been carried out to address human health risks resulting from exposure to MTBE. MTBE is an animal carcinogen, but its human carcinogenic potential remains unclear. Because MTBE functions as a non-traditional genotoxicant, several mechanisms were suggested to explain its mode of action, such as, functioning as a cytotoxic as opposed to a mitogenic agent; involvement of hormonal mechanisms; or operating as a promoter instead of being a complete carcinogen. Some studies suggested that carcinogenicity of MTBE might be due to its two main metabolites, formaldehyde or tributanol. A role for DNA repair in MTBE carcinogenesis was recently unveiled, which explains some, but not all effects. The totality of the evidence shows that, for the majority of the non-occupationally exposed human population, MTBE is unlikely to produce lasting adverse health effects, and may in some cases improve health by reducing the composition of emitted harmful VOCs and other substances. A small segment of the population (e.g. asthmatic children, the elderly, and those with immunodeficiency) may be at increased risk for toxicity. However, no studies have been conducted to investigate this hypothesis. Concern over ground and surface water contamination caused by persistent MTBE has lead the Environmental Protection Agency

Perspectives for integrating human and environmental exposure assessments.

Science.gov (United States)

Ciffroy, P; Péry, A R R; Roth, N

2016-10-15

Integrated Risk Assessment (IRA) has been defined by the EU FP7 HEROIC Coordination action as "the mutual exploitation of Environmental Risk Assessment for Human Health Risk Assessment and vice versa in order to coherently and more efficiently characterize an overall risk to humans and the environment for better informing the risk analysis process" (Wilks et al., 2015). Since exposure assessment and hazard characterization are the pillars of risk assessment, integrating Environmental Exposure assessment (EEA) and Human Exposure assessment (HEA) is a major component of an IRA framework. EEA and HEA typically pursue different targets, protection goals and timeframe. However, human and wildlife species also share the same environment and they similarly inhale air and ingest water and food through often similar overlapping pathways of exposure. Fate models used in EEA and HEA to predict the chemicals distribution among physical and biological media are essentially based on common properties of chemicals, and internal concentration estimations are largely based on inter-species (i.e. biota-to-human) extrapolations. Also, both EEA and HEA are challenged by increasing scientific complexity and resources constraints. Altogether, these points create the need for a better exploitation of all currently existing data, experimental approaches and modeling tools and it is assumed that a more integrated approach of both EEA and HEA may be part of the solution. Based on the outcome of an Expert Workshop on Extrapolations in Integrated Exposure Assessment organized by the HEROIC project in January 2014, this paper identifies perspectives and recommendations to better harmonize and extrapolate exposure assessment data, models and methods between Human Health and Environmental Risk Assessments to support the further development and promotion of the concept of IRA. Ultimately, these recommendations may feed into guidance showing when and how to apply IRA in the regulatory decision

Assessment of Nicotine Exposure From Active Human Cigarette Smoking Time

Directory of Open Access Journals (Sweden)

Cahours Xavier

2017-09-01

Full Text Available The burning of a cigarette is a series of consecutive sequences of both passive and active burnings when a smoking cycle is applied to the cigarette. A previous study, using a smoking machine, showed that cigarette nicotine yields are dependent linearly on the difference between the time of smouldering (passive burning and the time of smoking (active burning. It is predicted that the smoker’s nicotine yield increases when the intensity of smoking increases, i.e., when the time to smoke a cigarette (smoking time decreases. Note that observations made on machines might not be comparable to human behaviours. The aim of this study was to determine whether nicotine mouth-level exposure could be predicted through measurement of human smoking time. A smoking behaviour study was conducted to compare human smoking nicotine yields obtained from both filter tip analysis and the cigarette burning time model. Results showed that smokers’ exposure to the smoke depends essentially on the speed at which the cigarette is smoked. An increase in human smoking intensity, resulting in a decrease in smoking time, generates an increase in smoke exposure, whatever the puff number, puff duration, puff volume and filter ventilation (open or blocked. The association of a machine smoking yield with a corresponding smoking time, and the time taken by a consumer to smoke the cigarette would provide information on the exposure to smoke constituents in a simple and effective manner.

Cytogenetic adaptive response induced by pre-exposure in human lymphocytes and marrow cells of mice

International Nuclear Information System (INIS)

Zhang Lianzhen; Deng Zhicheng

1993-01-01

The cytogenetic adaptive response induced by pre-exposure in human lymphocytes and marrow cells of mice were studied. The results of this study showed that human lymphocytes in vitro and mouse marrow cells in vivo can become adapted to low-level irradiation from 3 H-TdR or exposure to a low dose of X-or γ-irradiation, so that they become less sensitive to the chromosomal damage effects of subsequent exposures. (4 tabs.)

Use of chromosome translocations for measuring prior environment exposures in humans

Energy Technology Data Exchange (ETDEWEB)

Tucker, J. D.

1997-05-01

Recent advances in cytogenetic methodology are beginning to have a major impact upon our ability to provide assessments of environmental exposure in humans. The advent of fluorescent-based techniques for `painting` whole chromosomes has made the analysis of chromosome translocations rapid, specific, sensitive and routine. Chromosome painting has been used to address a wide variety of scientific questions, resulting in an increased understanding of the biological consequences of adverse environmental exposure. This paper describes the use of chromosome translocations as a biological marker of exposure and effect in humans. The relevance of translocations is discussed, as are the advantages and disadvantages of painting compared to classical cytogenetic methods for translocation evaluation. The factors to consider in the use of translocations as a retrospective indicator of exposure are then described. Several theoretical parameters that are important to the use of translocations are provided, and the paper concludes with a vision for the future of cytogenetic methodology.

Assessment of Human Exposure to ENMs.

Science.gov (United States)

Jiménez, Araceli Sánchez; van Tongeren, Martie

2017-01-01

Human exposure assessment of engineered nanomaterials (ENMs) is hampered, among other factors, by the difficulty to differentiate ENM from other nanomaterials (incidental to processes or naturally occurring) and the lack of a single metric that can be used for health risk assessment. It is important that the exposure assessment is carried out throughout the entire life-cycle as releases can occur at the different stages of the product life-cycle, from the synthesis, manufacture of the nano-enable product (occupational exposure) to the professional and consumer use of nano-enabled product (consumer exposure) and at the end of life.Occupational exposure surveys should follow a tiered approach, increasing in complexity in terms of instruments used and sampling strategy applied with higher tiers in order tailor the exposure assessment to the specific materials used and workplace exposure scenarios and to reduce uncertainty in assessment of exposure. Assessment of consumer exposure and of releases from end-of-life processes currently relies on release testing of nano-enabled products in laboratory settings.

Antiretroviral pre-exposure prophylaxis prevents vaginal transmission of HIV-1 in humanized BLT mice.

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Paul W Denton

2008-01-01

Full Text Available Worldwide, vaginal transmission now accounts for more than half of newly acquired HIV-1 infections. Despite the urgency to develop and implement novel approaches capable of preventing HIV transmission, this process has been hindered by the lack of adequate small animal models for preclinical efficacy and safety testing. Given the importance of this route of transmission, we investigated the susceptibility of humanized mice to intravaginal HIV-1 infection.We show that the female reproductive tract of humanized bone marrow-liver-thymus (BLT mice is reconstituted with human CD4+ T and other relevant human cells, rendering these humanized mice susceptible to intravaginal infection by HIV-1. Effects of HIV-1 infection include CD4+ T cell depletion in gut-associated lymphoid tissue (GALT that closely mimics what is observed in HIV-1-infected humans. We also show that pre-exposure prophylaxis with antiretroviral drugs is a highly effective method for preventing vaginal HIV-1 transmission. Whereas 88% (7/8 of BLT mice inoculated vaginally with HIV-1 became infected, none of the animals (0/5 given pre-exposure prophylaxis of emtricitabine (FTC/tenofovir disoproxil fumarate (TDF showed evidence of infection (Chi square = 7.5, df = 1, p = 0.006.The fact that humanized BLT mice are susceptible to intravaginal infection makes this system an excellent candidate for preclinical evaluation of both microbicides and pre-exposure prophylactic regimens. The utility of humanized mice to study intravaginal HIV-1 transmission is particularly highlighted by the demonstration that pre-exposure prophylaxis can prevent intravaginal HIV-1 transmission in the BLT mouse model.

Cardiovascular health effects following exposure of human volunteers during fire extinction exercises

DEFF Research Database (Denmark)

Andersen, Maria Helena Guerra; Saber, Anne Thoustrup; Pedersen, Peter Bøgh

2017-01-01

firefighting exercises in a constructed firehouse and flashover container. The subjects were instructed to extinguish fires of either wood or wood with electrical cords and mattresses. The exposure to particulate matter ( PM) was assessed at various locations and personal exposure was assessed by portable PM...... of cardiovascular effects in young conscripts training to become firefighters. Methods: Healthy conscripts (n = 43) who participated in a rescue educational course for firefighting were enrolled in the study. The exposure period consisted of a three-day training course where the conscripts participated in various...... samplers and urinary excretion of 1-hydroxypyrene. Cardiovascular measurements included microvascular function and heart rate variability (HRV). Results: The subjects were primarily exposed to PM in bystander positions, whereas self-contained breathing apparatus effectively abolished pulmonary exposure...

Radiation exposure and radiation hazards of human population. Pt. 1

International Nuclear Information System (INIS)

Jacobi, W.

1982-01-01

The present Part I provides a survey on the various sources of natural and artificial radiation exposure of human population. Furthermore, biological radiation effects and radiation damages are surveyed. In an appendix, radiation types, radiation doses, and radiation dose units are explained. (orig./GSCH) [de

Risk assessment of human health from exposure to the discharged ballast water after full-scale electrolysis treatment.

Science.gov (United States)

Zhang, Nahui; Wang, Yidan; Xue, Junzeng; Yuan, Lin; Wang, Qiong; Liu, Liang; Wu, Huixian; Hu, Kefeng

2016-06-01

The presence of disinfection by-products (DBPs) releasing from ballast water management systems (BWMS) can cause a possible adverse effects on humans. The objectives of this study were to compute the Derived No Effect Levels (DNELs) for different exposure scenarios and to compare these levels with the exposure levels from the measured DBPs in treated ballast water. The risk assessment showed that when using animal toxicity data, all the DNELs values were approximately 10(3)-10(12) times higher than the exposure levels of occupational and general public exposure scenarios, indicating the level of risk was low (risk characterization ratios (RCRs) < 1). However, when using human data, the RCRs were higher than 1 for dichlorobromomethane and trichloromethane, indicating that the risk of adverse effects on human were significant. This implies that there are apparent discrepancies between risk characterization from animal and human data, which may affect the overall results. We therefore recommend that when appropriate, human data should be used in risk assessment as much as possible, although human data are very limited. Moreover, more appropriate assessment factors can be considered to be employed in estimating the DNELs for human when the animal data is selected as the dose descriptors. Copyright © 2016 Elsevier Inc. All rights reserved.

Exposure to bisphenol A and gender differences: from rodents to humans evidences and hypothesis about the health effects

Directory of Open Access Journals (Sweden)

Lidia Caporossi

2015-11-01

Full Text Available Bisphenol A (BPA interacts with the endocrine system and seems to produce different effects in relation to gender. The objective of the study was to clarify the possible health effects of exposure to BPA in relation to gender. A literature search was performed using three different search engines: Medline, PubMed and Scopus. Data on both animals and humans showed that BPA acts as a xenoestrogen and interacts with the androgens’ metabolism, producing different outcomes: uterotropic effects, decreasing sperm production, stimulation of prolactin release. Gender difference plays a key role in understanding the real toxic effects, the BPA serum concentrations were, all the time, higher in male subjects, possibly due to the difference in androgen-related enzyme activity levels, compared with the healthly female subjects, to equal levels of exposure; while higher BPA levels in women have been associated with a variety of conditions including obesity, endometrial hyperplasia, recurrent miscarriages, and polycystic ovarian syndrome. The data collected are sufficiently robust to raise concerns about the potentially deleterious impact of BPA on humans, even with some methodological limitations; the different impact of BPA in men and in women is documented and of a certain interest. In toxicology it is necessary to assess effects in relation to gender differences, in order to set up prevention plans in the work environment targeting the specific risk.

Time-Dependent Toxic and Genotoxic Effects of Zinc Oxide Nanoparticles after Long-Term and Repetitive Exposure to Human Mesenchymal Stem Cells

Directory of Open Access Journals (Sweden)

Pascal Ickrath

2017-12-01

Full Text Available Zinc oxide nanoparticles (ZnO-NP are widely spread in consumer products. Data about the toxicological characteristics of ZnO-NP is still under controversial discussion. The human skin is the most important organ concerning ZnO-NP exposure. Intact skin was demonstrated to be a sufficient barrier against NPs; however, defect skin may allow NP contact to proliferating cells. Within these cells, stem cells are the most important toxicological target for NPs. The aim of this study was to evaluate the genotoxic and cytotoxic effects of ZnO-NP at low-dose concentrations after long-term and repetitive exposure to human mesenchymal stem cells (hMSC. Cytotoxic effects of ZnO-NP were measured by the 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyl tetrazolium bromide (MTT assay. Furthermore, genotoxicity was evaluated by the comet assay. For long-term observation over 6 weeks, transmission electron microscopy (TEM was applied. The results of the study indicated cytotoxic effects of ZnO-NP beginning at high concentrations of 50 μg/mL and genotoxic effects in hMSC exposed to 1 and 10 μg/mL ZnO-NP. Repetitive exposure enhanced cyto- but not genotoxicity. Intracellular NP accumulation was observed up to 6 weeks. The results suggest cytotoxic and genotoxic potential of ZnO-NP. Even low doses of ZnO-NP may induce toxic effects as a result of repetitive exposure and long-term cellular accumulation. This data should be considered before using ZnO-NP on damaged skin.

Wildfire smoke exposure and human health: Significant gaps in research for a growing public health issue.

Science.gov (United States)

Black, Carolyn; Tesfaigzi, Yohannes; Bassein, Jed A; Miller, Lisa A

2017-10-01

Understanding the effect of wildfire smoke exposure on human health represents a unique interdisciplinary challenge to the scientific community. Population health studies indicate that wildfire smoke is a risk to human health and increases the healthcare burden of smoke-impacted areas. However, wildfire smoke composition is complex and dynamic, making characterization and modeling difficult. Furthermore, current efforts to study the effect of wildfire smoke are limited by availability of air quality measures and inconsistent air quality reporting among researchers. To help address these issues, we conducted a substantive review of wildfire smoke effects on population health, wildfire smoke exposure in occupational health, and experimental wood smoke exposure. Our goal was to evaluate the current literature on wildfire smoke and highlight important gaps in research. In particular we emphasize long-term health effects of wildfire smoke, recovery following wildfire smoke exposure, and health consequences of exposure in children. Copyright © 2017 Elsevier B.V. All rights reserved.

Knowledge of human immunodeficiency virus post-exposure ...

African Journals Online (AJOL)

2011-05-21

May 21, 2011 ... Appropriate post-exposure prophylaxis is an integral part of prevention, control and workplace safety. This study was undertaken to assess the level of knowledge of post-exposure prophylaxis (PEP) against human immunodeficiency virus (HIV) among doctors in Federal Medical Centre, Gombe, Nigeria.

Quantifying human exposure to air pollution--moving from static monitoring to spatio-temporally resolved personal exposure assessment.

Science.gov (United States)

Steinle, Susanne; Reis, Stefan; Sabel, Clive Eric

2013-01-15

Quantifying human exposure to air pollutants is a challenging task. Ambient concentrations of air pollutants at potentially harmful levels are ubiquitous in urban areas and subject to high spatial and temporal variability. At the same time, every individual has unique activity-patterns. Exposure results from multifaceted relationships and interactions between environmental and human systems, adding complexity to the assessment process. Traditionally, approaches to quantify human exposure have relied on pollutant concentrations from fixed air quality network sites and static population distributions. New developments in sensor technology now enable us to monitor personal exposure to air pollutants directly while people are moving through their activity spaces and varying concentration fields. The literature review on which this paper is based on reflects recent developments in the assessment of human exposure to air pollution. This includes the discussion of methodologies and concepts, and the elaboration of approaches and study designs applied in the field. We identify shortcomings of current approaches and discuss future research needs. We close by proposing a novel conceptual model for the integrated assessment of human exposure to air pollutants taking into account latest technological capabilities and contextual information. Copyright © 2012 Elsevier B.V. All rights reserved.

Biomonitoring of the mycotoxin Zearalenone: current state-of-the art and application to human exposure assessment.

Science.gov (United States)

Mally, Angela; Solfrizzo, Michele; Degen, Gisela H

2016-06-01

Zearalenone (ZEN), a mycotoxin with high estrogenic activity in vitro and in vivo, is a widespread food contaminant that is commonly detected in maize, wheat, barley, sorghum, rye and other grains. Human exposure estimates based on analytical data on ZEN occurrence in various food categories and food consumption data suggest that human exposure to ZEN and modified forms of ZEN may be close to or even exceed the tolerable daily intake (TDI) derived by the European Food Safety Authority (EFSA) for some consumer groups. Considering the inherent uncertainties in estimating dietary intake of ZEN that may lead to an under- or overestimation of ZEN exposure and consequently human risk and current lack of data on vulnerable consumer groups, there is a clear need for more comprehensive and reliable exposure data to refine ZEN risk assessment. Human biomonitoring (HBM) is increasingly being recognized as an efficient and cost-effective way of assessing human exposure to food contaminants, including mycotoxins. Based on animal and (limited) human data on the toxicokinetics of ZEN, it appears that excretion of ZEN and its major metabolites may present suitable biomarkers of ZEN exposure. In view of the limitations of available dietary exposure data on ZEN and its modified forms, the purpose of this review is to provide an overview of recent studies utilizing HBM to monitor and assess human exposure to ZEN. Considerations are given to animal and human toxicokinetic data relevant to HBM, analytical methods, and available HBM data on urinary biomarkers of ZEN exposure in different cohorts.

Effect of prolonged exposure to sublethal concentrations of DDT and DDE on protein expression in human pancreatic beta cells

Energy Technology Data Exchange (ETDEWEB)

Pavlikova, Nela, E-mail: nela.pavlikova@lf3.cuni.cz [Department of Cell and Molecular Biology, Third Faculty of Medicine, Charles University, Prague (Czech Republic); Smetana, Pavel [Department of Cell and Molecular Biology, Third Faculty of Medicine, Charles University, Prague (Czech Republic); Halada, Petr [Laboratory of Molecular Structure Characterization, Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague (Czech Republic); Kovar, Jan [Department of Cell and Molecular Biology, Third Faculty of Medicine, Charles University, Prague (Czech Republic)

2015-10-15

Pollution of the environment represents one of less explored potential reasons for the worldwide epidemic of type 2 diabetes. One of the most prevalent organochlorine pollutants remains the pesticide DDT and its degradation product DDE. Despite some epidemiologic correlations between levels of DDT and DDE in human organism and the prevalence of diabetes, there is almost no information about the exact targets of these compounds inside pancreatic beta cells. To detect functional areas of pancreatic beta cells that could be affected by exposure to DDT and DDE, we analyzed changes in protein expression in the NES2Y human pancreatic beta cell line exposed to three sublethal concentrations (0.1 μM, 1 μM, 10 μM) of DDT and DDE for 1 month. Protein separation and identification was achieved using high-resolution 2D-electrophoresis, computer analysis and mass spectrometry. With these techniques, four proteins were found downregulated after exposure to 10 μM DDT: three cytoskeletal proteins (cytokeratin 8, cytokeratin 18 and actin) and one protein involved in glycolysis (alpha-enolase). Two proteins were downregulated after exposure to 10 μM DDE: cytokeratin 18 and heterogenous nuclear ribonucleoprotein H1 (HNRH1). These changes correlate with previously described effects of other stress conditions (e.g. exposure to palmitate, hyperglycemia, imidazoline derivative, and cytokines) on protein expression in pancreatic beta cells. We conclude that cytoskeletal proteins and their processing, glucose metabolism, and mRNA processing may represent targets affected by exposure to conditions hostile to pancreatic beta cells, including exposure to DDT and DDE. - Highlights: • Epidemiologic studies connect pollution with incidence of diabetes mellitus. • We explored the effect of DDT and DDE on protein expression in the NES2Y pancreatic beta cell line. • One month exposure to three sublethal concentrations of DDT and DDE was employed. • Expression of alpha-enolase, actin

Effect of prolonged exposure to sublethal concentrations of DDT and DDE on protein expression in human pancreatic beta cells

International Nuclear Information System (INIS)

Pavlikova, Nela; Smetana, Pavel; Halada, Petr; Kovar, Jan

2015-01-01

Pollution of the environment represents one of less explored potential reasons for the worldwide epidemic of type 2 diabetes. One of the most prevalent organochlorine pollutants remains the pesticide DDT and its degradation product DDE. Despite some epidemiologic correlations between levels of DDT and DDE in human organism and the prevalence of diabetes, there is almost no information about the exact targets of these compounds inside pancreatic beta cells. To detect functional areas of pancreatic beta cells that could be affected by exposure to DDT and DDE, we analyzed changes in protein expression in the NES2Y human pancreatic beta cell line exposed to three sublethal concentrations (0.1 μM, 1 μM, 10 μM) of DDT and DDE for 1 month. Protein separation and identification was achieved using high-resolution 2D-electrophoresis, computer analysis and mass spectrometry. With these techniques, four proteins were found downregulated after exposure to 10 μM DDT: three cytoskeletal proteins (cytokeratin 8, cytokeratin 18 and actin) and one protein involved in glycolysis (alpha-enolase). Two proteins were downregulated after exposure to 10 μM DDE: cytokeratin 18 and heterogenous nuclear ribonucleoprotein H1 (HNRH1). These changes correlate with previously described effects of other stress conditions (e.g. exposure to palmitate, hyperglycemia, imidazoline derivative, and cytokines) on protein expression in pancreatic beta cells. We conclude that cytoskeletal proteins and their processing, glucose metabolism, and mRNA processing may represent targets affected by exposure to conditions hostile to pancreatic beta cells, including exposure to DDT and DDE. - Highlights: • Epidemiologic studies connect pollution with incidence of diabetes mellitus. • We explored the effect of DDT and DDE on protein expression in the NES2Y pancreatic beta cell line. • One month exposure to three sublethal concentrations of DDT and DDE was employed. • Expression of alpha-enolase, actin

Exposure to titanium dioxide and other metallic oxide nanoparticles induces cytotoxicity on human neural cells and fibroblasts

Directory of Open Access Journals (Sweden)

James C K Lai

2008-12-01

Full Text Available James C K Lai1, Maria B Lai1, Sirisha Jandhyam1, Vikas V Dukhande1, Alok Bhushan1, Christopher K Daniels1, Solomon W Leung21Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, and Biomedical Research Institute; 2Department of Civil and Environmental Engineering, College of Engineering and Biomedical Research Institute, Idaho State University, Pocatello, ID, USAAbstract: The use of titanium dioxide (TiO2 in various industrial applications (eg, production of paper, plastics, cosmetics, and paints has been expanding thereby increasing the occupational and other environmental exposure of these nanoparticles to humans and other species. However, the health effects of exposure to TiO2 nanoparticles have not been systematically assessed even though recent studies suggest that such exposure induces inflammatory responses in lung tissue and cells. Because the effects of such nanoparticles on human neural cells are unknown, we have determined the putative cytotoxic effects of these nanoparticles on human astrocytes-like astrocytoma U87 cells and compared their effects on normal human fibroblasts. We found that TiO2 micro- and nanoparticles induced cell death on both human cell types in a concentration-related manner. We further noted that zinc oxide (ZnO nanoparticles were the most effective, TiO2 nanoparticles the second most effective, and magnesium oxide (MgO nanoparticles the least effective in inducing cell death in U87 cells. The cell death mechanisms underlying the effects of TiO2 micro- and nanoparticles on U87 cells include apoptosis, necrosis, and possibly apoptosis-like and necrosis-like cell death types. Thus, our findings may have toxicological and other pathophysiological implications on exposure of humans and other mammalian species to metallic oxide nanoparticles.Keywords: cytotoxicity of titanium dioxide micro- and nanoparticles, cytotoxicity of zinc oxide and magnesium oxide nanoparticles, human neural cells

Human biological monitoring of occupational genotoxic exposures

DEFF Research Database (Denmark)

Knudsen, Lisbeth E.; Sorsa, M

1993-01-01

Human biological monitoring is a valuable tool for exposure assessment in groups of persons occupationally exposed to genotoxic agents. If the monitoring activity covers genetic material the term genetic monitoring is used. The methods used for genetic monitoring are either substance specific, e......) occupational exposure limit value of styrene in ambient air. The consideration of ethical issues in human genetic monitoring is an important but often overlooked aspect. This includes the scientific and preventional relevance of performing a test on individuals, pre- and post study information of donors...

Quantitative analysis of untreated human nails for monitoring human exposure to heavy metals

International Nuclear Information System (INIS)

Sera, Koichiro; Futatsugawa, Shouji; Murao, Satoshi; Clemente, E.

2002-01-01

In order to address global environmental issues, a standard-free method developed by ourselves has been successfully applied to various kinds of bio-samples. Especially, a method for untreated hairs has been applied in many polluted areas to study human exposure to toxic elements. In addition to hair, nail is expected to give us valuable information about human exposure to toxic elements. However, the analysis requires relatively large amounts of samples and laborious sample preparation techniques which necessitate internal standards. In this work, we have developed a quantitative method for untreated human-nail analysis based on the standard-free method. It requires neither large amounts of nails nor complicated target preparation procedure. Furthermore, it is perfectly free from any ambiguity in target preparation such as volatilization of certain elements and contamination of the sample during chemical ashing. The optimum conditions of irradiating nail samples are established, and accuracy and reproducibility of the present method are confirmed. It is found that ultrasonic washing in distilled water is effective for many nail samples preventing the loss of elements from the sample. It is also found that elemental concentration in nails strongly depends on their sampling positions. (author)

Effects of Moxa (Folium Artemisiae argyi Smoke Exposure on Heart Rate and Heart Rate Variability in Healthy Young Adults: A Randomized, Controlled Human Study

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Yingxue Cui

2013-01-01

Full Text Available Objective. To determine the effects of the moxa smoke on human heart rate (HR and heart rate variability (HRV. Methods. Fifty-five healthy young adults were randomly divided into experimental (n=28 and control (n=27 groups. Experimental subjects were exposed to moxa smoke (2.5 ± 0.5 mg/m3 twice for 25 minutes in one week. ECG monitoring was performed before, during, and after exposure. Control subjects were exposed to normal indoor air in a similar environment and similarly monitored. Followup was performed the following week. Short-term (5 min HRV parameters were analyzed with HRV analysis software. SPSS software was used for statistical analysis. Results. During and after the first exposure, comparison of percentage changes or changes in all parameters between groups showed no significant differences. During the second exposure, percentage decrease in HR, percentage increases in lnTP, lnHF, lnLF, and RMSSD, and increase in PNN50 were significantly greater in the experimental group than in control. Conclusion. No significant adverse HRV effects were associated with this clinically routine 25-minute exposure to moxa smoke, and the data suggests that short-term exposure to moxa smoke might have positive regulating effects on human autonomic function. Further studies are warranted to confirm these findings.

Effects of Long-Term Exposure to 60 GHz Millimeter-Wavelength Radiation on the Genotoxicity and Heat Shock Protein (Hsp Expression of Cells Derived from Human Eye

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Shin Koyama

2016-08-01

Full Text Available Human corneal epithelial (HCE-T and human lens epithelial (SRA01/04 cells derived from the human eye were exposed to 60 gigahertz (GHz millimeter-wavelength radiation for 24 h. There was no statistically significant increase in the micronucleus (MN frequency in cells exposed to 60 GHz millimeter-wavelength radiation at 1 mW/cm2 compared with sham-exposed controls and incubator controls. The MN frequency of cells treated with bleomycin for 1 h provided positive controls. The comet assay, used to detect DNA strand breaks, and heat shock protein (Hsp expression also showed no statistically significant effects of exposure. These results indicate that exposure to millimeter-wavelength radiation has no effect on genotoxicity in human eye cells.

Modelling ecological and human exposure to POPs in Venice lagoon - Part II: Quantitative uncertainty and sensitivity analysis in coupled exposure models.

Science.gov (United States)

Radomyski, Artur; Giubilato, Elisa; Ciffroy, Philippe; Critto, Andrea; Brochot, Céline; Marcomini, Antonio

2016-11-01

The study is focused on applying uncertainty and sensitivity analysis to support the application and evaluation of large exposure models where a significant number of parameters and complex exposure scenarios might be involved. The recently developed MERLIN-Expo exposure modelling tool was applied to probabilistically assess the ecological and human exposure to PCB 126 and 2,3,7,8-TCDD in the Venice lagoon (Italy). The 'Phytoplankton', 'Aquatic Invertebrate', 'Fish', 'Human intake' and PBPK models available in MERLIN-Expo library were integrated to create a specific food web to dynamically simulate bioaccumulation in various aquatic species and in the human body over individual lifetimes from 1932 until 1998. MERLIN-Expo is a high tier exposure modelling tool allowing propagation of uncertainty on the model predictions through Monte Carlo simulation. Uncertainty in model output can be further apportioned between parameters by applying built-in sensitivity analysis tools. In this study, uncertainty has been extensively addressed in the distribution functions to describe the data input and the effect on model results by applying sensitivity analysis techniques (screening Morris method, regression analysis, and variance-based method EFAST). In the exposure scenario developed for the Lagoon of Venice, the concentrations of 2,3,7,8-TCDD and PCB 126 in human blood turned out to be mainly influenced by a combination of parameters (half-lives of the chemicals, body weight variability, lipid fraction, food assimilation efficiency), physiological processes (uptake/elimination rates), environmental exposure concentrations (sediment, water, food) and eating behaviours (amount of food eaten). In conclusion, this case study demonstrated feasibility of MERLIN-Expo to be successfully employed in integrated, high tier exposure assessment. Copyright © 2016 Elsevier B.V. All rights reserved.

Exposure of Extremely-Low Frequency (ELF magnetic field may cause human cancer

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Daryoush Shahbazi-Gahrouei

2017-01-01

Full Text Available Introduction: Chronic exposure of non-ionizing extremely low-frequency magnetic fields (ELF-EMF is considered as a health hazard due to its adverse effects on human body such as generation of any type of cancer. Stem cells are appropriate models to assess the effects of ELF-EMF on other cell lines and human beings. Materials and methods: Adipose tissue has been known as source of multi potent stromal human mesenchymal stem cells (MSCs which can be obtained in less invasive method and in large amounts; so adipose-derived stem cells (ADSCs were used in this study. Effect of ELF-EMF (intensities of 0.5 and 1 mT and 50 Hz on proliferation rate of hADSCs was assessed in 20 and 40 min per day for 7 days. Trypan blue assay was performed to assess cell proliferation rate. Result: The results shown that 0.5 and 1 mT magnetic fields can promote the proliferation rate of adipose derived hMSCs according to the duration of exposure. Conclusion: These outcomes could approve the effect of ELF-EMF on cancer induction; although the effective mechanisms in this process are still unknown.

Dioxin exposure of human CD34+ hemopoietic cells induces gene expression modulation that recapitulates its in vivo clinical and biological effects

International Nuclear Information System (INIS)

Fracchiolla, Nicola Stefano; Todoerti, Katia; Bertazzi, Pier Alberto; Servida, Federica; Corradini, Paolo; Carniti, Cristiana; Colombi, Antonio; Cecilia Pesatori, Angela; Neri, Antonino; Deliliers, Giorgio Lambertenghi

2011-01-01

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) has a large number of biological effects, including skin, cardiovascular, neurologic diseases, diabetes, infertility, cancers and immunotoxicity. We analysed the in vitro TCDD effects on human CD34 + cells and tested the gene expression modulation by means of microarray analyses before and after TCDD exposure. We identified 257 differentially modulated probe sets, identifying 221 well characterized genes. A large part of these resulted associated to cell adhesion and/or angiogenesis and to transcription regulation. Synaptic transmission and visual perception functions, with the particular involvement of the GABAergic pathway were also significantly modulated. Numerous transcripts involved in cell cycle or cell proliferation, immune response, signal transduction, ion channel activity or calcium ion binding, tissue development and differentiation, female or male fertility or in several metabolic pathways were also affected after dioxin exposure. The transcriptional profile induced by TCDD treatment on human CD34 + cells strikingly reproduces the clinical and biological effects observed in individuals exposed to dioxin and in biological experimental systems. Our data support a role of dioxin in the neoplastic transformation of hemopoietic stem cells and in immune modulation processes after in vivo exposure, as indicated by the epidemiologic data in dioxin accidentally exposed populations, providing a molecular basis for it. In addition, TCDD alters genes associated to glucidic and lipidic metabolisms, to GABAergic transmission or involved in male and female fertility, thus providing a possible explanation of the diabetogenic, dyslipidemic, neurologic and fertility effects induced by TCDD in vivo exposure.

EVALUATION OF EMF EXPOSURE OF MOBILE PHONES ON HUMAN HEAD

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N. I. Vtornikova

2017-01-01

Full Text Available Introduction. Mobile phones are worldwide spread nowadays. Smartphones penetration is growing year after year. Numerous studies indicate the negative effect of EMF exposure of these devices on humans. Therefore, it is important to study the peculiarities of their influence on the target organ-the brain. It is important for solving this problem to find out the real situation of the distribution of energy flux density (EFD of EMF exposure near the front panel of the apparatus.The aim of the study is to determine and compare EMF exposure from smartphones and classic mobile phones on human head.Material and methods. The original method patented in the Russian Federation was used in this study. The used original measuring setup is also patented, developed and assembled by the authors of the study. The object of the study was classical mobile phones and smartphones widespread at the time of work.Results. We got the graphic of matrices of distribution of energy flux density (EFD of EMF exposure in the plane against the front panel of 10 apparatus corresponding to the topography of a human head. The study revealed peculiarities of this distribution in smartphones and the classic mobile phones and got the values of energy flux density (EFD of EMF exposure in the investigated devices acting primarily on the brain.Conclusions. The design of smartphones and mobile phones determines the overall picture of distribution of EFD of EMF exposure in the plane against the front panel for devices of a particular type. This picture must be taken into account when planning epidemiological and experimental studies to obtain comparable results. Progress in the development of mobile communication technologies has led to an increase in the electromagnetic load on users of modern devices.

Chronic Exposure to Particulate Nickel Induces Neoplastic Transformation in Human Lung Epithelial Cells

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Amie L. Holmes

2013-11-01

Full Text Available Nickel is a well-known human lung carcinogen with the particulate form being the most potent; however, the carcinogenic mechanism remains largely unknown. Few studies have investigated the genotoxicity and carcinogenicity of nickel in its target cell, human bronchial epithelial cells. Thus, the goal of this study was to investigate the effects of particulate nickel in human lung epithelial cells. We found that nickel subsulfide induced concentration- and time-dependent increases in both cytotoxicity and genotoxicity in human lung epithelial cells (BEP2D. Chronic exposure to nickel subsulfide readily induced cellular transformation, inducing 2.55, 2.9 and 2.35 foci per dish after exposure to 1, 2.5 and 5 μg/cm2 nickel subsulfide, respectively. Sixty-one, 100 and 70 percent of the foci isolated from 1, 2.5, and 5 μg/cm2 nickel subsulfide treatments formed colonies in soft agar and the degree of soft agar colony growth increased in a concentration-dependent manner. Thus, chronic exposure to particulate nickel induces genotoxicity and cellular transformation in human lung epithelial cells.

ASSESSING CHILDREN'S EXPOSURES TO PESTICIDES: AN IMPORTANT APPLICATION OF THE STOCHASTIC HUMAN EXPOSURE AND DOSE SIMULATION MODEL (SHEDS)

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Accurately quantifying human exposures and doses of various populations to environmental pollutants is critical for the Agency to assess and manage human health risks. For example, the Food Quality Protection Act of 1996 (FQPA) requires EPA to consider aggregate human exposure ...

Adverse effects of perinatal nicotine exposure on reproductive outcomes.

Science.gov (United States)

Wong, Michael K; Barra, Nicole G; Alfaidy, Nadia; Hardy, Daniel B; Holloway, Alison C

2015-12-01

Nicotine exposure during pregnancy through cigarette smoking, nicotine replacement therapies or e-cigarette use continues to be a widespread public health problem, impacting both fetal and postnatal health. Yet, at this time, there remains limited data regarding the safety and efficacy in using these nicotine products during pregnancy. Notably, reports assessing the effect of nicotine exposure on postnatal health outcomes in humans, including reproductive health, are severely lacking. Our current understanding regarding the consequences of nicotine exposure during pregnancy is limited to a few animal studies, which do not comprehensively address the underlying cellular mechanisms involved. This paper aims to critically review the current knowledge from human and animal studies regarding the direct and indirect effects (e.g. obesity) of maternal nicotine exposure, regardless of its source, on reproductive outcomes in pregnancy and postnatal life. Furthermore, this review highlights several key cellular mechanisms involved in these adverse reproductive deficits including oxidative stress, inflammation, and endoplasmic reticulum (ER) stress. By understanding the interplay of the cellular mechanisms involved, further strategies could be developed to prevent the reproductive abnormalities resulting from exposure to nicotine in utero and influence informed clinical guidelines for pregnant women. © 2015 Society for Reproduction and Fertility.

Development of human exposure standards for radio frequency fields

International Nuclear Information System (INIS)

Lin, James C.

2000-01-01

Historical aspects of the problem of developing human exposure standards for radio frequency (RF) electromagnetic fields are discussed. It is shown that biological effects and health implications of radiofrequency (RF) electromagnetic fields have been a subject of scientific investigation for more than 50 years. It has become a focus of attention because of the expanded use of RF radiation in the frequency range between 300 MHz and 6 GHz for wireless communication over the past decade. Another cause for the attention is the uncertainty of some observed responses and lack of understanding of the mechanism of interaction of RF electromagnetic fields with biological systems. At present, considerable efforts are devoted to developing and revising RF exposure standards. Each of these efforts should aim to make explicit the philosophy and process by which they reason and decide guidelines for deeming exposure as safe. Furthermore, the reconciliation of philosophies of protection will definitely be an asset, in practice, to those interested in international harmonization of RF exposure standards [ru

Reproductive endocrine-disrupting effects of triclosan: Population exposure, present evidence and potential mechanisms

International Nuclear Information System (INIS)

Wang, Cai-Feng; Tian, Ying

2015-01-01

Triclosan has been used as a broad-spectrum antibacterial agent for over 40 years worldwide. Increasing reports indicate frequent detection and broad exposure to triclosan in the natural environment and the human body. Current laboratory studies in various species provide strong evidence for its disrupting effects on the endocrine system, especially reproductive hormones. Multiple modes of action have been suggested, including disrupting hormone metabolism, displacing hormones from hormone receptors and disrupting steroidogenic enzyme activity. Although epidemiological studies on its effects in humans are mostly negative but conflicting, which is typical of much of the early evidence on the toxicity of EDCs, overall, the evidence suggests that triclosan is an EDC. This article reviews human exposure to triclosan, describes the current evidence regarding its reproductive endocrine-disrupting effects, and discusses potential mechanisms to provide insights for further study on its endocrine-disrupting effects in humans. - Highlights: • Triclosan is widely detected in human urine, blood and breast milk. • Laboratory studies suggest reproductive endocrine-disrupting effects of triclosan. • Laboratory studies suggest estrogenic properties of triclosan. • There are three potential mechanisms regarding the estrogenic effect of triclosan. • Prospective epidemiological studies on vulnerable populations are needed. - This review summarizes current evidence on human exposure to triclosan, and its reproductive endocrine-disrupting effects and potential mechanisms.

Biological Effects of Low-Dose Exposure

CERN Document Server

Komochkov, M M

2000-01-01

On the basis of the two-protection reaction model an analysis of stochastic radiobiological effects of low-dose exposure of different biological objects has been carried out. The stochastic effects are the results published in the last decade: epidemiological studies of human cancer mortality, the yield of thymocyte apoptosis of mice and different types of chromosomal aberrations. The results of the analysis show that as dependent upon the nature of biological object, spontanous effect, exposure conditions and radiation type one or another form dose - effect relationship is realized: downwards concave, near to linear and upwards concave with the effect of hormesis included. This result testifies to the incomplete conformity of studied effects of 1990 ICRP recomendations based on the linear no-threshold hypothesis about dose - effect relationship. Because of this the methodology of radiation risk estimation recomended by ICRP needs more precisian and such quantity as collective dose ought to be classified into...

Estimating the human exposure to chemical substances and radiation. Definition report

International Nuclear Information System (INIS)

Vermeire, T.G.; Van Veen, M.P.

1995-06-01

This report aims at boosting the human exposure assessment activities of the RIVM with regard to chemical substances and radiation. It is the result of thorough discussions with RIVM-experts. The report starts with an overview of past developments in the area of human exposure assessment at the RIVM and continues describing recent projects. Major developments outside the Institute are also discussed. An attempt is made to harmonize definitions which are relevant for exposure assessment, i.e. definitions on exposure, intake, uptake and dose. Important gaps in the human exposure assessment work at the RIVM are identified, leading to proposals for future work. 2 figs., 31 refs., 3 appendices

Occurrence, sources and human exposure assessment of SCCPs in indoor dust of northeast China.

Science.gov (United States)

Liu, Li-Hua; Ma, Wan-Li; Liu, Li-Yan; Huo, Chun-Yan; Li, Wen-Long; Gao, Chong-Jing; Li, Hai-Ling; Li, Yi-Fan; Chan, Hing Man

2017-06-01

Short-chain chlorinated paraffins (SCCPs) are widely used chemicals in household products and might cause adverse human health effects. However, limited information is available on the occurrence of SCCPs in indoor environments and their exposure risks on humans. In this study the concentrations, profiles and human exposure of SCCPs in indoor dust from five different indoor environments, including commercial stores, residential apartments, dormitories, offices and laboratories were characterized. The SCCPs levels ranged from 10.1 to 173.0 μg/g, with the median and mean concentration of 47.2 and 53.6 μg/g, respectively. No significant difference was found on concentrations among the five microenvironments. The most abundant compounds in indoor dust samples were homologues of C 13 group, Cl 7 group and N 20 (N is the total number of C and Cl) group. In the five microenvironments, commercial stores were more frequently exposed to shorter carbon chained and higher chlorinated homologues. Three potential sources for SCCPs were identified by the multiple linear regression of factor score model and correspondence analysis. The major sources of SCCPs in indoor dust were technical mixtures of CP-42 (42% chlorine, w/w) and CP-52 b (52% chlorine, w/w). The total daily exposure doses and hazard quotients (HQ) were calculated by the human exposure models, and they were all below the reference doses and threshold values, respectively. Monte Carlo simulation was applied to predict the human exposure risk of SCCPs. Infants and toddlers were at risk of SCCPs based on predicted HQ values, which were exceeded the threshold for neoplastic effects in the worst case. Our results on the occurrences, sources and human exposures of SCCPs will be useful to provide a better understanding of SCCPs behaviors in indoor environment in China, and to support environmental risk evaluation and regulation of SCCPs in the world. Copyright © 2017. Published by Elsevier Ltd.

Electronic cigarettes: human health effects.

Science.gov (United States)

Callahan-Lyon, Priscilla

2014-05-01

With the rapid increase in use of electronic nicotine delivery systems (ENDS), such as electronic cigarettes (e-cigarettes), users and non-users are exposed to the aerosol and product constituents. This is a review of published data on the human health effects of exposure to e-cigarettes and their components. Literature searches were conducted through September 2013 using multiple electronic databases. Forty-four articles are included in this analysis. E-cigarette aerosols may contain propylene glycol, glycerol, flavourings, other chemicals and, usually, nicotine. Aerosolised propylene glycol and glycerol produce mouth and throat irritation and dry cough. No data on the effects of flavouring inhalation were identified. Data on short-term health effects are limited and there are no adequate data on long-term effects. Aerosol exposure may be associated with respiratory function impairment, and serum cotinine levels are similar to those in traditional cigarette smokers. The high nicotine concentrations of some products increase exposure risks for non-users, particularly children. The dangers of secondhand and thirdhand aerosol exposure have not been thoroughly evaluated. Scientific evidence regarding the human health effects of e-cigarettes is limited. While e-cigarette aerosol may contain fewer toxicants than cigarette smoke, studies evaluating whether e-cigarettes are less harmful than cigarettes are inconclusive. Some evidence suggests that e-cigarette use may facilitate smoking cessation, but definitive data are lacking. No e-cigarette has been approved by FDA as a cessation aid. Environmental concerns and issues regarding non-user exposure exist. The health impact of e-cigarettes, for users and the public, cannot be determined with currently available data.

Study on indoor radon exposure and its effect on human health

International Nuclear Information System (INIS)

Lu Xinwei

2005-01-01

Radon and its daughters relate to people health. Radon widely exists in the nature. The paper discusses the source, exposure and activity level of indoor radon, systematically analyzes the hazards and dose-response of residential radon exposure, and at last indicates the concrete method of controlling residential radon concentration. By interdicting radon pollution source and ventilation might effectively reduce indoor radon concentration and improve environmental air quality. (authors)

Biomonitoring of Human Exposure to Prestige Oil: Effects on DNA and Endocrine Parameters

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Beatriz Pérez-Cadahía

2008-01-01

Full Text Available Since 1960, about 400 tankers spilled more than 377765 tons of oil, with the Prestige accident (Galician coast, NW Spain, November 2002 the most recent. Taking into account the consistent large number of individuals exposed to oil that exists all over the world, it seems surprising the absence in the literature of studies focused on the chronic effects of this exposure on human health. In this work we evaluated the level of DNA damage by means of comet assay, and the potential endocrine alterations (prolactin and cortisol caused by Prestige oil exposure in a population of 180 individuals, classified in 3 groups according to the tasks performed, and 60 controls. Heavy metals in blood were determined as exposure biomarkers, obtaining significant increases of aluminum, nickel and lead in the exposed groups as compared to controls. Higher levels of genetic damage and endocrine alterations were also observed in the exposed population. DNA damage levels were influenced by age, sex, and the use of protective clothes, and prolactin concentrations by the last two factors. Surprisingly, the use of mask did not seem to protect individuals from genetic or endocrine alterations. Moreover, polymorphisms in genes encoding for the main enzymes involved in the metabolism of oil components were analyzed as susceptibility biomarkers. CYP1A1-3’UTR and EPHX1 codons 113 and 139 variant alleles were related to higher damage levels, while lower DNA damage was observed in GSTM1 and GSTT1 null individuals.

Modeling human exposure to hazardous-waste sites: a question of completeness

International Nuclear Information System (INIS)

Daniels, J.I.; McKone, T.E.

1991-01-01

In risk analysis, we use human-exposure assessments to translate contaminant sources into quantitative estimates of the amount of contaminant that comes in contact with human-environment boundaries, that is, the lungs, the gastrointestinal tract, and the skin surface of individuals within a specified population. An assessment of intake requires that we determine how much crosses these boundaries. Exposure assessments often rely implicitly in the assumption that exposure can be linked by simple parameters to ambient concentration in air, water, and soil. However, more realistic exposure models require that we abandon such simple assumptions. To link contaminant concentrations in water, air, or soil with potential human intakes, we constrict pathway-exposure factors (PEFs). For each PEF we combine information in environmental partitioning as well as human anatomy, physiology, and patterns into an algebraic term that converts concentrations of contaminants (in mg/L water, mg/m 3 air, and mg/kg soil) into a daily intake per unit body weight in mg/kg-d for a specific rout of exposure such as inhalation, ingestion, or dermal uptake. Using examples involving human exposure to either a radionuclide (tritium, 3 H) or a toxic organic chemical (tetrachloroethylene, PCE) in soil, water, and air, we illustrate the use of PEFs and consider the implications for risk assessment. (au)

New experimental data on the human dermal absorption of Simazine and Carbendazim help to refine the assessment of human exposure.

Science.gov (United States)

Bányiová, Katarína; Nečasová, Anežka; Kohoutek, Jiří; Justan, Ivan; Čupr, Pavel

2016-02-01

Due to their widespread usage, people are exposed to pesticides on a daily basis. Although these compounds may have adverse effects on their health, there is a gap in the data and the methodology needed to reliably quantify the risks of non-occupational human dermal exposure to pesticides. We used Franz cells and human skin in order to measure the dermal absorption kinetics (steady-state flux, lag time and permeability coefficient) of Carbendazim and Simazine. These parameters were then used to refine the dermal exposure model and a probabilistic simulation was used to quantify risks resulting from exposure to pesticide-polluted waters. The experimentally derived permeability coefficient was 0.0034 cm h(-1) for Carbendazim and 0.0047 cm h(-1) for Simazine. Two scenarios (varying exposure duration and concentration, i.e. environmentally relevant and maximum solubility) were used to quantify the human health risks (hazard quotients) for Carbendazim and Simazine. While no risks were determined in the case of either scenario, the permeability coefficient, which is concentration independent and donor, formulation, compound and membrane specific, may be used in other scenarios and exposure models to quantify more precisely the dermally absorbed dose during exposure to polluted water. To the best of our knowledge, the dermal absorption kinetics parameters defined here are being published for the first time. The usage of experimental permeability parameters in combination with probabilistic risk assessment thus provides a new tool for quantifying the risks of human dermal exposure to pesticides. Copyright © 2015 Elsevier Ltd. All rights reserved.

Health Effects of Exposure to Low Dose of Radiation

International Nuclear Information System (INIS)

Alatas, Zubaidah

2003-01-01

Human beings are exposed to natural radiation from external sources include radionuclides in the earth and cosmic radiation, and by internal radiation from radionuclides, mainly uranium and thorium series, incorporated into the body. Living systems have adapted to the natural levels of radiation and radioactivity. But some industrial practices involving natural resources enhance these radionuclides to a degree that they may pose risk to humans and the environment if they are not controlled. Biological effects of ionizing radiation are the outcomes of physical and chemical processes that occur immediately after the exposure, then followed by biological process in the body. These processes will involve successive changes in the molecular, cellular, tissue and whole organism levels. Any dose of radiation, no matter how small, may produce health effects since even a single ionizing event can result in DNA damage. The damage to DNA in the nucleus is considered to be the main initiating event by which radiation causes damage to cells that results in the development of cancer and hereditary disease. It has also been indicated that cytogenetic damage can occur in cells that receive no direct radiation exposure, known as bystander effects. This paper reviews health risks of low dose radiation exposure to human body causing stochastic effects, i.e. cancer induction in somatic cells and hereditary disease in genetic cells. (author)

Effect of prolonged exposure to sublethal concentrations of DDT and DDE on protein expression in human pancreatic beta cells.

Science.gov (United States)

Pavlikova, Nela; Smetana, Pavel; Halada, Petr; Kovar, Jan

2015-10-01

Pollution of the environment represents one of less explored potential reasons for the worldwide epidemic of type 2 diabetes. One of the most prevalent organochlorine pollutants remains the pesticide DDT and its degradation product DDE. Despite some epidemiologic correlations between levels of DDT and DDE in human organism and the prevalence of diabetes, there is almost no information about the exact targets of these compounds inside pancreatic beta cells. To detect functional areas of pancreatic beta cells that could be affected by exposure to DDT and DDE, we analyzed changes in protein expression in the NES2Y human pancreatic beta cell line exposed to three sublethal concentrations (0.1 μM, 1 μM, 10 μM) of DDT and DDE for 1 month. Protein separation and identification was achieved using high-resolution 2D-electrophoresis, computer analysis and mass spectrometry. With these techniques, four proteins were found downregulated after exposure to 10 μM DDT: three cytoskeletal proteins (cytokeratin 8, cytokeratin 18 and actin) and one protein involved in glycolysis (alpha-enolase). Two proteins were downregulated after exposure to 10 μM DDE: cytokeratin 18 and heterogenous nuclear ribonucleoprotein H1 (HNRH1). These changes correlate with previously described effects of other stress conditions (e.g. exposure to palmitate, hyperglycemia, imidazoline derivative, and cytokines) on protein expression in pancreatic beta cells. We conclude that cytoskeletal proteins and their processing, glucose metabolism, and mRNA processing may represent targets affected by exposure to conditions hostile to pancreatic beta cells, including exposure to DDT and DDE. Copyright © 2015 Elsevier Inc. All rights reserved.

Human exposure assessment: Approaches for chemicals (REACH) and biocides (BPD)

NARCIS (Netherlands)

Hemmen, J.J. van; Gerritsen-Ebben, R.

2008-01-01

The approaches that are indicated in the various guidance documents for the assessment of human exposure for chemicals and biocides are summarised. This reflects the TNsG (Technical notes for Guidance) version 2: human exposure assessment for biocidal products (1) under the BPD (Biocidal Products

Climate change, ozone depletion and the impact on ultraviolet exposure of human skin

International Nuclear Information System (INIS)

Diffey, Brian

2004-01-01

For 30 years there has been concern that anthropogenic damage to the Earth's stratospheric ozone layer will lead to an increase of solar ultraviolet (UV) radiation reaching the Earth's surface, with a consequent adverse impact on human health, especially to the skin. More recently, there has been an increased awareness of the interactions between ozone depletion and climate change (global warming), which could also impact on human exposure to terrestrial UV. The most serious effect of changing UV exposure of human skin is the potential rise in incidence of skin cancers. Risk estimates of this disease associated with ozone depletion suggest that an additional peak incidence of 5000 cases of skin cancer per year in the UK would occur around the mid-part of this century. Climate change, which is predicted to lead to an increased frequency of extreme temperature events and high summer temperatures, will become more frequent in the UK. This could impact on human UV exposure by encouraging people to spend more time in the sun. Whilst future social trends remain uncertain, it is likely that over this century behaviour associated with climate change, rather than ozone depletion, will be the largest determinant of sun exposure, and consequent impact on skin cancer, of the UK population. (topical review)

Ecological and human exposure assessment to PBDEs in Adige River.

Science.gov (United States)

Giulivo, Monica; Suciu, Nicoleta Alina; Eljarrat, Ethel; Gatti, Marina; Capri, Ettore; Barcelo, Damia

2018-07-01

The interest for environmental issues and the concern resulting from the potential exposure to contaminants were the starting point to develop methodologies in order to evaluate the consequences that those might have over both the environment and human health. Considering the feature of POPs, including PBDEs, such as bioaccumulation, biomagnification, long-range transport and adverse effects even long time after exposure, risk assessment of POPs requires specific approaches and tools. In this particular context, the MERLIN-Expo tool was used to assess the aquatic environmental exposure of Adige River to PBDEs and the accumulation of PBDEs in humans through the consumption of possible contaminated local aquatic food. The aquatic food web models provided as output of the deterministic simulation the time trend of concentrations for twenty years of BDE-47 and total PBDEs, expressed using the physico-chemical properties of BDE-47, in aquatic organisms of the food web of Adige River. For BDE-47, the highest accumulated concentrations were detected for two benthic species: Thymallus thymallus and Squalius cephalus whereas the lowest concentrations were obtained for the pelagic specie Salmo trutta marmoratus. The trend obtained for the total PBDEs, calculated using the physico-chemical properties of BDE-47, follows the one of BDE-47. For human exposure, different BDE-47 and total PBDEs concentration trends between children, adolescent, adults and elderly were observed, probably correlated with the human intake of fish products in the daily diet and the ability to metabolize these contaminants. In detail, for the adolescents, adults and elderly a continuous accumulation of the target contaminants during the simulation's years was observed, whereas for children a plateau at the end of the simulation period was perceived. Copyright © 2018 Elsevier Inc. All rights reserved.

Effect of low and chronic radiation exposure to human population: Kollam study

International Nuclear Information System (INIS)

Ghosh, Anu; Kumar, Vinay

2018-01-01

Understanding the cellular and biological processes with low-level chronic radiation provides a rational basis for limits of exposure for occupational workers and general public. There are several high level natural radiation areas (HLNRA) of the world where human population is continuously exposed to natural radiation higher than the global average of 2.4 mGy/y. These areas provide unique opportunities to conduct studies which can provide better understanding of radiation effects and underlying mechanisms. The ∼55 km long monazite bearing belt of Kerala on the south-west coast of India is one such area. Over the last few decades, Bhabha Atomic Research Centre (BARC) has conducted extensive research on the human population residing in these areas to understand effects of low dose at the organismal, cellular and molecular levels. More recently, high resolution quantitative proteomic analysis of PBMCs using iTRAQ based LC-MS/MS identified differential expression of 1570 proteins in HLNRA individuals relative to individuals from the adjoining Normal Level Natural Radiation Areas (NLNRA). Almost 215 biological processes were distinctly altered in HLNRA samples, which included several pro-survival stress activated protein kinases and DNA repair networks. Many of the changes seen at the proteomics level were confirmed at the gene level using microarray expression data. This suggests an enhanced level of basal repair mechanisms in HLNRA individuals. The scientific program at BARC thus, focuses on fundamental scientific understanding of the mechanisms cells use to sense, repair and adapt to low dose radiation. Implications of these cellular processes for low dose radiation risk estimation will be discussed. (author)

Human Exposure Assessment for Air Pollution.

Science.gov (United States)

Han, Bin; Hu, Li-Wen; Bai, Zhipeng

2017-01-01

Assessment of human exposure to air pollution is a fundamental part of the more general process of health risk assessment. The measurement methods for exposure assessment now include personal exposure monitoring, indoor-outdoor sampling, mobile monitoring, and exposure assessment modeling (such as proximity models, interpolation model, air dispersion models, and land-use regression (LUR) models). Among these methods, personal exposure measurement is considered to be the most accurate method of pollutant exposure assessment until now, since it can better quantify observed differences and better reflect exposure among smaller groups of people at ground level. And since the great differences of geographical environment, source distribution, pollution characteristics, economic conditions, and living habits, there is a wide range of differences between indoor, outdoor, and individual air pollution exposure in different regions of China. In general, the indoor particles in most Chinese families comprise infiltrated outdoor particles, particles generated indoors, and a few secondary organic aerosol particles, and in most cases, outdoor particle pollution concentrations are a major contributor to indoor concentrations in China. Furthermore, since the time, energy, and expense are limited, it is difficult to measure the concentration of pollutants for each individual. In recent years, obtaining the concentration of air pollutants by using a variety of exposure assessment models is becoming a main method which could solve the problem of the increasing number of individuals in epidemiology studies.

Effects of acute exercise on fear extinction in rats and exposure therapy in humans: Null findings from five experiments.

Science.gov (United States)

Jacquart, Jolene; Roquet, Rheall F; Papini, Santiago; Powers, Mark B; Rosenfield, David; Smits, Jasper A J; Monfils, Marie-H

2017-08-01

Exposure therapy is an established learning-based intervention for the treatment of anxiety disorders with an average response rate of nearly 50%, leaving room for improvement. Emerging strategies to enhance exposure therapy in humans and fear extinction retention in animal models are primarily pharmacological. These approaches are limited as many patients report preferring non-pharmacological approaches in therapy. With general cognitive enhancement effects, exercise has emerged as a plausible non-pharmacological augmentation strategy. The present study tested the hypothesis that fear extinction and exposure therapy would be enhanced by a pre-training bout of exercise. We conducted four experiments with rats that involved a standardized conditioning and extinction paradigm and a manipulation of exercise. In a fifth experiment, we manipulated vigorous-intensity exercise prior to a standardized virtual reality exposure therapy session among adults with fear of heights. In experiments 1-4, exercise did not facilitate fear extinction, long-term memory, or fear relapse tests. In experiment 5, human participants showed an overall reduction in fear of heights but exercise did not enhance symptom improvement. Although acute exercise prior to fear extinction or exposure therapy, as operationalized in the present 5 studies, did not enhance outcomes, these results must be interpreted within the context of a broader literature that includes positive findings. Taken all together, this suggests that more research is necessary to identify optimal parameters and key individual differences so that exercise can be implemented successfully to treat anxiety disorders. Copyright © 2017 Elsevier Ltd. All rights reserved.

Metabolic profiling detects early effects of environmental and lifestyle exposure to cadmium in a human population

Directory of Open Access Journals (Sweden)

Ellis James K

2012-06-01

Full Text Available Abstract Background The 'exposome' represents the accumulation of all environmental exposures across a lifetime. Top-down strategies are required to assess something this comprehensive, and could transform our understanding of how environmental factors affect human health. Metabolic profiling (metabonomics/metabolomics defines an individual's metabolic phenotype, which is influenced by genotype, diet, lifestyle, health and xenobiotic exposure, and could also reveal intermediate biomarkers for disease risk that reflect adaptive response to exposure. We investigated changes in metabolism in volunteers living near a point source of environmental pollution: a closed zinc smelter with associated elevated levels of environmental cadmium. Methods High-resolution 1H NMR spectroscopy (metabonomics was used to acquire urinary metabolic profiles from 178 human volunteers. The spectral data were subjected to multivariate and univariate analysis to identify metabolites that were correlated with lifestyle or biological factors. Urinary levels of 8-oxo-deoxyguanosine were also measured, using mass spectrometry, as a marker of systemic oxidative stress. Results Six urinary metabolites, either associated with mitochondrial metabolism (citrate, 3-hydroxyisovalerate, 4-deoxy-erythronic acid or one-carbon metabolism (dimethylglycine, creatinine, creatine, were associated with cadmium exposure. In particular, citrate levels retained a significant correlation to urinary cadmium and smoking status after controlling for age and sex. Oxidative stress (as determined by urinary 8-oxo-deoxyguanosine levels was elevated in individuals with high cadmium exposure, supporting the hypothesis that heavy metal accumulation was causing mitochondrial dysfunction. Conclusions This study shows evidence that an NMR-based metabolic profiling study in an uncontrolled human population is capable of identifying intermediate biomarkers of response to toxicants at true environmental

Cadmium, lead, and arsenic contamination in paddy soils of a mining area and their exposure effects on human HEPG2 and keratinocyte cell-lines.

Science.gov (United States)

Xue, Shengguo; Shi, Lizheng; Wu, Chuan; Wu, Hui; Qin, Yanyan; Pan, Weisong; Hartley, William; Cui, Mengqian

2017-07-01

A mining district in south China shows significant metal(loid) contamination in paddy fields. In the soils, average Pb, Cd and As concentrations were 460.1, 11.7 and 35.1mgkg -1 respectively, which were higher than the environmental quality standard for agricultural soils in China (GB15618-1995) and UK Clea Soil Guideline Value. The average contents of Pb, Cd and As in rice were 5.24, 1.1 and 0.7mgkg -1 respectively, which were about 25, 4.5 or 2.5 times greater than the limit values of the maximum safe contaminant concentration standard in food of China (GB 2762-2012), and about 25, 10 or 1 times greater than the limit values of FAO/WHO standard. The elevated contents of Pb, Cd and As detected in soils around the factories, indicated that their spatial distribution was influenced by anthropogenic activity, while greater concentrations of Cd in rice appeared in the northwest region of the factories, indicating that the spatial distribution of heavy metals was also affected by natural factors. As human exposure around mining districts is mainly through oral intake of food and dermal contact, the effects of these metals on the viability and MT protein of HepG2 and KERTr cells were investigated. The cell viability decreased with increasing metal concentrations. Co-exposure to heavy metals (Pb+Cd) increased the metals (Pb or Cd)-mediated MT protein induction in both human HepG2 and KERTr cells. Increased levels of MT protein will lead to greater risk of carcinogenic manifestations, and it is likely that chronic exposure to metals may increase the risk to human health. Nevertheless, when co-exposure to two or more metals occur (such as As+Pb), they may have an antagonistic effect thus reducing the toxic effects of each other. Metal contaminations in paddy soils and rice were influenced by anthropogenic activity; metal co-exposure induced MT protein in human cells. Copyright © 2017 Elsevier Inc. All rights reserved.

Metabolic profiling detects early effects of environmental and lifestyle exposure to cadmium in a human population

OpenAIRE

Ellis, James K; Athersuch, Toby J; Thomas, Laura DK; Teichert, Friederike; Pérez-Trujillo, Miriam; Svendsen, Claus; Spurgeon, David J; Singh, Rajinder; Järup, Lars; Bundy, Jacob G; Keun, Hector C

2012-01-01

Background: The ‘exposome’ represents the accumulation of all environmental exposures across a lifetime. Topdown strategies are required to assess something this comprehensive, and could transform our understanding of how environmental factors affect human health. Metabolic profiling (metabonomics/metabolomics) defines an individual’s metabolic phenotype, which is influenced by genotype, diet, lifestyle, health and xenobiotic exposure, and could also reveal intermediate biomarkers...

Human exposure to static magnetic fields and basic precautions

International Nuclear Information System (INIS)

Vulevic, B.

1999-01-01

The development of new technologies using the static magnetic fields and their application in the last several years has increased the possibility of higher human exposure to such fields what has raised an issue of potential adverse health effects. The object of this work is to point, on the basis of the past knowledge, to the significance of the problem and therefore to contribute to its popularization. (author)

Electronic cigarettes: human health effects

Science.gov (United States)

Callahan-Lyon, Priscilla

2014-01-01

Objective With the rapid increase in use of electronic nicotine delivery systems (ENDS), such as electronic cigarettes (e-cigarettes), users and non-users are exposed to the aerosol and product constituents. This is a review of published data on the human health effects of exposure to e-cigarettes and their components. Methods Literature searches were conducted through September 2013 using multiple electronic databases. Results Forty-four articles are included in this analysis. E-cigarette aerosols may contain propylene glycol, glycerol, flavourings, other chemicals and, usually, nicotine. Aerosolised propylene glycol and glycerol produce mouth and throat irritation and dry cough. No data on the effects of flavouring inhalation were identified. Data on short-term health effects are limited and there are no adequate data on long-term effects. Aerosol exposure may be associated with respiratory function impairment, and serum cotinine levels are similar to those in traditional cigarette smokers. The high nicotine concentrations of some products increase exposure risks for non-users, particularly children. The dangers of secondhand and thirdhand aerosol exposure have not been thoroughly evaluated. Conclusions Scientific evidence regarding the human health effects of e-cigarettes is limited. While e-cigarette aerosol may contain fewer toxicants than cigarette smoke, studies evaluating whether e-cigarettes are less harmful than cigarettes are inconclusive. Some evidence suggests that e-cigarette use may facilitate smoking cessation, but definitive data are lacking. No e-cigarette has been approved by FDA as a cessation aid. Environmental concerns and issues regarding non-user exposure exist. The health impact of e-cigarettes, for users and the public, cannot be determined with currently available data. PMID:24732161

Adverse effects of e-cigarette exposures.

Science.gov (United States)

Cantrell, F Lee

2014-06-01

In 2007, a new source of nicotine exposure was introduced to the United States market, the electronic cigarette (ECIG) or "e-cigarette". Since then, the USA ECIG market has been doubling annually. Despite their widespread popularity, there is a paucity of existing data regarding ECIG toxicity. We report the experience of a statewide poison system. The database of a statewide poison system was queried for human ECIG exposures from 2010 (when Poisindex code first generated) through 2012. Year, age, manner and route of exposure, estimate exposure amount, product concentration, if evaluated at healthcare facility and symptoms were recorded. A total of 35 cases were identified--4 in 2010, 12 in 2011, 19 in 2012. Age range 8 months-60 years. Reported symptoms were mild and transient. Five patients were evaluated in an emergency department and none were admitted. Product concentrations ranged from 4 to 30 mg of nicotine per ml. Poison centers are likely to see an increase in exposures to ECIG given their growing popularity. Our modest results suggest that adverse effects and accidental exposures to ECIG cartridges are unlikely to result in serious toxicity.

Sampling strategy for estimating human exposure pathways to consumer chemicals

NARCIS (Netherlands)

Papadopoulou, Eleni; Padilla-Sanchez, Juan A.; Collins, Chris D.; Cousins, Ian T.; Covaci, Adrian; de Wit, Cynthia A.; Leonards, Pim E.G.; Voorspoels, Stefan; Thomsen, Cathrine; Harrad, Stuart; Haug, Line S.

2016-01-01

Human exposure to consumer chemicals has become a worldwide concern. In this work, a comprehensive sampling strategy is presented, to our knowledge being the first to study all relevant exposure pathways in a single cohort using multiple methods for assessment of exposure from each exposure pathway.

Sarin Exposures in A Cohort of British Military Participants in Human Experimental Research at Porton Down 1945-1987.

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Keegan, Thomas J; Carpenter, Lucy M; Brooks, Claire; Langdon, Toby; Venables, Katherine M

2017-12-15

The effects of exposure to chemical warfare agents in humans are topical. Porton Down is the UK's centre for research on chemical warfare where, since WWI, a programme of experiments involving ~30000 participants drawn from the UK armed services has been undertaken. Our aim is to report on exposures to nerve agents, particularly sarin, using detailed exposure data not explored in a previous analysis. In this paper, we have used existing data on exposures to servicemen who attended the human volunteer programme at Porton Down to examine exposures to nerve agents in general and to sarin in particular. Six principal nerve agents were tested on humans between 1945 and 1987. Of all 4299 nerve agent tests recorded, 3511 (82%) were with sarin, most commonly in an exposure chamber, with inhalation being the commonest exposure route (85%). Biological response to sarin exposure was expressed as percentage change in cholinesterase activity and, less commonly, change in pupil size. For red blood cell cholinesterase, median inhibition for inhalation tests was 41% (interquartile range 28-51%), with a maximum of 87%. For dermal exposures the maximum inhibition recorded was 99%. There was a clear association between increasing exposure to sarin and depression of cholinesterase activity but the strength and direction of the association varied by exposure route and the presence of chemical or physical protection. Pupil size decreased with increased exposure but this relationship was less clear when modifiers, such as atropine drops, were present. These results, drawn from high quality experimental data, offer a unique insight into the effects of these chemical agents on humans. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

The effects of brushing on human enamel surface roughness after NaF gel and theobromine gel exposure

Science.gov (United States)

Mahardhika, A.; Noerdin, A.; Eriwati, Y. K.

2017-08-01

This study aimed to determine the effects of brushing on human enamel surface roughness after different exposure times of 200 mg/L theobromine gel (8, 16, and 32 minutes) and 2% NaF gel (16 minutes). Twenty-four human upper premolars were used and divided into four groups. Group 1 was exposed to 2% NaF gel for 16 minutes. In contrast, groups 2, 3, and 4 were exposed to 200 mg/L theobromine gel for 8 minutes, 16 minutes, and 32 minutes, and each group was then brushed for 9 minutes and 20 seconds. After the treatment, samples were tested using a surface roughness tester (Mitutoyo SJ 301, Japan). The Wilcoxon test showed significant changes (p enamel surface and then increase roughness after brushing.

Methylmercury Exposure and Health Effects from Rice and Fish Consumption: A Review

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Ping Li

2010-06-01

Full Text Available Methylmercury (MeHg is highly toxic, and its principal target tissue in humans is the nervous system, which has made MeHg intoxication a public health concern for many decades. The general population is primarily exposed to MeHg through consumption of contaminated fish and marine mammals, but recent studies have reported high levels of MeHg in rice and confirmed that in China the main human exposure to MeHg is related to frequent rice consumption in mercury (Hg polluted areas. This article reviews the progress in the research on MeHg accumulation in rice, human exposure and health effects, and nutrient and co-contaminant interactions. Compared with fish, rice is of poor nutritional quality and lacks specific micronutrients identified as having health benefits (e.g., n-3 long chain polyunsaturated fatty acid, selenium, essential amino acids. The effects of these nutrients on the toxicity of MeHg should be better addressed in future epidemiologic and clinical studies. More emphasis should be given to assessing the health effects of low level MeHg exposure in the long term, with appropriate recommendations, as needed, to reduce MeHg exposure in the rice-eating population.

Non-human primates avoid the detrimental effects of prenatal androgen exposure in mixed-sex litters: combined demographic, behavioral, and genetic analyses.

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Bradley, Brenda J; Snowdon, Charles T; McGrew, William C; Lawler, Richard R; Guevara, Elaine E; McIntosh, Annick; O'Connor, Timothy

2016-12-01

Producing single versus multiple births has important life history trade-offs, including the potential benefits and risks of sharing a common in utero environment. Sex hormones can diffuse through amniotic fluid and fetal membranes, and females with male littermates risk exposure to high levels of fetal testosterone, which are shown to have masculinizing effects and negative fitness consequences in many mammals. Whereas most primates give birth to single offspring, several New World monkey and strepsirrhine species regularly give birth to small litters. We examined whether neonatal testosterone exposure might be detrimental to females in mixed-sex litters by compiling data from long-term breeding records for seven primate species (Saguinus oedipus; Varecia variegata, Varecia rubra, Microcebus murinis, Mirza coquereli, Cheirogaleus medius, Galago moholi). Litter sex ratios did not differ from the expected 1:2:1 (MM:MF:FF for twins) and 1:2:2:1 (MMM:MMF:MFF:FFF for triplets). Measures of reproductive success, including female survivorship, offspring-survivorship, and inter-birth interval, did not differ between females born in mixed-sex versus all-female litters, indicating that litter-producing non-human primates, unlike humans and rodents, show no signs of detrimental effects from androgen exposure in mixed sex litters. Although we found no evidence for CYP19A1 gene duplications-a hypothesized mechanism for coping with androgen exposure-aromatase protein evolution shows patterns of convergence among litter-producing taxa. That some primates have effectively found a way to circumvent a major cost of multiple births has implications for understanding variation in litter size and life history strategies across mammals. © 2016 Wiley Periodicals, Inc.

Lead remediation and changes in human lead exposure: some physiological and biokinetic dimensions.

Science.gov (United States)

Mushak, Paul

2003-02-15

This paper presents a qualitative and quantitative analysis of the various aspects of lead remediation effectiveness with particular reference to human health risk assessment. One of the key elements of lead remediation efforts at such sites as those under the Superfund program deals with populations at elevated exposure and toxicity risk in the proximity of, or at, the site of remediation, especially remediation workers, workers at other tasks on sites that were remediated down to some action level of lead concentration in soils, and groups at risk in nearby communities. A second element has to do with how one measures or models lead exposure changes with special reference to baseline and post-remediation conditions. Various biomarkers of lead exposure can be employed, but their use requires detailed knowledge of what results using each means. The most commonly used approach is measurement of blood lead (Pb-B). Recognized limitations in the use of Pb-B has led to the use of predictive Pb exposure models, which are less vulnerable to the many behavioral, physiological, and environmental parameters that can distort isolated or 'single shot' Pb-B testings. A third aspect covered in this paper presents various physiological factors that affect the methods by which one evaluates Pb remediation effectiveness. Finally, this article offers an integrated look at how lead remediation actions directed at one lead source or pathway affect the total lead exposure picture for human populations at elevated lead exposure and toxicity risk.

Mercury Exposure in Ireland: Results of the DEMOCOPHES Human Biomonitoring Study

Directory of Open Access Journals (Sweden)

Elizabeth Cullen

2014-09-01

Full Text Available Background: Monitoring of human exposure to mercury is important due to its adverse health effects. This study aimed to determine the extent of mercury exposure among mothers and their children in Ireland, and to identify factors associated with elevated levels. It formed part of the Demonstration of a study to Coordinate and Perform Human Biomonitoring on a European Scale (DEMOCOPHES pilot biomonitoring study. Methods: Hair mercury concentrations were determined from a convenience sample of 120 mother/child pairs. Mothers also completed a questionnaire. Rigorous quality assurance within DEMOCOPHES guaranteed the accuracy and international comparability of results. Results: Mercury was detected in 79.2% of the samples from mothers, and 62.5% of children’s samples. Arithmetic mean levels in mothers (0.262 µg/g hair and children (0.149 µg /g hair did not exceed the US EPA guidance value. Levels were significantly higher for those with higher education, and those who consumed more fish. Conclusions: The study demonstrates the benefit of human biomonitoring for assessing and comparing internal exposure levels, both on a population and an individual basis. It enables the potential harmful impact of mercury to be minimised in those highly exposed, and can therefore significantly contribute to population health.

Assessment of human dietary exposure to arsenic through rice.

Science.gov (United States)

Davis, Matthew A; Signes-Pastor, Antonio J; Argos, Maria; Slaughter, Francis; Pendergrast, Claire; Punshon, Tracy; Gossai, Anala; Ahsan, Habibul; Karagas, Margaret R

2017-05-15

Rice accumulates 10-fold higher inorganic arsenic (i-As), an established human carcinogen, than other grains. This review summarizes epidemiologic studies that examined the association between rice consumption and biomarkers of arsenic exposure. After reviewing the literature we identified 20 studies, among them included 18 observational and 2 human experimental studies that reported on associations between rice consumption and an arsenic biomarker. Among individuals not exposed to contaminated water, rice is a source of i-As exposure - rice consumption has been consistently related to arsenic biomarkers, and the relationship has been clearly demonstrated in experimental studies. Early-life i-As exposure is of particular concern due to its association with lifelong adverse health outcomes. Maternal rice consumption during pregnancy also has been associated with infant toenail total arsenic concentrations indicating that dietary exposure during pregnancy results in fetal exposure. Thus, the collective evidence indicates that rice is an independent source of arsenic exposure in populations around the world and highlights the importance of investigating its affect on health. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Exposure to 60-Hz magnetic fields and proliferation of human astrocytoma cells in vitro.

Science.gov (United States)

Wei, M; Guizzetti, M; Yost, M; Costa, L G

2000-02-01

Epidemiological studies have suggested that exposure to electric and magnetic fields (EMF) may be associated with an increased incidence of brain tumors, most notably astrocytomas. However, potential cellular or molecular mechanisms involved in these effects of EMF are not known. In this study we investigated whether exposure to 60-Hz sinusoidal magnetic fields (0.3-1.2 G for 3-72 h) would cause proliferation of human astrocytoma cells. Sixty-Hertz magnetic fields (MF) caused a time- and dose-dependent increase in proliferation of astrocytoma cells, measured by (3)H-thymidine incorporation and by flow cytometry, and strongly potentiated the effect of two agonists (the muscarinic agonist carbachol and the phorbol ester PMA). However, MF had no effect on DNA synthesis of rat cortical astrocytes, i.e., of similar, nontransformed cells. To determine the amount of heating induced by MF, temperatures were also recorded in the medium. Both 1.2 G MF and a sham exposure caused a 0.7 degrees C temperature increase in the medium; however, (3)H-thymidine incorporation induced by sham exposure was significantly less than that caused by MF. GF 109203X, a rather specific protein kinase C (PKC) inhibitor, and down-regulation of PKC inhibited the effect of MF on basal and on agonist-stimulated (3)H-thymidine incorporation. These data indicate that MF can increase the proliferation of human astrocytoma cells and strongly potentiate the effects of two agonists. These findings may provide a biological basis for the observed epidemiological associations between MF exposure and brain tumors. Copyright 2000 Academic Press.

Critical elements for human health risk assessment of less than lifetime exposures.

Science.gov (United States)

Geraets, Liesbeth; Nijkamp, Monique M; Ter Burg, Wouter

2016-11-01

Less than lifetime exposure has confronted risk assessors as to how to interpret the risks for human health in case a chronic health-based limit is exceeded. Intermittent, fluctuating and peak exposures do not match with the basis of the chronic limit values possibly leading to conservative outcomes. This paper presents guidance on how to deal with human risk assessment of less than lifetime exposure. Important steps to be considered are characterization of the human exposure situation, evaluation whether the human less than lifetime exposure scenario corresponds to a non-chronic internal exposure: toxicokinetic and toxicodynamic considerations, and, finally, re-evaluation of the risk assessment. Critical elements for these steps are the mode of action, Haber's rule, and toxicokinetics (ADME) amongst others. Previous work for the endpoints non-genotoxic carcinogenicity and developmental toxicity is included in the guidance. The guidance provides a way to consider the critical elements, without setting default factors to correct for the less than lifetime exposure in risk assessment. Copyright © 2016 Elsevier Inc. All rights reserved.

Biocides Steering Group on human exposure assessment: a preliminary report.

Science.gov (United States)

van Hemmen, J J

1999-06-30

In a project granted by DG XI of the European Commission, it is attempted to collate experimental and theoretical data on human (workers and consumers) exposure assessment to biocidal products, and to outline the methodology for sampling and measurement. On the basis of the available evidence, approaches are presented for the exposure assessment to be used for estimation of risks in authorization procedures under the recently accepted Directive 98/8/EC. Gaps in knowledge are indicated, making it possible to study the issues involved in a comprehensive and cost-effective way. Some recommendations are given on how to best do this. The current project has been detailed in a final report.

Human performance analysis of industrial radiography radiation exposure events

International Nuclear Information System (INIS)

Reece, W.J.; Hill, S.G.

1995-01-01

A set of radiation overexposure event reports were reviewed as part of a program to examine human performance in industrial radiography for the US Nuclear Regulatory Commission. Incident records for a seven year period were retrieved from an event database. Ninety-five exposure events were initially categorized and sorted for further analysis. Descriptive models were applied to a subset of severe overexposure events. Modeling included: (1) operational sequence tables to outline the key human actions and interactions with equipment, (2) human reliability event trees, (3) an application of an information processing failures model, and (4) an extrapolated use of the error influences and effects diagram. Results of the modeling analyses provided insights into the industrial radiography task and suggested areas for further action and study to decrease overexposures

Ozone exposure increases respiratory epithelial permeability in humans

International Nuclear Information System (INIS)

Kehrl, H.R.; Vincent, L.M.; Kowalsky, R.J.; Horstman, D.H.; O'Neil, J.J.; McCartney, W.H.; Bromberg, P.A.

1987-01-01

Ozone is a respiratory irritant that has been shown to cause an increase in the permeability of the respiratory epithelium in animals. We used inhaled aerosolized /sup 99m/Tc-labeled diethylene triamine pentacetic acid (/sup 99m/Tc-DTPA) to investigate whether human respiratory epithelial permeability is similarly affected by exposure to ozone. In a randomized, crossover double-blinded study, 8 healthy, nonsmoking young men were exposed for 2 h to purified air and 0.4 ppm ozone while performing intermittent high intensity treadmill exercise (minute ventilation = 66.8 L/min). SRaw and FVC were measured before and at the end of exposures. Seventy-five minutes after the exposures, the pulmonary clearance of /sup 99m/Tc-DTPA was measured by sequential posterior lung imaging with a computer-assisted gamma camera. Ozone exposure caused respiratory symptoms in all 8 subjects and was associated with a 14 +/- 2.8% (mean +/- SEM) decrement in FVC (p less than 0.001) and a 71 +/- 22% increase in SRaw (p = 0.04). Compared with the air exposure day, 7 of the 8 subjects showed increased /sup 99m/Tc-DTPA clearance after the ozone exposure, with the mean value increasing from 0.59 +/- 0.08 to 1.75 +/- 0.43%/min (p = 0.03). These data show that ozone exposure sufficient to produce decrements in the pulmonary function of human subjects also causes an increase in /sup 99m/Tc-DTPA clearance

Human dermal absorption of chlorinated organophosphate flame retardants; implications for human exposure

Energy Technology Data Exchange (ETDEWEB)

Abou-Elwafa Abdallah, Mohamed, E-mail: mae_abdallah@yahoo.co.uk [Division of Environmental Health and Risk Management, School of Geography, Earth, and Environmental Sciences, University of Birmingham, Birmingham B15 2TT (United Kingdom); Department of Analytical Chemistry, Faculty of Pharmacy, Assiut University, 71526 Assiut (Egypt); Pawar, Gopal; Harrad, Stuart [Division of Environmental Health and Risk Management, School of Geography, Earth, and Environmental Sciences, University of Birmingham, Birmingham B15 2TT (United Kingdom)

2016-01-15

Tris-2-chloroethyl phosphate (TCEP), tris (1-chloro-2-propyl) phosphate (TCIPP) and tris-1,3-dichloropropyl phosphate (TDCIPP) are organophosphate flame retardants (PFRs) widely applied in a plethora of consumer products despite their carcinogenic potential. Human dermal absorption of these PFRs is investigated for the first time using human ex vivo skin and EPISKIN™ models. Results of human ex vivo skin experiments revealed 28%, 25% and 13% absorption of the applied dose (500 ng/cm{sup 2}, finite dose) of TCEP, TCIPP and TDCIPP, respectively after 24 h exposure. The EPISKIN™ model showed enhanced permeability values (i.e. weaker barrier), that were respectively 16%, 11% and 9% for TCEP, TCIPP and TDCIPP compared to human ex vivo skin. However, this difference was not significant (P > 0.05). Estimated permeability constants (K{sub p}, cm/h) showed a significant negative correlation with log K{sub ow} for the studied contaminants. The effect of hand-washing on dermal absorption of PFRs was investigated. Washing reduced overall dermal absorption, albeit to varying degrees depending on the physicochemical properties of the target PFRs. Moreover, slight variations of the absorbed dose were observed upon changing the dosing solution from acetone to 20% Tween 80 in water, indicating the potential influence of the dose vehicle on the dermal absorption of PFRs. Finally, estimated dermal uptake of the studied PFRs via contact with indoor dust was higher in UK toddlers (median ΣPFRs = 36 ng/kg bw day) than adults (median ΣPFRs = 4 ng/kg bw day). More research is required to fully elucidate the toxicological implications of such exposure. - Highlights: • Human dermal absorption of PFRs was studied using human ex vivo skin and EPISKIN™. • Absorbed fractions of TCEP, TCIPP and TDCIPP were 28%, 25% and 13% of applied dose. • Permeability constants showed significant negative correlation to log K{sub ow} of PFRs. • Skin washing reduced the overall dermal

Human dermal absorption of chlorinated organophosphate flame retardants; implications for human exposure

International Nuclear Information System (INIS)

Abou-Elwafa Abdallah, Mohamed; Pawar, Gopal; Harrad, Stuart

2016-01-01

Tris-2-chloroethyl phosphate (TCEP), tris (1-chloro-2-propyl) phosphate (TCIPP) and tris-1,3-dichloropropyl phosphate (TDCIPP) are organophosphate flame retardants (PFRs) widely applied in a plethora of consumer products despite their carcinogenic potential. Human dermal absorption of these PFRs is investigated for the first time using human ex vivo skin and EPISKIN™ models. Results of human ex vivo skin experiments revealed 28%, 25% and 13% absorption of the applied dose (500 ng/cm 2 , finite dose) of TCEP, TCIPP and TDCIPP, respectively after 24 h exposure. The EPISKIN™ model showed enhanced permeability values (i.e. weaker barrier), that were respectively 16%, 11% and 9% for TCEP, TCIPP and TDCIPP compared to human ex vivo skin. However, this difference was not significant (P > 0.05). Estimated permeability constants (K p , cm/h) showed a significant negative correlation with log K ow for the studied contaminants. The effect of hand-washing on dermal absorption of PFRs was investigated. Washing reduced overall dermal absorption, albeit to varying degrees depending on the physicochemical properties of the target PFRs. Moreover, slight variations of the absorbed dose were observed upon changing the dosing solution from acetone to 20% Tween 80 in water, indicating the potential influence of the dose vehicle on the dermal absorption of PFRs. Finally, estimated dermal uptake of the studied PFRs via contact with indoor dust was higher in UK toddlers (median ΣPFRs = 36 ng/kg bw day) than adults (median ΣPFRs = 4 ng/kg bw day). More research is required to fully elucidate the toxicological implications of such exposure. - Highlights: • Human dermal absorption of PFRs was studied using human ex vivo skin and EPISKIN™. • Absorbed fractions of TCEP, TCIPP and TDCIPP were 28%, 25% and 13% of applied dose. • Permeability constants showed significant negative correlation to log K ow of PFRs. • Skin washing reduced the overall dermal absorption of target PFRs

An introduction to the indirect exposure assessment approach: modeling human exposure using microenvironmental measurements and the recent National Human Activity Pattern Survey.

Science.gov (United States)

Klepeis, N E

1999-01-01

Indirect exposure approaches offer a feasible and accurate method for estimating population exposures to indoor pollutants, including environmental tobacco smoke (ETS). In an effort to make the indirect exposure assessment approach more accessible to people in the health and risk assessment fields, this paper provides examples using real data from (italic>a(/italic>) a week-long personal carbon monoxide monitoring survey conducted by the author; and (italic>b(/italic>) the 1992 to 1994 National Human Activity Pattern Survey (NHAPS) for the United States. The indirect approach uses measurements of exposures in specific microenvironments (e.g., homes, bars, offices), validated microenvironmental models (based on the mass balance equation), and human activity pattern data obtained from questionnaires to predict frequency distributions of exposure for entire populations. This approach requires fewer resources than the direct approach to exposure assessment, for which the distribution of monitors to a representative sample of a given population is necessary. In the indirect exposure assessment approach, average microenvironmental concentrations are multiplied by the total time spent in each microenvironment to give total integrated exposure. By assuming that the concentrations encountered in each of 10 location categories are the same for different members of the U.S. population (i.e., the NHAPS respondents), the hypothetical contribution that ETS makes to the average 24-hr respirable suspended particle exposure for Americans working their main job is calculated in this paper to be 18 microg/m3. This article is an illustrative review and does not contain an actual exposure assessment or model validation. Images Figure 3 Figure 4 PMID:10350522

Ozone exposure and pulmonary effects in panel and human clinical studies: Considerations for design and interpretation.

Science.gov (United States)

Rohr, Annette C

2018-04-01

A wealth of literature exists regarding the pulmonary effects of ozone, a photochemical pollutant produced by the reaction of nitrogen oxide and volatile organic precursors in the presence of sunlight. This paper focuses on epidemiological panel studies and human clinical studies of ozone exposure, and discusses issues specific to this pollutant that may influence study design and interpretation as well as other, broader considerations relevant to ozone-health research. The issues are discussed using examples drawn from the wider literature. The recent panel and clinical literature is also reviewed. Health outcomes considered include lung function, symptoms, and pulmonary inflammation. Issues discussed include adversity, reversibility, adaptation, variability in ozone exposure metric used and health outcomes evaluated, co-pollutants in panel studies, influence of temperature in panel studies, and multiple comparisons. Improvements in and standardization of panel study approaches are recommended to facilitate comparisons between studies as well as meta-analyses. Additional clinical studies at or near the current National Ambient Air Quality Standard (NAAQS) of 70 ppb are recommended, as are clinical studies in sensitive subpopulations such as asthmatics. The pulmonary health impacts of ozone exposure have been well documented using both epidemiological and chamber study designs. However, there are a number of specific methodological and related issues that should be considered when interpreting the results of these studies and planning additional research, including the standardization of exposure and health metrics to facilitate comparisons among studies.

Risk of human exposure to polycyclic aromatic hydrocarbons: A case study in Beijing, China

International Nuclear Information System (INIS)

Yu, Yanxin; Li, Qi; Wang, Hui; Wang, Bin; Wang, Xilong; Ren, Aiguo; Tao, Shu

2015-01-01

Polycyclic aromatic hydrocarbons (PAHs) can cause adverse effects on human health. The relative contributions of their two major intake routes (diet and inhalation) to population PAH exposure are still unclear. We modeled the contributions of diet and inhalation to the overall PAH exposure of the population of Beijing in China, and assessed their human incremental lifetime cancer risks (ILCR) using a Mont Carlo simulation approach. The results showed that diet accounted for about 85% of low-molecular-weight PAH (L-PAH) exposure, while inhalation accounted for approximately 57% of high-molecular-weight PAH (H-PAH) exposure of the Beijing population. Meat and cereals were the main contributors to dietary PAH exposure. Both gaseous- and particulate-phase PAHs contributed to L-PAH exposure through inhalation, whereas exposure to H-PAHs was mostly from the particulate-phase. To reduce the cancer incidence of the Beijing population, more attention should be given to inhaled particulate-phase PAHs with considerable carcinogenic potential. - Highlights: • We modeled the contributions of diet and inhalation to population PAH exposure. • Diet contributed 85% of population exposure to low molecular-weight PAHs. • Inhalation contributed 57% of population exposure to high molecular-weight PAHs. • The PAH exposure level with body-weight adjustment decreased with age increasing. • The population cancer risk of PAH exposure is lower than the serious risk level. - The exposure of the Beijing population to carcinogenic polycyclic aromatic hydrocarbons was mainly from inhaled particulate matter

Exposure to ozone modulates human airway protease/antiprotease balance contributing to increased influenza A infection.

Directory of Open Access Journals (Sweden)

Matthew J Kesic

Full Text Available Exposure to oxidant air pollution is associated with increased respiratory morbidities and susceptibility to infections. Ozone is a commonly encountered oxidant air pollutant, yet its effects on influenza infections in humans are not known. The greater Mexico City area was the primary site for the spring 2009 influenza A H1N1 pandemic, which also coincided with high levels of environmental ozone. Proteolytic cleavage of the viral membrane protein hemagglutinin (HA is essential for influenza virus infectivity. Recent studies suggest that HA cleavage might be cell-associated and facilitated by the type II transmembrane serine proteases (TTSPs human airway trypsin-like protease (HAT and transmembrane protease, serine 2 (TMPRSS2, whose activities are regulated by antiproteases, such as secretory leukocyte protease inhibitor (SLPI. Based on these observations, we sought to determine how acute exposure to ozone may modulate cellular protease/antiprotease expression and function, and to define their roles in a viral infection. We utilized our in vitro model of differentiated human nasal epithelial cells (NECs to determine the effects of ozone on influenza cleavage, entry, and replication. We show that ozone exposure disrupts the protease/antiprotease balance within the airway liquid. We also determined that functional forms of HAT, TMPRSS2, and SLPI are secreted from human airway epithelium, and acute exposure to ozone inversely alters their expression levels. We also show that addition of antioxidants significantly reduces virus replication through the induction of SLPI. In addition, we determined that ozone-induced cleavage of the viral HA protein is not cell-associated and that secreted endogenous proteases are sufficient to activate HA leading to a significant increase in viral replication. Our data indicate that pre-exposure to ozone disrupts the protease/antiprotease balance found in the human airway, leading to increased influenza susceptibility.

Prenatal Exposure to Progesterone Affects Sexual Orientation in Humans.

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Reinisch, June M; Mortensen, Erik Lykke; Sanders, Stephanie A

2017-07-01

Prenatal sex hormone levels affect physical and behavioral sexual differentiation in animals and humans. Although prenatal hormones are theorized to influence sexual orientation in humans, evidence is sparse. Sexual orientation variables for 34 prenatally progesterone-exposed subjects (17 males and 17 females) were compared to matched controls (M age = 23.2 years). A case-control double-blind design was used drawing on existing data from the US/Denmark Prenatal Development Project. Index cases were exposed to lutocyclin (bioidentical progesterone = C 21 H 30 O 2 ; M W : 314.46) and no other hormonal preparation. Controls were matched on 14 physical, medical, and socioeconomic variables. A structured interview conducted by a psychologist and self-administered questionnaires were used to collect data on sexual orientation, self-identification, attraction to the same and other sex, and history of sexual behavior with each sex. Compared to the unexposed, fewer exposed males and females identified as heterosexual and more of them reported histories of same-sex sexual behavior, attraction to the same or both sexes, and scored higher on attraction to males. Measures of heterosexual behavior and scores on attraction to females did not differ significantly by exposure. We conclude that, regardless of sex, exposure appeared to be associated with higher rates of bisexuality. Prenatal progesterone may be an underappreciated epigenetic factor in human sexual and psychosexual development and, in light of the current prevalence of progesterone treatment during pregnancy for a variety of pregnancy complications, warrants further investigation. These data on the effects of prenatal exposure to exogenous progesterone also suggest a potential role for natural early perturbations in progesterone levels in the development of sexual orientation.

Indoor human exposure to size-fractionated aerosols during the 2015 Southeast Asian smoke haze and assessment of exposure mitigation strategies

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Sharma, Ruchi; Balasubramanian, Rajasekhar

2017-11-01

The 2015 smoke haze episode was one of the most severe and prolonged transboundary air pollution events ever seen in Southeast Asia (SEA), affecting the air quality of several countries within the region including Indonesia, Malaysia and Singapore. The 24 h mean outdoor PM2.5 (particulate matter (PM) with aerodynamic diameter ≤ 2.5 μm) concentrations ranged from 72-157 μg m-3 in Singapore during this episode, exceeding the WHO 24 h mean PM2.5 guidelines (25 μg m-3) several times over. The smoke haze episode not only affected ambient air quality, but also indoor air quality due to the migration of PM of different sizes from the outdoor to the indoor environment. Despite the frequent occurrence of smoke haze episodes over the years, their potential health impacts on indoor building occupants remain largely unknown in SEA due to the lack of systematic investigations and observational data. The current work was carried out in Singapore to assess human exposure to size-resolved PM during the 2015 smoke haze episode, and to evaluate the effectiveness of exposure mitigation measures in smoke-haze-impacted naturally ventilated indoor environments. The potential health risks associated with exposure to PM2.5 were assessed based on the concentrations of redox active particulate-bound trace elements, which are known to be harmful to human health, with and without exposure mitigation. Overall, it was observed that human health exposure to PM2.5 and its carcinogenic chemical components was reduced substantially by 62% (p health.

Sex-Dependent Effects of Developmental Lead Exposure on the Brain

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Singh, Garima; Singh, Vikrant; Sobolewski, Marissa; Cory-Slechta, Deborah A.; Schneider, Jay S.

2018-01-01

The role of sex as an effect modifier of developmental lead (Pb) exposure has until recently received little attention. Lead exposure in early life can affect brain development with persisting influences on cognitive and behavioral functioning, as well as, elevated risks for developing a variety of diseases and disorders in later life. Although both sexes are affected by Pb exposure, the incidence, manifestation, and severity of outcomes appears to differ in males and females. Results from epidemiologic and animal studies indicate significant effect modification by sex, however, the results are not consistent across studies. Unfortunately, only a limited number of human epidemiological studies have included both sexes in independent outcome analyses limiting our ability to draw definitive conclusions regarding sex-differentiated outcomes. Additionally, due to various methodological differences across studies, there is still not a good mechanistic understanding of the molecular effects of lead on the brain and the factors that influence differential responses to Pb based on sex. In this review, focused on prenatal and postnatal Pb exposures in humans and animal models, we discuss current literature supporting sex differences in outcomes in response to Pb exposure and explore some of the ideas regarding potential molecular mechanisms that may contribute to sex-related differences in outcomes from developmental Pb exposure. The sex-dependent variability in outcomes from developmental Pb exposure may arise from a combination of complex factors, including, but not limited to, intrinsic sex-specific molecular/genetic mechanisms and external risk factors including sex-specific responses to environmental stressors which may act through shared epigenetic pathways to influence the genome and behavioral output. PMID:29662502

Sex-Dependent Effects of Developmental Lead Exposure on the Brain

Directory of Open Access Journals (Sweden)

Garima Singh

2018-03-01

Full Text Available The role of sex as an effect modifier of developmental lead (Pb exposure has until recently received little attention. Lead exposure in early life can affect brain development with persisting influences on cognitive and behavioral functioning, as well as, elevated risks for developing a variety of diseases and disorders in later life. Although both sexes are affected by Pb exposure, the incidence, manifestation, and severity of outcomes appears to differ in males and females. Results from epidemiologic and animal studies indicate significant effect modification by sex, however, the results are not consistent across studies. Unfortunately, only a limited number of human epidemiological studies have included both sexes in independent outcome analyses limiting our ability to draw definitive conclusions regarding sex-differentiated outcomes. Additionally, due to various methodological differences across studies, there is still not a good mechanistic understanding of the molecular effects of lead on the brain and the factors that influence differential responses to Pb based on sex. In this review, focused on prenatal and postnatal Pb exposures in humans and animal models, we discuss current literature supporting sex differences in outcomes in response to Pb exposure and explore some of the ideas regarding potential molecular mechanisms that may contribute to sex-related differences in outcomes from developmental Pb exposure. The sex-dependent variability in outcomes from developmental Pb exposure may arise from a combination of complex factors, including, but not limited to, intrinsic sex-specific molecular/genetic mechanisms and external risk factors including sex-specific responses to environmental stressors which may act through shared epigenetic pathways to influence the genome and behavioral output.

EVALUATION OF A PERSONAL NEPHELOMETER FOR HUMAN EXPOSURE MONITORING

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Current particulate matter (PM) exposure studies are using continuous personal nephelometers (pDR-1000, MIE, Inc.) to measure human exposure to PM. The personal nephelometer is a passive sampler which uses light scattering technology to measure particles ranging in size from 0....

Quantitative assessment of human and pet exposure to Salmonella associated with dry pet foods.

Science.gov (United States)

Lambertini, Elisabetta; Buchanan, Robert L; Narrod, Clare; Ford, Randall M; Baker, Robert C; Pradhan, Abani K

2016-01-04

Recent Salmonella outbreaks associated with dry pet foods and treats highlight the importance of these foods as previously overlooked exposure vehicles for both pets and humans. In the last decade efforts have been made to raise the safety of this class of products, for instance by upgrading production equipment, cleaning protocols, and finished product testing. However, no comprehensive or quantitative risk profile is available for pet foods, thus limiting the ability to establish safety standards and assess the effectiveness of current and proposed Salmonella control measures. This study sought to develop an ingredients-to-consumer quantitative microbial exposure assessment model to: 1) estimate pet and human exposure to Salmonella via dry pet food, and 2) assess the impact of industry and household-level mitigation strategies on exposure. Data on prevalence and concentration of Salmonella in pet food ingredients, production process parameters, bacterial ecology, and contact transfer in the household were obtained through literature review, industry data, and targeted research. A probabilistic Monte Carlo modeling framework was developed to simulate the production process and basic household exposure routes. Under the range of assumptions adopted in this model, human exposure due to handling pet food is null to minimal if contamination occurs exclusively before extrusion. Exposure increases considerably if recontamination occurs post-extrusion during coating with fat, although mean ingested doses remain modest even at high fat contamination levels, due to the low percent of fat in the finished product. Exposure is highly variable, with the distribution of doses ingested by adult pet owners spanning 3Log CFU per exposure event. Child exposure due to ingestion of 1g of pet food leads to significantly higher doses than adult doses associated with handling the food. Recontamination after extrusion and coating, e.g., via dust or equipment surfaces, may also lead to

Mixtures of endocrine disrupting contaminants modelled on human high end exposures

DEFF Research Database (Denmark)

Christiansen, Sofie; Kortenkamp, A.; Petersen, Marta Axelstad

2012-01-01

exceeding 1 is expected to lead to effects in the rat, a total dose more than 62 times higher than human exposures should lead to responses. Considering the high uncertainty of this estimate, experience on lowest‐observed‐adverse‐effect‐level (LOAEL)/NOAEL ratios and statistical power of rat studies, we...... expected that combined doses 150 times higher than high end human intake estimates should give no, or only borderline effects, whereas doses 450 times higher should produce significant responses. Experiments indeed showed clear developmental toxicity of the 450‐fold dose in terms of increased nipple...... though each individual chemical is present at low, ineffective doses, but the effects of mixtures modelled based on human intakes have not previously been investigated. To address this issue for the first time, we selected 13 chemicals for a developmental mixture toxicity study in rats where data about...

The effects of adolescent methamphetamine exposure

Directory of Open Access Journals (Sweden)

Jordan M Buck

2015-04-01

Full Text Available Methamphetamine use among adolescents is a significant social and public health concern. Despite increased awareness of methamphetamine use among younger people, relatively little research has examined the effects of adolescent methamphetamine use compared to adult use. Thus much remains to be learned about how methamphetamine alters adolescent brain function and behavior. In this article we review recent trends in adolescent methamphetamine use and data examining the effects of adolescent methamphetamine use on the dopaminergic system and behavior in humans and animal models. Future research is warranted to expand our understanding of the effects of adolescent methamphetamine exposure and how those effects differ from those seen in adults.

A systematic review of Bisphenol A "low dose" studies in the context of human exposure: a case for establishing standards for reporting "low-dose" effects of chemicals.

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Teeguarden, Justin G; Hanson-Drury, Sesha

2013-12-01

Human exposure to the chemical Bisphenol A is almost ubiquitous in surveyed industrialized societies. Structural features similar to estrogen confer the ability of Bisphenol A (BPA) to bind estrogen receptors, giving BPA membership in the group of environmental pollutants called endocrine disruptors. References by scientists, the media, political entities, and non-governmental organizations to many toxicity studies as "low dose" has led to the belief that exposure levels in these studies are similar to humans, implying that BPA is toxic to humans at current exposures. Through systematic, objective comparison of our current, and a previous compilation of the "low-dose" literature to multiple estimates of human external and internal exposure levels, we found that the "low-dose" moniker describes exposures covering 8-12 orders of magnitude, the majority (91-99% of exposures) being greater than the upper bound of human exposure in the general infant, child and adult U.S. Population. "low dose" is therefore a descriptor without specific meaning regarding human exposure. Where human exposure data are available, for BPA and other environmental chemicals, reference to toxicity study exposures by direct comparison to human exposure would be more informative, more objective, and less susceptible to misunderstanding. Copyright © 2013 Elsevier Ltd. All rights reserved.

Sampling strategy for estimating human exposure pathways to consumer chemicals

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Eleni Papadopoulou

2016-03-01

Full Text Available Human exposure to consumer chemicals has become a worldwide concern. In this work, a comprehensive sampling strategy is presented, to our knowledge being the first to study all relevant exposure pathways in a single cohort using multiple methods for assessment of exposure from each exposure pathway. The selected groups of chemicals to be studied are consumer chemicals whose production and use are currently in a state of transition and are; per- and polyfluorinated alkyl substances (PFASs, traditional and “emerging” brominated flame retardants (BFRs and EBFRs, organophosphate esters (OPEs and phthalate esters (PEs. Information about human exposure to these contaminants is needed due to existing data gaps on human exposure intakes from multiple exposure pathways and relationships between internal and external exposure. Indoor environment, food and biological samples were collected from 61 participants and their households in the Oslo area (Norway on two consecutive days, during winter 2013-14. Air, dust, hand wipes, and duplicate diet (food and drink samples were collected as indicators of external exposure, and blood, urine, blood spots, hair, nails and saliva as indicators of internal exposure. A food diary, food frequency questionnaire (FFQ and indoor environment questionnaire were also implemented. Approximately 2000 samples were collected in total and participant views on their experiences of this campaign were collected via questionnaire. While 91% of our participants were positive about future participation in a similar project, some tasks were viewed as problematic. Completing the food diary and collection of duplicate food/drink portions were the tasks most frequent reported as “hard”/”very hard”. Nevertheless, a strong positive correlation between the reported total mass of food/drinks in the food record and the total weight of the food/drinks in the collection bottles was observed, being an indication of accurate performance

Acrolein and Human Disease: Untangling the Knotty Exposure Scenarios Accompanying Several Diverse Disorders.

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Burcham, Philip C

2017-01-17

Acrolein is a highly toxic electrophile that participates in many diseases, yet efforts to delineate its precise mechanistic contributions to specific conditions are complicated by its wide distribution within human environments. This Perspective develops the proposal that due to its mixed status as environmental pollutant, metabolic byproduct, and endotoxicant which forms via ubiquitous pathophysiological processes, many diseases likely involve acrolein released from multiple sources. Although the category boundaries are indistinct, at least four identifiable exposure scenarios are identifiable. First, in some syndromes, such as those accompanying chronic or acute intoxication with smoke, whatever role acrolein plays in disease pathogenesis mainly traces to exogenous sources such as the combustion of tobacco or other organic matter. A second exposure category involves xenobiotics that undergo metabolism within the body to release acrolein. Still other health conditions, however, involve acrolein that forms via several endogenous pathways, some of which are activated upon intoxication with xenobiotics (i.e., Exposure Category 3), while still others accompany direct physical trauma to body tissues (Exposure Category 4). Further complicating efforts to clarify the role of endogenous acrolein in human disease is the likelihood that many such syndromes are complex phenomena that resemble "chemical mixture exposures" by involving multiple toxic substances simultaneously. This Perspective contends that while recent decades have witnessed much progress in describing the deleterious effects of acrolein at the cellular and molecular levels, more work is needed to define the contributions of different acrolein sources to "real-world" health conditions in human subjects.

Exposure Setup and Dosimetry for a Study on Effects of Mobile Communication Signals on Human Hematopoietic Stem Cells in vitro

Directory of Open Access Journals (Sweden)

M. Rohland

2017-09-01

Full Text Available In this paper we describe the design of an exposure setup used to study possible non-thermal effects due to the exposure of human hematopoietic stem cells to GSM, UMTS and LTE mobile communication signals. The experiments are performed under fully blinded conditions in a TEM waveguide located inside an incubator to achieve defined environmental conditions as required for the living cells. Chamber slides containing the cells in culture medium are placed on the septum of the waveguide. The environmental and exposure parameters such as signal power, temperatures, relative humidity and CO2 content of the surrounding atmosphere are monitored permanently during the exposure experiment. The power of the exposure signals required to achieve specific absorption rates of 0.5, 1, 2 and 4 W kg−1 are determined by numerical calculation of the field distribution inside the cell culture medium at 900 MHz (GSM, 1950 MHz (UMTS and 2535 MHz (LTE. The dosimetry is verified both with scattering parameter measurements on the waveguide with and without containers filled with cell culture medium and with temperature measurements with non-metallic probes in separate heating experiments.

A changing climate: impacts on human exposures to O3 using ...

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Predicting the impacts of changing climate on human exposure to air pollution requires future scenarios that account for changes in ambient pollutant concentrations, population sizes and distributions, and housing stocks. An integrated methodology to model changes in human exposures due to these impacts was developed by linking climate, air quality, land-use, and human exposure models. This methodology was then applied to characterize changes in predicted human exposures to O3 under multiple future scenarios. Regional climate projections for the U.S. were developed by downscaling global circulation model (GCM) scenarios for three of the Intergovernmental Panel on Climate Change’s (IPCC’s) Representative Concentration Pathways (RCPs) using the Weather Research and Forecasting (WRF) model. The regional climate results were in turn used to generate air quality (concentration) projections using the Community Multiscale Air Quality (CMAQ) model. For each of the climate change scenarios, future U.S. census-tract level population distributions from the Integrated Climate and Land Use Scenarios (ICLUS) model for four future scenarios based on the IPCC’s Special Report on Emissions Scenarios (SRES) storylines were used. These climate, air quality, and population projections were used as inputs to EPA’s Air Pollutants Exposure (APEX) model for 12 U.S. cities. Probability density functions show changes in the population distribution of 8 h maximum daily O3 exposur

Phytoaccumulation of antimicrobials from biosolids: impacts on environmental fate and relevance to human exposure.

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Aryal, Niroj; Reinhold, Dawn M

2011-11-01

Triclocarban and triclosan, two antimicrobials widely used in consumer products, can adversely affect ecosystems and potentially impact human health. The application of biosolids to agricultural fields introduces triclocarban and triclosan to soil and water resources. This research examined the phytoaccumulation of antimicrobials, effects of plant growth on migration of antimicrobials to water resources, and relevance of phytoaccumulation in human exposure to antimicrobials. Pumpkin, zucchini, and switch grass were grown in soil columns to which biosolids were applied. Leachate from soil columns was assessed every other week for triclocarban and triclosan. At the end of the trial, concentrations of triclocarban and triclosan were determined for soil, roots, stems, and leaves. Results indicated that plants can reduce leaching of antimicrobials to water resources. Pumpkin and zucchini growth significantly reduced soil concentrations of triclosan to less than 0.001 mg/kg, while zucchini significantly reduced soil concentrations of triclocarban to 0.04 mg/kg. Pumpkin, zucchini, and switch grass accumulated triclocarban and triclosan in mg per kg (dry) concentrations. Potential human exposure to triclocarban from consumption of pumpkin or zucchini was substantially less than exposure from product use, but was greater than exposure from drinking water consumption. Consequently, research indicated that pumpkin and zucchini may beneficially impact the fate of antimicrobials in agricultural fields, while presenting minimal acute risk to human health. Copyright © 2011 Elsevier Ltd. All rights reserved.

Exposure to Non-Extreme Solar UV Daylight: Spectral Characterization, Effects on Skin and Photoprotection

Directory of Open Access Journals (Sweden)

Claire Marionnet

2014-12-01

Full Text Available The link between chronic sun exposure of human skin and harmful clinical consequences such as photo-aging and skin cancers is now indisputable. These effects are mostly due to ultraviolet (UV rays (UVA, 320–400 nm and UVB, 280–320 nm. The UVA/UVB ratio can vary with latitude, season, hour, meteorology and ozone layer, leading to different exposure conditions. Zenithal sun exposure (for example on a beach around noon under a clear sky can rapidly induce visible and well-characterized clinical consequences such as sunburn, predominantly induced by UVB. However, a limited part of the global population is exposed daily to such intense irradiance and until recently little attention has been paid to solar exposure that does not induce any short term clinical impact. This paper will review different studies on non-extreme daily UV exposures with: (1 the characterization and the definition of the standard UV daylight and its simulation in the laboratory; (2 description of the biological and clinical effects of such UV exposure in an in vitro reconstructed human skin model and in human skin in vivo, emphasizing the contribution of UVA rays and (3 analysis of photoprotection approaches dedicated to prevent the harmful impact of such UV exposure.

Exposure to non-extreme solar UV daylight: spectral characterization, effects on skin and photoprotection.

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Marionnet, Claire; Tricaud, Caroline; Bernerd, Françoise

2014-12-23

The link between chronic sun exposure of human skin and harmful clinical consequences such as photo-aging and skin cancers is now indisputable. These effects are mostly due to ultraviolet (UV) rays (UVA, 320-400 nm and UVB, 280-320 nm). The UVA/UVB ratio can vary with latitude, season, hour, meteorology and ozone layer, leading to different exposure conditions. Zenithal sun exposure (for example on a beach around noon under a clear sky) can rapidly induce visible and well-characterized clinical consequences such as sunburn, predominantly induced by UVB. However, a limited part of the global population is exposed daily to such intense irradiance and until recently little attention has been paid to solar exposure that does not induce any short term clinical impact. This paper will review different studies on non-extreme daily UV exposures with: (1) the characterization and the definition of the standard UV daylight and its simulation in the laboratory; (2) description of the biological and clinical effects of such UV exposure in an in vitro reconstructed human skin model and in human skin in vivo, emphasizing the contribution of UVA rays and (3) analysis of photoprotection approaches dedicated to prevent the harmful impact of such UV exposure.

Cardiovascular health effects following exposure of human volunteers during fire extinction exercises

DEFF Research Database (Denmark)

Andersen, Maria Helena Guerra; Saber, Anne Thoustrup; Pedersen, Peter Bøgh

2017-01-01

Background: Firefighters have increased risk of cardiovascular disease and of sudden death from coronary heart disease on duty while suppressing fires. This study investigated the effect of firefighting activities, using appropriate personal protective equipment (PPE), on biomarkers...... firefighting exercises in a constructed firehouse and flashover container. The subjects were instructed to extinguish fires of either wood or wood with electrical cords and mattresses. The exposure to particulate matter ( PM) was assessed at various locations and personal exposure was assessed by portable PM...

A flexible matrix-based human exposure assessment framework suitable for LCA and CAA

DEFF Research Database (Denmark)

Jolliet, Olivier; Ernstoff, Alexi; Huang, Lei

2016-01-01

are not applicable to all types of near-field chemical releases from consumer products, e.g. direct dermal application. A consistent near-and far-field framework is needed for life cycle assessment (LCA) and chemical alternative assessment (CAA) to inform mitigation of human exposure to harmful chemicals. To close......Humans can be exposed to chemicals via near-field exposure pathways (e.g. through consumer product use) and far-field exposure pathways (e.g. through environmental emissions along product life cycles). Pathways are often complex where chemicals can transfer directly from products to humans during...... use or exchange between near-and far-field compartments until sub -fractions reach humans via inhalation, ingestion or dermal uptake. Currently, however, multimedia exposure models mainly focus on far-field exposure pathways. Metrics and modeling approaches used in far-field, emission-based models...

Digital music exposure reliably induces temporary threshold shift in normal-hearing human subjects.

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Le Prell, Colleen G; Dell, Shawna; Hensley, Brittany; Hall, James W; Campbell, Kathleen C M; Antonelli, Patrick J; Green, Glenn E; Miller, James M; Guire, Kenneth

2012-01-01

One of the challenges for evaluating new otoprotective agents for potential benefit in human populations is the availability of an established clinical paradigm with real-world relevance. These studies were explicitly designed to develop a real-world digital music exposure that reliably induces temporary threshold shift (TTS) in normal-hearing human subjects. Thirty-three subjects participated in studies that measured effects of digital music player use on hearing. Subjects selected either rock or pop music, which was then presented at 93 to 95 (n = 10), 98 to 100 (n = 11), or 100 to 102 (n = 12) dBA in-ear exposure level for a period of 4 hr. Audiograms and distortion product otoacoustic emissions (DPOAEs) were measured before and after music exposure. Postmusic tests were initiated 15 min, 1 hr 15 min, 2 hr 15 min, and 3 hr 15 min after the exposure ended. Additional tests were conducted the following day and 1 week later. Changes in thresholds after the lowest-level exposure were difficult to distinguish from test-retest variability; however, TTS was reliably detected after higher levels of sound exposure. Changes in audiometric thresholds had a "notch" configuration, with the largest changes observed at 4 kHz (mean = 6.3 ± 3.9 dB; range = 0-14 dB). Recovery was largely complete within the first 4 hr postexposure, and all subjects showed complete recovery of both thresholds and DPOAE measures when tested 1 week postexposure. These data provide insight into the variability of TTS induced by music-player use in a healthy, normal-hearing, young adult population, with music playlist, level, and duration carefully controlled. These data confirm the likelihood of temporary changes in auditory function after digital music-player use. Such data are essential for the development of a human clinical trial protocol that provides a highly powered design for evaluating novel therapeutics in human clinical trials. Care must be taken to fully inform potential subjects in

Post exposure prophylaxis against human immunodeficiency virus ...

African Journals Online (AJOL)

Objective: To determine the level of awareness, knowledge and practice of human immunodeficiency virus post exposure prophylaxis (HIV PEP) among paediatricians in Nigeria. Methodology: The study was a cross sectional questionnairebased survey conducted among paediatrcians that attended the Paediatric ...

Digital music exposure reliably induces temporary threshold shift (TTS) in normal hearing human subjects

Science.gov (United States)

Le Prell, C. G.; Dell, S.; Hensley, B.; Hall, J. W.; Campbell, K. C. M.; Antonelli, P. J.; Green, G. E.; Miller, J. M.; Guire, K.

2012-01-01

Objectives One of the challenges for evaluating new otoprotective agents for potential benefit in human populations is availability of an established clinical paradigm with real world relevance. These studies were explicitly designed to develop a real-world digital music exposure that reliably induces temporary threshold shift (TTS) in normal hearing human subjects. Design Thirty-three subjects participated in studies that measured effects of digital music player use on hearing. Subjects selected either rock or pop music, which was then presented at 93–95 (n=10), 98–100 (n=11), or 100–102 (n=12) dBA in-ear exposure level for a period of four hours. Audiograms and distortion product otoacoustic emissions (DPOAEs) were measured prior to and after music exposure. Post-music tests were initiated 15 min, 1 hr 15 min, 2 hr 15 min, and 3 hr 15 min after the exposure ended. Additional tests were conducted the following day and one week later. Results Changes in thresholds after the lowest level exposure were difficult to distinguish from test-retest variability; however, TTS was reliably detected after higher levels of sound exposure. Changes in audiometric thresholds had a “notch” configuration, with the largest changes observed at 4 kHz (mean=6.3±3.9dB; range=0–13 dB). Recovery was largely complete within the first 4 hours post-exposure, and all subjects showed complete recovery of both thresholds and DPOAE measures when tested 1-week post-exposure. Conclusions These data provide insight into the variability of TTS induced by music player use in a healthy, normal-hearing, young adult population, with music playlist, level, and duration carefully controlled. These data confirm the likelihood of temporary changes in auditory function following digital music player use. Such data are essential for the development of a human clinical trial protocol that provides a highly powered design for evaluating novel therapeutics in human clinical trials. Care must be

Surveillance of laboratory exposures to human pathogens and toxins: Canada 2016.

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Bienek, A; Heisz, M; Su, M

2017-11-02

Canada recently enacted legislation to authorize the collection of data on laboratory incidents involving a biological agent. This is done by the Public Health Agency of Canada (PHAC) as part of a comprehensive national program that protects Canadians from the health and safety risks posed by human and terrestrial animal pathogens and toxins. To describe the first year of data on laboratory exposure incidents and/or laboratory-acquired infections in Canada since the Human Pathogens and Toxins Regulations came into effect. Incidents that occurred between January 1 and December 31, 2016 were self-reported by federally-regulated parties across Canada using a standardized form from the Laboratory Incident Notification Canada (LINC) surveillance system. Exposure incidents were described by sector, frequency of occurrence, timeliness of reporting, number of affected persons, human pathogens and toxins involved, causes and corrective actions taken. Microsoft Excel 2010 was used for basic descriptive analyses. In 2016, 46 exposure incidents were reported by holders of 835 active licences in Canada representing 1,352 physical areas approved for work involving a biological agent, for an overall incidence of 3.4%. The number of incidents was highest in the academic (n=16; 34.8%) and hospital (n=12; 26.1%) sectors, while the number of reported incidents was relatively low in the private industry sector. An average of four to five incidents occurred each month; the month of September presented as an outlier with 10 incidents. ​: A total of 100 people were exposed, with no reports of secondary exposure. Four incidents led to suspected (n=3) or confirmed (n=1) cases of laboratory-acquired infection. Most incidents involved pathogens classified at a risk group 2 level that were manipulated in a containment level 2 laboratory (91.3%). Over 22 different species of human pathogens and toxins were implicated, with bacteria the most frequent (34.8%), followed by viruses (26

Radiation transport modeling and assessment to better predict radiation exposure, dose, and toxicological effects to human organs on long duration space flights

Science.gov (United States)

Denkins, P.; Badhwar, G.; Obot, V.; Wilson, B.; Jejelewo, O.

2001-01-01

NASA is very interested in improving its ability to monitor and forecast the radiation levels that pose a health risk to space-walking astronauts as they construct the International Space Station and astronauts that will participate in long-term and deep-space missions. Human exploratory missions to the moon and Mars within the next quarter century, will expose crews to transient radiation from solar particle events which include high-energy galactic cosmic rays and high-energy protons. Because the radiation levels in space are high and solar activity is presently unpredictable, adequate shielding is needed to minimize the deleterious health effects of exposure to radiation. Today, numerous models have been developed and used to predict radiation exposure. Such a model is the Space Environment Information Systems (SPENVIS) modeling program, developed by the Belgian Institute for Space Aeronautics. SPENVIS, which has been assessed to be an excellent tool in characterizing the radiation environment for microelectronics and investigating orbital debris, is being evaluated for its usefulness with determining the dose and dose-equivalent for human exposure. Thus far. the calculations for dose-depth relations under varying shielding conditions have been in agreement with calculations done using HZETRN and PDOSE, which are well-known and widely used models for characterizing the environments for human exploratory missions. There is disagreement when assessing the impact of secondary radiation particles since SPENVIS does a crude estimation of the secondary radiation particles when calculating LET versus Flux. SPENVIS was used to model dose-depth relations for the blood-forming organs. Radiation sickness and cancer are life-threatening consequences resulting from radiation exposure. In space. exposure to radiation generally includes all of the critical organs. Biological and toxicological impacts have been included for discussion along with alternative risk mitigation

Radiation transport modeling and assessment to better predict radiation exposure, dose, and toxicological effects to human organs on long duration space flights

Science.gov (United States)

Denkins, Pamela; Badhwar, Gautam; Obot, Victor; Wilson, Bobby; Jejelewo, Olufisayo

2001-08-01

NASA is very interested in improving its ability to monitor and forecast the radiation levels that pose a health risk to space-walking astronauts as they construct the International Space Station and astronauts that will participate in long-term and deep-space missions. Human exploratory missions to the moon and Mars within the next quarter century, will expose crews to transient radiation from solar particle events which include high-energy galactic cosmic rays and high-energy protons. Because the radiation levels in space are high and solar activity is presently unpredictable, adequate shielding is needed to minimize the deleterious health effects of exposure to radiation. Today, numerous models have been developed and used to predict radiation exposure. Such a model is the Space Environment Information Systems (SPENVIS) modeling program, developed by the Belgian Institute for Space Aeronautics. SPENVIS, which has been assessed to be an excellent tool in characterizing the radiation environment for microelectronics and investigating orbital debris, is being evaluated for its usefulness with determining the dose and dose-equivalent for human exposure. Thus far, the calculations for dose-depth relations under varying shielding conditions have been in agreement with calculations done using HZETRN and PDOSE, which are well-known and widely used models for characterizing the environments for human exploratory missions. There is disagreement when assessing the impact of secondary radiation particles since SPENVIS does a crude estimation of the secondary radiation particles when calculating LET versus Flux. SPENVIS was used to model dose-depth relations for the blood-forming organs. Radiation sickness and cancer are life-threatening consequences resulting from radiation exposure. In space, exposure to radiation generally includes all of the critical organs. Biological and toxicological impacts have been included for discussion along with alternative risk mitigation

Effects of occupational exposure to polychlorinated biphenyls on urinary metabolites of neurotransmitters: A cross-sectional and longitudinal perspective.

Science.gov (United States)

Putschögl, Franziska Maria; Gaum, Petra Maria; Schettgen, Thomas; Kraus, Thomas; Gube, Monika; Lang, Jessica

2015-07-01

Polychlorinated biphenyls (PCBs) are chemicals which were used for industrial purposes and are known to induce various adverse health effects. They are also known to be neurotoxic and numerous targets within the central nervous system have been identified in previous studies. Specifically, the neurotransmitters dopamine (DA) and norepinephrine (NE) are influenced by PCBs as indicated in studies involving animals. However, limited evidence has been published documenting PCB induced changes in the neurotransmitter system in humans. In the present study, we examined the association between a higher PCB body burden following occupational exposure and possible changes in human neurotransmitter metabolites. Within a medical surveillance programme called HELPcB (Health Effects in High-Level Exposure to PCB) that monitors adverse health effects of occupational PCB exposure, urine samples were obtained (n(T1) = 166; n(T2) = 177 and n(T3) = 141). The urinary concentrations of the metabolites homovanillic acid (HVA; for DA) and vanillylmandelic acid (VMA; for NE) were analyzed. Blood samples were obtained by vena puncture in order to determine the internal exposure to PCBs with human biomonitoring. A cross-sectional analysis indicated a significant negative effect of PCB exposure on HVA and VMA. Longitudinally, an initially higher exposure to higher chlorinated PCBs was followed by constant reduced HVA level over three consecutive years. Exploratory analyses show different long-term effects for different PCBs according to their chlorination degree. A higher exposure with lower chlorinated PCBs leads to an increase of VMA and HVA. Conversely, a higher exposure to all PCBs results in a reduction of HVA. This study, to our knowledge, is the first to document changes in neurotransmitter metabolites after occupational PCB exposure in humans. This finding advances evidence obtained from past research, and identifies one potential pathomechanism in the central dopaminergic system of

Human Physiological Responses to Acute and Chronic Cold Exposure

Science.gov (United States)

Stocks, Jodie M.; Taylor, Nigel A. S.; Tipton, Michael J.; Greenleaf, John E.

2001-01-01

When inadequately protected humans are exposed to acute cold, excessive body heat is lost to the environment and unless heat production is increased and heat loss attenuated, body temperature will decrease. The primary physiological responses to counter the reduction in body temperature include marked cutaneous vasoconstriction and increased metabolism. These responses, and the hazards associated with such exposure, are mediated by a number of factors which contribute to heat production and loss. These include the severity and duration of the cold stimulus; exercise intensity; the magnitude of the metabolic response; and individual characteristics such as body composition, age, and gender. Chronic exposure to a cold environment, both natural and artificial, results in physiological alterations leading to adaptation. Three quite different, but not necessarily exclusive, patterns of human cold adaptation have been reported: metabolic, hypothermic, and insulative. Cold adaptation has also been associated with an habituation response, in which there is a desensitization, or damping, of the normal response to a cold stress. This review provides a comprehensive analysis of the human physiological and pathological responses to cold exposure. Particular attention is directed to the factors contributing to heat production and heat loss during acute cold stress, and the ability of humans to adapt to cold environments.

Biomarkers of nanomaterial exposure and effect: current status

Science.gov (United States)

Iavicoli, Ivo; Leso, Veruscka; Manno, Maurizio; Schulte, Paul A.

2014-03-01

Recent advances in nanotechnology have induced a widespread production and application of nanomaterials. As a consequence, an increasing number of workers are expected to undergo exposure to these xenobiotics, while the possible hazards to their health remain not being completely understood. In this context, biological monitoring may play a key role not only to identify potential hazards from and to evaluate occupational exposure to nanomaterials, but also to detect their early biological effects to better assess and manage risks of exposure in respect of the health of workers. Therefore, the aim of this review is to provide a critical evaluation of potential biomarkers of nanomaterial exposure and effect investigated in human and animal studies. Concerning exposure biomarkers, internal dose of metallic or metal oxide nanoparticle exposure may be assessed measuring the elemental metallic content in blood or urine or other biological materials, whereas specific molecules may be carefully evaluated in target tissues as possible biomarkers of biologically effective dose. Oxidative stress biomarkers, such as 8-hydroxy-deoxy-guanosine, genotoxicity biomarkers, and inflammatory response indicators may also be useful, although not specific, as biomarkers of nanomaterial early adverse health effects. Finally, potential biomarkers from "omic" technologies appear to be quite innovative and greatly relevant, although mechanistic, ethical, and practical issues should all be resolved before their routine application in occupational settings could be implemented. Although all these findings are interesting, they point out the need for further research to identify and possibly validate sensitive and specific biomarkers of exposure and effect, suitable for future use in occupational biomonitoring programs. A valuable contribution may derive from the studies investigating the biological behavior of nanomaterials and the factors influencing their toxicokinetics and reactivity. In

A margin-of-exposure approach to assessment of noncancer risks of dioxins based on human exposure and response data.

Science.gov (United States)

Aylward, Lesa L; Goodman, Julie E; Charnley, Gail; Rhomberg, Lorenz R

2008-10-01

Risk assessment of human environmental exposure to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDFs) and other dioxin-like compounds is complicated by several factors, including limitations in measuring intakes because of the low concentrations of these compounds in foods and the environment and interspecies differences in pharmacokinetics and responses. We examined the feasibility of relying directly on human studies of exposure and potential responses to PCDD/PCDFs and related compounds in terms of measured lipid-adjusted concentrations to assess margin of exposure (MOE) in a quantitative, benchmark dose (BMD)-based framework using representative exposure and selected response data sets. We characterize estimated central tendency and upper-bound general U.S. population lipid-adjusted concentrations of PCDD/PCDFs from the 1970s and early 2000s based on available data sets. Estimates of benchmark concentrations for three example responses of interest (induction of cytochrome P4501A2 activity, dental anomalies, and neonatal thyroid hormone alterations) were derived based on selected human studies. The exposure data sets indicate that current serum lipid concentrations in young adults are approximately 6- to 7-fold lower than 1970s-era concentrations. Estimated MOEs for each end point based on current serum lipid concentrations range from 100 for dental anomalies-approximately 6-fold greater than would have existed during the 1970s. Human studies of dioxin exposure and outcomes can be used in a BMD framework for quantitative assessments of MOE. Incomplete exposure characterization can complicate the use of such studies in a BMD framework.

Case definitions for human poisonings postulated to palytoxins exposure.

Science.gov (United States)

Tubaro, A; Durando, P; Del Favero, G; Ansaldi, F; Icardi, G; Deeds, J R; Sosa, S

2011-03-01

A series of case reports and anecdotal references describe the adverse effects on human health ascribed to the marine toxin palytoxin (PLTX) after different exposure routes. They include poisonings after oral intake of contaminated seafood, but also inhalation and cutaneous/systemic exposures after direct contact with aerosolized seawater during Ostreopsis blooms and/or through maintaining aquaria containing cnidarian zoanthids. The symptoms commonly recorded during PLTX intoxication are general malaise and weakness, associated with myalgia, respiratory effects, impairment of the neuromuscular apparatus and abnormalities in cardiac function. Systemic symptoms are often recorded together with local damages whose intensity varies according to the route and length of exposure. Gastrointestinal malaise or respiratory distress is common for oral and inhalational exposure, respectively. In addition, irritant properties of PLTX probably account for the inflammatory reactions typical of cutaneous and inhalational contact. Unfortunately, the toxin identification and/or quantification are often incomplete or missing and cases of poisoning are indirectly ascribed to PLTXs, according only to symptoms, anamnesis and environmental/epidemiological investigations (i.e. zoanthid handling or ingestion of particular seafood). Based on the available literature, we suggest a "case definition of PLTX poisonings" according to the main exposure routes, and, we propose the main symptoms to be checked, as well as, hemato-clinical analysis to be carried out. We also suggest the performance of specific analyses both on biological specimens of patients, as well as, on the contaminated materials responsible for the poisoning. A standardized protocol for data collection could provide a more rapid and reliable diagnosis of palytoxin-poisoning, but also the collection of necessary data for the risk assessment for this family of toxins. Copyright © 2011 Elsevier Ltd. All rights reserved.

HExpoChem: a systems biology resource to explore human exposure to chemicals

DEFF Research Database (Denmark)

Taboureau, Olivier; Jacobsen, Ulrik Plesner; Kalhauge, Christian Gram

2013-01-01

of computational biology approaches are needed to assess the health risks of chemical exposure. Here we present HExpoChem, a tool based on environmental chemicals and their bioactivities on human proteins with the objective of aiding the qualitative exploration of human exposure to chemicals. The chemical...

Systematic review on the health effects of exposure to radiofrequency electromagnetic fields from mobile phone base stations.

Science.gov (United States)

Röösli, Martin; Frei, Patrizia; Mohler, Evelyn; Hug, Kerstin

2010-12-01

to review and evaluate the recent literature on the health effects of exposure to mobile phone base station (MPBS) radiation. we performed a systematic review of randomized human trials conducted in laboratory settings and of epidemiological studies that investigated the health effects of MPBS radiation in the everyday environment. we included in the analysis 17 articles that met our basic quality criteria: 5 randomized human laboratory trials and 12 epidemiological studies. The majority of the papers (14) examined self-reported non-specific symptoms of ill-health. Most of the randomized trials did not detect any association between MPBS radiation and the development of acute symptoms during or shortly after exposure. The sporadically observed associations did not show a consistent pattern with regard to symptoms or types of exposure. We also found that the more sophisticated the exposure assessment, the less likely it was that an effect would be reported. Studies on health effects other than non-specific symptoms and studies on MPBS exposure in children were scarce. the evidence for a missing relationship between MPBS exposure up to 10 volts per metre and acute symptom development can be considered strong because it is based on randomized, blinded human laboratory trials. At present, there is insufficient data to draw firm conclusions about health effects from long-term low-level exposure typically occurring in the everyday environment.

The injury and cumulative effects on human skin by UV exposure from artificial fluorescence emission.

Science.gov (United States)

Tian, Yan; Liu, Wei; Niu, TianHui; Dai, CaiHong; Li, Xiaoxin; Cui, Caijuan; Zhao, Xinyan; E, Yaping; Lu, Hui

2014-01-01

The injury and cumulative effects of UV emission from fluorescence lamp were studied. UV intensity from fluorescence lamp was measured, and human skin samples (hips, 10 volunteers) were exposed to low-dose UV irradiation (three times per week for 13 consecutive weeks). Three groups were examined: control group without UV radiation; low-dose group with a cumulative dose of 50 J cm(-2) which was equivalent to irradiation of the face during indoor work for 1.5 years; and high-dose group with 1000 J cm(-2) cumulative dose equivalent to irradiation of the face during outdoor activities for 1 year. Specific indicators were measured before and after UVA irradiation. The findings showed that extending the low-dose UVA exposure decreased the skin moisture content and increased the transepidermal water loss as well as induced skin color changes (decreased L* value, increased M index). Furthermore, irradiated skin showed an increased thickness of cuticle and epidermis, skin edema, light color and unclear staining collagen fibers in the dermis, and elastic fiber fragmentation. In addition, MMP-1, p53 and SIRT1 expression was also increased. Long-term exposure of low-dose UVA radiation enhanced skin photoaging. The safety of the fluorescent lamp needs our attention. © 2014 The American Society of Photobiology.

Effects of RF-EMF Exposure from GSM Mobile Phones on Proliferation Rate of Human Adipose-derived Stem Cells: An In-vitro Study

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Shahbazi-Gahrouei D

2016-12-01

Full Text Available Background: As the use of mobile phones is increasing, public concern about the harmful effects of radiation emitted by these devices is also growing. In addition, protection questions and biological effects are among growing concerns which have remained largely unanswered. Stem cells are useful models to assess the effects of radiofrequency electromagnetic fields (RF-EMF on other cell lines. Stem cells are undifferentiated biological cells that can differentiate into specialized cells. Adipose tissue represents an abundant and accessible source of adult stem cells. The aim of this study is to investigate the effects of GSM 900 MHz on growth and proliferation of mesenchymal stem cells derived from adipose tissue within the specific distance and intensity. Materials and Methods: ADSCs were exposed to GSM mobile phones 900 MHz with intensity of 354.6 µW/cm2 square waves (217 Hz pulse frequency, 50% duty cycle, during different exposure times ranging from 6 to 21 min/day for 5 days at 20 cm distance from the antenna. MTT assay was used to determine the growth and metabolism of cells and trypan blue test was also done for cell viability. Statistical analyses were carried out using analysis of one way ANOVA. P<0.05 was considered to be statistically significant. Results: The proliferation rates of human ADSCs in all exposure groups were significantly lower than control groups (P<0.05 except in the group of 6 minutes/day which did not show any significant difference with control groups. Conclusion: The results show that 900 MHz RF signal radiation from antenna can reduce cell viability and proliferation rates of human ADSCs regarding the duration of exposure.

Diacetyl and 2,3-pentanedione exposure of human cultured airway epithelial cells: Ion transport effects and metabolism of butter flavoring agents

Energy Technology Data Exchange (ETDEWEB)

Zaccone, Eric J. [Department of Pharmaceutical Sciences, West Virginia University, Morgantown, WV (United States); Goldsmith, W. Travis [Pathology and Physiology Research Branch, National Institute for Occupational Safety and Health, Morgantown, WV (United States); Shimko, Michael J. [Department of Pharmaceutical Sciences, West Virginia University, Morgantown, WV (United States); Wells, J.R.; Schwegler-Berry, Diane; Willard, Patsy A.; Case, Shannon L.; Thompson, Janet A. [Pathology and Physiology Research Branch, National Institute for Occupational Safety and Health, Morgantown, WV (United States); Fedan, Jeffrey S. [Department of Pharmaceutical Sciences, West Virginia University, Morgantown, WV (United States); Pathology and Physiology Research Branch, National Institute for Occupational Safety and Health, Morgantown, WV (United States)

2015-12-15

Inhalation of butter flavoring by workers in the microwave popcorn industry may result in “popcorn workers' lung.” In previous in vivo studies rats exposed for 6 h to vapor from the flavoring agents, diacetyl and 2,3-pentanedione, acquired flavoring concentration-dependent damage of the upper airway epithelium and airway hyporeactivity to inhaled methacholine. Because ion transport is essential for lung fluid balance, we hypothesized that alterations in ion transport may be an early manifestation of butter flavoring-induced toxicity. We developed a system to expose cultured human bronchial/tracheal epithelial cells (NHBEs) to flavoring vapors. NHBEs were exposed for 6 h to diacetyl or 2,3-pentanedione vapors (25 or ≥ 60 ppm) and the effects on short circuit current and transepithelial resistance (R{sub t}) were measured. Immediately after exposure to 25 ppm both flavorings reduced Na{sup +} transport, without affecting Cl{sup −} transport or Na{sup +},K{sup +}-pump activity. R{sub t} was unaffected. Na{sup +} transport recovered 18 h after exposure. Concentrations (100–360 ppm) of diacetyl and 2,3-pentanedione reported earlier to give rise in vivo to epithelial damage, and 60 ppm, caused death of NHBEs 0 h post-exposure. Analysis of the basolateral medium indicated that NHBEs metabolize diacetyl and 2,3-pentanedione to acetoin and 2-hydroxy-3-pentanone, respectively. The results indicate that ion transport is inhibited transiently in airway epithelial cells by lower concentrations of the flavorings than those that result in morphological changes of the cells in vivo or in vitro. - Highlights: • Butter flavoring vapor effects on human cultured airway epithelium were studied. • Na transport was reduced by a 6-h exposure to 25 ppm diacetyl and 2,3-pentanedione. • Na transport recovered 18 h after exposure. • > 60 ppm transepithelial voltage and resistance were abolished; cells were damaged. • Cells metabolized diacetyl and 2,3-pentanedione

Diacetyl and 2,3-pentanedione exposure of human cultured airway epithelial cells: Ion transport effects and metabolism of butter flavoring agents

International Nuclear Information System (INIS)

Zaccone, Eric J.; Goldsmith, W. Travis; Shimko, Michael J.; Wells, J.R.; Schwegler-Berry, Diane; Willard, Patsy A.; Case, Shannon L.; Thompson, Janet A.; Fedan, Jeffrey S.

2015-01-01

Inhalation of butter flavoring by workers in the microwave popcorn industry may result in “popcorn workers' lung.” In previous in vivo studies rats exposed for 6 h to vapor from the flavoring agents, diacetyl and 2,3-pentanedione, acquired flavoring concentration-dependent damage of the upper airway epithelium and airway hyporeactivity to inhaled methacholine. Because ion transport is essential for lung fluid balance, we hypothesized that alterations in ion transport may be an early manifestation of butter flavoring-induced toxicity. We developed a system to expose cultured human bronchial/tracheal epithelial cells (NHBEs) to flavoring vapors. NHBEs were exposed for 6 h to diacetyl or 2,3-pentanedione vapors (25 or ≥ 60 ppm) and the effects on short circuit current and transepithelial resistance (R t ) were measured. Immediately after exposure to 25 ppm both flavorings reduced Na + transport, without affecting Cl − transport or Na + ,K + -pump activity. R t was unaffected. Na + transport recovered 18 h after exposure. Concentrations (100–360 ppm) of diacetyl and 2,3-pentanedione reported earlier to give rise in vivo to epithelial damage, and 60 ppm, caused death of NHBEs 0 h post-exposure. Analysis of the basolateral medium indicated that NHBEs metabolize diacetyl and 2,3-pentanedione to acetoin and 2-hydroxy-3-pentanone, respectively. The results indicate that ion transport is inhibited transiently in airway epithelial cells by lower concentrations of the flavorings than those that result in morphological changes of the cells in vivo or in vitro. - Highlights: • Butter flavoring vapor effects on human cultured airway epithelium were studied. • Na transport was reduced by a 6-h exposure to 25 ppm diacetyl and 2,3-pentanedione. • Na transport recovered 18 h after exposure. • > 60 ppm transepithelial voltage and resistance were abolished; cells were damaged. • Cells metabolized diacetyl and 2,3-pentanedione into acetoin and 2-OH-3-pentanone.

The Lunar Environment: Determining the Health Effects of Exposure to Moon Dusts

Science.gov (United States)

Khan-Mayberry, Noreen

2007-01-01

The moon's surface is covered with a thin layer of fine, charged, reactive dust capable of layer of fine, charged, reactive dust capable of capable of entering habitats and vehicle compartments, where it can result in crewmember health problems. NASA formed the Lunar Airborne Dust Toxicity Advisory Group (LADTAG) to study the effects of exposure to Lunar Dust on human health. To date, no scientifically defensible toxicological studies have been performed on lunar dusts, specifically the determination of exposure limits and their affect on human health. The multi-center LADTAG (Lunar Airborne Dust Toxicology center LADTAG (Lunar Airborne Dust Toxicology Advisory Group) was formed in response to the Office of the Chief Health and Medical Office s (OCHMO) request to develop recommendations for defining risk (OCHMO) request to develop recommendations for defining risk defining risk criteria for human lunar dust exposure.

Toxicity levels to humans during acute exposure to hydrogen fluoride - An update

International Nuclear Information System (INIS)

Halton, D.M.

1995-09-01

In March 1993, the Atomic Energy Control Board (AECB) commissioned and update of a 1984 review on the acute toxicity of hydrogen fluoride (HF). The study places particular emphasis on the effects of inhalation of gaseous HF and is divided into two main parts: a literature review and a lethal concentration (LC) estimation. The literature review summarizes data under four categories: animal studies, controlled human studies, community exposure, and industrial exposure. Data in these areas were critically reviewed for their relevance to lethal concentrations at LC LO , LC 10 and LC 50 levels that were derived in the 1984 report. In the last ten years, only one relevant animal study has been published. No new controlled human studies were found but a community exposure incident was reported. There were three new industrial/accidental exposures reported since 1984. Evaluation of new data does not change the lethal concentration estimates made in the 1984 report, but does indicate the absence of appropriate models to estimate the lethality of irritant and corrosive gases. In the last 10 years, much literature on the evaluation of major hazards has been published and suggests that such assessments are of growing political, economic and social importance. Numerous articles have been published on the acute toxicity of HF from skin contact and chronic toxicity from repeated airborne exposure. These publications offer important insights into the nature of HF toxicity. Several avenues of investigative research are suggested. (author). 55 refs., 4 tabs

Toxicity levels to humans during acute exposure to hydrogen fluoride - An update

Energy Technology Data Exchange (ETDEWEB)

Halton, D M

1995-09-01

In March 1993, the Atomic Energy Control Board (AECB) commissioned and update of a 1984 review on the acute toxicity of hydrogen fluoride (HF). The study places particular emphasis on the effects of inhalation of gaseous HF and is divided into two main parts: a literature review and a lethal concentration (LC) estimation. The literature review summarizes data under four categories: animal studies, controlled human studies, community exposure, and industrial exposure. Data in these areas were critically reviewed for their relevance to lethal concentrations at LC{sub LO}, LC{sub 10} and LC{sub 50} levels that were derived in the 1984 report. In the last ten years, only one relevant animal study has been published. No new controlled human studies were found but a community exposure incident was reported. There were three new industrial/accidental exposures reported since 1984. Evaluation of new data does not change the lethal concentration estimates made in the 1984 report, but does indicate the absence of appropriate models to estimate the lethality of irritant and corrosive gases. In the last 10 years, much literature on the evaluation of major hazards has been published and suggests that such assessments are of growing political, economic and social importance. Numerous articles have been published on the acute toxicity of HF from skin contact and chronic toxicity from repeated airborne exposure. These publications offer important insights into the nature of HF toxicity. Several avenues of investigative research are suggested. (author). 55 refs., 4 tabs.

Effects of low-level blast exposure on the nervous system: Is there really a controversy?

Directory of Open Access Journals (Sweden)

Gregory A Elder

2014-12-01

Full Text Available High-pressure blast waves can cause extensive CNS injury in humans. However, in combat settings such as Iraq and Afghanistan, lower level exposures associated with mild TBI (mTBI or subclinical exposure have been much more common. Yet controversy exists concerning what traits can be attributed to low-level blast, in large part due to the difficulty of distinguishing blast-related mTBI from post-traumatic stress disorder (PTSD. We describe how TBI is defined in humans and the problems posed in using current definitions to recognize blast-related mTBI. We next consider the problem of applying definitions of human mTBI to animal models, in particular that TBI severity in humans is defined in relation to alteration of consciousness at the time of injury, which typically cannot be assessed in animals. However, based on outcome assessments a condition of low-level blast exposure can be defined in animals that likely approximates human mTBI or subclinical exposure. We review blast injury modeling in animals noting that inconsistencies in experimental approach have contributed to uncertainty over the effects of low-level blast. Yet animal studies show that low-level blast pressure waves are transmitted to the brain. In brain low-level blast exposures cause behavioral, biochemical, pathological and physiological effects on the nervous system including the induction of PTSD-related behavioral traits in the absence of a psychological stressor. We review the relationship of blast exposure to chronic neurodegenerative diseases noting the paradoxical lowering of Abeta by blast, which along with other observations suggest that blast-related TBI is pathophysiologically distinct from non-blast TBI. Human neuroimaging studies show that blast-related mTBI is associated with a variety of chronic effects that are unlikely to be explained by co-morbid PTSD. We conclude that abundant evidence supports low-level blast as having long-term effects on the nervous system.

Chronic exposure to low environmental concentrations and legal aquaculture doses of antibiotics cause systemic adverse effects in Nile tilapia and provoke differential human health risk.

Science.gov (United States)

Limbu, Samwel M; Zhou, Li; Sun, Sheng-Xiang; Zhang, Mei-Ling; Du, Zhen-Yu

2018-06-01

Antibiotics used globally to treat human and animal diseases exist ubiquitously in the environment at low doses because of misuse, overdose and poor absorption after ingestion, coupled with their high-water solubility and degradation resistance. However, the systemic chronic effects of exposure to low environmental concentrations of antibiotics (LECAs) and legal aquaculture doses of antibiotics (LADAs) in fish and their human health risk are currently unknown. To investigate the in vivo chronic effects of exposure to LECAs and LADAs using oxytetracycline (OTC) and sulfamethoxazole (SMZ) in Nile tilapia (Oreochromis niloticus) and their human health risk. Twenty O. niloticus weighing 27.73 ± 0.81 g were exposed to water containing LECAs (OTC at 420 ng/L and SMZ at 260 ng/L) and diets supplemented with LADAs (OTC 80 mg/kg/day and SMZ 100 mg/kg/day) for twelve weeks. General physiological functions, metabolic activities, intestinal and hepatic health were systemically evaluated. The possible human health risks of the consumption of the experimental Nile tilapia fillets in adults and children were assessed by using risk quotient. After exposure, we observed retarded growth performance accompanied by reduced nutrients digestibility, feed efficiency, organ indices, and lipid body composition in treated fish. Antibiotics distorted intestinal morphological features subsequently induced microbiota dysbiosis and suppressed intestinal tight junction proteins. Exposure of fish to LECAs and LADAs induced oxidative stress, suppressed innate immunity, stimulated inflammatory and detoxification responses, concomitantly inhibited antioxidant capacity and caused lipid peroxidation in intestine and liver organs. Both LECAs and LADAs enhanced gluconeogenesis, inhibited lipogenesis and fatty acid beta oxidation in intestine and liver organs. The exposure of fish to LECAs and LADAs induced anaerobic glycolytic pathway and affected intestinal fat catabolism in intestine

Perfluoroalkyl substances exposure and thyroid hormones in humans: epidemiological observations and implications

Directory of Open Access Journals (Sweden)

Jung Eun Lee

2017-03-01

Full Text Available Thyroid hormones play crucial roles in normal neurodevelopment of fetus and child. Many chemicals can affect control and homeostasis of thyroid hormones, and eventually lead to various adverse health effects including neurodevelopmental disorders. Perfluoroalkyl substances (PFASs are among the thyroid disrupting chemicals that can be encountered among general human population. Due to their unique physicochemical characteristics, PFASs have been used as surfactants and surface coating materials in many applications. Therefore, PFASs have been frequently detected in humans and environment worldwide. In cross-sectional studies using nationally representative general human populations of United States, several PFASs have shown significant associations with thyroid hormones. Moreover, among pregnant women and their infants, not only major PFASs such as perfluorooctane sulfonic acid and perfluorooctanoic acid, but also those with shorter or longer carbon chains showed significant associations with thyroid hormones. Often demographic characteristics such as sex, age, and disease status appear to influence the associations between PFASs exposure and thyroid hormones. In general, major PFASs showed hypothyroidism effects among pregnant women and infants. As 8 carbon based PFASs have been phased out, those with shorter or longer carbon chains have been used in growing amount as replacement. However, only limited information is available for their occurrences and toxicity among humans. Further investigations on these substituting PFASs are required. In addition, efforts are warranted to identify sources of and mitigate exposure to these thyroid disrupting chemicals especially during pregnancy and early stages of life.

Organic UV filters exposure induces the production of inflammatory cytokines in human macrophages.

Science.gov (United States)

Ao, Junjie; Yuan, Tao; Gao, Li; Yu, Xiaodan; Zhao, Xiaodong; Tian, Ying; Ding, Wenjin; Ma, Yuning; Shen, Zhemin

2018-09-01

Organic ultraviolet (UV) filters, found in many personal care products, are considered emerging contaminants due to growing concerns about potential long-term deleterious effects. We investigated the immunomodulatory effects of four commonly used organic UV filters (2-hydroxy-4-methoxybenzophenone, BP-3; 4-methylbenzylidene camphor, 4-MBC; 2-ethylhexyl 4-methoxycinnamate, EHMC; and butyl-methoxydibenzoylmethane, BDM) on human macrophages. Our results indicated that exposure to these four UV filters significantly increased the production of various inflammatory cytokines in macrophages, particular tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). After exposure to the UV filters, a significant 1.1-1.5 fold increase were found in TNF-α and IL-6 mRNA expression. In addition, both the p38 MAPK and the NF-κB signaling pathways were enhanced 2 to 10 times in terms of phosphorylation after exposure to the UV filters, suggesting that these pathways are involved in the release of TNF-α and IL-6. Molecular docking analysis predicted that all four UV filter molecules would efficiently bind transforming growth factor beta-activated kinase 1 (TAK1), which is responsible for the activation of the p38 MAPK and NF-κB pathways. Our results therefore demonstrate that exposure to the four organic UV filters investigated may alter human immune system function. It provides new clue for the development of asthma or allergic diseases in terms of the environmental pollutants. Copyright © 2018 Elsevier B.V. All rights reserved.

Exposure to perfluorononanoic acid combined with a low-dose mixture of 14 human-relevant compounds disturbs energy/lipid homeostasis in rats

DEFF Research Database (Denmark)

Skov, Kasper; Kongsbak, Kristine Grønning; Hadrup, Niels

2015-01-01

, whereas effects on lipid metabolism in the liver were mainly driven by PFNA. This study verifies that a chemical mixture given at high-end human exposure levels can affect lipid homeostasis and that the combined use of metabolomics and transcriptomics can provide complimentary information allowing......Humans are constantly exposed to a significant number of compounds and many are readily detected in human body fluids. Worryingly, several of these compounds are either suspected to be, or have already been shown to be harmful to humans either individually or in combination. However, the potential...... consequences of low-dose exposure to complex mixtures remain poorly understood. We have profiled the effects on rat blood plasma and liver homeostasis using metabolomics and transcriptomics following 2-week exposure to either a mixture of 14 common chemicals (Mix), perfluorononanoic acid (PFNA) at low (0...

Pesticide Flow Analysis to Assess Human Exposure in Greenhouse Flower Production in Colombia

Directory of Open Access Journals (Sweden)

Claudia R. Binder

2013-03-01

Full Text Available Human exposure assessment tools represent a means for understanding human exposure to pesticides in agricultural activities and managing possible health risks. This paper presents a pesticide flow analysis modeling approach developed to assess human exposure to pesticide use in greenhouse flower crops in Colombia, focusing on dermal and inhalation exposure. This approach is based on the material flow analysis methodology. The transfer coefficients were obtained using the whole body dosimetry method for dermal exposure and the button personal inhalable aerosol sampler for inhalation exposure, using the tracer uranine as a pesticide surrogate. The case study was a greenhouse rose farm in the Bogota Plateau in Colombia. The approach was applied to estimate the exposure to pesticides such as mancozeb, carbendazim, propamocarb hydrochloride, fosetyl, carboxin, thiram, dimethomorph and mandipropamide. We found dermal absorption estimations close to the AOEL reference values for the pesticides carbendazim, mancozeb, thiram and mandipropamide during the study period. In addition, high values of dermal exposure were found on the forearms, hands, chest and legs of study participants, indicating weaknesses in the overlapping areas of the personal protective equipment parts. These results show how the material flow analysis methodology can be applied in the field of human exposure for early recognition of the dispersion of pesticides and support the development of measures to improve operational safety during pesticide management. Furthermore, the model makes it possible to identify the status quo of the health risk faced by workers in the study area.

[DNA damage in human pleural mesothelial cells induced by exposure to carbon nanotubes].

Science.gov (United States)

Ogasawara, Yuki; Umezu, Noriaki; Ishii, Kazuyuki

2012-01-01

Nanomaterials are currently used in electronics, industrial materials, cosmetics, and medicine because they have useful physicochemical properties, such as strength, conductivity, durability, and chemical stability. As these materials have become widespread, many questions have arisen regarding their effects on health and the environment. In particular, recent studies have demonstrated that carbon nanotubes (CNTs) cause significant inflammation and mesothelioma in vivo. In this study, we investigated the potential risk posed by singlewalled carbon nanotube (SWCNT) and multiwalled carbon nanotube (MWCNT) exposure in human pleural mesothelial cells. CNT cytotoxicity was determined by a trypan blue exclusion assay, and DNA damage was detected by an alkaline comet assay. The concentration of 8-oxodeoxyguanosine (8-OHdG) in DNA was measured by high perhormance liquid chromatography with electrochemical detection. The expression of base excision repair enzymes in the cell was estimated by immunoblot analysis. We observed inhibitory effects on cell proliferation and the induction of DNA damage following exposure of cells to purified CNTs that were suspended in dispersion medium. However, accumulation of 8-OHdG in DNA was not found. In addition, the expression levels of base excision enzymes that are involved in hOGG1, hMTH1, and MYH in MeT-5A cells remained unchanged for 24 h after carbon nanotube exposure. CNTs significantly inhibit cell proliferation and decrease DNA damage in human pleural mesothelial cells. Our results indicate that the mechanism of CNT-induced genotoxicity is different from that following exposure to reactive oxygen species, which causes oxidative DNA modifications and 8-OHdG production. Further investigation is required to characterize the specific DNA mutations that occur following CNT exposure.

How Does Chronic Cigarette Smoke Exposure Affect Human Skin? A Global Proteomics Study in Primary Human Keratinocytes.

Science.gov (United States)

Rajagopalan, Pavithra; Nanjappa, Vishalakshi; Raja, Remya; Jain, Ankit P; Mangalaparthi, Kiran K; Sathe, Gajanan J; Babu, Niraj; Patel, Krishna; Cavusoglu, Nükhet; Soeur, Jeremie; Pandey, Akhilesh; Roy, Nita; Breton, Lionel; Chatterjee, Aditi; Misra, Namita; Gowda, Harsha

2016-11-01

Cigarette smoking has been associated with multiple negative effects on human skin. Long-term physiological effects of cigarette smoke are through chronic and not acute exposure. Molecular alterations due to chronic exposure to cigarette smoke remain unclear. Primary human skin keratinocytes chronically exposed to cigarette smoke condensate (CSC) showed a decreased wound-healing capacity with an increased expression of NRF2 and MMP9. Using quantitative proteomics, we identified 4728 proteins, of which 105 proteins were overexpressed (≥2-fold) and 41 proteins were downregulated (≤2-fold) in primary skin keratinocytes chronically exposed to CSC. We observed an alteration in the expression of several proteins involved in maintenance of epithelial barrier integrity, including keratin 80 (5.3 fold, p value 2.5 × 10 -7 ), cystatin A (3.6-fold, p value 3.2 × 10 -3 ), and periplakin (2.4-fold, p value 1.2 × 10 -8 ). Increased expression of proteins associated with skin hydration, including caspase 14 (2.2-fold, p value 4.7 × 10 -2 ) and filaggrin (3.6-fold, p value 5.4 × 10 -7 ), was also observed. In addition, we report differential expression of several proteins, including adipogenesis regulatory factor (2.5-fold, p value 1.3 × 10 -3 ) and histone H1.0 (2.5-fold, p value 6.3 × 10 -3 ) that have not been reported earlier. Bioinformatics analyses demonstrated that proteins differentially expressed in response to CSC are largely related to oxidative stress, maintenance of skin integrity, and anti-inflammatory responses. Importantly, treatment with vitamin E, a widely used antioxidant, could partially rescue adverse effects of CSC exposure in primary skin keratinocytes. The utility of antioxidant-based new dermatological formulations in delaying or preventing skin aging and oxidative damages caused by chronic cigarette smoke exposure warrants further clinical investigations and multi-omics research.

The effects of exposure to environmental factors on Heart Rate Variability: An ecological perspective

International Nuclear Information System (INIS)

Schnell, Izhak; Potchter, Oded; Epstein, Yoram; Yaakov, Yaron; Hermesh, Hagai; Brenner, Shmuel; Tirosh, Emanuel

2013-01-01

The impact of human exposure to environmental factors on Heart Rate Variability (HRV) was examined in the urban space of Tel-Aviv-Jaffa. Four environmental factors were investigated: thermal and social loads; CO concentrations and noise. Levels of HRV are explained mainly by subjective social stresses, noise and CO. The most interesting result is the fact that while subjective social stress and noise increase HRV, low levels of CO are reducing HRV to some extent moderating the impact of subjective social stress and noise. Beyond the poisoning effect of CO and the fact that extremely low levels of HRV associated with high dozes of CO increase risk for life, low levels of CO may have a narcotic effect, as it is measured by HRV. The effects of thermal loads on HRV are negligible probably due to the use of behavioral means in order to neutralize heat and cold effects. -- Highlights: ► The impact of human exposure to environmental factors on Heart Rate Variability (HRV) was examined. ► Previous studies measured human exposure to pollution by fixed monitoring stations. ► This study measured actual personal exposure by mini sensors. ► High level of subjective social load and noise increase HRV. ► Low levels of CO may have a narcotic effect, as it is measured by HRV. -- The research focuses on the effects of environmental factors; noise, subjective social stress, thermal load and CO on Heart Rate Variability

ACUTE BEHAVORIAL EFFECTS FROM EXPOSURE TO TWO-STROKE ENGINE EXHAUST

Science.gov (United States)

Benefits of changing from two-stroke to four-stroke engines (and other remedial requirements) can be evaluated (monetized) from the standpoint of acute behavioral effects of human exposure to exhaust from these engines. The monetization process depends upon estimates of the magn...

Critical evaluation of key evidence on the human health hazards of exposure to bisphenol A

Science.gov (United States)

Hengstler, JG; Foth, H; Gebel, T; Kramer, P-J; Lilienblum, W; Schweinfurth, H; Völkel, W; Wollin, K-M; Gundert-Remy, U

2011-01-01

Despite the fact that more than 5000 safety-related studies have been published on bisphenol A (BPA), there seems to be no resolution of the apparently deadlocked controversy as to whether exposure of the general population to BPA causes adverse effects due to its estrogenicity. Therefore, the Advisory Committee of the German Society of Toxicology reviewed the background and cutting-edge topics of this BPA controversy. The current tolerable daily intake value (TDI) of 0.05 mg/kg body weight [bw]/day, derived by the European Food Safety Authority (EFSA), is mainly based on body weight changes in two- and three-generation studies in mice and rats. Recently, these studies and the derivation of the TDI have been criticized. After having carefully considered all arguments, the Committee had to conclude that the criticism was scientifically not justified; moreover, recently published additional data further support the reliability of the two-and three-generation studies demonstrating a lack of estrogen-dependent effects at and below doses on which the current TDI is based. A frequently discussed topic is whether doses below 5 mg/ kg bw/day may cause adverse health effects in laboratory animals. Meanwhile, it has become clear that positive results from some explorative studies have not been confirmed in subsequent studies with higher numbers of animals or a priori defined hypotheses. Particularly relevant are some recent studies with negative outcomes that addressed effects of BPA on the brain, behavior, and the prostate in rodents for extrapolation to the human situation. The Committee came to the conclusion that rodent data can well be used as a basis for human risk evaluation. Currently published conjectures that rats are insensitive to estrogens compared to humans can be refuted. Data from toxicokinetics studies show that the half-life of BPA in adult human subjects is less than 2 hours and BPA is completely recovered in urine as BPA-conjugates. Tissue deconjugation

Human Exposure Model (HEM): A modular, web-based application to characterize near-field chemical exposures and releases

Science.gov (United States)

The U.S. EPA’s Chemical Safety and Sustainability research program is developing the Human Exposure Model (HEM) to assess near-field exposures to chemicals that occur in various populations over the entire life cycle of a consumer product. The model will be implemented as a...

Source attribution of human campylobacteriosis at the point of exposure by combining comparative exposure assessment and subtype comparison based on comparative genomic fingerprinting.

Directory of Open Access Journals (Sweden)

André Ravel

Full Text Available Human campylobacteriosis is a common zoonosis with a significant burden in many countries. Its prevention is difficult because humans can be exposed to Campylobacter through various exposures: foodborne, waterborne or by contact with animals. This study aimed at attributing campylobacteriosis to sources at the point of exposure. It combined comparative exposure assessment and microbial subtype comparison with subtypes defined by comparative genomic fingerprinting (CGF. It used isolates from clinical cases and from eight potential exposure sources (chicken, cattle and pig manure, retail chicken, beef, pork and turkey meat, and surface water collected within a single sentinel site of an integrated surveillance system for enteric pathogens in Canada. Overall, 1518 non-human isolates and 250 isolates from domestically-acquired human cases were subtyped and their subtype profiles analyzed for source attribution using two attribution models modified to include exposure. Exposure values were obtained from a concurrent comparative exposure assessment study undertaken in the same area. Based on CGF profiles, attribution was possible for 198 (79% human cases. Both models provide comparable figures: chicken meat was the most important source (65-69% of attributable cases whereas exposure to cattle (manure ranked second (14-19% of attributable cases, the other sources being minor (including beef meat. In comparison with other attributions conducted at the point of production, the study highlights the fact that Campylobacter transmission from cattle to humans is rarely meat borne, calling for a closer look at local transmission from cattle to prevent campylobacteriosis, in addition to increasing safety along the chicken supply chain.

Source attribution of human campylobacteriosis at the point of exposure by combining comparative exposure assessment and subtype comparison based on comparative genomic fingerprinting.

Science.gov (United States)

Ravel, André; Hurst, Matt; Petrica, Nicoleta; David, Julie; Mutschall, Steven K; Pintar, Katarina; Taboada, Eduardo N; Pollari, Frank

2017-01-01

Human campylobacteriosis is a common zoonosis with a significant burden in many countries. Its prevention is difficult because humans can be exposed to Campylobacter through various exposures: foodborne, waterborne or by contact with animals. This study aimed at attributing campylobacteriosis to sources at the point of exposure. It combined comparative exposure assessment and microbial subtype comparison with subtypes defined by comparative genomic fingerprinting (CGF). It used isolates from clinical cases and from eight potential exposure sources (chicken, cattle and pig manure, retail chicken, beef, pork and turkey meat, and surface water) collected within a single sentinel site of an integrated surveillance system for enteric pathogens in Canada. Overall, 1518 non-human isolates and 250 isolates from domestically-acquired human cases were subtyped and their subtype profiles analyzed for source attribution using two attribution models modified to include exposure. Exposure values were obtained from a concurrent comparative exposure assessment study undertaken in the same area. Based on CGF profiles, attribution was possible for 198 (79%) human cases. Both models provide comparable figures: chicken meat was the most important source (65-69% of attributable cases) whereas exposure to cattle (manure) ranked second (14-19% of attributable cases), the other sources being minor (including beef meat). In comparison with other attributions conducted at the point of production, the study highlights the fact that Campylobacter transmission from cattle to humans is rarely meat borne, calling for a closer look at local transmission from cattle to prevent campylobacteriosis, in addition to increasing safety along the chicken supply chain.

Inhale while Dreaming: Human Exposure to Pollutants while Sleeping

DEFF Research Database (Denmark)

Corsi, Richard; Spilak, Michal; Boor, E., Brandon

2012-01-01

of indoor pollutants, e.g., flame retardants to isocyanates. As such, there is a need for increased dialogue on this subject, end-point relevant research, and action to reduce exposures to high-risk contaminants for most of humanity. This workshop will involve an opening 5–minute presentation related...... discussion related to practical implications of new findings as well as past studies, geographic variations in emissions from mattresses and beddings, methods for reducing population exposures, and suggestions for future research that has practical endpoints and that can lead to reduced exposures....

The Mere Exposure Instruction Effect.

Science.gov (United States)

Van Dessel, Pieter; Mertens, Gaëtan; Smith, Colin Tucker; De Houwer, Jan

2017-09-01

The mere exposure effect refers to the well-established finding that people evaluate a stimulus more positively after repeated exposure to that stimulus. We investigated whether a change in stimulus evaluation can occur also when participants are not repeatedly exposed to a stimulus, but are merely instructed that one stimulus will occur frequently and another stimulus will occur infrequently. We report seven experiments showing that (1) mere exposure instructions influence implicit stimulus evaluations as measured with an Implicit Association Test (IAT), personalized Implicit Association Test (pIAT), or Affect Misattribution Procedure (AMP), but not with an Evaluative Priming Task (EPT), (2) mere exposure instructions influence explicit evaluations, and (3) the instruction effect depends on participants' memory of which stimulus will be presented more frequently. We discuss how these findings inform us about the boundary conditions of mere exposure instruction effects, as well as the mental processes that underlie mere exposure and mere exposure instruction effects.

Effects of embryonic and fetal exposure to x-ray, microwaves, and ultrasound

International Nuclear Information System (INIS)

Brent, R.L.

1986-01-01

Many professionals are unfamiliar with radiation biology or the quantitative nature of the risks. Frequently, microwave, ultrasound, and ionizing radiation risks are confused. Although it is impossible to prove no risk for any environmental hazard, it appears that exposure to microwave radiation below the maximal permissible levels present no measurable risk to the embryo. Ultrasound exposure from diagnostic ultrasonographic imaging equipment also is quite innocuous. It is true that continued surveillance and research into potential risks of these low-level exposures should continue, but at present ultrasound not only improves obstetric care but also reduces the necessity of diagnostic x-ray procedures. In the field of ionizing radiation, we have as good a comprehension of the biologic effects and the quantitative maximum risks as of any other environmental hazard. Although the animal and human data support the conclusion that no increases in the incidence of gross congenital malformations, intrauterine growth retardation, or abortion will occur with exposures less than 5 rad, that does not mean that there are definitely no risks to the embryo exposed to lower doses of radiation. Whether there exists a linear or exponential dose-response relationship or a threshold exposure for genetic, carcinogenic, cell-depleting, and life-shortening effects has not been determined. In establishing maximum permissible levels for the embryo at low exposures, refer to Tables 4, 5, 6, 8, and 9. It is obvious that the risks of 1-rad or 5-rad acute exposure are far below the spontaneous risks of the developing embryo because 15 per cent of human embryos abort, 2.7 to 3.0 per cent of human embryos have major malformations, 4 per cent have intrauterine growth retardation, and 8 to 10 per cent have early- or late-onset genetic disease. 98 references

The EPA's human exposure research program for assessing cumulative risk in communities.

Science.gov (United States)

Zartarian, Valerie G; Schultz, Bradley D

2010-06-01

Communities are faced with challenges in identifying and prioritizing environmental issues, taking actions to reduce their exposures, and determining their effectiveness for reducing human health risks. Additional challenges include determining what scientific tools are available and most relevant, and understanding how to use those tools; given these barriers, community groups tend to rely more on risk perception than science. The U.S. Environmental Protection Agency's Office of Research and Development, National Exposure Research Laboratory (NERL) and collaborators are developing and applying tools (models, data, methods) for enhancing cumulative risk assessments. The NERL's "Cumulative Communities Research Program" focuses on key science questions: (1) How to systematically identify and prioritize key chemical stressors within a given community?; (2) How to develop estimates of exposure to multiple stressors for individuals in epidemiologic studies?; and (3) What tools can be used to assess community-level distributions of exposures for the development and evaluation of the effectiveness of risk reduction strategies? This paper provides community partners and scientific researchers with an understanding of the NERL research program and other efforts to address cumulative community risks; and key research needs and opportunities. Some initial findings include the following: (1) Many useful tools exist for components of risk assessment, but need to be developed collaboratively with end users and made more comprehensive and user-friendly for practical application; (2) Tools for quantifying cumulative risks and impact of community risk reduction activities are also needed; (3) More data are needed to assess community- and individual-level exposures, and to link exposure-related information with health effects; and (4) Additional research is needed to incorporate risk-modifying factors ("non-chemical stressors") into cumulative risk assessments. The products of this

Exposure to CB-153 and p,p'-DDE and human sperm chromatin integrity

Energy Technology Data Exchange (ETDEWEB)

Rignell-Hydbom, A; Rylander, L; Joensson, B A.G.; Hagmar, L [Dept. of Occupational and Environmental Medicine, Lund Univ. Hospital (Sweden); Giwercman, A [Fertility Centre, Malmoe Univ. hospital (Sweden); Spano, M [Section of Toxicology and Biomedical Sciences, ENEA Casaccia Research Centre, Rome (Italy)

2004-09-15

In Sweden, the consumption of fatty fish from the Baltic Sea (off the Swedish east coast) is the single most important source of exposure to persistent organochlorine pollutants (POPs). Fishermen from the east coast have averagely higher plasma levels of polychlorinated biphenyls (PCBs) and total POP derived TEQ in plasma than both west coast fishermen and men from the general population. Dichlorodiphenyl dichloroethene (p,p'-DDE), a relevant biomarker for POP is still present in relatively high serum concentrations in men consuming fish from the Baltic Sea. Several studies have shown that POPs are capable of interfering with reproductive and endocrine function in animals. Human studies have shown that exposure to PCBs and polychlorinated dibenzofurans (PCDFs) has a negative effect on male reproductive function, and especially sperm motility seems vulnerable. However, studies relating to human sperm genetic integrity are few. The aim of the study was to investigate whether exposure to POP using 2,2',4,4',5,5'- hexachlorobiphenyl (CB-153) and p,p'-DDE as biomarkers, are associated with sperm chromatin integrity. In order to ensure a sufficient variation in POP exposure fishermen from both the Swedish east (''more exposed'') and west coasts (''less exposed'') formed the study base.

Mathematical models for radiation effects on human health

International Nuclear Information System (INIS)

Negi, U.S.; Petwal, K.C.

2015-01-01

In this paper, we are proposing a theoretical approach of basic mathematical models for radiation effect on human health. The largest natural sources of radiation exposure to humans are radon gas. While radon gas has always been in the environment, awareness of its contribution to human radiation exposure has increased in recent years. Radon's primary pathway is through air space in soil and rock. Pressure differences between the soil and the inside of buildings may cause radon gas to move indoors. Radon decays to radon daughters, some of which emit alpha radiation. Alpha-emitting radon daughters are adsorbed on to dust particles which, when inhaled, are trapped in the lungs and may cause gene damage, mutations and finally cancer. Exposure to excess UV radiation increases risk of skin cancer but there is also a dark side. The incidence of all types of skin cancer is related to exposure to UV radiation. Non-melanoma skin cancer, eye melanoma, and lip cancer have also been related to natural UV light

Foetal exposure to food and environmental carcinogens in human beings.

Science.gov (United States)

Myöhänen, Kirsi; Vähäkangas, Kirsi

2012-02-01

Exposure to many different chemicals during pregnancy through maternal circulation is possible. Transplacental transfer of xenobiotics can be demonstrated using human placental perfusion. Also, placental perfusion can give information about the placental kinetics as well as metabolism and accumulation in the placenta because it retains the tissue structure and function. Although human placental perfusion has been used extensively to study the transplacental transfer of drugs, the information on food and environmental carcinogens is much more limited. This review deals with the foetal exposure to food and environmental carcinogens in human beings. In particular, human transplacental transfer of the food carcinogens such as acrylamide, glycidamide and nitrosodimethylamine are in focus. Because these carcinogens are genotoxic, the functional capacity of human placenta to induce DNA adduct formation or metabolize these above mentioned CYP2E1 substrates is of interest in this context. © 2011 The Authors. Basic & Clinical Pharmacology & Toxicology © 2011 Nordic Pharmacological Society.

CYP1A1 and CYP1B1 in human lymphocytes as biomarker of exposure: effect of dioxin exposure and polymorphisms

Energy Technology Data Exchange (ETDEWEB)

Duursen, M. van; Sanderson, T.; Berg, M. van den [Inst. for Risk Assessment Sciences, Utrecht (Netherlands)

2004-09-15

There are several known genetic polymorphisms of the CYP1A1 and CYP1B1 genes. A polymorphism in the 3'-untranslated region of the CYP1A1 gene (CYP1A1 MspI or CYP1A1 m1) is often studied in relation with breast or lung cancer, but little is known about the functional effect of this polymorphism. An amino acid substitution in codon 432 (Val to Leu) of the CYP1B1 gene is associated with a lower catalytic activity of the enzyme. However, the involvement of these polymorphisms on the inducibility of CYP1A1 and CYP1B1 gene expression is unclear. CYP1A1 and CYP1B1 mRNA expression levels can be determined in peripheral blood lymphocytes. This makes them potential candidates for use as biomarker of exposure to environmental compounds. Interindividual variations in mRNA expression patterns, catalytic activity and polymorphisms are very important factors when CYP1A1 and CYP1B1 expression patterns are used as biomarker of exposure, but little is known about it. Spencer et al. showed a concentration-dependent increase of CYP1B1 mRNA in lymphocytes upon exposure in vitro to 2,3,7,8-tetrachloro-p-dibenzodioxin (TCDD), the most potent dioxin. Yet, only a few studies describe the in vivo correlation between polymorphisms, mRNA expression level and exposure to environmental factors. In this study, we wanted to obtain a better insight in the CYP1A1 and CYP1B1 mRNA expression and enzyme activity in human lymphocytes. We determined the constitutive CYP1A1 and CYP1B1 mRNA expression in lymphocytes of ten healthy volunteers and the variability in sensitivity toward enzyme induction by TCDD. Further, the CYP1A1 m1 and CYP1B1 Val432Leu polymorphisms were determined.

Effect of environmental exposure to mercury on the functioning of the human body

Directory of Open Access Journals (Sweden)

Maciej Cyran

2013-09-01

Full Text Available Mercury is classified as a heavy metal and thus is commonly referred to as a death metal due to its high toxicity. In the environment it occurs in metallic form or in combination with other compounds. Amidst the sources of exposure to mercury, the most important environmental sources are dental amalgam and mercury vapor from the production of chlorine which is the most important source of occupational exposure. Mercury is easily soluble in fats, so it penetrates through biological membranes. Both - acute and chronic mercury poisoning causes characteristic clinical symptoms. There are several connections between exposure to this metal and toxic effects on the nervous system, cardiovascular system, endocrine system and kidneys. Thus mercury damages the structure of many organs and impairs their function

Consolidated Human Activity Database (CHAD) for use in human exposure and health studies and predictive models

Science.gov (United States)

EPA scientists have compiled detailed data on human behavior from 22 separate exposure and time-use studies into CHAD. The database includes more than 54,000 individual study days of detailed human behavior.

A Margin-of-Exposure Approach to Assessment of Noncancer Risks of Dioxins Based on Human Exposure and Response Data

OpenAIRE

Aylward, Lesa L.; Goodman, Julie E.; Charnley, Gail; Rhomberg, Lorenz R.

2008-01-01

Background Risk assessment of human environmental exposure to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDFs) and other dioxin-like compounds is complicated by several factors, including limitations in measuring intakes because of the low concentrations of these compounds in foods and the environment and interspecies differences in pharmacokinetics and responses. Objectives We examined the feasibility of relying directly on human studies of exposure and potential responses to...

Considering human exposure to pesticides in food products: Importance of dissipation dynamics

DEFF Research Database (Denmark)

Fantke, Peter; Juraske, Ronnie; Jolliet, Olivier

2014-01-01

The general public is continuously concerned about effects from pesticide exposure via residues in food crops. However, impacts from pesticide exposure are mostly neglected in food product-related LCAs. Time-to-harvest and dissipation from crops mainly drive residue dynamics with dissipation...... as most uncertain aspect in characterization modeling. We analyzed measured half-lives (n=4513) with 95% falling between 0.6 and 29 days. With ~500 pesticides authorized alone in the EU for several hundred crops, however, experimental stud-ies only cover few possible pesticide-crop combinations. Therefore......, we estimated dissipation from measured data and provide reference half-lives for 333 pesticides applied at 20°C under field conditions. Our framework allows for detailed explorations of dietary choices in LCA with respect to human health impacts from pesticide exposure via crop consumption. The next...

An Agent-Based Modeling Framework for Simulating Human Exposure to Environmental Stresses in Urban Areas

Directory of Open Access Journals (Sweden)

Liang Emlyn Yang

2018-04-01

Full Text Available Several approaches have been used to assess potential human exposure to environmental stresses and achieve optimal results under various conditions, such as for example, for different scales, groups of people, or points in time. A thorough literature review in this paper identifies the research gap regarding modeling approaches for assessing human exposure to environment stressors, and it indicates that microsimulation tools are becoming increasingly important in human exposure assessments of urban environments, in which each person is simulated individually and continuously. The paper further describes an agent-based model (ABM framework that can dynamically simulate human exposure levels, along with their daily activities, in urban areas that are characterized by environmental stresses such as air pollution and heat stress. Within the framework, decision-making processes can be included for each individual based on rule-based behavior in order to achieve goals under changing environmental conditions. The ideas described in this paper are implemented in a free and open source NetLogo platform. A basic modeling scenario of the ABM framework in Hamburg, Germany, demonstrates its utility in various urban environments and individual activity patterns, as well as its portability to other models, programs, and frameworks. The prototype model can potentially be extended to support environmental incidence management through exploring the daily routines of different groups of citizens, and comparing the effectiveness of different strategies. Further research is needed to fully develop an operational version of the model.

Assessing human exposure risk to cadmium through inhalation and seafood consumption

International Nuclear Information System (INIS)

Ju, Yun-Ru; Chen, Wei-Yu; Liao, Chung-Min

2012-01-01

Highlights: ► Trophically available fraction in seafood and bioaccessibility is linked. ► Human health risk to Cd can via inhalation and seafood consumption. ► Female had the higher Cd accumulation in urine and blood than male. ► Cigarette smoking is a major determinant of human Cd intake. - Abstract: The role of cadmium (Cd) bioaccessibility in risk assessment is less well studied. The aim of this study was to assess human health risk to Cd through inhalation and seafood consumption by incorporating bioaccessibility. The relationships between trophically available Cd and bioaccessibility were constructed based on available experimental data. We estimated Cd concentrations in human urine and blood via daily intake from seafood consumption and inhalation based on a physiologically-based pharmacokinetic (PBPK) model. A Hill-based dose–response model was used to assess human renal dysfunction and peripheral arterial disease risks for long-term Cd exposure. Here we showed that fish had higher bioaccessibility (∼83.7%) than that of shellfish (∼73.2%) for human ingestion. Our results indicated that glomerular and tubular damage among different genders and smokers ranged from 18.03 to 18.18%. Our analysis showed that nonsmokers had 50% probability of peripheral arterial disease level exceeding from 3.28 to 8.80%. Smoking populations had 2–3 folds higher morbidity risk of peripheral arterial disease than those of nonsmokers. Our study concluded that the adverse effects of Cd exposure are exacerbated when high seafood consumption coincides with cigarette smoking. Our work provides a framework that could more accurately address risk dose dependency of Cd hazard.

Human convection flow in spaces with and without ventilation: personal exposure to floor-released particles and cough-released droplets

DEFF Research Database (Denmark)

Licina, Dusan; Melikov, Arsen Krikor; Pantelic, Jovan

2015-01-01

The effects of the human convective boundary layer (CBL), room airflow patterns, and their velocities on personal exposure are examined. Two pollutants are studied which simulate particles released from the feet and generated at distances of 2 and 3 m by a human cough. A thermal manikin whose body...... shape, size, and surface temperatures correspond to those of an average person is used to simulate the CBL. The findings of the study reveal that for accurate predictions of personal exposure, the CBL needs to be considered, as it can transport the pollution around the human body. The best way...... to control and reduce personal exposure when the pollution originates at the feet is to employ transverse flow from in front and from the side, relative to the exposed occupant. The flow from the above opposing the CBL create the most unfavorable velocity field that can increase personal exposure by 85...

Risks and health effects from exposure to engineered nanostructures: A critical review

International Nuclear Information System (INIS)

Nikodinovska, Violeta Vasilevska; Mladenovska, Kristina; Grozdanov, Anita

2015-01-01

Nanotechnology and engineered nanostructures (ENSs) are becoming part of everyday life, starting from industrial application, even in food products, to gene therapy. Thus, tons and tons of nanoparticles (NPs) enter the environment and indirectly or directly - into the biological systems, including the human body. There are many controversial papers that describe interactions of the ENSs with biological systems and raise concern that intentional or unintentional human exposure to certain types of ENSs, may lead to significant health, i.e. toxicological effects. Because of our insufficient and contradictory knowledge about the health effects associated with the ENSs exposure, the aim of this paper is to summarize and systematize the already confirmed data and the latest found facts about ENSs and their health effects and to discuss the future opportunities and tasks in the field of nanotoxicology. Keywords: engineered nano sized structures, nanotoxicology.

The linear non threshold conception 'Dose-effect' as a base for standardization of human exposure to ionizing radiation. Arguments pro and con

International Nuclear Information System (INIS)

Vassilev, G.

2000-01-01

Examples and argument are presented for reconsidering of the application of the threshold conception in low dose risk assessment. Some of the reasons mentioned are: inapplicability of the quantity 'collective dose' for low doses; serious reassessment of risk coefficients for radiation mutagenesis; report on increasing data on the so called hormesis - stimulation and potential effects from exposure of test animals nas humans to low doses of ionizing radiation

Climate Change Impacts on Environmental and Human Exposure to Mercury in the Arctic

Science.gov (United States)

Sundseth, Kyrre; Pacyna, Jozef M.; Banel, Anna; Pacyna, Elisabeth G.; Rautio, Arja

2015-01-01

This paper reviews information from the literature and the EU ArcRisk project to assess whether climate change results in an increase or decrease in exposure to mercury (Hg) in the Arctic, and if this in turn will impact the risks related to its harmful effects. It presents the state-of-the art of knowledge on atmospheric mercury emissions from anthropogenic sources worldwide, the long-range transport to the Arctic, and it discusses the likely environmental fate and exposure effects on population groups in the Arctic under climate change conditions. The paper also includes information about the likely synergy effects (co-benefits) current and new climate change polices and mitigation options might have on mercury emissions reductions in the future. The review concludes that reductions of mercury emission from anthropogenic sources worldwide would need to be introduced as soon as possible in order to assure lowering the adverse impact of climate change on human health. Scientific information currently available, however, is not in the position to clearly answer whether climate change will increase or decrease the risk of exposure to mercury in the Arctic. New research should therefore be undertaken to model the relationships between climate change and mercury exposure. PMID:25837201

Climate change impacts on environmental and human exposure to mercury in the arctic.

Science.gov (United States)

Sundseth, Kyrre; Pacyna, Jozef M; Banel, Anna; Pacyna, Elisabeth G; Rautio, Arja

2015-03-31

This paper reviews information from the literature and the EU ArcRisk project to assess whether climate change results in an increase or decrease in exposure to mercury (Hg) in the Arctic, and if this in turn will impact the risks related to its harmful effects. It presents the state-of-the art of knowledge on atmospheric mercury emissions from anthropogenic sources worldwide, the long-range transport to the Arctic, and it discusses the likely environmental fate and exposure effects on population groups in the Arctic under climate change conditions. The paper also includes information about the likely synergy effects (co-benefits) current and new climate change polices and mitigation options might have on mercury emissions reductions in the future. The review concludes that reductions of mercury emission from anthropogenic sources worldwide would need to be introduced as soon as possible in order to assure lowering the adverse impact of climate change on human health. Scientific information currently available, however, is not in the position to clearly answer whether climate change will increase or decrease the risk of exposure to mercury in the Arctic. New research should therefore be undertaken to model the relationships between climate change and mercury exposure.

Glucosamine exposure reduces proteoglycan synthesis in primary human endothelial cells in vitro

Directory of Open Access Journals (Sweden)

Trine M. Reine

2016-09-01

Full Text Available Purpose: Glucosamine (GlcN supplements are promoted for medical reasons, for example, for patients with arthritis and other joint-related diseases. Oral intake of GlcN is followed by uptake in the intestine, transport in the circulation and thereafter delivery to chondrocytes. Here, it is postulated to have an effect on synthesis and turnover of extracellular matrix constituents expressed by these cells. Following uptake in the intestine, serum levels are transiently increased, and the endothelium is exposed to increased levels of GlcN. We investigated the possible effects of GlcN on synthesis of proteoglycans (PGs, an important matrix component, in primary human endothelial cells. Methods: Primary human endothelial cells were cultured in vitro in medium with 5 mM glucose and 0–10 mM GlcN. PGs were recovered and analysed by western blotting, or by SDS-PAGE, gel chromatography or ion-exchange chromatography of 35S-PGs after 35S-sulphate labelling of the cells. Results: The synthesis and secretion of 35S-PGs from cultured endothelial cells were reduced in a dose- and time-dependent manner after exposure to GlcN. PGs are substituted with sulphated glycosaminoglycan (GAG chains, vital for PG function. The reduction in 35S-PGs was not related to an effect on GAG chain length, number or sulphation, but rather to the total expression of PGs. Conclusion: Exposure of endothelial cells to GlcN leads to a general decrease in 35S-PG synthesis. These results suggest that exposure to high levels of GlcN can lead to decreased matrix synthesis, contrary to what has been claimed by supporters of such supplements.

Modification by antioxidant supplementation of changes in human lung function associated with air pollutant exposure: A systematic review

Directory of Open Access Journals (Sweden)

Chow Katherine S

2011-07-01

Full Text Available Abstract Background Outdoor air pollution, given its demonstrated negative effects on the respiratory system, is a growing public health concern worldwide, particularly in urban cities. Human exposure to pollutants such as ozone, nitrogen oxides, combustion-related particulate matter and oxides of sulfur is responsible for significant cardiopulmonary morbidity and mortality in both adults and children. Several antioxidants have shown an ability to partially attenuate the negative physiological and functional impacts of air pollutants. This study systematically presents current data on the potential benefits of antioxidant supplementation on lung function outcomes associated with air pollutant exposures in intact humans. Methods Electronic databases (MEDLINE, EMBASE, BIOSIS Previews, Web of Sciences, Environmental Sciences & Pollution Management and TOXNET were systematically searched for all studies published up to April 2009. Search terms relating to the concepts of respiratory tract diseases, respiratory function tests, air pollution, and antioxidants were used. Data was systematically abstracted from original articles that satisfied selection criteria for inclusion. For inclusion, the studies needed to have evaluated human subjects, given supplemental antioxidants, under conditions of known levels of air pollutants with measured lung function before and after antioxidant administration and/or air pollution exposure. Selected studies were summarized and conclusions presented. Results Eight studies investigated the role of antioxidant supplementation on measured lung function outcomes after subject exposure to air pollutants under controlled conditions; 5 of these studies concluded that pollutant-induced airway hyper-responsiveness and diminution in lung function measurements were attenuated by antioxidant supplementation. The remaining five studies took place under ambient (uncontrolled exposures and unanimously concluded that antioxidant

Effect of controlled human exposure to diesel exhaust and allergen on airway surfactant protein D, myeloperoxidase and club (Clara) cell secretory protein 16.

Science.gov (United States)

Biagioni, B J; Tam, S; Chen, Y-W R; Sin, D D; Carlsten, C

2016-09-01

Air pollution is a major cause of global morbidity and mortality. Air pollution and aeroallergens aggravate respiratory illness, but the variable effects of air pollutants and allergens in the lung are poorly understood. To determine the effects of diesel exhaust (DE) and bronchial allergen challenge as single and dual exposures on aspects of innate immunity in the airway as reflected by surfactant protein D (SPD), myeloperoxidase (MPO) and club (Clara) cell secretory protein 16 (CC16) in 18 atopic individuals. In this double-blind, randomized crossover study, atopic individuals were exposed to DE or filtered air, followed by endobronchial allergen or saline 1 hour after inhalational exposure. Bronchoalveolar lavage, bronchial washings, nasal lavage and blood samples were obtained 48 hours after exposures and assayed for CC16, MPO and SPD by ELISA. In bronchial samples, the concentration of SPD increased from 53.3 to 91.8 ng/mL after endobronchial allergen, with no additional contribution from DE. MPO also increased significantly in response to allergen (6.8 to 14.7 ng/mL), and there was a small additional contribution from exposure to DE. The concentration of CC16 decreased from 340.7 to 151.0 ng/mL in response to DE, with minor contribution from allergen. These changes were not reflected in nasal lavage fluid or plasma samples. These findings suggest that allergen and DE variably influence different aspects of the innate immune response of the lung. SPD and MPO, known markers of allergic inflammation in the lung, are strongly increased by allergen while DE has a minor effect therein. DE induces a loss of CC16, a protective protein, while allergen has a minor effect therein. Results support site- and exposure-specific responses in the human lung upon multiple exposures. © 2016 John Wiley & Sons Ltd.

Resistance to asbestos-induced apoptosis with continuous exposure to crocidolite on a human T cell

Energy Technology Data Exchange (ETDEWEB)

Maeda, Megumi [Department of Biofunctional Chemistry, Graduate School of Natural Science and Technology, Okayama University, 1-1-1 Tsushima-Naka, Okayama 700-8530 (Japan); Department of Hygiene, Kawasaki Medical School, 577 Matsushima, Kurashiki 701-0192 (Japan); Yamamoto, Shoko [Department of Hygiene, Kawasaki Medical School, 577 Matsushima, Kurashiki 701-0192 (Japan); Chen, Ying [Division of Pneumoconiosis, School of Public Health, China Medical University, 92 North 2nd, Heping District, Shenyang 110001 (China); Kumagai-Takei, Naoko [Department of Hygiene, Kawasaki Medical School, 577 Matsushima, Kurashiki 701-0192 (Japan); Hayashi, Hiroaki [Department of Hygiene, Kawasaki Medical School, 577 Matsushima, Kurashiki 701-0192 (Japan); Department of Dermatology, Kawasaki Medical School, 577 Matsushima, Kurashiki 701-0192 (Japan); Matsuzaki, Hidenori; Lee, Suni; Hatayama, Tamayo; Miyahara, Naomi; Katoh, Minako [Department of Hygiene, Kawasaki Medical School, 577 Matsushima, Kurashiki 701-0192 (Japan); Hiratsuka, Juni-ichi [Department of Radiation Oncology, Kawasaki Medical School, 577 Matsushima, Kurashiki 701-0192 (Japan); Nishimura, Yasumitsu [Department of Hygiene, Kawasaki Medical School, 577 Matsushima, Kurashiki 701-0192 (Japan); Otsuki, Takemi, E-mail: takemi@med.kawasaki-m.ac.jp [Department of Hygiene, Kawasaki Medical School, 577 Matsushima, Kurashiki 701-0192 (Japan)

2012-07-01

We have been investigating the immunological effects of asbestos. The establishment of a low-dose and continuously exposed human T cell line, HTLV-1 immortalized MT-2, to chrysotile (CB) revealed reduction of CXCR3 chemokine receptor and production of IFN-{gamma} that caused a decline of tumor immunity. These effects were coupled with upregulation of IL-10, TGF-{beta}, and BCL-2 in asbestos-exposed patients. To observe the immunological effects of crocidolite (CR) on human T cells, a trial to establish a low-dose and continuously exposed model was conducted and compared with a previously reported CB-exposed model (MT-2CB). Transient exposure of MT-2 original cells to CB or CR induced a similar level of apoptosis and growth inhibition. The establishment of a continuously exposed subline to CR (MT-2CR) revealed resistance against CR-induced apoptosis and upregulation of the BCL-2/BAX ratio similar to that recorded for MT-2CB. Both sublines showed reduced production of IFN-{gamma}, TNF-{alpha}, and IL-6 with increased IL-10. cDNA microarray with network/pathway analyses focusing on transcription factors revealed that many similar factors related to cell proliferation were involved following continuous exposure to asbestos in both MT-2CB and MT-2CR. These results indicate that both CB and CR fibers affect human T cells with similar degrees even though the carcinogenic activity of these substances differs due to their chemical and physical forms. Trials to identify early detection markers for asbestos exposure or the occurrence of asbestos-inducing malignancies using these findings may lead to the development of clinical tools for asbestos-related diseases and chemoprevention that modifies the reduced tumor immunity. - Highlights: Black-Right-Pointing-Pointer Comparison of effects of chrysotile and crocidolite on human T cell was done. Black-Right-Pointing-Pointer Both fibers caused apoptosis of T cells by transient exposure. Black-Right-Pointing-Pointer T cells

Dosimetry Methods for Human Exposure to Non-Ionising Radiation

International Nuclear Information System (INIS)

Poljak, D.; Sarolic, A.; Doric, V.; Peratta, C.; Peratta, A.

2011-01-01

The paper deals with human exposure to electromagnetic fields from extremely low frequencies (ELF) to GSM frequencies. The problem requires (1) the assessment of external field generated by electromagnetic interference (EMI) source at a given frequency (incident field dosimetry) and then (2) the assessment of corresponding fields induced inside the human body (internal field dosimetry). Several methods used in theoretical and experimental dosimetry are discussed within this work. Theoretical dosimetry models at low frequencies are based on quasistatic approaches, while analyses at higher frequencies use the full-wave models. Experimental techniques involve near and far field measurement. Human exposure to power lines, transformer substations, power line communication (PLC) systems, Radio Frequency Identification (RFID) antennas and GSM base station antenna systems is analyzed. The results o are compared to the exposure limits proposed by relevant safety guidelines. Theoretical incident dosimetry used in this paper is based on the set of Pocklington integro-differential equations for the calculation of the current distribution and subsequently radiated field from power lines. Experimental incident dosimetry techniques involve measurement techniques of fields radiated by RFID antennas and GSM base station antennas. First example set of numerical results is related to the internal dosimetry of realistic well-grounded body model exposed to vertical component of the electric field E = 10 kV/m generated by high voltage power line. The results obtained via the HNA model exceed the ICNIRP basic restrictions for public exposure (2 mA/m 2 ) in knee (8.6 mA/m 2 ) and neck (9.8 mA/m 2 ) and for occupational exposure (10 mA/m 2 ) in ankle (32 mA/m 2 ). In the case of a conceptual model of a realistic human body inside a transformer substation room touching a control panel at the potential φ0 = 400 V and with two scenarios for dry-air between worker's hand and panel, the values

Baseline repeated measures from controlled human exposure studies: associations between ambient air pollution exposure and the systemic inflammatory biomarkers IL-6 and fibrinogen.

Science.gov (United States)

Thompson, Aaron M S; Zanobetti, Antonella; Silverman, Frances; Schwartz, Joel; Coull, Brent; Urch, Bruce; Speck, Mary; Brook, Jeffrey R; Manno, Michael; Gold, Diane R

2010-01-01

Systemic inflammation may be one of the mechanisms mediating the association between ambient air pollution and cardiovascular morbidity and mortality. Interleukin-6 (IL-6) and fibrinogen are biomarkers of systemic inflammation that are independent risk factors for cardio-vascular disease. We investigated the association between ambient air pollution and systemic inflammation using baseline measurements of IL-6 and fibrinogen from controlled human exposure studies. In this retrospective analysis we used repeated-measures data in 45 nonsmoking subjects. Hourly and daily moving averages were calculated for ozone, nitrogen dioxide, sulfur dioxide, and particulate matter pollutants on systemic IL-6 and fibrinogen. Effect modification by season was considered. We observed a positive association between IL-6 and O3 [0.31 SD per O3 interquartile range (IQR); 95% confidence interval (CI), 0.080.54] and between IL-6 and SO2 (0.25 SD per SO2 IQR; 95% CI, 0.060.43). We observed the strongest effects using 4-day moving averages. Responses to pollutants varied by season and tended to be higher in the summer, particularly for O3 and PM2.5. Fibrinogen was not associated with pollution. This study demonstrates a significant association between ambient pollutant levels and baseline levels of systemic IL-6. These findings have potential implications for controlled human exposure studies. Future research should consider whether ambient pollution exposure before chamber exposure modifies IL-6 response.

Considerations for the design and technical setup of a human whole-body exposure chamber.

Science.gov (United States)

Monsé, Christian; Sucker, Kirsten; van Thriel, Christoph; Broding, Horst Christoph; Jettkant, Birger; Berresheim, Hans; Wiethege, Thorsten; Käfferlein, Heiko; Merget, Rolf; Bünger, Jürgen; Brüning, Thomas

2012-01-01

Exposures to air contaminants, such as chemical vapors and particulate matter, pose important health hazards at workplaces. Short-term experimental exposures to chemical vapors and particles in humans are a promising attempt to investigate acute effects of such hazards. However, a significant challenge in this field is the determination of effects of co-exposures to more than one chemical or mixtures of chemical vapors and/or particles. To overcome such a challenge, studies have to be conducted under standardized exposure characterization and real time measurements, if possible. A new exposure laboratory (ExpoLab) was installed at IPA, combining sophisticated engineering designs with new analytical techniques, to fulfill these requirements. Low-dose as well as high-dose exposure scenarios are achieved by means of a calibration-gas-generator. Exposure monitoring can be carried out with a high performance real time mass spectrometer and other suitable analyzers (e.g. gas chromatograph). Numerous automated security facilities guarantee the physical integrity of the volunteers, and the waste atmosphere is removed using either charcoal filtration or catalytic post-combustion. Measurements of sulfur hexafluoride, carbon dioxide, aniline and carbon black are presented to demonstrate the performance of the exposure unit with respect to the temporal and spatial stability of generated atmospheres. The variations of generated contents in the atmospheres at steady state are slightly higher than the measurement precision of the analyzers (the typical standard deviation of generated atmospheres is standards in validity and reliability of generating and measuring exposure atmospheres.

The evaluation of stack metal emissions from hazardous waste incinerators: assessing human exposure through noninhalation pathways.

OpenAIRE

Sedman, R M; Polisini, J M; Esparza, J R

1994-01-01

Potential public health effects associated with exposure to metal emissions from hazardous waste incinerators through noninhalation pathways were evaluated. Instead of relying on modeling the movement of toxicants through various environmental media, an approach based on estimating changes from baseline levels of exposure was employed. Changes in soil and water As, Cd, Hg, Pb, Cr, and Be concentrations that result from incinerator emissions were first determined. Estimates of changes in human...

Model for screening-level assessment of near-field human exposure to neutral organic chemicals released indoors.

Science.gov (United States)

Zhang, Xianming; Arnot, Jon A; Wania, Frank

2014-10-21

Screening organic chemicals for hazard and risk to human health requires near-field human exposure models that can be readily parametrized with available data. The integration of a model of human exposure, uptake, and bioaccumulation into an indoor mass balance model provides a quantitative framework linking emissions in indoor environments with human intake rates (iRs), intake fractions (iFs) and steady-state concentrations in humans (C) through consideration of dermal permeation, inhalation, and nondietary ingestion exposure pathways. Parameterized based on representative indoor and adult human characteristics, the model is applied here to 40 chemicals of relevance in the context of human exposure assessment. Intake fractions and human concentrations (C(U)) calculated with the model based on a unit emission rate to air for these 40 chemicals span 2 and 5 orders of magnitude, respectively. Differences in priority ranking based on either iF or C(U) can be attributed to the absorption, biotransformation and elimination processes within the human body. The model is further applied to a large data set of hypothetical chemicals representative of many in-use chemicals to show how the dominant exposure pathways, iF and C(U) change as a function of chemical properties and to illustrate the capacity of the model for high-throughput screening. These simulations provide hypotheses for the combination of chemical properties that may result in high exposure and internal dose. The model is further exploited to highlight the role human contaminant uptake plays in the overall fate of certain chemicals indoors and consequently human exposure.

Effects of ozone exposure on lung function in man: a review

Energy Technology Data Exchange (ETDEWEB)

Folinsbee, L J

1981-01-01

Ozone, an important component of photochemical smog, has a decided impact on lung function in man. In this review, the effects of zone on human lung function are discussed with particular attention to levels which are near the threshold of producing no effect. Attempts to define dose-response relationships and effects on sensitive subject populations are described. The relationship between exercise and ozone toxicity is presented in addition to the potential impact of ambient ozone exposure on athletic performance. Effects of ozone on respiratory symptoms and the interaction of ozone with other pollutants are briefly examined. Considerable attention has been directed at the phenomenon of adaptation to repeated ozone exposure and to possible mechanism of action of ozone.

Integrating population dynamics into mapping human exposure to seismic hazard

Directory of Open Access Journals (Sweden)

S. Freire

2012-11-01

Full Text Available Disaster risk is not fully characterized without taking into account vulnerability and population exposure. Assessment of earthquake risk in urban areas would benefit from considering the variation of population distribution at more detailed spatial and temporal scales, and from a more explicit integration of this improved demographic data with existing seismic hazard maps. In the present work, "intelligent" dasymetric mapping is used to model population dynamics at high spatial resolution in order to benefit the analysis of spatio-temporal exposure to earthquake hazard in a metropolitan area. These night- and daytime-specific population densities are then classified and combined with seismic intensity levels to derive new spatially-explicit four-class-composite maps of human exposure. The presented approach enables a more thorough assessment of population exposure to earthquake hazard. Results show that there are significantly more people potentially at risk in the daytime period, demonstrating the shifting nature of population exposure in the daily cycle and the need to move beyond conventional residence-based demographic data sources to improve risk analyses. The proposed fine-scale maps of human exposure to seismic intensity are mainly aimed at benefiting visualization and communication of earthquake risk, but can be valuable in all phases of the disaster management process where knowledge of population densities is relevant for decision-making.

Exposure assessment in studies on health effects of traffic exhaust

Energy Technology Data Exchange (ETDEWEB)

Setaelae, S. [Association for the Pulmonary Disabled, Helsinki (Finland); Jaakkola, J.J.K. [Helsinki Univ. (Finland). Dept. of Public Health

1995-12-31

A main source of outdoor air pollution is road traffic, which produces a complex mixture of nitrogen oxides, carbon monoxide, volatile hydrocarbons, airborne particles and some other compounds. Traffic exhaust affects also the concentrations of ozone and other photo chemical oxidants. In earlier studies those components have had remarkable health effects. Several studies on occupational exposure to automobile exhaust have been published and several studies have been observed an association between both outdoor and indoor pollutant levels and health outcomes. However, there are only a few epidemiological studies in which traffic exhaust, a complex mixture, has been studied in its entirety. During recent years, interesting epidemiological studies of the health effects of this complex mixture have been published. Human exposure assessment for traffic exhaust can be categorized according to the environment of exposure (indoors, outdoors, in-traffic) or to the method of exposure assessment (direct or indirect methods). In this presentation the methods are further categorized into (1) traffic activity, (2) air concentration measurements, and (3) dispersion models, in order to better understand the advantages and disadvantages of different approaches. The objective of this presentation is to make a critical review of exposure assessments in the epidemiological studies on health effects of traffic exhaust. (author)

Exposure assessment in studies on health effects of traffic exhaust

Energy Technology Data Exchange (ETDEWEB)

Setaelae, S [Association for the Pulmonary Disabled, Helsinki (Finland); Jaakkola, J J.K. [Helsinki Univ. (Finland). Dept. of Public Health

1996-12-31

A main source of outdoor air pollution is road traffic, which produces a complex mixture of nitrogen oxides, carbon monoxide, volatile hydrocarbons, airborne particles and some other compounds. Traffic exhaust affects also the concentrations of ozone and other photo chemical oxidants. In earlier studies those components have had remarkable health effects. Several studies on occupational exposure to automobile exhaust have been published and several studies have been observed an association between both outdoor and indoor pollutant levels and health outcomes. However, there are only a few epidemiological studies in which traffic exhaust, a complex mixture, has been studied in its entirety. During recent years, interesting epidemiological studies of the health effects of this complex mixture have been published. Human exposure assessment for traffic exhaust can be categorized according to the environment of exposure (indoors, outdoors, in-traffic) or to the method of exposure assessment (direct or indirect methods). In this presentation the methods are further categorized into (1) traffic activity, (2) air concentration measurements, and (3) dispersion models, in order to better understand the advantages and disadvantages of different approaches. The objective of this presentation is to make a critical review of exposure assessments in the epidemiological studies on health effects of traffic exhaust. (author)

Non-targeted and delayed effects of exposure to ionizing radiation: II. Radiation-induced genomic instability and bystander effects in vivo, clastogenic factors and transgenerational effects

Science.gov (United States)

Morgan, William F.

2003-01-01

The goal of this review is to summarize the evidence for non-targeted and delayed effects of exposure to ionizing radiation in vivo. Currently, human health risks associated with radiation exposures are based primarily on the assumption that the detrimental effects of radiation occur in irradiated cells. Over the years a number of non-targeted effects of radiation exposure in vivo have been described that challenge this concept. These include radiation-induced genomic instability, bystander effects, clastogenic factors produced in plasma from irradiated individuals that can cause chromosomal damage when cultured with nonirradiated cells, and transgenerational effects of parental irradiation that can manifest in the progeny. These effects pose new challenges to evaluating the risk(s) associated with radiation exposure and understanding radiation-induced carcinogenesis.

Epidemiological studies on radiation carcinogenesis in human populations following acute exposure: nuclear explosions and medical radiation

International Nuclear Information System (INIS)

Fabrikant, J.I.

1981-05-01

The current knowledge of the carcinogenic effect of radiation in man is considered. The discussion is restricted to dose-incidence data in humans, particularly to certain of those epidemiological studies of human populations that are used most frequently for risk estimation for low-dose radiation carcinogenesis in man. Emphasis is placed solely on those surveys concerned with nuclear explosions and medical exposures

Comparison of cytogenetic effects after occupational exposure to X-rays with those after foetal pelvimetric exposure

International Nuclear Information System (INIS)

Kirsch-Volders, M.; Poma, K.; Verschaeve, L.; Hens, L.; Susanne, C.; Elegem, P. van

1978-01-01

In utero acute low-level exposure to X-rays (300 to 350 mrads) induces a significant increase of band-loss in G-trypsin banded chromosomes of umbilical lymphocytes. Results, however, have to be confirmed by dose-effect relation studies and analysis with spectro-photometric scanning of deleted chromosomes. The same in utero exposure induces a significant dissociaton of chromosome pair 13 as revealed by centromere-centromere, angle and association tendency analysis of chromosome distribution in comparison with a control group. Occupational chronic low-level exposure to ionizing radiation does not modify significantly the amount of SCE in lymphocytes of peripheral blood. However, an analysis of centromere-centromere distances, angle values and associaton tendencies of the different chromosome combinations clearly shows an association of chromosome pair 12-16 after exposure to ionizing radiation. It is difficult to assess the exact biological importance of the observed chromosome modifications. However, referring to the already described dissociation of human acrocentric chromosomes after in vivo exposure to low levels of phenyl Hg acetate or inorganic Pb, the chromosome distribution seems not to be significantly disturbed by chronic or acute low-level exposure to ionizing radiation. (author)

Pre-exposure Prophylaxis Against Human Immunodeficiency Virus

Directory of Open Access Journals (Sweden)

Güle ÇINAR

2018-03-01

Full Text Available According to the Center for Disease Control and Prevention (CDC, there were 2.1 million new human immunodeficiency virus (HIV cases reported worldwide in 2015, which shows that siginificant work needs to be done to prevent the transmission of HIV. Research to date has focused mainly on high-risk men who have sex with men, but many women around the world are also at a high risk for HIV transmissions. In studies conducted, the incidence of HIV infection in high-risk individuals decreases over 90% when high-risk individuals use pre-exposure prophylaxis (PreP HIV, tenofovir disoproxil fumarate-emtricitabine (TDF-FTC safely. Current data and studies on pre-exposure prophylaxis were discussed in this review.

The impact of environmental conditions on human performance: A handbood of environmental exposures. Volume 1

International Nuclear Information System (INIS)

Echeverria, D.; Barnes, V.; Bittner, A.

1994-09-01

A comprehensive review of the technical literature was conducted regarding the impact of environmental conditions on hyman performance applicable to nuclear power plant workers. The environmental conditions considered were vibration, noise, heat, cold, and light. Research staff identified potential human performance deficits (e.g., decreased dexterity, impaired vision, hearing loss, memory deficiency) along a continuum of increasing occupational exposure, ranging from exposures that result in no deficit to exposures that resulted in significant performance problems. Specific deficits were included in the report if there was sound scientific evidence that environmental exposure resulted in those performance deficits. The levels associated with each deficit were then compared to the protection afforded by existing occupational exposure standards. Volume 1 is a handbook for use by NRC inspectors to help them determine the impact of specific environmental conditions on licensee personnel performance. it discusses the units used to measure each condition, discusses the effects of the condition on task performance, presents an example of the assessment of each condition in a nuclear power plant, and discusses potential methods for reducing the effects of

Health effects assessment of exposure to particles from wood smoke

Energy Technology Data Exchange (ETDEWEB)

Nielsen, Elsa; Dybdahl, M [Technical Univ. of Denmark, National Food Institute, Dept. of Toxicology and Risk Assessment, Soeborg (Denmark); Larsen, Poul Bo [Danish Environmental Protection Agency, Copenhagen (Denmark)

2008-07-01

The number of residential wood burning devices has increased in Denmark during the latest years and it has been estimated that there in 2005 were about 551,000 wood stoves and about 48,000 wood boilers in Denmark. This has resulted in an increased exposure of the general Danish population to pollutants associated with residential wood smoke. New Danish monitoring results on particulate matter (PM) in ambient air have shown elevated PM levels in areas with many wood stoves, particularly during wintertime when wood burning is common. Due to the size distribution of wood smoke particles essentially all will be contained in the PM{sub 2.5} fraction. It has been estimated that about 17,665 tonnes PM{sub 2.5} per year (2005) in Denmark come from residential wood combustion. Therefore, there is an increasing concern that adverse human health effects might be associated with the increased exposure to residential wood smoke. This project has been set up in order to review the scientific literature concerning adverse health effects of pollutants associated with residential wood smoke with the main focus on particulate matter and to quantify and evaluate, if possible, the impact on human health of the increased exposure to particles in residential wood smoke. (au)

Human exposure to ionizing radiation for medical reasons

International Nuclear Information System (INIS)

Thomas, R.H.; Busick, D.D.

1977-01-01

The central issue in this debate is not whether there is a threshold dose below which deleterious effects in humans occur nor whether the dose-effect relationship is linear or curvilinear. The central issue is whether there is merit in a continuing effort to reduce radiation exposures to patients no matter at what level. This should be determined by a careful balancing of potential risks against expected benefits. It is this element of risk-benefit analysis that is absent in Morgan's philosophy. A good example of the changing nature on the risk-benefit balance is that of the use of mass radiography programs to diagnose tuberculosis. Before the Second World War this disease was a terrible scourge of the poor who could ill-afford adequate medical care. The use of mass radiography programs have played a large part in the elimination of this disease

Major national human biomonitoring programs in chemical exposure assessment

Directory of Open Access Journals (Sweden)

Judy Choi

2015-07-01

Full Text Available Human biomonitoring (HBM programs have been established in several countries around the world in order to monitor the levels of chemical exposures in the general population and qualify health risk assessment of national and international interest. Study design, population, sample collection, and chemical analysis must be considered when comparing and interpreting the results. In this review, the objectives and brief descriptions of the major national HBM programs in North America, Europe, and Asia are provided. Similarities and differences observed from a comparative analysis among these programs, including the stratification of data according to age, sex, socioeconomic background, etc. as well as the identification of chemical exposure associated with food intake, are discussed. Overall, although there are some discrepancies in the study designs among the reviewed national HBM programs, results from the programs can provide useful information such as chemical levels found within the general population of a country that can be compared. Furthermore, the results can be used by regulatory authorities or the government to enforce legislations in order to reduce the exposure of chemicals into the human body.

Human exposure, biomarkers, and fate of organotins in the environment.

Science.gov (United States)

Okoro, Hussein K; Fatoki, Olalekan S; Adekola, Folahan A; Ximba, Bhekumusa J; Snyman, Reinette G; Opeolu, Beatrice

2011-01-01

Organotin compounds result from the addition of organic moieties to inorganic tin.Thus, one or more tin-carbon bonds exist in each organotin molecule. The organo-tin compounds are ubiquitous in the environment. Organotin compounds have many uses, including those as fungicides and stabilizers in plastics, among others in industry. The widespread use of organotins as antifouling agents in boat paints has resulted in pollution of freshwater and marine ecosystems. The presence of organotin compounds in freshwater and marine ecosystems is now understood to be a threat, because of the amounts found in water and the toxicity of some organotin compounds to aquatic organisms, and perhaps to humans as well. Organotin com-pounds are regarded by many to be global pollutants of a stature similar to biphenyl,mercury, and the polychlorinated dibenzodioxins. This stature results from the high toxicity, persistence, bioaccumulation, and endocrine disruptive features of even very low levels of selected organotin compounds.Efforts by selected governmental agencies and others have been undertaken to find a global solution to organotin pollution. France was the first country to ban the use of the organotins in 1980. This occurred before the international maritime organization (IMO) called for a global treaty to ban the application of tributyltin (TBT)-based paints. In this chapter, we review the organotin compounds with emphasis on the human exposure, fate, and distribution of them in the environment. The widespread use of the organotins and their high stability have led to contamination of some aquatic ecosystems. As a result, residues of the organotins may reach humans via food consumption. Notwithstanding the risk of human exposure, only limited data are available on the levels at which the organotins exist in foodstuffs consumed by humans. Moreover, the response of marine species to the organotins, such as TBT, has not been thoroughly investigated. Therefore, more data on the

Assessing Sources of Human Methylmercury Exposure Using Stable Mercury Isotopes

DEFF Research Database (Denmark)

Li, Miling; Sherman, Laura S; Blum, Joel D

2014-01-01

Seafood consumption is the primary route of methylmercury (MeHg) exposure for most populations. Inherent uncertainties in dietary survey data point to the need for an empirical tool to confirm exposure sources. We therefore explore the utility of Hg stable isotope ratios in human hair as a new...... method for discerning MeHg exposure sources. We characterized Hg isotope fractionation between humans and their diets using hair samples from Faroese whalers exposed to MeHg predominantly from pilot whales. We observed an increase of 1.75‰ in δ(202)Hg values between pilot whale muscle tissue and Faroese...... whalers' hair but no mass-independent fractionation. We found a similar offset in δ(202)Hg between consumed seafood and hair samples from Gulf of Mexico recreational anglers who are exposed to lower levels of MeHg from a variety of seafood sources. An isotope mixing model was used to estimate individual...

Exposure to Carbon Nanotube Material: Assessment of Nanotube Cytotoxicity Using Human Keratinocyte Cells

Science.gov (United States)

Shvedova, Anna A.; Castranova, Vincent; Kisin, Elena R.; Schwegler-Berry, Diane; Murray, Ashley R.; Gandelsman, Vadim Z.; Maynard, Andrew; Baron, Paul

2003-01-01

Carbon nanotubes are new members of carbon allotropes similar to fullerenes and graphite. Because of their unique electrical, mechanical, and thermal properties, carbon nanotubes are important for novel applications in the electronics, aerospace, and computer industries. Exposure to graphite and carbon materials has been associated with increased incidence of skin diseases, such as carbon fiber dermatitis, hyperkeratosis, and naevi. We investigated adverse effects of single-wall carbon nanotubes (SWCNT) using a cell culture of immortalized human epidermal keratinocytes (HaCaT). After 18 h of exposure of HaCaT to SWCNT, oxidative stress and cellular toxicity were indicated by formation of free radicals, accumulation of peroxidative products, antioxidant depletion, and loss of cell viability. Exposure to SWCNT also resulted in ultrastructural and morphological changes in cultured skin cells. These data indicate that dermal exposure to unrefined SWCNT may lead to dermal toxicity due to accelerated oxidative stress in the skin of exposed workers.

FDTD computation of human eye exposure to ultra-wideband electromagnetic pulses

Energy Technology Data Exchange (ETDEWEB)

Simicevic, Neven [Center for Applied Physics Studies, Louisiana Tech University, Ruston, LA 71272 (United States)], E-mail: neven@phys.latech.edu

2008-03-21

With an increase in the application of ultra-wideband (UWB) electromagnetic pulses in the communications industry, radar, biotechnology and medicine, comes an interest in UWB exposure safety standards. Despite an increase of the scientific research on bioeffects of exposure to non-ionizing UWB pulses, characterization of those effects is far from complete. A numerical computational approach, such as a finite-difference time domain (FDTD) method, is required to visualize and understand the complexity of broadband electromagnetic interactions. The FDTD method has almost no limits in the description of the geometrical and dispersive properties of the simulated material, it is numerically robust and appropriate for current computer technology. In this paper, a complete calculation of exposure of the human eye to UWB electromagnetic pulses in the frequency range of 3.1-10.6, 22-29 and 57-64 GHz is performed. Computation in this frequency range required a geometrical resolution of the eye of 0.1 mm and an arbitrary precision in the description of its dielectric properties in terms of the Debye model. New results show that the interaction of UWB pulses with the eye tissues exhibits the same properties as the interaction of the continuous electromagnetic waves (CWs) with the frequencies from the pulse's frequency spectrum. It is also shown that under the same exposure conditions the exposure to UWB pulses is from one to many orders of magnitude safer than the exposure to CW.

FDTD computation of human eye exposure to ultra-wideband electromagnetic pulses.

Science.gov (United States)

Simicevic, Neven

2008-03-21

With an increase in the application of ultra-wideband (UWB) electromagnetic pulses in the communications industry, radar, biotechnology and medicine, comes an interest in UWB exposure safety standards. Despite an increase of the scientific research on bioeffects of exposure to non-ionizing UWB pulses, characterization of those effects is far from complete. A numerical computational approach, such as a finite-difference time domain (FDTD) method, is required to visualize and understand the complexity of broadband electromagnetic interactions. The FDTD method has almost no limits in the description of the geometrical and dispersive properties of the simulated material, it is numerically robust and appropriate for current computer technology. In this paper, a complete calculation of exposure of the human eye to UWB electromagnetic pulses in the frequency range of 3.1-10.6, 22-29 and 57-64 GHz is performed. Computation in this frequency range required a geometrical resolution of the eye of 0.1 mm and an arbitrary precision in the description of its dielectric properties in terms of the Debye model. New results show that the interaction of UWB pulses with the eye tissues exhibits the same properties as the interaction of the continuous electromagnetic waves (CWs) with the frequencies from the pulse's frequency spectrum. It is also shown that under the same exposure conditions the exposure to UWB pulses is from one to many orders of magnitude safer than the exposure to CW.

FDTD computation of human eye exposure to ultra-wideband electromagnetic pulses

International Nuclear Information System (INIS)

Simicevic, Neven

2008-01-01

With an increase in the application of ultra-wideband (UWB) electromagnetic pulses in the communications industry, radar, biotechnology and medicine, comes an interest in UWB exposure safety standards. Despite an increase of the scientific research on bioeffects of exposure to non-ionizing UWB pulses, characterization of those effects is far from complete. A numerical computational approach, such as a finite-difference time domain (FDTD) method, is required to visualize and understand the complexity of broadband electromagnetic interactions. The FDTD method has almost no limits in the description of the geometrical and dispersive properties of the simulated material, it is numerically robust and appropriate for current computer technology. In this paper, a complete calculation of exposure of the human eye to UWB electromagnetic pulses in the frequency range of 3.1-10.6, 22-29 and 57-64 GHz is performed. Computation in this frequency range required a geometrical resolution of the eye of 0.1 mm and an arbitrary precision in the description of its dielectric properties in terms of the Debye model. New results show that the interaction of UWB pulses with the eye tissues exhibits the same properties as the interaction of the continuous electromagnetic waves (CWs) with the frequencies from the pulse's frequency spectrum. It is also shown that under the same exposure conditions the exposure to UWB pulses is from one to many orders of magnitude safer than the exposure to CW

Characterizing the impact of projected changes in climate and air quality on human exposures to ozone.

Science.gov (United States)

Dionisio, Kathie L; Nolte, Christopher G; Spero, Tanya L; Graham, Stephen; Caraway, Nina; Foley, Kristen M; Isaacs, Kristin K

2017-05-01

The impact of climate change on human and environmental health is of critical concern. Population exposures to air pollutants both indoors and outdoors are influenced by a wide range of air quality, meteorological, behavioral, and housing-related factors, many of which are also impacted by climate change. An integrated methodology for modeling changes in human exposures to tropospheric ozone (O 3 ) owing to potential future changes in climate and demographics was implemented by linking existing modeling tools for climate, weather, air quality, population distribution, and human exposure. Human exposure results from the Air Pollutants Exposure Model (APEX) for 12 US cities show differences in daily maximum 8-h (DM8H) exposure patterns and levels by sex, age, and city for all scenarios. When climate is held constant and population demographics are varied, minimal difference in O 3 exposures is predicted even with the most extreme demographic change scenario. In contrast, when population is held constant, we see evidence of substantial changes in O 3 exposure for the most extreme change in climate. Similarly, we see increases in the percentage of the population in each city with at least one O 3 exposure exceedance above 60 p.p.b and 70 p.p.b thresholds for future changes in climate. For these climate and population scenarios, the impact of projected changes in climate and air quality on human exposure to O 3 are much larger than the impacts of changing demographics. These results indicate the potential for future changes in O 3 exposure as a result of changes in climate that could impact human health.

Exposure to CB-153 and p,p'-DDE and human sperm chromatin integrity

Energy Technology Data Exchange (ETDEWEB)

Rignell-Hydbom, A.; Rylander, L.; Joensson, B.A.G.; Hagmar, L. [Dept. of Occupational and Environmental Medicine, Lund Univ. Hospital (Sweden); Giwercman, A. [Fertility Centre, Malmoe Univ. hospital (Sweden); Spano, M. [Section of Toxicology and Biomedical Sciences, ENEA Casaccia Research Centre, Rome (Italy)

2004-09-15

In Sweden, the consumption of fatty fish from the Baltic Sea (off the Swedish east coast) is the single most important source of exposure to persistent organochlorine pollutants (POPs). Fishermen from the east coast have averagely higher plasma levels of polychlorinated biphenyls (PCBs) and total POP derived TEQ in plasma than both west coast fishermen and men from the general population. Dichlorodiphenyl dichloroethene (p,p'-DDE), a relevant biomarker for POP is still present in relatively high serum concentrations in men consuming fish from the Baltic Sea. Several studies have shown that POPs are capable of interfering with reproductive and endocrine function in animals. Human studies have shown that exposure to PCBs and polychlorinated dibenzofurans (PCDFs) has a negative effect on male reproductive function, and especially sperm motility seems vulnerable. However, studies relating to human sperm genetic integrity are few. The aim of the study was to investigate whether exposure to POP using 2,2',4,4',5,5'- hexachlorobiphenyl (CB-153) and p,p'-DDE as biomarkers, are associated with sperm chromatin integrity. In order to ensure a sufficient variation in POP exposure fishermen from both the Swedish east (''more exposed'') and west coasts (''less exposed'') formed the study base.

A hybrid modeling with data assimilation to evaluate human exposure level

Science.gov (United States)

Koo, Y. S.; Cheong, H. K.; Choi, D.; Kim, A. L.; Yun, H. Y.

2015-12-01

Exposure models are designed to better represent human contact with PM (Particulate Matter) and other air pollutants such as CO, SO2, O3, and NO2. The exposure concentrations of the air pollutants to human are determined by global and regional long range transport of global and regional scales from Europe and China as well as local emissions from urban and road vehicle sources. To assess the exposure level in detail, the multiple scale influence from background to local sources should be considered. A hybrid air quality modeling methodology combing a grid-based chemical transport model with a local plume dispersion model was used to provide spatially and temporally resolved air quality concentration for human exposure levels in Korea. In the hybrid modeling approach, concentrations from a grid-based chemical transport model and a local plume dispersion model are added to provide contributions from photochemical interactions, long-range (regional) transport and local-scale dispersion. The CAMx (Comprehensive Air quality Model with Extensions was used for the background concentrations from anthropogenic and natural emissions in East Asia including Korea while the road dispersion by vehicle emission was calculated by CALPUFF model. The total exposure level of the pollutants was finally assessed by summing the background and road contributions. In the hybrid modeling, the data assimilation method based on the optimal interpolation was applied to overcome the discrepancies between the model predicted concentrations and observations. The air quality data from the air quality monitoring stations in Korea. The spatial resolution of the hybrid model was 50m for the Seoul Metropolitan Ares. This example clearly demonstrates that the exposure level could be estimated to the fine scale for the exposure assessment by using the hybrid modeling approach with data assimilation.

Health effects assessment of chemical exposures: ARIES methodology

Energy Technology Data Exchange (ETDEWEB)

Sierra, L; Montero, M.; Rabago, I.; Vidania, R.

1995-07-01

In this work, we present ARIES* update: a system designed in order to facilitate the human health effects assessment produced by accidental release of toxic chemicals. The first version of ARIES was developed in relation to 82/501/EEC Directive about mayor accidents in the chemical industry. So, the first aim was the support of the effects assessment derived for the chemicals included into this directive. From this establishment, it was considered acute exposures for high concentrations. In this report, we present the actual methodology for considering other type of exposures, such as environmental and occupational. Likewise other versions, the methodology comprises two approaches: quantitative and qualitative assessments. Quantitative assessment incorporates the mathematical algorithms useful to evaluate the effects produced by the most important routes of exposure: inhalation, ingestion, eye contact and skin absorption, in a short, medium and long term. It has been included models that realizes an accurate quantification of doses, effects,... and so on, such as simple approaches when the available information is not enough. Qualitative assessment, designed in order to complement or replace the previous one, is incorporated into an informatics system, developed in Clipper. It executes and displays outstanding and important toxicological information of about 100 chemicals. This information comes from ECDIN (Environmental Chemicals Data and Information Network) database through a collaboration with JRC-ISPRA working group. (Author) 24 refs.

Health effects assessment of chemical exposures: ARIES methodology

International Nuclear Information System (INIS)

Sierra, L; Montero, M.; Rabago, I.; Vidania, R.

1995-01-01

In this work, we present ARIES* update: a system designed in order to facilitate the human health effects assessment produced by accidental release of toxic chemicals. The first version of ARIES was developed in relation to 82/501/EEC Directive about mayor accidents in the chemical industry. So, the first aim was the support of the effects assessment derived for the chemicals included into this directive. From this establishment, it was considered acute exposures for high concentrations. In this report, we present the actual methodology for considering other type of exposures, such as environmental and occupational. Likewise other versions, the methodology comprises two approaches: quantitative and qualitative assessments. Quantitative assessment incorporates the mathematical algorithms useful to evaluate the effects produced by the most important routes of exposure: inhalation, ingestion, eye contact and skin absorption, in a short, medium and long term. It has been included models that realizes an accurate quantification of doses, effects,... and so on, such as simple approaches when the available information is not enough. Qualitative assessment, designed in order to complement or replace the previous one, is incorporated into an informatics system, developed in Clipper. It executes and displays outstanding and important toxicological information of about 100 chemicals. This information comes from ECDIN (Environmental Chemicals Data and Information Network) database through a collaboration with JRC-ISPRA working group. (Author) 24 refs

The U.S. National Health and Nutrition Examination Survey and human exposure to environmental chemicals.

Science.gov (United States)

Calafat, Antonia M

2012-02-01

Researchers are increasingly interested in using human biomonitoring - the measurement of chemicals, their metabolites or specific reaction products in biological specimens/body fluids - for investigating exposure to environmental chemicals. General population human biomonitoring programs are useful for investigating human exposure to environmental chemicals and an important tool for integrating environment and health. One of these programs, the National Health and Nutrition Examination Survey (NHANES), conducted in the United States is designed to collect data on the health and nutritional status of the noninstitutionalized, civilian U.S. population. NHANES includes a physical examination, collecting a detailed medical history, and collecting biological specimens (i.e., blood and urine). These biological specimens can be used to assess exposure to environmental chemicals. NHANES human biomonitoring data can be used to establish reference ranges for selected chemicals, provide exposure data for risk assessment, and monitor exposure trends. Published by Elsevier GmbH.

Effects after prenatal radiation exposures

International Nuclear Information System (INIS)

Streffer, C.

2001-01-01

The mammalian organism is highly radiosensitive during all prenatal developmental periods. For most effects a dose relationship with a threshold is observed. These threshold doses are generally above the exposures from medical diagnostic procedures. The quality and extent of radiation effects are very much dependent on the developmental stage during which an exposure takes place and on the radiation dose. An exposure during the preimplantation period will cause lethality. Malformations are usually induced after exposures during the major organogenesis. Growth retardation is also possible during the late organogenesis and foetal periods. The lower limits of threshold doses for these effects are in the range of 100 mGy. A radiation exposure during the early foetal period can lead to severe mental retardation and impairment of intelligence. There are very serious effects with radiation doses above 0.3 Gy. Carcinogenesis can apparently occur after radiation exposures during the total prenatal development period. The radiation risk factor up to now has not been clear, but it seems that it is in the range of risk factors for cancer that are observed after exposures during childhood. For radiation doses that are used in radiological diagnostics the risk is zero or very low. A termination of pregnancy after doses below 100 mGy should not be considered. (author)

Exposure to perfluorinated compounds and human semen quality in Arctic and European populations

DEFF Research Database (Denmark)

Toft, G; Jönsson, B A G; Lindh, C H

2012-01-01

Perfluorinated compounds (PFCs) have been suspected to adversely affect human reproductive health. The aim of this study was to investigate the associations between PFC exposure and male semen quality.......Perfluorinated compounds (PFCs) have been suspected to adversely affect human reproductive health. The aim of this study was to investigate the associations between PFC exposure and male semen quality....

77 FR 52025 - Notification of a Public Teleconference of the Science Advisory Board; Exposure and Human Health...

Science.gov (United States)

2012-08-28

... Science Advisory Board; Exposure and Human Health Committee AGENCY: Environmental Protection Agency (EPA... Office announces a public teleconference of the SAB Exposure and Human Health Committee to discuss its... hereby given that the SAB Exposure and Human Health Committee (EHHC) will hold a public teleconference to...

Epigenetic Effects of Cannabis Exposure

Science.gov (United States)

Szutorisz, Henrietta; Hurd, Yasmin L.

2015-01-01

The past decade has witnessed a number of societal and political changes that have raised critical questions about the long-term impact of marijuana (Cannabis sativa) that are especially important given the prevalence of its abuse and that potential long-term effects still largely lack scientific data. Disturbances of the epigenome have generally been hypothesized as the molecular machinery underlying the persistent, often tissue-specific transcriptional and behavioral effects of cannabinoids that have been observed within one’s lifetime and even into the subsequent generation. Here, we provide an overview of the current published scientific literature that examined epigenetic effects of cannabinoids. Though mechanistic insights about the epigenome remain sparse, accumulating data in humans and animal models have begun to reveal aberrant epigenetic modifications in brain and the periphery linked to cannabis exposure. Expansion of such knowledge and causal molecular relationships could help provide novel targets for future therapeutic interventions. PMID:26546076

Can profiles of poly- and Perfluoroalkyl substances (PFASs) in human serum provide information on major exposure sources?

Science.gov (United States)

Hu, Xindi C; Dassuncao, Clifton; Zhang, Xianming; Grandjean, Philippe; Weihe, Pál; Webster, Glenys M; Nielsen, Flemming; Sunderland, Elsie M

2018-02-01

Humans are exposed to poly- and perfluoroalkyl substances (PFASs) from diverse sources and this has been associated with negative health impacts. Advances in analytical methods have enabled routine detection of more than 15 PFASs in human sera, allowing better profiling of PFAS exposures. The composition of PFASs in human sera reflects the complexity of exposure sources but source identification can be confounded by differences in toxicokinetics affecting uptake, distribution, and elimination. Common PFASs, such as perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS) and their precursors are ubiquitous in multiple exposure sources. However, their composition varies among sources, which may impact associated adverse health effects. We use available PFAS concentrations from several demographic groups in a North Atlantic seafood consuming population (Faroe Islands) to explore whether chemical fingerprints in human sera provide insights into predominant exposure sources. We compare serum PFAS profiles from Faroese individuals to other North American populations to investigate commonalities in potential exposure sources. We compare individuals with similar demographic and physiological characteristics and samples from the same years to reduce confounding by toxicokinetic differences and changing environmental releases. Using principal components analysis (PCA) confirmed by hierarchical clustering, we assess variability in serum PFAS concentrations across three Faroese groups. The first principal component (PC)/cluster consists of C9-C12 perfluoroalkyl carboxylates (PFCAs) and is consistent with measured PFAS profiles in consumed seafood. The second PC/cluster includes perfluorohexanesulfonic acid (PFHxS) and the PFOS precursor N-ethyl perfluorooctane sulfonamidoacetate (N-EtFOSAA), which are directly used or metabolized from fluorochemicals in consumer products such as carpet and food packaging. We find that the same compounds are associated with the same

Human brain wave activity during exposure to radiofrequency field emissions from mobile phones

International Nuclear Information System (INIS)

D'Costa, H.; Cosic, I.

2003-01-01

The aim of this study was to determine whether there is an effect of mobile phone electromagnetic field emissions on the human electroencephalograph (EEG). EEG recordings from ten awake subjects were taken during exposure to radiofrequency (RF) emissions from a mobile phone positioned behind the head. Two experimental trials were conducted. In the first trial, RF exposures were generated by a GSM mobile phone with the speaker disabled and configured to transmit at full-radiated power. During the second trial, exposures were generated by a non-modified GSM mobile phone in active standby mode. For each trial, subjects were exposed in five minute intervals to a randomized, interrupted sequence of five active and five sham exposures. The experiment was conducted under single-blind conditions. The average EEG band power in active exposure recordings was compared to corresponding sham recordings. Statistical tests indicated significant difference in the full-power mode trial within the EEG alpha (8-13 Hz) and beta (13-32 Hz) bands. A subsequent statistical analysis of median spectral power in discrete EEG rhythms revealed significant differences in 7 of the 32 distinct frequencies overall. In conclusion, the results of this study lend support to EEG effects from mobile phones activated in talk-mode. Copyright (2003) Australasian College of Physical Scientists and Engineers in Medicine

Co-exposure to nickel and cobalt chloride enhances cytotoxicity and oxidative stress in human lung epithelial cells.

Science.gov (United States)

Patel, Eshan; Lynch, Christine; Ruff, Victoria; Reynolds, Mindy

2012-02-01

Nickel and cobalt are heavy metals found in land, water, and air that can enter the body primarily through the respiratory tract and accumulate to toxic levels. Nickel compounds are known to be carcinogenic to humans and animals, while cobalt compounds produce tumors in animals and are probably carcinogenic to humans. People working in industrial and manufacturing settings have an increased risk of exposure to these metals. The cytotoxicity of nickel and cobalt has individually been demonstrated; however, the underlying mechanisms of co-exposure to these heavy metals have not been explored. In this study, we investigated the effect of exposure of H460 human lung epithelial cells to nickel and cobalt, both alone and in combination, on cell survival, apoptotic mechanisms, and the generation of reactive oxygen species and double strand breaks. For simultaneous exposure, cells were exposed to a constant dose of 150 μM cobalt or nickel, which was found to be relatively nontoxic in single exposure experiments. We demonstrated that cells exposed simultaneously to cobalt and nickel exhibit a dose-dependent decrease in survival compared to the cells exposed to a single metal. The decrease in survival was the result of enhanced caspase 3 and 7 activation and cleavage of poly (ADP-ribose) polymerase. Co-exposure increased the production of ROS and the formation of double strand breaks. Pretreatment with N-acetyl cysteine alleviated the toxic responses. Collectively, this study demonstrates that co-exposure to cobalt and nickel is significantly more toxic than single exposure and that toxicity is related to the formation of ROS and DSB. Copyright © 2011 Elsevier Inc. All rights reserved.

Human mercury exposure associated with small-scale gold mining in Burkina Faso.

Science.gov (United States)

Tomicic, Catherine; Vernez, David; Belem, Tounaba; Berode, Michèle

2011-06-01

In Burkina Faso, gold ore is one of the main sources of income for an important part of the active population. Artisan gold miners use mercury in the extraction, a toxic metal whose human health risks are well known. The aim of the present study was to assess mercury exposure as well as to understand the exposure determinants of gold miners in Burkinabe small-scale mines. The examined gold miners' population on the different selected gold mining sites was composed by persons who were directly and indirectly related to gold mining activities. But measurement of urinary mercury was performed on workers most susceptible to be exposed to mercury. Thus, occupational exposure to mercury was evaluated among ninety-three workers belonging to eight different gold mining sites spread in six regions of Burkina Faso. Among others, work-related exposure determinants were taken into account for each person during urine sampling as for example amalgamating or heating mercury. All participants were medically examined by a local medical team in order to identify possible symptoms related to the toxic effect of mercury. Mercury levels were high, showing that 69% of the measurements exceeded the ACGIH (American Conference of Industrial Hygienists) biological exposure indice (BEI) of 35 μg per g of creatinine (μg/g-Cr) (prior to shift) while 16% even exceeded 350 μg/g-Cr. Basically, unspecific but also specific symptoms related to mercury toxicity could be underlined among the persons who were directly related to gold mining activities. Only one-third among the studied subpopulation reported about less than three symptoms possibly associated to mercury exposure and nearly half of them suffered from at least five of these symptoms. Ore washers were more involved in the direct handling of mercury while gold dealers in the final gold recovery activities. These differences may explain the overexposure observed in gold dealers and indicate that the refining process is the major source

Risk of Adverse Health and Performance Effects of Celestial Dust Exposure

Science.gov (United States)

Scully, Robert R.; Meyers, Valerie E.

2015-01-01

silica (Permissible Exposure Limit [PEL] 0.05 mg/m3) but more toxic than the nuisance dust titanium dioxide (TiO2 [PEL 5.0 mg/m3]). A PEL for episodic exposure to airborne lunar dust during a six-month stay on the lunar surface was established, in consultation with an independent, extramural panel of expert pulmonary toxicologists, at 0.3 mg/m3. The PEL provided for lunar dust is limited to the conditions and exposure specified therefore additional research remains to be accomplished with lunar dust to further address the issues of activation, address other areas of more unique lunar geology (Glotch et al., 2010; Greenhagen et al., 2010), examine potential toxicological effects of inhaled or ingested dust upon other organ systems, such cardiovascular, nervous systems, and examine effects of acute exposure to massive doses of dust such as may occur during off-nominal situations. Work to support the establishment of PELs for Martian dust and dusts of asteroids remains to be accomplished. The literature that describes health effects of exposure to toxic terrestrial dusts provides substantial basis for concern that prolonged exposure to respirable celestial dust could be detrimental to human health. Celestial bodies where a substantial portion of the dust is in the respirable range or where the dusts have large reactive surface areas or contain transition metals or volatile organics, represent greater risks of adverse effects from exposure to the dust. It is possible that in addition to adverse effects to the respiratory system, inhalation and ingestion of celestial dusts could pose risks to other systems

Developing human health exposure scenarios for petroleum substances under REACH

Energy Technology Data Exchange (ETDEWEB)

Carter, M.; De Wilde, P.; Maksimainen, K.; Margary, A.; Money, C.; Pizzella, G.; Svanehav, T.; Tsang, W.; Urbanus, J.; Rohde, A.

2012-12-15

This report describes the approaches that were adopted by CONCAWE to prepare the human exposure estimates in the chemical safety assessments of the REACH registration dossiers for petroleum substances based on all applicable regulatory guidance. Separate exposure estimates were developed for workers and for consumers and included inhalation and dermal routes. The complex nature of petroleum substances required various scientifically justified refinements of the regulatory guidance.

Limited infection upon human exposure to a recombinant raccoon pox vaccine vector

Science.gov (United States)

Rocke, T.E.; Dein, F.J.; Fuchsberger, M.; Fox, B.C.; Stinchcomb, D.T.; Osorio, J.G.

2004-01-01

A laboratory accident resulted in human exposure to a recombinant raccoon poxvirus (RCN) developed as a vaccine vector for antigens of Yersinia pestis for protection of wild rodents (and other animals) against plague. Within 9 days, the patient developed a small blister that healed within 4 weeks. Raccoon poxvirus was cultured from the lesion, and the patient developed antibody to plague antigen (F1) and RCN. This is the first documented case of human exposure to RCN.

Limited infection upon human exposure to a recombinant raccoon pox vaccine vector.

Science.gov (United States)

Rocke, Tonie E; Dein, F Joshua; Fuchsberger, Martina; Fox, Barry C; Stinchcomb, Dan T; Osorio, Jorge E

2004-07-29

A laboratory accident resulted in human exposure to a recombinant raccoon poxvirus (RCN) developed as a vaccine vector for antigens of Yersinia pestis for protection of wild rodents (and other animals) against plague. Within 9 days, the patient developed a small blister that healed within 4 weeks. Raccoon poxvirus was cultured from the lesion, and the patient developed antibody to plague antigen (F1) and RCN. This is the first documented case of human exposure to RCN.

Development of Combining of Human Bronchial Mucosa Models with XposeALI® for Exposure of Air Pollution Nanoparticles.

Directory of Open Access Journals (Sweden)

Jie Ji

Full Text Available Exposure to agents via inhalation is of great concerns both in workplace environment and in the daily contact with particles in the ambient air. Reliable human airway exposure systems will most likely replace animal experiment in future toxicity assessment studies of inhaled agents.In this study, we successfully established a combination of an exposure system (XposeALI with 3D models mimicking both healthy and chronic bronchitis-like mucosa by co-culturing human primary bronchial epithelial cells (PBEC and fibroblast at air-liquid interface (ALI. Light-, confocal microscopy, scanning- and transmission electron microscopy, transepithelial electrical resistance (TEER measurement and RT-PCR were performed to identify how the PBEC differentiated under ALI culture condition. Both models were exposed to palladium (Pd nanoparticles which sized 6-10 nm, analogous to those released from modern car catalysts, at three different concentrations utilizing the XposeALI module of the PreciseInhale® exposure system.Exposing the 3D models to Pd nanoparticles induced increased secretion of IL-8, yet the chronic bronchitis-like model released significantly more IL-8 than the normal model. The levels of IL-8 in basal medium (BM and apical lavage medium (AM were in the same ranges, but the secretion of MMP-9 was significantly higher in the AM compared to the BM.This combination of relevant human bronchial mucosa models and sophisticated exposure system can mimic in vivo conditions and serve as a useful alternative animal testing tool when studying adverse effects in humans exposed to aerosols, air pollutants or particles in an occupational setting.

Development of Combining of Human Bronchial Mucosa Models with XposeALI® for Exposure of Air Pollution Nanoparticles.

Science.gov (United States)

Ji, Jie; Hedelin, Anna; Malmlöf, Maria; Kessler, Vadim; Seisenbaeva, Gulaim; Gerde, Per; Palmberg, Lena

2017-01-01

Exposure to agents via inhalation is of great concerns both in workplace environment and in the daily contact with particles in the ambient air. Reliable human airway exposure systems will most likely replace animal experiment in future toxicity assessment studies of inhaled agents. In this study, we successfully established a combination of an exposure system (XposeALI) with 3D models mimicking both healthy and chronic bronchitis-like mucosa by co-culturing human primary bronchial epithelial cells (PBEC) and fibroblast at air-liquid interface (ALI). Light-, confocal microscopy, scanning- and transmission electron microscopy, transepithelial electrical resistance (TEER) measurement and RT-PCR were performed to identify how the PBEC differentiated under ALI culture condition. Both models were exposed to palladium (Pd) nanoparticles which sized 6-10 nm, analogous to those released from modern car catalysts, at three different concentrations utilizing the XposeALI module of the PreciseInhale® exposure system. Exposing the 3D models to Pd nanoparticles induced increased secretion of IL-8, yet the chronic bronchitis-like model released significantly more IL-8 than the normal model. The levels of IL-8 in basal medium (BM) and apical lavage medium (AM) were in the same ranges, but the secretion of MMP-9 was significantly higher in the AM compared to the BM. This combination of relevant human bronchial mucosa models and sophisticated exposure system can mimic in vivo conditions and serve as a useful alternative animal testing tool when studying adverse effects in humans exposed to aerosols, air pollutants or particles in an occupational setting.

Measuring the Bioenergetic Effects of 1,2-Naphthoquinone Exposure on Human Lung Macrophages Using Seahorse Extracellular Flux Analyses

Science.gov (United States)

Exposure to ambient particulate matter (PM) is one of the leading causes of morbidity and mortality in humans. Quinones are organic PM components that induce inflammatory responses through redox cycling and electrophilic attack. 1,2-naphthoquinone (1,2-NQ) has previously been sho...

Effects of Low Doses of Ionizing Radiation Exposures on Stress-Responsive Gene Expression in Human Embryonic Stem Cells

Directory of Open Access Journals (Sweden)

Mykyta Sokolov

2014-01-01

Full Text Available There is a great deal of uncertainty on how low (≤0.1 Gy doses of ionizing radiation (IR affect human cells, partly due to a lack of suitable experimental model systems for such studies. The uncertainties arising from low-dose IR human data undermine practical societal needs to predict health risks emerging from diagnostic medical tests’ radiation, natural background radiation, and environmental radiological accidents. To eliminate a variability associated with remarkable differences in radioresponses of hundreds of differentiated cell types, we established a novel, human embryonic stem cell (hESC-based model to examine the radiobiological effects in human cells. Our aim is to comprehensively elucidate the gene expression changes in a panel of various hESC lines following low IR doses of 0.01; 0.05; 0.1 Gy; and, as a reference, relatively high dose of 1 Gy of IR. Here, we examined the dynamics of transcriptional changes of well-established IR-responsive set of genes, including CDKN1A, GADD45A, etc. at 2 and 16 h post-IR, representing “early” and “late” radioresponses of hESCs. Our findings suggest the temporal- and hESC line-dependence of stress gene radioresponses with no statistically significant evidence for a linear dose-response relationship within the lowest doses of IR exposures.

Evaluating the effect of human activity patterns on air pollution exposure using an integrated field-based and agent-based modelling framework

Science.gov (United States)

Schmitz, Oliver; Beelen, Rob M. J.; de Bakker, Merijn P.; Karssenberg, Derek

2015-04-01

Constructing spatio-temporal numerical models to support risk assessment, such as assessing the exposure of humans to air pollution, often requires the integration of field-based and agent-based modelling approaches. Continuous environmental variables such as air pollution are best represented using the field-based approach which considers phenomena as continuous fields having attribute values at all locations. When calculating human exposure to such pollutants it is, however, preferable to consider the population as a set of individuals each with a particular activity pattern. This would allow to account for the spatio-temporal variation in a pollutant along the space-time paths travelled by individuals, determined, for example, by home and work locations, road network, and travel times. Modelling this activity pattern requires an agent-based or individual based modelling approach. In general, field- and agent-based models are constructed with the help of separate software tools, while both approaches should play together in an interacting way and preferably should be combined into one modelling framework, which would allow for efficient and effective implementation of models by domain specialists. To overcome this lack in integrated modelling frameworks, we aim at the development of concepts and software for an integrated field-based and agent-based modelling framework. Concepts merging field- and agent-based modelling were implemented by extending PCRaster (http://www.pcraster.eu), a field-based modelling library implemented in C++, with components for 1) representation of discrete, mobile, agents, 2) spatial networks and algorithms by integrating the NetworkX library (http://networkx.github.io), allowing therefore to calculate e.g. shortest routes or total transport costs between locations, and 3) functions for field-network interactions, allowing to assign field-based attribute values to networks (i.e. as edge weights), such as aggregated or averaged

Effects of organophosphorus flame retardant TDCPP on normal human corneal epithelial cells: Implications for human health.

Science.gov (United States)

Xiang, Ping; Liu, Rong-Yan; Li, Chao; Gao, Peng; Cui, Xin-Yi; Ma, Lena Q

2017-11-01

Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) is one of the most detected organophosphorus flame retardants (OPFRs) in the environment, especially in indoor dust. Continuous daily exposure to TDCPP-containing dust may adversely impact human cornea. However, its detrimental effects on human corneal epithelium are largely unknown. In this study, we investigated the cell apoptosis in normal human corneal epithelial cells (HCECs) after TDCPP exposure and elucidated the underlying molecular mechanisms. Our data indicated a dose-dependent decrease of cell viability after TDCPP exposure with LC 50 at 202 μg/mL. A concentration-dependent apoptotic sign was observed in HCECs after exposing to ≥2 μg/mL TDCPP. Endoplasmic reticulum stress induction was evidenced by up-regulation of its biomarker genes (ATF-4, CHOP, BiP, and XBP1). Furthermore, alternation of Bcl-2/Bax expression, mitochondrial membrane potential loss, cellular ATP content decrease, and caspase-3 and -9 activity increase were observed after exposing to 2 or 20 μg/mL TDCPP. Taken together, the data implicated the involvement of endoplasmic reticulum stress in TDCPP-induced HCEC apoptosis, probably mediated by mitochondrial apoptotic pathway. Our findings showed TDCPP exposure induced toxicity to human cornea. Due to TDCPP's presence at high levels in indoor dust, further study is warranted to evaluate its health risk on human corneas. Published by Elsevier Ltd.

Brief oral stimulation, but especially oral fat exposure, elevates serum triglycerides in humans

Science.gov (United States)

Mattes, Richard D.

2009-01-01

Oral exposure to dietary fat results in an early initial spike, followed by a prolonged elevation, of serum triglycerides in humans. The physiological and pathophysiological implications remain unknown. This study sought to determine the incidence of the effect, the required fat exposure duration, and its reliability. Thirty-four healthy adults participated in four to six response-driven trials held at least a week apart. They reported to the laboratory after an overnight fast, a catheter was placed in an antecubital vein, and a blood sample was obtained. Participants then ingested 50 g of safflower oil in capsules with 500 ml of water within 15 min to mimic a high fat meal but without oral fat exposure. Blood was collected 0, 10, 20, 30, 40, 50, 60, 120, 240, 360, and 480 min after capsule ingestion with different forms (full fat, nonfat, none) and durations of oral fat exposures (10 s, 5 min, 20 min, and/or 2 h). A triglyceride response (increase of triglyceride >10 mg/dl within 30 min) was observed in 88.2%, 70.5%, and 50% of participants with full-fat, nonfat, and no oral exposure, respectively. Test-retest reliability was 75% with full-fat exposure but only 45.4% with nonfat exposure. Full-fat and nonfat exposures led to comparable significant elevations of triglyceride over no oral stimulation with 10-s exposures, but full fat led to a greater rise than nonfat with 20 min of exposure. These data indicate that nutritionally relevant oral fat exposures reliably elevate serum triglyceride concentrations in most people. PMID:19074638

Assessment of human exposure to environmental sources of nickel in Europe: Inhalation exposure.

Science.gov (United States)

Buekers, Jurgen; De Brouwere, Katleen; Lefebvre, Wouter; Willems, Hanny; Vandenbroele, Marleen; Van Sprang, Patrick; Eliat-Eliat, Maxime; Hicks, Keegan; Schlekat, Christian E; Oller, Adriana R

2015-07-15

The paper describes the inhalation nickel (Ni) exposure of humans via the environment for the regional scale in the EU, together with a tiered approach for assessing additional local exposure from industrial emissions. The approach was designed, in the context of REACH, for the purpose of assessing and controlling emissions and air quality in the neighbourhood of Ni producers and downstream users. Two Derived No Effect Level (DNEL) values for chronic inhalation exposure to total Ni in PM10 (20 and 60ngNi/m(3)) were considered. The value of 20ngNi/m(3) is the current EU air quality guidance value. The value of 60ngNi/m(3) is derived here based on recently published Ni data (Oller et al., 2014). Both values are protective for respiratory toxicity and carcinogenicity but differ in the application of toxicokinetic adjustments and cancer threshold considerations. Estimates of air Ni concentrations at the European regional scale were derived from the database of the European Environment Agency. The 50th and 90th percentile regional exposures were below both DNEL values. To assess REACH compliance at the local scale, measured ambient air data are preferred but are often unavailable. A tiered approach for the use of modelled ambient air concentrations was developed, starting with the application of the default EUSES model and progressing to more sophisticated models. As an example, the tiered approach was applied to 33 EU Ni sulphate producers' and downstream users' sites. Applying the EUSES model demonstrates compliance with a DNEL of 60ngNi/m(3) for the majority of sites, while the value of the refined modelling is demonstrated when a DNEL of 20ngNi/m(3) is considered. The proposed approach, applicable to metals in general, can be used in the context of REACH, for refining the risk characterisation and guiding the selection of risk management measures. Copyright © 2015 Elsevier B.V. All rights reserved.

Aerosol exposure versus aerosol cooling of climate: what is the optimal emission reduction strategy for human health?

Directory of Open Access Journals (Sweden)

J. Löndahl

2010-10-01

Full Text Available Particles, climate change, and health have thought-provoking interactions. Air pollution is one of the largest environmental problems concerning human health. On the other hand, aerosol particles can have a cooling effect on climate and a reduction of those emissions may result in an increased temperature globally, which in turn may have negative health effects. The objective of this work was to investigate the "total health effects" of aerosol emissions, which include both exposure to particles and consequences for climate change initiated by particles. As a case study the "total health effect" from ship emissions was derived by subtracting the number of deaths caused by exposure with the estimated number of lives saved from the cooling effect of the emissions. The analysis showed that, with current level of scientific understanding, it could not be determined whether ship emissions are negative or positive for human health on a short time scale. This first attempt to approximate the combined effect of particle emissions on health shows that reductions of particulate air pollution will in some cases (black carbon have win-win effects on health and climate, but sometimes also cause a shift from particle exposure-related health effects towards an increasing risk of health consequences from climate change. Thus, measures to reduce aerosol emissions have to be coupled with climate change mitigation actions to achieve a full health benefit on a global level.

Effects of fetal microwave radiation exposure on offspring behavior in mice

International Nuclear Information System (INIS)

Zhang Yanchun; Li Zhihui; Gao Yan; Zhang Chenggang

2015-01-01

The recent rapid development of electronic communication techniques is resulting in a marked increase in exposure of humans to electromagnetic fields (EMFs). This has raised public concerns about the health hazards of long-term environmental EMF exposure for fetuses and children. Some studies have suggested EMF exposure in children could induce nervous system disorders. However, gender-dependent effects of microwave radiation exposure on cognitive dysfunction have not previously been reported. Here we investigated whether in utero exposure to 9.417-GHz microwave throughout gestation (Days 3.5–18) affected behavior, using the open field test (OFT), elevated-plus maze (EPM), tail suspension test (TST), forced swimming test (FST) and Morris water maze (MWM). We found that mice showed less movement in the center of an open field (using the OFT) and in an open arm (using the EPM) after in utero exposure to 9.417-GHz radiation, which suggested that the mice had increased anxiety-related behavior. Mice demonstrated reduced immobility in TST and FST after in utero exposure to 9.417-GHz radiation, which suggested that the mice had decreased depression-related behavior. From the MWM test, we observed that male offspring demonstrated decreased learning and memory, while females were not affected in learning and memory, which suggested that microwaves had gender-dependent effects. In summary, we have provided the first experimental evidence of microwaves inducing gender-dependent effects. (author)

Tobacco and Pregnancy: Overview of exposures and effects

Science.gov (United States)

This opening paper will review the epidemiology of the impact of cigarette smoking and other forms of tobacco exposure on human development. Sources of exposure described include cigarettes and other forms of smoked tobacco, secondhand (environmental) tobacco smoke, several forms...

Human Rights Engagement and Exposure: New Scales to Challenge Social Work Education

Science.gov (United States)

McPherson, Jane; Abell, Neil

2012-01-01

Objectives: Advancing human rights is a core competency of U.S. social work education; yet, human rights attitudes and behaviors have never been measured in the social work literature. Thus, this article describes the development and initial validation of two scales, Human Rights Engagement in Social Work (HRESW) and Human Rights Exposure in…

Overview of Emerging Contaminants and Associated Human Health Effects

Science.gov (United States)

Lei, Meng; Zhang, Lun; Lei, Jianjun; Zong, Liang; Li, Jiahui; Wu, Zheng; Wang, Zheng

2015-01-01

In recent decades, because of significant progress in the analysis and detection of trace pollutants, emerging contaminants have been discovered and quantified in living beings and diverse environmental substances; however, the adverse effects of environmental exposure on the general population are largely unknown. This review summarizes the conclusions of the comprehensive epidemic literature and representative case reports relevant to emerging contaminants and the human body to address concerns about potential harmful health effects in the general population. The most prevalent emerging contaminants include perfluorinated compounds, water disinfection byproducts, gasoline additives, manufactured nanomaterials, human and veterinary pharmaceuticals, and UV-filters. Rare but statistically meaningful connections have been reported for a number of contaminants and cancer and reproductive risks. Because of contradictions in the outcomes of some investigations and the limited number of articles, no significant conclusions regarding the relationship between adverse effects on humans and extents of exposure can be drawn at this time. Here, we report that the current evidence is not conclusive and comprehensive and suggest prospective cohort studies in the future to evaluate the associations between human health outcomes and emerging environmental contaminants. PMID:26713315

Overview of Emerging Contaminants and Associated Human Health Effects

Directory of Open Access Journals (Sweden)

Meng Lei

2015-01-01

Full Text Available In recent decades, because of significant progress in the analysis and detection of trace pollutants, emerging contaminants have been discovered and quantified in living beings and diverse environmental substances; however, the adverse effects of environmental exposure on the general population are largely unknown. This review summarizes the conclusions of the comprehensive epidemic literature and representative case reports relevant to emerging contaminants and the human body to address concerns about potential harmful health effects in the general population. The most prevalent emerging contaminants include perfluorinated compounds, water disinfection byproducts, gasoline additives, manufactured nanomaterials, human and veterinary pharmaceuticals, and UV-filters. Rare but statistically meaningful connections have been reported for a number of contaminants and cancer and reproductive risks. Because of contradictions in the outcomes of some investigations and the limited number of articles, no significant conclusions regarding the relationship between adverse effects on humans and extents of exposure can be drawn at this time. Here, we report that the current evidence is not conclusive and comprehensive and suggest prospective cohort studies in the future to evaluate the associations between human health outcomes and emerging environmental contaminants.

Contaminant mixtures and repoductive health: Developmental toxicity effects in rats after mixed exposure to environmentally relevant endocrine disrupting chemicals, with focus on effects in females

DEFF Research Database (Denmark)

Jacobsen, Pernille Rosenskjold; Christiansen, Sofie; Hass, Ulla

proposed that a similar syndrome, called the ovarian dysgenesis syndrome (ODS), exists for females. This syndrome encompasses alterations in reproductive development caused by chemical exposure in sensitive windows of development that may result in fecundity impairments, gravid diseases, gynecological...... disorders or later onset adult diseases. However, experimental evidence on the effects of developmental exposure to environmentally relevant endocrine disrupting chemicals in females has been missing attention. Since chemical exposure can affect female reproductive development it is important to investigate......, mixtures were modeled based on high end human intakes, and the project involved two developmental mixture studies in rats, called Contamed 1 and 2. In these studies 13 chemicals where data on in vivo endocrine disrupting effects and information on human exposures was available, were selected. The tested...

Co-exposure to nickel and cobalt chloride enhances cytotoxicity and oxidative stress in human lung epithelial cells

International Nuclear Information System (INIS)

Patel, Eshan; Lynch, Christine; Ruff, Victoria; Reynolds, Mindy

2012-01-01

Nickel and cobalt are heavy metals found in land, water, and air that can enter the body primarily through the respiratory tract and accumulate to toxic levels. Nickel compounds are known to be carcinogenic to humans and animals, while cobalt compounds produce tumors in animals and are probably carcinogenic to humans. People working in industrial and manufacturing settings have an increased risk of exposure to these metals. The cytotoxicity of nickel and cobalt has individually been demonstrated; however, the underlying mechanisms of co-exposure to these heavy metals have not been explored. In this study, we investigated the effect of exposure of H460 human lung epithelial cells to nickel and cobalt, both alone and in combination, on cell survival, apoptotic mechanisms, and the generation of reactive oxygen species and double strand breaks. For simultaneous exposure, cells were exposed to a constant dose of 150 μM cobalt or nickel, which was found to be relatively nontoxic in single exposure experiments. We demonstrated that cells exposed simultaneously to cobalt and nickel exhibit a dose-dependent decrease in survival compared to the cells exposed to a single metal. The decrease in survival was the result of enhanced caspase 3 and 7 activation and cleavage of poly (ADP-ribose) polymerase. Co-exposure increased the production of ROS and the formation of double strand breaks. Pretreatment with N-acetyl cysteine alleviated the toxic responses. Collectively, this study demonstrates that co-exposure to cobalt and nickel is significantly more toxic than single exposure and that toxicity is related to the formation of ROS and DSB. -- Highlights: ► Decreased survival following simultaneous exposure to NiCl 2 and CoCl 2 . ► Enhanced caspase and PARP cleavage following co-exposure. ► Increased formation of ROS in dual exposed cells. ► N-acetyl cysteine pretreatment decreases Co and Ni toxicity. ► Co-exposure to Ni and Co enhances the formation of double strand

Truncated Levy flights and agenda-based mobility are useful for the assessment of personal human exposure

International Nuclear Information System (INIS)

Schlink, Uwe; Ragas, Ad M.J.

2011-01-01

Receptor-oriented approaches can assess the individual-specific exposure to air pollution. In such an individual-based model we analyse the impact of human mobility to the personal exposure that is perceived by individuals simulated in an exemplified urban area. The mobility models comprise random walk (reference point mobility, RPM), truncated Levy flights (TLF), and agenda-based walk (RPMA). We describe and review the general concepts and provide an inter-comparison of these concepts. Stationary and ergodic behaviour are explained and applied as well as performance criteria for a comparative evaluation of the investigated algorithms. We find that none of the studied algorithm results in purely random trajectories. TLF and RPMA prove to be suitable for human mobility modelling, because they provide conditions for very individual-specific trajectories and exposure. Suggesting these models we demonstrate the plausibility of their results for exposure to air-borne benzene and the combined exposure to benzene and nonane. - Highlights: → Human exposure to air pollutants is influenced by a person's movement in the urban area. → We provide a simulation study of approaches to modelling personal exposure. → Agenda-based models and truncated Levy flights are recommended for exposure assessment. → The procedure is demonstrated for benzene exposure in an urban region. - Truncated Levy flights and agenda-based mobility are useful for the assessment of personal human exposure.

Long-term human exposure to lead from different media and intake pathways.

Science.gov (United States)

Pizzol, Massimo; Thomsen, Marianne; Andersen, Mikael Skou

2010-10-15

Lead (Pb) is well known as an environmental pollutant: it can accumulate in various media, so actual lead exposure reflects both historical and present contaminations. Two main challenges then emerge: obtaining updated information to gain an overall picture of the sources of exposure, and predicting the resulting internal body exposure levels and effects that occur under long-term exposure conditions. In this paper, a modeling approach is used to meet these challenges with reference to Danish exposure conditions. Levels of lead content in various media have been coupled with data for lead intake and absorption in the human body, for both children and adults. An age-dependent biokinetic model allows then for determination of the blood lead levels resulting from chronic exposure. The study shows that the actual intake of lead is up to 27% of the Provisional Tolerable Daily Intake (PTDI) for children and around 8% for adults. It is confirmed that the critical route of exposure is via ingestion, accounting for 99% of total lead intake, while inhalation contributes only to 1% of total lead intake. The resulting lead levels in the blood after 2 years of exposure to actual contamination conditions have been estimated as up to 2.2μg/dl in children and almost 1μg/dl in adults. Impacts from lead can occur even at such levels. The role of historical and present sources to lead in the environment is discussed, and, for specific child and adult exposure scenarios, external-internal concentration relationships for the direct linkage between lead in environmental media and resulting concentrations of lead in blood are then presented. Copyright © 2010 Elsevier B.V. All rights reserved.

Micronucleus formation in cultured human keratinocytes following exposure to mitomycin C and cyclophosphamide.

Science.gov (United States)

van Pelt, F N; Haring, R M; Overkamp, M J; Weterings, P J

1991-02-01

A method is described to investigate the induction of micronuclei in cultured human keratinocytes after short-term exposure to known clastogenic agents. The cytokinesis-block method was applied to facilitate the scoring of micronucleated cells. Mitomycin C, a direct-acting compound, caused a 5-20-fold increase in micronuclei over the controls at the highest concentration tested (1 microgram/ml). Cyclophosphamide, an agent requiring metabolic activation, did not induce the formation of micronuclei in cultured keratinocytes. However, after pretreatment of the keratinocyte cultures with Aroclor 1254 for 72 h, exposure to cyclophosphamide resulted in a 3-fold increase in micronucleus frequency over the controls. No cytogenetic effect of Aroclor 1254 was observed in control experiments.

A model of human nasal epithelial cells adapted for direct and repeated exposure to airborne pollutants.

Science.gov (United States)

Bardet, Gaëlle; Achard, Sophie; Loret, Thomas; Desauziers, Valérie; Momas, Isabelle; Seta, Nathalie

2014-08-17

Airway epithelium lining the nasal cavity plays a pivotal role in respiratory tract defense and protection mechanisms. Air pollution induces alterations linked to airway diseases such as asthma. Only very few in vitro studies to date have succeeded in reproducing physiological conditions relevant to cellular type and chronic atmospheric pollution exposure. We therefore, set up an in vitro model of human Airway Epithelial Cells of Nasal origin (hAECN) close to real human cell functionality, specifically adapted to study the biological effects of exposure to indoor gaseous pollution at the environmental level. hAECN were exposed under air-liquid interface, one, two, or three-times at 24 h intervals for 1 h, to air or formaldehyde (200 μg/m(3)), an indoor air gaseous pollutant. All experiments were ended at day 4, when both cellular viability and cytokine production were assessed. Optimal adherence and confluence of cells were obtained 96 h after cell seeding onto collagen IV-precoated insert. Direct and repeated exposure to formaldehyde did not produce any cellular damage or IL-6 production change, although weak lower IL-8 production was observed only after the third exposure. Our model is significantly better than previous ones due to cell type and the repeated exposure protocol. Copyright © 2014. Published by Elsevier Ireland Ltd.

A dermatotoxicokinetic model of human exposures to jet fuel.

Science.gov (United States)

Kim, David; Andersen, Melvin E; Nylander-French, Leena A

2006-09-01

Workers, both in the military and the commercial airline industry, are exposed to jet fuel by inhalation and dermal contact. We present a dermatotoxicokinetic (DTK) model that quantifies the absorption, distribution, and elimination of aromatic and aliphatic components of jet fuel following dermal exposures in humans. Kinetic data were obtained from 10 healthy volunteers following a single dose of JP-8 to the forearm over a surface area of 20 cm2. Blood samples were taken before exposure (t = 0 h), after exposure (t = 0.5 h), and every 0.5 h for up to 3.5 h postexposure. The DTK model that best fit the data included five compartments: (1) surface, (2) stratum corneum (SC), (3) viable epidermis, (4) blood, and (5) storage. The DTK model was used to predict blood concentrations of the components of JP-8 based on dermal-exposure measurements made in occupational-exposure settings in order to better understand the toxicokinetic behavior of these compounds. Monte Carlo simulations of dermal exposure and cumulative internal dose demonstrated no overlap among the low-, medium-, and high-exposure groups. The DTK model provides a quantitative understanding of the relationship between the mass of JP-8 components in the SC and the concentrations of each component in the systemic circulation. The model may be used for the development of a toxicokinetic modeling strategy for multiroute exposure to jet fuel.

A novel application of capnography during controlled human exposure to air pollution

Directory of Open Access Journals (Sweden)

Fila Michael

2006-10-01

waves in controlled human air pollution exposure studies is a feasible tool for characterization of cardio-pulmonary effects of such exposures.

The causes and consequences of human exposure to ionising radiation

International Nuclear Information System (INIS)

Clarke, R.H.

1991-01-01

Few phenomena cause as much concern in developed countries as human exposure to artificial sources of radiation, and yet there are more potent threats to health: natural radiation is more pervasive and exposures more substantial; common practices such as smoking and drinking are more detrimental. Developing countries may be more anxious to establish radiological procedures than radiological protection. This paper gives the ranges of exposure to which people are subjected from natural and artificial sources which should help to put all doses in perspective. The relationship between dose and risk is established and used to show that exposures to radiation leak to low levels of risk. Finally, the new recommendations of ICRP for the control of radiation risk are presented. (Author)

Attentional Modulation of the Mere Exposure Effect

Science.gov (United States)

Yagi, Yoshihiko; Ikoma, Shinobu; Kikuchi, Tadashi

2009-01-01

The "mere exposure effect" refers to the phenomenon where previous exposures to stimuli increase participants' subsequent affective preference for those stimuli. This study explored the effect of selective attention on the mere exposure effect. The experiments manipulated the to-be-attended drawings in the exposure period (either red or green…

An approach for assessing human exposures to chemical mixtures in the environment

International Nuclear Information System (INIS)

Rice, Glenn; MacDonell, Margaret; Hertzberg, Richard C.; Teuschler, Linda; Picel, Kurt; Butler, Jim; Chang, Young-Soo; Hartmann, Heidi

2008-01-01

Humans are exposed daily to multiple chemicals, including incidental exposures to complex chemical mixtures released into the environment and to combinations of chemicals that already co-exist in the environment because of previous releases from various sources. Exposures to chemical mixtures can occur through multiple pathways and across multiple routes. In this paper, we propose an iterative approach for assessing exposures to environmental chemical mixtures; it is similar to single-chemical approaches. Our approach encompasses two elements of the Risk Assessment Paradigm: Problem Formulation and Exposure Assessment. Multiple phases of the assessment occur in each element of the paradigm. During Problem Formulation, analysts identify and characterize the source(s) of the chemical mixture, ensure that dose-response and exposure assessment measures are concordant, and develop a preliminary evaluation of the mixture's fate. During Exposure Assessment, analysts evaluate the fate of the chemicals comprising the mixture using appropriate models and measurement data, characterize the exposure scenario, and estimate human exposure to the mixture. We also describe the utility of grouping the chemicals to be analyzed based on both physical-chemical properties and an understanding of environmental fate. In the article, we also highlight the need for understanding of changes in the mixture composition in the environment due to differential transport, differential degradation, and differential partitioning to other media. The section describes the application of the method to various chemical mixtures, highlighting issues associated with assessing exposures to chemical mixtures in the environment

Exposures to natural radiation in Switzerland

International Nuclear Information System (INIS)

Murith, Ch.; Gurtner, A.

1999-01-01

The exposure of human beings to ionising radiation from natural sources is a continuing and inescapable feature of life on earth. There are two main sources that contribute to this exposure: high-energy cosmic-ray particles incident to the earth's atmosphere and radioactive nuclides that originated in the earth's crust and are present everywhere in the environment, including human body itself. Both external and internal exposures to humans arise from these sources. Exposures to natural radiation sources in Switzerland and some of their variations are here summarised and the resulting effective doses are compared to those from man-made sources exposures. It results that the natural background exposures are more significant for the population than most exposures to man-made sources. (authors)

Acute behavioral effects of exposure to some organic solvents -psychophysiological aspects

Energy Technology Data Exchange (ETDEWEB)

Winneke, G

1982-01-01

Acute low-level exposure to organic solvent vapours may result in prenarcotic states of CNS-depression, often characterized by behavioral dysfunction. Behavioral findings from experimental acute human exposures to toluene, trichloroethylene (TCE), and methylene chloride (MC) are covered in this review. Perceptual measures (e.g. critical flicker fusion . CFF), measures of sustained attention (vigilance), measures of psychomotor performance (as e.g. reaction time, motor speed, coordination) as well as EEG-measures (sensory evoked potentials) are used to illustrate the main effects from such studies. Progressive increase of reaction time was observed at toluene-exposures of only 300 ppm (30 minutes). No consistent behavioral deficit has been reported for trichloroethylene below 300 ppm; instead, visual and auditory evoked potentials were found to be affected at TCE vapour-concentrations between 50 and 100 ppm (3 1/2 - 7 1/2 hours of exposure). CFF-depression, vigilance-decrement and disruption of psychomotor performance has been observed during MC-exposure (200 - 800 ppm; 2-4 hours). Although such behavioral effects are usually considered reversible and of no demonstrated pathological impact, they may nevertheless contribute to accident-prone behavior in occupational settings.

Development of a ECOREA-II code for human exposures from radionuclides through food chain

International Nuclear Information System (INIS)

Yoo, D. H.; Choi, Y. H.

2001-01-01

The release of radionuclides from nuclear facilities following an accident into air results in human exposures through two pathways. One is direct human exposures by inhalation or dermal absorption of these radionucles. Another is indirect human exposures through food chain which includes intakes of plant products such as rice, vegetables from contaiminated soil and animal products such as meet, milk and eggs feeded by contaminated grasses or plants on the terrestial surface. This study presents efforts of the development of a computer code for the assessment of the indirect human exposure through such food chains. The purpose of ECOREA-II code is to develop appropriate models suitable for a specific soil condition in Korea based on previous experimental efforts and to provide a more user-friendly environment such as GUI for the use of the code. Therefore, the current code, when more fully developed, is expected to increase the understanding of environmental safety assessment of nuclear facilities following an accident and provide a reasonable regulatory guideline with respecte to food safety issues

Mutagenic effect of cadmium on tetranucleotide repeats in human cells

Energy Technology Data Exchange (ETDEWEB)

Slebos, Robbert J.C. [Department of Cancer Biology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232 (United States) and Department of Otolaryngology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232 (United States)]. E-mail: r.slebos@vanderbilt.edu; Li Ming [Department of Biostatistics, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232 (United States); Evjen, Amy N. [Department of Cancer Biology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232 (United States); Coffa, Jordy [Department of Cancer Biology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232 (United States); Shyr, Yu [Department of Biostatistics, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232 (United States); Yarbrough, Wendell G. [Department of Cancer Biology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232 (United States); Department of Otolaryngology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232 (United States)

2006-12-01

Cadmium is a human carcinogen that affects cell proliferation, apoptosis and DNA repair processes that are all important to carcinogenesis. We previously demonstrated that cadmium inhibits DNA mismatch repair (MMR) in yeast cells and in human cell-free extracts (H.W. Jin, A.B. Clark, R.J.C. Slebos, H. Al-Refai, J.A. Taylor, T.A. Kunkel, M.A. Resnick, D.A. Gordenin, Cadmium is a mutagen that acts by inhibiting mismatch repair, Nat. Genet. 34 (3) (2003) 326-329), but cadmium also inhibits DNA excision repair. For this study, we selected a panel of three hypermutable tetranucleotide markers (MycL1, D7S1482 and DXS981) and studied their suitability as readout for the mutagenic effects of cadmium. We used a clonal derivative of the human fibrosarcoma cell line HT1080 to assess mutation levels in microsatellites after cadmium and/or N-methyl-N-nitro-N-nitrosoguanidine (MNNG) exposure to study effects of cadmium in the presence or absence of base damage. Mutations were measured in clonally expanded cells obtained by limiting dilution after exposure to zero dose, 0.5 {mu}M cadmium, 5 nM MNNG or a combination of 0.5 {mu}M cadmium and 5 nM MNNG. Exposure of HT1080-C1 to cadmium led to statistically significant increases in microsatellite mutations, either with or without concurrent exposure to MNNG. A majority of the observed mutant molecules involved 4-nucleotide shifts consistent with DNA slippage mutations that are normally repaired by MMR. These results provide evidence for the mutagenic effects of low, environmentally relevant levels of cadmium in intact human cells and suggest that inhibition of DNA repair is involved.

Co-Exposure with Fullerene May Strengthen Health Effects of Organic Industrial Chemicals

DEFF Research Database (Denmark)

Lehto, M.; Karilainen, T.; Rog, T.

2014-01-01

In vitro toxicological studies together with atomistic molecular dynamics simulations show that occupational co-exposure with C-60 fullerene may strengthen the health effects of organic industrial chemicals. The chemicals studied are acetophenone, benzaldehyde, benzyl alcohol, m-cresol, and toluene...... which can be used with fullerene as reagents or solvents in industrial processes. Potential co-exposure scenarios include a fullerene dust and organic chemical vapor, or a fullerene solution aerosolized in workplace air. Unfiltered and filtered mixtures of C-60 and organic chemicals represent different...... co-exposure scenarios in in vitro studies where acute cytotoxicity and immunotoxicity of C-60 and organic chemicals are tested together and alone by using human THP-1-derived macrophages. Statistically significant co-effects are observed for an unfiltered mixture of benzaldehyde and C-60 that is more...

Effect of physical exertion on the biological monitoring of exposure to various solvents following exposure by inhalation in human volunteers: III. Styrene.

Science.gov (United States)

Truchon, Ginette; Brochu, Martin; Tardif, Robert

2009-08-01

This study evaluated the impact of different work load intensities on biological indicators of styrene exposure. Four adult Caucasian men, aged 20 to 44 years, were recruited. Groups of 2-4 volunteers were exposed to 20 ppm of styrene in an exposure chamber according to scenarios involving either aerobic, muscular, or both types of physical exercise for 3 or 7 hr. The target intensities for each 30-min exercise period-interspaced with 15 min at rest-were the following: REST, 38 watts AERO (time-weighted average intensity), 34 watts AERO/MUSC, 49 watts AERO/MUSC, and 54 watts AERO for 7 hr and 22 watts MUSC for 3 hr. End-exhaled air samples were collected at 15 time points during and after 7-hr exposures for the determination of styrene concentrations. Urine samples were collected before the start of exposure, after the first 3 hr of exposure, and at the end of exposure for the determination of mandelic acid (MA) and phenylglyoxilic acid (PGA) concentrations. Compared with exposure at rest, styrene in alveolar air increased by a factor up to 1.7, while the sum of urinary MA and PGA increased by a factor ranging from 1.2 to 3.5, depending on the exposure scenario. Concentrations of biological indicators of styrene fluctuated with physical exertion and were correlated with the magnitude of the physical activity and pulmonary ventilation. Despite the physical exertion effect, urinary concentrations of styrene metabolites after a single-day exposure remain below the current biological exposure index value recommended by ACGIH; therefore, no additional health risk is expected. However, results shows that work load intensities must be considered in the interpretation of biological monitoring data and in the evaluation of the health risk associated with styrene exposure.

Health effect from EMF exposure of Korea population

Energy Technology Data Exchange (ETDEWEB)

Kim, Y. S.; Cho, Y. S.; Lee, J. T.; Yup, M. J.; Hong, J. H. [Institute of Environmental and Industrrial Medicine, Hanyang Univ., Seoul (Korea, Republic of)

2002-07-01

This study on health effect from EMF exposure was performed from June 2001 to April 2002 to compare changes in melatonin levels in urine of 40 subjects during their normal sleeping hours, to evaluate heart rate, ST segment in ventricular, and ventricular premature beat for cardiac function, to evaluate microwave exposure from cellular phones which may have a potential influence on the electro physiologic function of human brain, and each 20 subjects in occupational and non-occupational group measured personal 24-h continual exposure, using EMDEX(for 40-800Hz, Enertech Consultant, Inc.). An urine samples for analysis of melatonin excretion level were collected 1 times a day(immediately after wake-up) for five days from each subjects and analyzed by radioimmunoassay, HRV-test for relationship between heart rate and EMF exposure was performed heart rate beat using Holter for subjects, and double EEG-test were performed in 10 long-term users of the cellularphones when using and not using them, and a single EEG-test in 10 short-term users of the cellular phones. Each EEG-recording took 40 min consisting of 30 min filed exposure and 10 min measurement. And We estimated the economic value of the potential damage of electromagnetic radiation from cellular phone, and the willingness to pay of people for the study of the radiation damage led by the government, by applying contingent variation method. The results of this study were followed; 1. Personal exposure assessment 2. We showed not significant difference for the subjective average melatonin levels between occupational and non- occupational groups exposed to electromagnetic fields. 3. We showed no difference in the awake EEGs in terms of spectral power density measures between long-term users and short-term users of cellular phones. 4. We found that the economic value of the potential damage by the radiation for a typical cellular phone user is about 20,000 won per year and he would be willing to pay about 1,800 won

Multi-pathway human exposure assessment of phthalate esters and DINCH.

Science.gov (United States)

Giovanoulis, Georgios; Bui, Thuy; Xu, Fuchao; Papadopoulou, Eleni; Padilla-Sanchez, Juan A; Covaci, Adrian; Haug, Line S; Cousins, Anna Palm; Magnér, Jörgen; Cousins, Ian T; de Wit, Cynthia A

2018-03-01

Phthalate esters are substances mainly used as plasticizers in various applications. Some have been restricted and phased out due to their adverse health effects and ubiquitous presence, leading to the introduction of alternative plasticizers, such as DINCH. Using a comprehensive dataset from a Norwegian study population, human exposure to DMP, DEP, DnBP, DiBP, BBzP, DEHP, DINP, DIDP, DPHP and DINCH was assessed by measuring their presence in external exposure media, allowing an estimation of the total intake, as well as the relative importance of different uptake pathways. Intake via different uptake routes, in particular inhalation, dermal absorption, and oral uptake was estimated and total intake based on all uptake pathways was compared to the calculated intake from biomonitoring data. Hand wipe results were used to determine dermal uptake and compared to other exposure sources such as air, dust and personal care products. Results showed that the calculated total intakes were similar, but slightly higher than those based on biomonitoring methods by 1.1 to 3 times (median), indicating a good understanding of important uptake pathways. The relative importance of different uptake pathways was comparable to other studies, where inhalation was important for lower molecular weight phthalates, and negligible for the higher molecular weight phthalates and DINCH. Dietary intake was the predominant exposure route for all analyzed substances. Dermal uptake based on hand wipes was much lower (median up to 2000 times) than the total dermal uptake via air, dust and personal care products. Still, dermal uptake is not a well-studied exposure pathway and several research gaps (e.g. absorption fractions) remain. Based on calculated intakes, the exposure for the Norwegian participants to the phthalates and DINCH was lower than health based limit values. Nevertheless, exposure to alternative plasticizers, such as DPHP and DINCH, is expected to increase in the future and continuous

Risks from accidental exposures to engineered nanoparticles and neurological health effects: A critical review

Directory of Open Access Journals (Sweden)

Mattsson Mats-Olof

2010-12-01

Full Text Available Abstract There are certain concerns regarding the safety for the environment and human health from the use of engineered nanoparticles (ENPs which leads to unintended exposures, as opposed to the use of ENPs for medical purposes. This review focuses on the unintended human exposure of ENPs. In particular, possible effects in the brain are discussed and an attempt to assess risks is performed. Animal experiments have shown that investigated ENPs (metallic nanoparticles, quantum dots, carbon nanotubes can translocate to the brain from different entry points (skin, blood, respiratory pathways. After inhalation or instillation into parts of the respiratory tract a very small fraction of the inhaled or instilled ENPs reaches the blood and subsequently secondary organs, including the CNS, at a low translocation rate. Experimental in vivo and in vitro studies have shown that several types of ENPs can have various biological effects in the nervous system. Some of these effects could also imply that ENPs can cause hazards, both acutely and in the long term. The relevance of these data for risk assessment is far from clear. There are at present very few data on exposure of the general public to either acute high dose exposure or on chronic exposure to low levels of air-borne ENPs. It is furthermore unlikely that acute high dose exposures would occur. The risk from such exposures for damaging CNS effects is thus probably very low, irrespective of any biological hazard associated with ENPs. The situation is more complicated regarding chronic exposures, at low doses. The long term accumulation of ENPs can not be excluded. However, we do not have exposure data for the general public regarding ENPs. Although translocation to the brain via respiratory organs and the circulation appears to be very low, there remains a possibility that chronic exposures, and/or biopersistent ENPs, can influence processes within the brain that are triggering or aggravating

Abundant Rodent Furan-Derived Urinary Metabolites Are Associated with Tobacco Smoke Exposure in Humans.

Science.gov (United States)

Grill, Alex E; Schmitt, Thaddeus; Gates, Leah A; Lu, Ding; Bandyopadhyay, Dipankar; Yuan, Jian-Min; Murphy, Sharon E; Peterson, Lisa A

2015-07-20

Furan, a possible human carcinogen, is found in heat treated foods and tobacco smoke. Previous studies have shown that humans are capable of converting furan to its reactive metabolite, cis-2-butene-1,4-dial (BDA), and therefore may be susceptible to furan toxicity. Human risk assessment of furan exposure has been stymied because of the lack of mechanism-based exposure biomarkers. Therefore, a sensitive LC-MS/MS assay for six furan metabolites was applied to measure their levels in urine from furan-exposed rodents as well as in human urine from smokers and nonsmokers. The metabolites that result from direct reaction of BDA with lysine (BDA-N(α)-acetyllysine) and from cysteine-BDA-lysine cross-links (N-acetylcysteine-BDA-lysine, N-acetylcysteine-BDA-N(α)-acetyllysine, and their sulfoxides) were targeted in this study. Five of the six metabolites were identified in urine from rodents treated with furan by gavage. BDA-N(α)-acetyllysine, N-acetylcysteine-BDA-lysine, and its sulfoxide were detected in most human urine samples from three different groups. The levels of N-acetylcysteine-BDA-lysine sulfoxide were more than 10 times higher than that of the corresponding sulfide in many samples. The amount of this metabolite was higher in smokers relative to that in nonsmokers and was significantly reduced following smoking cessation. Our results indicate a strong relationship between BDA-derived metabolites and smoking. Future studies will determine if levels of these biomarkers are associated with adverse health effects in humans.

Small airway epithelial cells exposure to printer-emitted engineered nanoparticles induces cellular effects on human microvascular endothelial cells in an alveolar-capillary co-culture model.

Science.gov (United States)

Sisler, Jennifer D; Pirela, Sandra V; Friend, Sherri; Farcas, Mariana; Schwegler-Berry, Diane; Shvedova, Anna; Castranova, Vincent; Demokritou, Philip; Qian, Yong

2015-01-01

The printer is one of the most common office equipment. Recently, it was reported that toner formulations for printing equipment constitute nano-enabled products (NEPs) and contain engineered nanomaterials (ENMs) that become airborne during printing. To date, insufficient research has been performed to understand the potential toxicological properties of printer-emitted particles (PEPs) with several studies using bulk toner particles as test particles. These studies demonstrated the ability of toner particles to cause chronic inflammation and fibrosis in animal models. However, the toxicological implications of inhalation exposures to ENMs emitted from laser printing equipment remain largely unknown. The present study investigates the toxicological effects of PEPs using an in vitro alveolar-capillary co-culture model with Human Small Airway Epithelial Cells (SAEC) and Human Microvascular Endothelial Cells (HMVEC). Our data demonstrate that direct exposure of SAEC to low concentrations of PEPs (0.5 and 1.0 µg/mL) caused morphological changes of actin remodeling and gap formations within the endothelial monolayer. Furthermore, increased production of reactive oxygen species (ROS) and angiogenesis were observed in the HMVEC. Analysis of cytokine and chemokine levels demonstrates that interleukin (IL)-6 and MCP-1 may play a major role in the cellular communication observed between SAEC and HMVEC and the resultant responses in HMVEC. These data indicate that PEPs at low, non-cytotoxic exposure levels are bioactive and affect cellular responses in an alveolar-capillary co-culture model, which raises concerns for potential adverse health effects.

Effects of noise exposure on young adults with normal audiograms I: Electrophysiology.

Science.gov (United States)

Prendergast, Garreth; Guest, Hannah; Munro, Kevin J; Kluk, Karolina; Léger, Agnès; Hall, Deborah A; Heinz, Michael G; Plack, Christopher J

2017-02-01

Noise-induced cochlear synaptopathy has been demonstrated in numerous rodent studies. In these animal models, the disorder is characterized by a reduction in amplitude of wave I of the auditory brainstem response (ABR) to high-level stimuli, whereas the response at threshold is unaffected. The aim of the present study was to determine if this disorder is prevalent in young adult humans with normal audiometric hearing. One hundred and twenty six participants (75 females) aged 18-36 were tested. Participants had a wide range of lifetime noise exposures as estimated by a structured interview. Audiometric thresholds did not differ across noise exposures up to 8 kHz, although 16-kHz audiometric thresholds were elevated with increasing noise exposure for females but not for males. ABRs were measured in response to high-pass (1.5 kHz) filtered clicks of 80 and 100 dB peSPL. Frequency-following responses (FFRs) were measured to 80 dB SPL pure tones from 240 to 285 Hz, and to 80 dB SPL 4 kHz pure tones amplitude modulated at frequencies from 240 to 285 Hz (transposed tones). The bandwidth of the ABR stimuli and the carrier frequency of the transposed tones were chosen to target the 3-6 kHz characteristic frequency region which is usually associated with noise damage in humans. The results indicate no relation between noise exposure and the amplitude of the ABR. In particular, wave I of the ABR did not decrease with increasing noise exposure as predicted. ABR wave V latency increased with increasing noise exposure for the 80 dB peSPL click. High carrier-frequency (envelope) FFR signal-to-noise ratios decreased as a function of noise exposure in males but not females. However, these correlations were not significant after the effects of age were controlled. The results suggest either that noise-induced cochlear synaptopathy is not a significant problem in young, audiometrically normal adults, or that the ABR and FFR are relatively insensitive to this disorder in

Dose-rate models for human survival after exposure to ionizing radiation

International Nuclear Information System (INIS)

Jones, T.D.; Morris, M.D.; Young, R.W.

1987-01-01

This paper reviews new estimates of the LD 50 in man by Mole and by Rotblat, the biological processes contributing to hematologic death, the collection of animal experiments dealing with hematologic death, and the use of regression analysis to make new estimates of human mortality based on all relevant animal studies. Regression analysis of animal mortality data has shown that mortality is dependent strongly on dose rate, species, body weight, and time interval over which the exposure is delivered. The model has predicted human LD 50 s of 194, 250, 310, and 360 rad to marrow when the exposure time is a minute, an hour, a day, and a week, respectively

Dose-rate models for human survival after exposure to ionizing radiation

International Nuclear Information System (INIS)

Jones, T.D.; Morris, M.D.; Young, R.W.

1986-01-01

This paper reviews new estimates of the L 50 in man by Mole and by Rotblat, the biological processes contributing to hematologic death, the collection of animal experiments dealing with hematologic death, and the use of regression analysis to make new estimates of human mortality based on all relevant animal studies. Regression analysis of animal mortality data has shown that mortality is dependent strongly on dose rate, species, body weight, and time interval over which the exposure is delivered. The model has predicted human LD 50 s of 194, 250, 310, and 360 rad to marrow when the exposure time is a minute, an hour, a day, and a week, respectively

Effect of physical exertion on the biological monitoring of exposure to various solvents following exposure by inhalation in human volunteers: II. n-Hexane.

Science.gov (United States)

Tardif, Robert; Nadeau, Véronique; Truchon, Ginette; Brochu, Martin

2007-07-01

This study evaluated the impact of physical exertion on two n-hexane (HEX) exposure indicators in human volunteers exposed under controlled conditions in an inhalation chamber. A group of four volunteers (two women, two men) were exposed to HEX (50 ppm; 176 mg/m(3)) according to several scenarios involving several periods when volunteers performed either aerobic (AERO), muscular (MUSC), or both AERO/MUSC types of exercise. The target intensities for 30-min exercise periods separated by 15-min rest periods were the following: REST, 50W AERO [time-weighted average intensity including resting period (TWAI): 38W], 50W AERO/MUSC (TWAI: 34W), 100W AERO/MUSC (TWAI: 63W), and 100W AERO (TWAI: 71W) for 7 hr (two 3-hr exposure periods separated by 1 hr without exposure) and 50W MUSC for 3 hr (TWAI: 31W). Alveolar air and urine samples were collected at different time intervals before, during, and after exposure to measure unchanged HEX in expired air (HEX-A) and urinary 2,5-hexanedione (2,5-HD). HEX-A levels during exposures involving AERO activities (TWAI: 38W and 71W) were significantly enhanced (approximately +14%) compared with exposure at rest. MUSC or AERO/MUSC exercises were also associated with higher HEX-A levels but only at some sampling times. In contrast, end-of-exposure (7 hr) urinary 2,5-HD (mean +/- SD) was not modified by physical exertion: 4.14 +/- 1.51 micromol/L (REST), 4.02 +/- 1.52 micromol/L (TWAI 34W), 4.25 +/- 1.53 micromol/L (TWAI 38W), 3.73 +/- 2.09 micromol/L (TWAI 63W), 3.6 +/- 1.34 micromol/L (TWAI 71W) even though a downward trend was observed. Overall, this study showed that HEX kinetics is practically insensitive to moderate variations in workload intensity; only HEX-A levels increased slightly, and urinary 2,5-HD levels remained unchanged despite the fact that all types of physical exercise increased the pulmonary ventilation rate.

Mechanical impedance of the sitting human body in single-axis compared to multi-axis whole-body vibration exposure.

Science.gov (United States)

Holmlund, P; Lundström, R

2001-01-01

The study was aimed to investigate the mechanical impedance of the sitting human body and to compare data obtained in laboratory single-axis investigations with multi-axis data from in vehicle measurements. The experiments were performed in a laboratory for single-axis measurements. The multi-axis exposure was generated with an eight-seat minibus where the rear seats had been replaced with a rigid one. The subjects in the multi-axis experiment all participated in the single-axis experiments. There are quite a few investigations in the literature describing the human response to single-axis exposure. The response from the human body can be expected to be affected by multi-axis input in a different way than from a single-axis exposure. The present knowledge of the effect of multiple axis exposure is very limited. The measurements were performed using a specially designed force and accelerometer plate. This plate was placed between the subject and the hard seat. Outcome shows a clear difference between mechanical impedance for multi-axis exposure compared to single-axis. This is especially clear in the x-direction where the difference is very large. The conclusion is that it seems unlikely that single-axis mechanical impedance data can be directly transferred to a multi-axis environment. This is due to the force cross-talk between different directions.

Health effects of long-term exposure to air pollution: An overview of major respiratory and cardiovascular diseases and diabetes

Directory of Open Access Journals (Sweden)

Jovanovic-Andersen Zorana

2012-01-01

Full Text Available Large number of studies provided convincing evidence for adverse effects of exposure to outdoor air pollution on human health, and served as basis for current USA and EU Air Quality Standards and limit values. Still, new knowledge is emerging, expanding our understanding of vast effects of exposure to air pollution on human health of this ubiquitous exposure affecting millions of people in urban setting. This paper focuses on the studies of health effects of long-term (chronic exposures to air pollution, and includes major chronic and acute diseases in adults and especially elderly, which will present increasing public health burden, due to improving longevity and projected increasing numbers of elderly. The paper gives overview over the most relevant and latest literature presented by different health outcomes: chronic obstructive pulmonary disease, asthma, pneumonia, cardiovascular disease, and diabetes.

Anxiolytic effect of music exposure on BDNFMet/Met transgenic mice.

Science.gov (United States)

Li, Wen-Jing; Yu, Hui; Yang, Jian-Min; Gao, Jing; Jiang, Hong; Feng, Min; Zhao, Yu-Xia; Chen, Zhe-Yu

2010-08-06

Brain-derived neurotrophic factor (BDNF) has been reported to play important roles in the modulation of anxiety, mood stabilizers, and pathophysiology of affective disorders. Recently, a single nucleotide polymorphism (SNP) in the BDNF gene (Val66Met) has been found to be associated with depression and anxiety disorders. The humanized BDNF(Met/Met) knock-in transgenic mice exhibited increased anxiety-related behaviors that were unresponsive to serotonin reuptake inhibitors, fluoxetine. Music is known to be able to elicit emotional changes, including anxiolytic effects. In this study, we found that music treatment could significantly decrease anxiety state in BDNF(Met/Met) mice, but not in BDNF(+/)(-), mice compared with white noise exposure in open field and elevated plus maze test. Moreover, in contrast to white noise exposure, BDNF expression levels in the prefrontal cortex (PFC), amygdala and hippocampus were significantly increased in music-exposed adult BDNF(Met/Met) mice. However, music treatment could not upregulate BDNF levels in the PFC, amygdala, and hippocampus in BDNF(+/)(-) mice, which suggests the essential role of BDNF in the anxiolytic effect of music. Together, our results imply that music may provide an effective therapeutic intervention for anxiety disorders in humans with this genetic BDNF(Met) variant. Copyright 2010 Elsevier B.V. All rights reserved.

Electronic cigarettes: human health effects

OpenAIRE

Callahan-Lyon, Priscilla

2014-01-01

Objective With the rapid increase in use of electronic nicotine delivery systems (ENDS), such as electronic cigarettes (e-cigarettes), users and non-users are exposed to the aerosol and product constituents. This is a review of published data on the human health effects of exposure to e-cigarettes and their components. Methods Literature searches were conducted through September 2013 using multiple electronic databases. Results Forty-four articles are included in this analysis. E-cigarette ae...

Nanogold – Biological effects and occupational exposure levels

Directory of Open Access Journals (Sweden)

Anna Maria Świdwińska-Gajewska

2017-08-01

Full Text Available Nanogold has different properties and biological activity compared to metallic gold. It can be applied in many fields, such as medicine, laboratory diagnostics and electronics. Studies on laboratory animals show that nanogold can be absorbed by inhalation and ingestion. It can penetrate deep into the epidermis and dermis, but there is no evidence that it is absorbed through the skin. Gold nanoobjects accumulate mainly in the liver and spleen, but they can also reach other internal organs. Nanogold can cross the blood–brain and blood–placenta barriers. Toxicokinetics of nanogold depends on the particle size, shape and surface charge. In animals exposure to gold nanoparticles via inhalation induces slight changes in the lungs. Exposure to nanogold by the oral route does not cause adverse health effects in rodents. In animals after injection of gold nanoobjects changes in the liver and lungs were observed. Nanogold induced genotoxic effects in cells, but not in animals. No adverse effects on the fetus or reproduction were found. There are no carcinogenicity studies on gold nanoparticles. The mechanism of toxicity may be related to the interaction of gold nanoobjects with proteins and DNA, and it leads to the induction of oxidative stress and genetic material damage. The impact of nanostructures on human health has not yet been fully understood. The person, who works with nanomaterials should exercise extreme caution and apply existing recommendations on the evaluation of nanoobjects exposure. The risk assessment should be the basis for taking appropriate measures to limit potential exposure to nanometals, including nanogold. Med Pr 2017;68(4:545–556

Relative importance of different exposure routes of heavy metals for humans living near a municipal solid waste incinerator

International Nuclear Information System (INIS)

Li, Tong; Wan, Yi; Ben, Yujie; Fan, Senrong; Hu, Jianying

2017-01-01

The potential health effects of toxic chemicals (e.g. heavy metals) emitted by municipal solid waste incinerators (MSWIs) are of great concern to local residents, however there have been few studies on the contributions of different exposure pathways and their subsequent effects on the body burden of residents living near MSWIs. In this study, multiple exposure routes of heavy metals including Pb, Cr, Cd and Mn were assessed by investigating the metals in foods (such as vegetables, crops, meats and fruits etc.), drinking water, ambient air and soil collected surrounding an MSWI in Shenzhen, south China. Vegetable ingestion played the most important role in the total average daily dose of Pb and Cr, and cereals were the key exposure routes for Mn and Cd. Compound-specific contaminations were observed in the investigated areas, with Pb and Cr present in the surrounding environment, having accumulated to relatively high levels in the local vegetables, and the intake of contaminated vegetable foods greatly influencing the body burden of Pb and Cr. Consistently, significantly high blood concentrations of Pb and Cr were detected in the local residents compared to a referenced population, and a lack of significant differences was found for Cd and Mn. The results possibly suggested that emission of MSWI influenced the external exposure doses of the major pathways of Pb and Cr in this study, and resulted in the different body burden of metals in humans living near a MSWI. MSWI-local food-humans is an important exposure pathway for residents living near MSWI, and thus should not be neglected in developing future strategies and policies to prevent the high risks suffered by residents living near MSWIs. - Highlights: • Vegetable and cereal ingestion were the main contributors to exposure of Pb/Cr and Mn/Cd, respectively. • Concentrations of Pb/Cr in vegetables grown near MSWI were significantly higher. • Blood concentrations of Pb/Cr in populations near MSWI were

Physical, behavioral, and cognitive effects of prenatal tobacco and postnatal secondhand smoke exposure.

Science.gov (United States)

Zhou, Sherry; Rosenthal, David G; Sherman, Scott; Zelikoff, Judith; Gordon, Terry; Weitzman, Michael

2014-09-01

The purpose of this review is to examine the rapidly expanding literature regarding the effects of prenatal tobacco and postnatal secondhand smoke (SHS) exposure on child health and development. Mechanisms of SHS exposure are reviewed, including critical periods during which exposure to tobacco products appears to be particularly harmful to the developing fetus and child. The biological, biochemical, and neurologic effects of the small fraction of identified components of SHS are described. Research describing these adverse effects of both in utero and childhood exposure is reviewed, including findings from both animal models and humans. The following adverse physical outcomes are discussed: sudden infant death syndrome, low birth weight, decreased head circumference, respiratory infections, otitis media, asthma, childhood cancer, hearing loss, dental caries, and the metabolic syndrome. In addition, the association between the following adverse cognitive and behavioral outcomes and such exposures is described: conduct disorder, attention-deficit/hyperactivity disorder, poor academic achievement, and cognitive impairment. The evidence supporting the adverse effects of SHS exposure is extensive yet rapidly expanding due to improving technology and increased awareness of this profound public health problem. The growing use of alternative tobacco products, such as hookahs (a.k.a. waterpipes), and the scant literature on possible effects from prenatal and secondhand smoke exposure from these products are also discussed. A review of the current knowledge of this important subject has implications for future research as well as public policy and clinical practice. Published by Mosby, Inc.

Approaches for establishing human health no effect levels for engineered nanomaterials

International Nuclear Information System (INIS)

Aschberger, K; Christensen, F M

2011-01-01

Current Technical Guidance Documents for preparing risk assessments, like the guidance for the implementation of REACH, have limited focus on chemical substances in the particulate form and generally do not focus on substances in the nanoform. Within the ENRHES project a comprehensive and critical scientific review of publicly available health and safety information on four types of nanoparticles was performed. Based on the identified exposure and hazard data, basic human health risk assessment appraisals were carried out for fullerenes, carbon nanotubes, nano-silver and nano-titanium dioxide. These risk assessment appraisals followed the structure of a regulatory risk assessment and if possible and relevant, it was attempted to derive indicative human no-effect levels from key studies by applying assessment factors as suggested in the technical guidance document for REACH. These assessment factors address differences and uncertainty related to exposure features between test animals and humans (time, respiratory volume), other interspecies and intraspecies differences and factors for extrapolation to chronic duration. If required, the severity of effects and the quality of the database can be addressed by additional factors. Recently other procedures for deriving human no-effect levels have been published and these are compared to the ENRHES basic risk assessment appraisals. The main differences were observed in relation to evaluating the differences in animal and human exposure situations and interspecies differences, and in applying assessment factors for intraspecies differences for local effects. The applicability of the REACH guidance for nanomaterials is currently being investigated for possible adaptations, considering the specific behaviour and mode of action of nanomaterials.

Approaches for establishing human health no effect levels for engineered nanomaterials

Science.gov (United States)

Aschberger, K.; Christensen, F. M.

2011-07-01

Current Technical Guidance Documents for preparing risk assessments, like the guidance for the implementation of REACH, have limited focus on chemical substances in the particulate form and generally do not focus on substances in the nanoform. Within the ENRHES project a comprehensive and critical scientific review of publicly available health and safety information on four types of nanoparticles was performed. Based on the identified exposure and hazard data, basic human health risk assessment appraisals were carried out for fullerenes, carbon nanotubes, nano-silver and nano-titanium dioxide. These risk assessment appraisals followed the structure of a regulatory risk assessment and if possible and relevant, it was attempted to derive indicative human no-effect levels from key studies by applying assessment factors as suggested in the technical guidance document for REACH. These assessment factors address differences and uncertainty related to exposure features between test animals and humans (time, respiratory volume), other interspecies and intraspecies differences and factors for extrapolation to chronic duration. If required, the severity of effects and the quality of the database can be addressed by additional factors. Recently other procedures for deriving human no-effect levels have been published and these are compared to the ENRHES basic risk assessment appraisals. The main differences were observed in relation to evaluating the differences in animal and human exposure situations and interspecies differences, and in applying assessment factors for intraspecies differences for local effects. The applicability of the REACH guidance for nanomaterials is currently being investigated for possible adaptations, considering the specific behaviour and mode of action of nanomaterials.

Induction of anchorage-independent growth in primary human cells exposed to protons or HZE ions separately or in dual exposures.

Science.gov (United States)

Sutherland, B M; Cuomo, N C; Bennett, P V

2005-10-01

Travelers on space missions will be exposed to a complex radiation environment that includes protons and heavy charged particles. Since protons are present at much higher levels than are heavy ions, the most likely scenario for cellular radiation exposure will be proton exposure followed by a hit by a heavy ion. Although the effects of individual ion species on human cells are being investigated extensively, little is known about the effects of exposure to both radiation types. One useful measure of mammalian cell damage is induction of the ability to grow in a semi-solid agar medium highly inhibitory to the growth of normal human cells, termed neoplastic transformation. Using primary human cells, we evaluated induction of soft-agar growth and survival of cells exposed to protons only or to heavy charged particles (600 MeV/nucleon silicon) only as well as of cells exposed to protons followed after a 4-day interval by silicon ions. Both ions alone efficiently transformed the human cells to anchorage-independent growth. Initial experiments indicate that the dose responses for neoplastic transformation of cells exposed to protons and then after 4 days to silicon ions appear similar to that of cells exposed to silicon ions alone.

Children's exposure to polybrominated diphenyl ethers.

Science.gov (United States)

Zuurbier, Moniek; Leijs, Marike; Schoeters, Greet; ten Tusscher, Gavin; Koppe, Janna G

2006-10-01

Polybrominated biphenyl ethers (PBDEs), a class of brominated flame retardants, are frequently used in consumer products. PBDEs levels in environmental and human samples have increased in recent decades. Children are exposed to PBDEs through diet, mainly through fish, meat and milk. Total dietary exposure of children in Europe was calculated to be 2-3 ng/kg b.w./day. For nursing infants the main source of PBDE exposure is breast milk; exposure levels are around 15 ng/kg b.w./day. PBDE exposure levels in North America are 10 to a 100 times higher. Because of their persistence and their similarity to polychlorinated biphenyls (PCBs), concern has been raised about the effects of PBDEs on human health. Exposure to penta- and octa-BDE led to learning impairment and impaired motor behaviour in rodents. Exposure to penta-, octa- and also deca-BDE caused effects on thyroid homeostasis in animals. The EU has banned the production and use of penta- and octa-BDE since 2004; however, exposure will continue during the coming decades. Based upon current toxicological evidence, human exposure to deca-BDEs is not expected to lead to health effects, but data on exposure to deca-BDE and data on toxicity of deca-BDE are scarce. Therefore, monitoring studies and toxicity studies on deca-BDEs and other BDEs should continue.

Exposure to Non-Extreme Solar UV Daylight: Spectral Characterization, Effects on Skin and Photoprotection

OpenAIRE

Marionnet, Claire; Tricaud, Caroline; Bernerd, Fran?oise

2014-01-01

The link between chronic sun exposure of human skin and harmful clinical consequences such as photo-aging and skin cancers is now indisputable. These effects are mostly due to ultraviolet (UV) rays (UVA, 320–400 nm and UVB, 280–320 nm). The UVA/UVB ratio can vary with latitude, season, hour, meteorology and ozone layer, leading to different exposure conditions. Zenithal sun exposure (for example on a beach around noon under a clear sky) can rapidly induce visible and well-characterized clinic...

Spatial Analysis of Human Exposure and Vulnerability to Coastal ...

African Journals Online (AJOL)

Disasters in coastal cities have shown an ever-increasing frequency of occurrence. Population growth and urbanisation have increased the vulnerability of properties and societies in coastal flood-prone areas. Analysis of human exposure and vulnerability is one of the main strategies used to determine the necessary ...

Frequency of Extreme Heat Event as a Surrogate Exposure Metric for Examining the Human Health Effects of Climate Change.

Directory of Open Access Journals (Sweden)

Crystal Romeo Upperman

Full Text Available Epidemiological investigation of the impact of climate change on human health, particularly chronic diseases, is hindered by the lack of exposure metrics that can be used as a marker of climate change that are compatible with health data. Here, we present a surrogate exposure metric created using a 30-year baseline (1960-1989 that allows users to quantify long-term changes in exposure to frequency of extreme heat events with near unabridged spatial coverage in a scale that is compatible with national/state health outcome data. We evaluate the exposure metric by decade, seasonality, area of the country, and its ability to capture long-term changes in weather (climate, including natural climate modes. Our findings show that this generic exposure metric is potentially useful to monitor trends in the frequency of extreme heat events across varying regions because it captures long-term changes; is sensitive to the natural climate modes (ENSO events; responds well to spatial variability, and; is amenable to spatial/temporal aggregation, making it useful for epidemiological studies.

The relationship of animal experiments in predicting the effects on intrauterine radiation effects in the human

International Nuclear Information System (INIS)

Brent, R.L.; Beckmann, D.A.; Jensh, R.P.; Thomas Jefferson Univ., Philadelphia, PA

1986-01-01

Although animal studies cannot be used to predict human disease, they can be utilized to study the mechanisms and the risk of radiation embryological effects reported in humans. The radiation embryological effects dealing with sterility, tumor development, life span studies and certain aspects of central nervous system functions cannot be so evaluated because of marked discordance in development or function between the rodent and human. It is important to recognize that, although the effects are markedly different, all stages of gestation have pathological effects following intrauterine radiation. There is no stage that will not be affected by 50 cGy: death in the preimplantation period; major malformations during early organogenesis; minor malformations during later organogenesis; histogenetic depletion, disorganization and cell depletion in midgestation; and cell depletion during the later part of gestation. The threshold dose for each of these effects is approximately 20 cGy, except during late gestation when permanent effects may not be produced at this low dose. All radiation embryological effects are multicellular phenomenona and, since it is unlikely that they are stochastic phenomena, the risks are not linearly related to radiation dose. The only exception may be the lethal effect produced on the first day of gestation. The present maximum permissible exposure of 0.5 cGy per years is appropriate for women of reproductive age exposed to radiation in the work place. Exposures from diagnostic radiation below 5 cGy present such a small or non-measurable risk, that counselors can support the continuation of wanted pregnancies. Inadvertant or medically necessary radiographic examinations present no greater concern whether in the first or second half of the menstrual cycle since pre-ovulation exposures or post-conception exposures before the first missed menstrual period of 5 cGy or less present a similar minimal risk. (orig.)

Bisphenol A in supermarket receipts and its exposure to human in Shenzhen, China.

Science.gov (United States)

Lu, Shao-You; Chang, Wen-Jing; Sojinu, Samuel O; Ni, Hong-Gang

2013-08-01

Paper receipt has been documented as one major source of bisphenol A (BPA) for human exposure but little has been done by researchers to elaborate the potential health risk caused by handling paper receipt up to date. In the present study, BPA was analyzed in 42 supermarket receipts collected from Shenzhen, China. BPA was detected in all samples at concentrations ranging from 2.58 to 14.7mgg(-1). In most cases, the total amount of BPA on the receipt was at least one thousand times the amount found in the epoxy lining of a food can, another controversial use of the chemical. The estimated daily intakes (EDI) of BPA via handling of supermarket receipt ranged from 2 to 347μgday(-1) (mean, 40.4μgday(-1)) for a supermarket cashier and from 0.24 to 3.98μgday(-1) (mean, 0.69μgday(-1)) for general population. Based on the cumulative probability distribution of the calculated daily exposure to BPA via handling supermarket receipt, the EDI at the 0.1th and 1th percentile for supermarket cashier and general population, were already larger than 100ng (kgbw)(-1)day(-1), while at the 0.2th and 71th percentile, the EDI for both populations reached 1000ng (kgbw)(-1)day(-1). Considering the adverse endocrine disruptive effects of BPA and the dosage exposure level (from tens to hundreds ng (kgbw)(-1)day(-1)), human exposure to BPA in Shenzhen deserves more attention. Sensitivity analysis result showed that the handling time and frequency of supermarket receipts are the most important variables that contributed to most of the total variance of exposure. Copyright © 2013 Elsevier Ltd. All rights reserved.

Nanoparticle exposure biomonitoring: exposure/effect indicator development approaches

Science.gov (United States)

Marie-Desvergne, C.; Dubosson, M.; Lacombe, M.; Brun, V.; Mossuz, V.

2015-05-01

The use of engineered nanoparticles (NP) is more and more widespread in various industrial sectors. The inhalation route of exposure is a matter of concern (adverse effects of air pollution by ultrafine particles and asbestos). No NP biomonitoring recommendations or standards are available so far. The LBM laboratory is currently studying several approaches to develop bioindicators for occupational health applications. As regards exposure indicators, new tools are being implemented to assess potentially inhaled NP in non-invasive respiratory sampling (nasal sampling and exhaled breath condensates (EBC)). Diverse NP analytical characterization methods are used (ICP-MS, dynamic light scattering and electron microscopy coupled to energy-dispersive X-ray analysis). As regards effect indicators, a methodology has been developed to assess a range of 29 cytokines in EBCs (potential respiratory inflammation due to NP exposure). Secondly, collaboration between the LBM laboratory and the EDyp team has allowed the EBC proteome to be characterized by means of an LC-MS/MS process. These projects are expected to facilitate the development of individual NP exposure biomonitoring tools and the analysis of early potential impacts on health. Innovative techniques such as field-flow fractionation combined with ICP-MS and single particle-ICPMS are currently being explored. These tools are directly intended to assist occupational physicians in the identification of exposure situations.

Nanoparticle exposure biomonitoring: exposure/effect indicator development approaches

International Nuclear Information System (INIS)

Marie-Desvergne, C; Dubosson, M; Mossuz, V; Lacombe, M; Brun, V

2015-01-01

The use of engineered nanoparticles (NP) is more and more widespread in various industrial sectors. The inhalation route of exposure is a matter of concern (adverse effects of air pollution by ultrafine particles and asbestos). No NP biomonitoring recommendations or standards are available so far. The LBM laboratory is currently studying several approaches to develop bioindicators for occupational health applications. As regards exposure indicators, new tools are being implemented to assess potentially inhaled NP in non-invasive respiratory sampling (nasal sampling and exhaled breath condensates (EBC)). Diverse NP analytical characterization methods are used (ICP-MS, dynamic light scattering and electron microscopy coupled to energy-dispersive X-ray analysis). As regards effect indicators, a methodology has been developed to assess a range of 29 cytokines in EBCs (potential respiratory inflammation due to NP exposure). Secondly, collaboration between the LBM laboratory and the EDyp team has allowed the EBC proteome to be characterized by means of an LC-MS/MS process. These projects are expected to facilitate the development of individual NP exposure biomonitoring tools and the analysis of early potential impacts on health. Innovative techniques such as field-flow fractionation combined with ICP-MS and single particle-ICPMS are currently being explored. These tools are directly intended to assist occupational physicians in the identification of exposure situations. (paper)

No Effect of TETRA Hand Portable Transmission Signals on Human Cognitive Function and Symptoms

DEFF Research Database (Denmark)

Riddervold, Ingunn Skogstad; Kjærgaard, Søren K.; Pedersen, Gert F.

2010-01-01

Current radio frequency radiation exposure guidelines rest on well-established thermal effects. However, recent research into analogue and digital transmission fields at levels covered by the exposure guidelines has indicated possible detrimental effects on human cognitive performance. To investi......Current radio frequency radiation exposure guidelines rest on well-established thermal effects. However, recent research into analogue and digital transmission fields at levels covered by the exposure guidelines has indicated possible detrimental effects on human cognitive performance....... To investigate this, we conducted a controlled climate chamber study of possible changes in cognitive performance in healthy volunteers exposed to transmission signals from TETRA hand portables (TETRA handsets). The trial deployed a balanced, randomized, double-blinded cross-over design. Performance on different...... paper-and-pencil, auditory and computer-based cognitive tasks was monitored in 53 male volunteers (mean age 36.41 years, SD 8.35) during 45-min exposure to a TETRA handset and sham control signals remotely controlled from a laboratory more than 100 km away. The main cognitive outcome was the Trail...

The properties of human body phantoms used in calculations of electromagnetic fields exposure by wireless communication handsets or hand-operated industrial devices.

Science.gov (United States)

Zradziński, Patryk

2013-06-01

According to international guidelines, the assessment of biophysical effects of exposure to electromagnetic fields (EMF) generated by hand-operated sources needs the evaluation of induced electric field (E(in)) or specific energy absorption rate (SAR) caused by EMF inside a worker's body and is usually done by the numerical simulations with different protocols applied to these two exposure cases. The crucial element of these simulations is the numerical phantom of the human body. Procedures of E(in) and SAR evaluation due to compliance analysis with exposure limits have been defined in Institute of Electrical and Electronics Engineers standards and International Commission on Non-Ionizing Radiation Protection guidelines, but a detailed specification of human body phantoms has not been described. An analysis of the properties of over 30 human body numerical phantoms was performed which has been used in recently published investigations related to the assessment of EMF exposure by various sources. The differences in applicability of these phantoms in the evaluation of E(in) and SAR while operating industrial devices and SAR while using mobile communication handsets are discussed. The whole human body numerical phantom dimensions, posture, spatial resolution and electric contact with the ground constitute the key parameters in modeling the exposure related to industrial devices, while modeling the exposure from mobile communication handsets, which needs only to represent the exposed part of the human body nearest to the handset, mainly depends on spatial resolution of the phantom. The specification and standardization of these parameters of numerical human body phantoms are key requirements to achieve comparable and reliable results from numerical simulations carried out for compliance analysis against exposure limits or within the exposure assessment in EMF-related epidemiological studies.

Human hair follicle benzo(a)pyrene and benzo(a)pyrene 7, 8-diol metabolism: effect of exposure to a coal tar-containing shampoo

Energy Technology Data Exchange (ETDEWEB)

Merk, H.F.; Mukhtar, H.; Kaufmann, I.; Das, M.; Bickers, D.R.

1987-01-01

Hair follicles are a readily available source of human epithelial tissue and offer an excellent system with which to study carcinogen metabolism in human populations. In this study hair follicles were employed to measure the metabolism of benzo(a)pyrene (BP), benzo(a)pyrene - 7,8-diol (BP 7,8-diol) and the enzyme mediated binding of /sup 3/H-BP to DNA. The effect of human exposure to a crude coal tar (CCT) - containing shampoo, a preparation rich in polycyclic aromatic hydrocarbons (PAHs on these parameters was also evaluated. It was found that aryl hydrocarbon hydroxylase (AHH) activity increased after use of the shampoo and enhancement of enzyme-mediated binding of BP to DNA was detected in most subjects. Hair follicles were shown to convert BP to several metabolic species and BP, 7,8-diol was also metabolised. Clotrimazole, a known inhibitor of the metabolism of BP was found to inhibit AHH and the metabolism of BP and BP 7,8-diol in human hair follicles, as were other imidazole compounds. The studies show that hair follicles represent an accessible tissue suitable for assessing the extent of PAH carcinogen metabolism in human subjects. Furthermore enzyme activity critical to cancer induction by PAHs was shown to be inducible following the use of a CCT-containing shampoo. Imidazole compounds were shown to be possible effective anti-carcinogens in human populations. 29 refs.

Eliminating the mere exposure effect through changes in context between exposure and test.

Science.gov (United States)

de Zilva, Daniel; Mitchell, Chris J; Newell, Ben R

2013-01-01

The present study examined the extent to which increased liking of exposed stimuli--the mere exposure effect--is dependent on experiencing the stimuli in the same context in exposure and on test. Participants were repeatedly exposed to pairs of cues (nonsense words) and target stimuli (faces and shapes), and were asked to rate the pleasantness of the target stimuli in a subsequent test phase. Familiar targets were preferred to novel targets-a mere exposure effect was obtained. This preference for familiar targets was disrupted, however, when the cue-target pairings were rearranged between exposure and test, or a novel cue was introduced at test. Overall, the study suggests that the context of exposure and test moderates the mere exposure effect. Liking of stimuli due to exposure is specific to the context of exposure and does not apply to new or familiar but different contexts.

Human internal and external exposure to PBDEs--a review of levels and sources

DEFF Research Database (Denmark)

Frederiksen, Marie; Vorkamp, Katrin; Thomsen, Marianne

2009-01-01

This paper reviews the existing literature on human exposure to polybrominated diphenyl ethers (PBDEs), with particular focus on external exposure routes (e.g. dust, diet, and air) and the resulting internal exposure to PBDEs (e.g. breast milk and blood). Being lipophilic and persistent organic...... ingest more dust than adults. Infants are also exposed to PBDEs via breast milk. Internal human exposure has generally been found to be one order of magnitude larger in North America than in Europe and Asia. These differences cannot solely be explained by the dietary intake as meat products are the only...... food group where some differences has been observed. However, indoor air and dust concentrations have been found to be approximately one order of magnitude higher in North America than in Europe, possibly a result of different fire safety standards. Within Europe, higher PBDE concentrations in dust...

Female sexual maturation and reproduction after prepubertal exposure to estrogens and endocrine disrupting chemicals: a review of rodent and human data.

Science.gov (United States)

Rasier, G; Toppari, J; Parent, A-S; Bourguignon, J-P

2006-07-25

Natural hormones and some synthetic chemicals spread into our surrounding environment share the capacity to interact with hormone action and metabolism. Exposure to such compounds can cause a variety of developmental and reproductive detrimental abnormalities in wildlife species and, potentially, in human. Many experimental and epidemiological data have reported that exposure of the developing fetus or neonate to environmentally relevant concentrations of some among these endocrine disrupters induces morphological, biochemical and/or physiological disorders in brain and reproductive organs, by interfering with the hormone actions. The impact of such exposures on the hypothalamic-pituitary-gonadal axis and subsequent sexual maturation is the subject of the present review. We will highlight epidemiological human studies and the effects of early exposure during gestational, perinatal or postnatal life in female rodents.

Directed Differentiation of Human Embryonic Stem Cells into Prostate Organoids In Vitro and its Perturbation by Low-Dose Bisphenol A Exposure.

Directory of Open Access Journals (Sweden)

Esther L Calderon-Gierszal

Full Text Available Studies using rodent and adult human prostate stem-progenitor cell models suggest that developmental exposure to the endocrine disruptor Bisphenol-A (BPA can predispose to prostate carcinogenesis with aging. Unknown at present is whether the embryonic human prostate is equally susceptible to BPA during its natural developmental window. To address this unmet need, we herein report the construction of a pioneer in vitro human prostate developmental model to study the effects of BPA. The directed differentiation of human embryonic stem cells (hESC into prostatic organoids in a spatial system was accomplished with precise temporal control of growth factors and steroids. Activin-induced definitive endoderm was driven to prostate specification by combined exposure to WNT10B and FGF10. Matrigel culture for 20-30 days in medium containing R-Spondin-1, Noggin, EGF, retinoic acid and testosterone was sufficient for mature prostate organoid development. Immunofluorescence and gene expression analysis confirmed that organoids exhibited cytodifferentiation and functional properties of the human prostate. Exposure to 1 nM or 10 nM BPA throughout differentiation culture disturbed early morphogenesis in a dose-dependent manner with 1 nM BPA increasing and 10 nM BPA reducing the number of branched structures formed. While differentiation of branched structures to mature organoids seemed largely unaffected by BPA exposure, the stem-like cell population increased, appearing as focal stem cell nests that have not properly entered lineage commitment rather than the rare isolated stem cells found in normally differentiated structures. These findings provide the first direct evidence that low-dose BPA exposure targets hESC and perturbs morphogenesis as the embryonic cells differentiate towards human prostate organoids, suggesting that the developing human prostate may be susceptible to disruption by in utero BPA exposures.

AirPEx. Air Pollution Exposure Model

Energy Technology Data Exchange (ETDEWEB)

Freijer, J.I.; Bloemen, H.J.Th.; De Loos, S.; Marra, M.; Rombout, P.J.A.; Steentjes, G.M.; Van Veen, M.P.

1997-12-01

Analysis of inhalatory exposure to air pollution is an important area of investigation when assessing the risks of air pollution for human health. Inhalatory exposure research focuses on the exposure of humans to air pollutants and the entry of these pollutants into the human respiratory tract. The principal grounds for studying the inhalatory exposure of humans to air pollutants are formed by the need for realistic exposure/dose estimates to evaluate the health effects of these pollutants. The AirPEx (Air Pollution Exposure) model, developed to assess the time- and space-dependence of inhalatory exposure of humans to air pollution, has been implemented for use as a Windows 3.1 computer program. The program is suited to estimating various exposure and dose quantities for individuals, as well as for populations and subpopulations. This report describes the fundamentals of the AirPEx model and provides a user manual for the computer program. Several examples included in the report illustrate the possibilities of the AirPEx model in exposure assessment. The model will be used at the National Institute of Public Health and the Environment as a tool in analysing the current exposure of the Dutch population to air pollutants. 57 refs.

Deoxynivalenol Exposure in Norway, Risk Assessments for Different Human Age Groups

Science.gov (United States)

Sundheim, Leif; Lillegaard, Inger Therese; Fæste, Christiane Kruse; Brantsæter, Anne-Lise; Brodal, Guro; Eriksen, Gunnar Sundstøl

2017-01-01

Deoxynivalenol (DON) is the most common mycotoxin in Norwegian cereals, and DON is detected in most samples of crude cereal grain and cereal food commodities such as flour, bran, and oat flakes. The Norwegian Scientific Committee for Food Safety assessed the risk for adverse effects of deoxynivalenol (DON) in different age groups of the domestic population. This review presents the main results from the risk assessment, supplemented with some recently published data. Impairment of the immune system together with reduced feed intake and weight gain are the critical effects of DON in experimental animals on which the current tolerable daily intake was established. Based on food consumption and occurrence data, the mean exposure to DON in years with low and high levels of DON in the flour, respectively, were in the range of or up to two times the Tolerable Daily Intake (TDI) in 1-year-old infants and 2-year-old children. In years with high mean DON concentration, the high (95th-percentile) exposure exceeded the TDI by up to 3.5 times in 1-, 2- , 4-, and 9-year-old children. The assessment concluded that exceeding the TDI in infants and children is of concern. The estimated dietary DON intakes in adolescent and adult populations are in the range of the TDI or below, and are not a health concern. Acute human exposure to DON is not of concern in any age group. PMID:28165414

Deoxynivalenol Exposure in Norway, Risk Assessments for Different Human Age Groups

Directory of Open Access Journals (Sweden)

Leif Sundheim

2017-02-01

Full Text Available Deoxynivalenol (DON is the most common mycotoxin in Norwegian cereals, and DON is detected in most samples of crude cereal grain and cereal food commodities such as flour, bran, and oat flakes. The Norwegian Scientific Committee for Food Safety assessed the risk for adverse effects of deoxynivalenol (DON in different age groups of the domestic population. This review presents the main results from the risk assessment, supplemented with some recently published data. Impairment of the immune system together with reduced feed intake and weight gain are the critical effects of DON in experimental animals on which the current tolerable daily intake was established. Based on food consumption and occurrence data, the mean exposure to DON in years with low and high levels of DON in the flour, respectively, were in the range of or up to two times the Tolerable Daily Intake (TDI in 1-year-old infants and 2-year-old children. In years with high mean DON concentration, the high (95th-percentile exposure exceeded the TDI by up to 3.5 times in 1-, 2- , 4-, and 9-year-old children. The assessment concluded that exceeding the TDI in infants and children is of concern. The estimated dietary DON intakes in adolescent and adult populations are in the range of the TDI or below, and are not a health concern. Acute human exposure to DON is not of concern in any age group.