Targeting pre-exposure prophylaxis among men who have sex with men in the United States and Peru: partnership types, contact rates, and sexual role.

PubMed

Carnegie, Nicole B; Goodreau, Steven M; Liu, Albert; Vittinghoff, Eric; Sanchez, Jorge; Lama, Javier R; Buchbinder, Susan

2015-05-01

We aim to identify optimal strategies for deploying pre-exposure prophylaxis among men who have sex with men (MSM) in the United States and Peru to maximize population-level effectiveness in an efficient manner. We use epidemic models to simulate the impact of targeting strategies. Most studies have focused on targeting either the general population or high-risk MSM. Alternative strategies, including serodiscordant couples, may better balance effectiveness and efficiency. We use dynamic stochastic sexual network models based on exponential-family random graph modeling, parameterized from behavioral surveys of MSM in the United States and Peru. These models represent main partnerships and casual contacts separately, permitting modeling of interventions targeting men whose risk derives from combinations of relational types. We also model varying rates of uptake and adherence to pre-exposure prophylaxis (PrEP). We assess sensitivity of results to risk compensation through increases in condomless casual contacts and condomless sex in main partnerships. Targeting all men who are not exclusively insertive has the largest impact on HIV incidence, but targeting only those with high levels of casual activity yields comparable results using fewer person-years on PrEP. The effect is robust to risk compensation in the United States, but less so in Peru. Targeting serodiscordant main partnerships does not significantly impact incidence, but requires fewer person-years on PrEP per infection averted than other strategies. PrEP could be effective in reducing new infections at the population level in both settings. Serodiscordant partnerships are an attractive component of a targeting program, but targeting should include other high-risk men.

The intersection of aggregate-level lead exposure and crime.

PubMed

Boutwell, Brian B; Nelson, Erik J; Emo, Brett; Vaughn, Michael G; Schootman, Mario; Rosenfeld, Richard; Lewis, Roger

2016-07-01

Childhood lead exposure has been associated with criminal behavior later in life. The current study aimed to analyze the association between elevated blood lead levels (n=59,645) and crime occurrence (n=90,433) across census tracts within St. Louis, Missouri. Longitudinal ecological study. Saint Louis, Missouri. Blood lead levels. Violent, Non-violent, and total crime at the census tract level. Spatial statistical models were used to account for the spatial autocorrelation of the data. Greater lead exposure at the census-tract level was associated with increased violent, non-violent, and total crime. In addition, we examined whether non-additive effects existed in the data by testing for an interaction between lead exposure and concentrated disadvantage. Some evidence of a negative interaction emerged, however, it failed to reach traditional levels of statistical significance (supplementary models, however, revealed a similar negative interaction that was significant). More precise measurements of lead exposure in the aggregate, produced additional evidence that lead is a potent predictor of criminal outcomes. Copyright © 2016 Elsevier Inc. All rights reserved.

High-Intensity Targeted Screening for Elevated Blood Lead Levels Among Children in 2 Inner-City Chicago Communities

PubMed Central

Dignam, Timothy A.; Evens, Anne; Eduardo, Eduard; Ramirez, Shokufeh M.; Caldwell, Kathleen L.; Kilpatrick, Nikki; Noonan, Gary P.; Flanders, W. Dana; Meyer, Pamela A.; McGeehin, Michael A.

2004-01-01

Objectives. We assessed the prevalence of elevated blood lead levels (≥ 10 micrograms of lead per deciliter of blood), risk factors, and previous blood lead testing among children in 2 high-risk Chicago, Ill, communities. Methods. Through high-intensity targeted screening, blood lead levels were tested and risks were assessed among a representative sample of children aged 1 to 5 years who were at risk for lead exposure. Results. Of the 539 children who were tested, 27% had elevated blood lead levels, and 61% had never been tested previously. Elevated blood lead levels were associated with chipped exterior house paint. Conclusions. Most of the children who lived in these communities—where the prevalence for elevated blood lead levels among children was 12 times higher than the national prevalence—were not tested for lead poisoning. Our findings highlight the need for targeted community outreach that includes testing blood lead levels in accordance with the American Academy of Pediatrics’ recommendations. PMID:15514235

Levels of exposure from drinking water.

PubMed

van Dijk-Looijaard, A M; van Genderen, J

2000-01-01

The relative exposure from drinking water is generally small, although there is a lack of information on total daily intake of individual organic micropollutants. There are, however, a few exceptions. Materials used in domestic distribution systems (lead, copper and plastics) may cause a deterioration of the water quality, especially in stagnant water. The relative exposure to the related compounds may increase considerably. Monitoring data from the tap (with defined sampling techniques) are needed. Also, disinfection/oxidation by-products (bromate, trihalomethanes) can be present in drinking water in considerable amounts and the relative exposure from drinking water may even approach 100%. Especially for volatile organic micropollutants, exposure routes from drinking water other than ingestion must be taken into account (inhalation, percutaneous uptake). When there is a need for detection of substances at very low levels it is important that the measurements are reliable. International interlaboratory comparisons for organic micropollutants are lacking at the moment.

Anticoagulant rodenticide toxicity to non-target wildlife under controlled exposure conditions

USGS Publications Warehouse

Rattner, Barnett A.; Mastrota, F. Nicholas; van den Brink, Nico; Elliott, J.; Shore, R.; Rattner, B.

2018-01-01

Much of our understanding of anticoagulant rodenticide toxicity to non-target wildlife has been derived from molecular through whole animal research and registration studies in domesticated birds and mammals, and to a lesser degree from trials with captive wildlife. Using these data, an adverse outcome pathway identifying molecular initiating and anchoring events (inhibition of vitamin K epoxide reductase, failure to activate clotting factors), and established and plausible linkages (coagulopathy, hemorrhage, anemia, reduced fitness) associated with toxicity, is presented. Controlled exposure studies have demonstrated that second-generation anticoagulant rodenticides (e.g., brodifacoum) are more toxic than first- and intermediate-generation compounds (e.g., warfarin, diphacinone), however the difference in potency is diminished when first- and intermediate-generation compounds are administered on multiple days. Differences in species sensitivity are inconsistent among compounds. Numerous studies have compared mortality rate of predators fed prey or tissue containing anticoagulant rodenticides. In secondary exposure studies in birds, brodifacoum appears to pose the greatest risk, with bromadiolone, difenacoum, flocoumafen and difethialone being less hazardous than brodifacoum, and warfarin, coumatetralyl, coumafuryl, chlorophacinone and diphacinone being even less hazardous. In contrast, substantial mortality was noted in secondary exposure studies in mammals ingesting prey or tissue diets containing either second- or intermediate-generation compounds. Sublethal responses (e.g., prolonged clotting time, reduced hematocrit and anemia) have been used to study the sequelae of anticoagulant intoxication, and to some degree in the establishment of toxicity thresholds or toxicity reference values. Surprisingly few studies have undertaken histopathological evaluations to identify cellular lesions and hemorrhage associated with anticoagulant rodenticide exposure in non-target

Recent and long-term occupational noise exposure and salivary cortisol level.

PubMed

Stokholm, Zara Ann; Hansen, Åse Marie; Grynderup, Matias Brødsgaard; Bonde, Jens Peter; Christensen, Kent Lodberg; Frederiksen, Thomas Winther; Lund, Søren Peter; Vestergaard, Jesper Medom; Kolstad, Henrik Albert

2014-01-01

Environmental and occupational noise exposure have been related to increased risk of cardiovascular disease, hypothetically mediated by stress-activation of the hypothalamic-pituitary-adrenal (HPA) axis. The objective of this study was to investigate the relation between recent and long-term occupational noise exposure and cortisol level measured off work to assess a possible sustained HPA-axis effect. We included 501 industrial, finance, and service workers who were followed for 24h during work, leisure, and sleep. Ambient occupational noise exposure levels were recorded every 5s by personal dosimeters and we calculated the full-shift LAEq value and estimated duration and cumulative exposure based on their work histories since 1980. For 332 workers who kept a log-book on the use of hearing protection devices (HPD), we subtracted 10 dB from every noise recording obtained during HPD use and estimated the noise level at the ear. Salivary cortisol concentration was measured at 20.00 h, the following day at awakening, and 30 min after awakening on average 5, 14 and 14.5h after finishing work. The mean ambient noise exposure level was 79.9 dB(A) [range: 55.0-98.9] and the mean estimated level at the ear 77.7 dB(A) [range: 55.0-94.2]. In linear and mixed regression models that adjusted for age, sex, current smoking, heavy alcohol consumption, personal income, BMI, leisure-time noise exposure level, time since occupational noise exposure ceased, awakening time, and time of saliva sampling, we observed no statistically significant exposure response relation between recent, or long-term ambient occupational noise exposure level and any cortisol parameter off work. This was neither the case for recent noise level at the ear. To conclude, neither recent nor long-term occupational noise exposure levels were associated with increased cortisol level off work. Thus, our results do not indicate that a sustained activation of the HPA axis, as measured by cortisol, is involved in

Examining the target levels of state renewable portfolio standards

NASA Astrophysics Data System (ADS)

Helwig, Laurence Douglas

At present 37 U.S. states have passed Renewable Portfolio Standards (RPS) or have a legislative driven goal that supports investment in renewable energy (RE) technologies. Previous research has identified economic, governmental, ideological and infrastructural characteristics as key predictors of policy adoption and renewable energy deployment efforts (Carley, 2009; Davis & Davis, 2009; Bohn & Lant, 2009; Lyon & Yin, 2010). To date, only a few studies have investigated the target levels of renewable portfolio standards. Carley & Miller (2012) found that policies of differing stringencies were motivated by systematically different factors that included governmental ideology. The purpose of this dissertation is to replicate and expand upon earlier models that predicted RPS adoption and RE deployment efforts by adding regulatory, infrastructural and spatial characteristics to predict RPS target levels. Hypotheses were tested using three alternative measurements of RPS target level strength to determine to what extent a combination of explanatory variables explain variation in policy target levels. Multivariate linear regression and global spatial autocorrelation results indicated that multiple state internal determinants influenced RPS target level including average electricity price, state government ideology and to a lesser extent actual RE potential capacity. In addition, some diffusion effects were found to exist that indicated that states are setting their RPS target levels lower than their neighboring states and a local geo-spatial clustering effect was observed in the target levels for a grouping of northeastern states.

Changes in the level of perforin and its transcript during effector and target cell interactions.

PubMed

Kim, K K; Blakely, A; Zhou, Z; Davis, J; Clark, W; Kwon, B S

1993-05-01

Perforin is a cytoplasmic granule protein expressed in cytotoxic lymphocytes, and is capable of lysing target cells. This protein is induced as cytotoxic T cells are activated, and the mRNA expression is modulated by various stimulators. These observations suggest possible changes in the level of perforin transcripts and protein when killer lymphocytes meet specific target cells leading to target cell death. To address this question, we examined three murine T-cell clones and primary human NK cells in perforin expression. When the cytotoxic lymphocytes were exposed to sensitive targets, perforin mRNA disappeared within 5 to 30 min and appeared within an hour thereafter. Among the murine T cell clones, L3 and OE4 showed two phases of mRNA decrease while human NK cells and the third murine T cell clone, AB.1, showed only one phase of mRNA loss during a 240 min period. The data indicate that when cytotoxic lymphocytes receive signals from a sensitive target, the cells rapidly degrade previously accumulated perforin mRNA and synthesize new transcripts. Interestingly, heat shock protein 70 mRNA was induced as the perforin mRNA levels recovered, while P55 Il-2 receptor mRNA was downregulated within 5 min after exposure to targets. The perforin protein level also rapidly decreased immediately after the interaction with the target, followed by a recovery, and then another decrease as seen in primary human NK cells, OE4 and L3 cells. However, in the AB.1 clone, no change in perforin content was detectable, despite the loss of perforin mRNA.(ABSTRACT TRUNCATED AT 250 WORDS)

After the master settlement agreement: targeting and exposure of youth to magazine tobacco advertising.

PubMed

Alpert, Hillel R; Koh, Howard K; Connolly, Gregory N

2008-01-01

Targeting and exposure of youth to magazine advertising of tobacco products is associated with increased smoking initiation. National magazine advertising and youth exposure declined in the period following the Master Settlement Agreement (MSA). However, tobacco companies continued targeting youth with brands that were popular among them through magazine advertising and placement of ads in magazines with high youth readership. Existing restrictions, followed by enforcement through litigation, have achieved a marked reduction in overall magazine advertising but may be less adequate compared with pending federal legislation to fully protect youth from the marketing of tobacco products designed to appeal to them.

UV exposure, genetic targets in melanocytic tumors and transgenic mouse models.

PubMed

de Gruijl, Frank R; van Kranen, Henk J; van Schanke, Arne

2005-01-01

The genetic changes and corruption of kinase activity in melanomas appear to revolve around a central axis: mitogenic signaling along the RAS pathway down to transcription regulation by pRB. Epidemiological studies point to the importance of ultraviolet (UV) radiation in the etiology of melanoma, but where and how UV radiation is targeted to contribute to the oncogenic signaling remains obscure. Animal models of melanoma genesis could serve to clarify this issue, but many of these models are not responsive to UV exposure. Most interesting advances have been made by using transgenic mice that carry genetic defects that are known to be relevant to human melanoma: specifically, dysfunction in the tumor suppressive action of p16INK4a or a receptor tyrosine kinase/RAS pathway, that is constitutively activated in melanocytes. The latter types of mice appear to be most responsive to (neonatal) UV exposure. Whether this is due to a general increase in target cells by melanocytosis and a paucity or complete lack of pigment, or a possible UV-induced response of the promoter-enhancer of the transgene or a genuinely independent and additional genetic alteration caused by UV exposure needs to be established. Importantly, the full effect of UV radiation needs to be ascertained in mice with different pigmentation by varying the wavelengths, UV-B versus UV-A1, and the exposure schedules, i.e. neonatal versus adult and chronic versus intermittent overexposure. Intermittent UV-B overexposure deserves special attention because it most strongly evokes proliferative responses in melanocytes.

SU-E-I-27: Establishing Target Exposure Index Values for Computed Radiography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murphy, N; Tchou, P; Belcher, K

2014-06-01

Purpose: To develop a standard set of target exposure index (TEI) values to be applied to Agfa Computed Radiography (CR) readers in accordance with International Electrotechnical Committee 62494-1 (ed. 1.0). Methods: A large data cohort was collected from six USAF Medical Treatment Facilities that exclusively use Agfa CR Readers. Dose monitoring statistics were collected from each reader. The data was analyzed based on anatomic region, view, and processing speed class. The Agfa specific exposure metric, logarithmic mean (LGM), was converted to exposure index (EI) for each data set. The optimum TEI value was determined by minimizing the number of studiesmore » that fell outside the acceptable deviation index (DI) range of +/− 2 for phototimed techniques or a range of +/−3 for fixed techniques. An anthropomorphic radiographic phantom was used to corroborate the TEI recommendations. Images were acquired of several anatomic regions and views using standard techniques. The images were then evaluated by two radiologists as either acceptable or unacceptable. The acceptable image with the lowest exposure and EI value was compared to the recommended TEI values using a passing DI range. Results: Target EI values were determined for a comprehensive list of anatomic regions and views. Conclusion: Target EI values must be established on each CR unit in order to provide a positive feedback system for the technologist. This system will serve as a mechanism to prevent under or overexposures of patients. The TEI recommendations are a first attempt at a large scale process improvement with the goal of setting reasonable and standardized TEI values. The implementation and effectiveness of the recommended TEI values should be monitored and adjustments made as necessary.« less

The forward masking effects of low-level laser glare on target location performance in a visual search task

NASA Astrophysics Data System (ADS)

Reddix, M. D.; Dandrea, J. A.; Collyer, P. D.

1992-01-01

The present study examined the effects of low-intensity laser glue, far below a level that would cause ocular damage or flashblindness, on the visually guided performance of aviators. With a forward-masking paradigm, this study showed that the time at which laser glare is experienced, relative to initial acquisition of visual information, differentially affects the speed and accuracy of target-location performance. Brief exposure (300 ms) to laser glare, terminating with a visual scene's onset, produced significant decrements in target-location performance relative to a no-glare control whereas a 150 and 300-ms delay of display onset (DDO) had very little effect. The intensity of the light entering the eye and producing these effects was far below the Maximum Permissible Exposure (MPE) limit for safe viewing of coherent light produced by an argon laser. In addition, these effects were modulated by the distance of the target from the center of the visual display. This study demonstrated that the presence of laser glare is not sufficient, in and of itself, to diminish target-location performance. The time at which laser glare is experienced is an important factor in determining the probability and extent of visually mediated performance decrements.

Assessment of road users' elemental carbon personal exposure levels, London, UK

NASA Astrophysics Data System (ADS)

Adams, H. S.; Nieuwenhuijsen, M. J.; Colvile, R. N.; Older, M. J.; Kendall, M.

Little is known about particulate elemental carbon (EC) personal exposure levels, a key component of diesel exhaust, specifically in transport microenvironments. A method utilizing the optical properties of EC particles has been applied to personal exposure measurement filter samples. In a series of field studies carried out in London, UK, during 1999-2000 over 400 fine particle (PM 2.5) personal exposure level measurements were taken for journeys in bicycle, bus, car and underground rail transport microenvironments, along three main fixed routes. The particulate EC contribution to the PM 2.5 personal exposure was assessed indirectly by means of an optical technique and with the development and use of a size fraction specific and site-specific calibration curve. In this first EC personal exposure study of transport users geometric mean exposure levels in the summer field campaign were 11.2 μg m -3 (GSD=2.7) for cyclists, 13.6 μg m -3 (GSD=1.9) for bus passengers and 21.6 μg m -3 (GSD=2.1) for car drivers; corresponding exposure levels in the winter were 16.4 μg m -3 (GSD=1.8), 18.6 μg m -3 (GSD=2.3) and 27.3 μg m -3 (GSD=2.0), respectively. EC/PM 2.5 ratios were approximately 0.5-0.6 for bicycle and bus modes and 0.7-0.8 for the car mode. EC/PM 2.5 ratios for different routes ranged from approximately 0.7 for Route 1 to 0.4 for Route 3. Cyclists had the lowest exposure to EC, and car occupants the highest exposure. A large difference in exposure levels between a central high traffic density route and the other less central routes was observed. Particulate EC was a very significant proportion of the total PM 2.5 personal exposure and EC personal exposure levels were considerably higher than reported fixed site monitor EC concentrations.

Enhanced UV exposure on a ski-field compared with exposures at sea level.

PubMed

Allen, Martin; McKenzie, Richard

2005-05-01

Personal erythemal UV monitoring badges, which were developed to monitor the UV exposure of school children, were used to measure UV exposures received by one of the authors (MA) at the Mt Hutt ski-field, in New Zealand. These were then compared with measurements taken at the same times from a nearby sea level site in Christchurch city. The badges were designed to give instantaneous readings of erythemally-weighted (i.e., "sun burning") UV radiation and were cross-calibrated against meteorological grade UV instruments maintained by the National Institute of Water & Atmospheric Research (NIWA). All skiing and calibration days were clear and almost exclusively cloud free. It was found that the UV maxima for horizontal surfaces at the ski-field (altitude approximately 2 km) were 20-30% greater than at the low altitude site. Larger differences between the sites were observed when the sensor was oriented perpendicular to the sun. The personal doses of UV received by a sensor on the skier's lapel during two days of skiing activity were less than those received by a stationary detector on a horizontal surface near sea level. The exposures depended strongly on the time of year, and in mid-October the maximum UV intensity on the ski-field was 60% greater than in mid-September. The UV exposure levels experienced during skiing were smaller than the summer maxima at low altitudes.

Effects of developmental lead exposure on the hippocampal methylome: Influences of sex and timing and level of exposure.

PubMed

Singh, G; Singh, V; Wang, Zi-Xuan; Voisin, G; Lefebvre, F; Navenot, J-M; Evans, B; Verma, M; Anderson, D W; Schneider, J S

2018-06-15

Developmental lead (Pb) exposure results in persistent cognitive/behavioral impairments as well as an elevated risk for developing a variety of diseases in later life. Environmental exposures during development can result in a variety of epigenetic changes, including alterations in DNA methylation, that can influence gene expression patterns and affect the function and development of the nervous system. The present promoter-based methylation microarray profiling study explored the extent to which developmental Pb exposure may modify the methylome of a brain region, hippocampus, known to be sensitive to the effects of Pb exposure. Male and female Long Evans rats were exposed to 0 ppm, 150 ppm, 375 ppm, or 750 ppm Pb through perinatal exposures (gestation through lactation), early postnatal exposures (birth through weaning), or long-term postnatal exposures (birth through postnatal day 55). Results showed a significant contribution of sex to the hippocampal methylome and effects of Pb exposure level, with non-linear dose response effects on methylation. Surprisingly, the developmental period of exposure contributed only a small amount of variance to the overall data and gene ontology (GO) analysis revealed the largest number of overrepresented GO terms in the groups with the lowest level of exposure. The highest number of significant differentially methylated regions was found in females exposed to Pb at the lowest exposure level. Our data reinforce the significant effect that low level Pb exposure may have on gene-specific DNA methylation patterns in brain and that this occurs in a sex-dependent manner. Copyright © 2018 Elsevier B.V. All rights reserved.

Neuropsychological Effects of Low-Level Manganese Exposure in Welders

PubMed Central

Laohaudomchok, Wisanti; Lin, Xihong; Herrick, Robert F.; Fang, Shona C.; Cavallari, Jennifer M.; Shrairman, Ruth; Landau, Alexander; Christiani, David C.; Weisskopf, Marc G.

2011-01-01

While the neuropsychological effects of high manganese (Mn) exposure in occupational settings are well known, the effects of lower levels of exposure are less understood. In this study, we investigated the neuropsychological effects of lower level occupational Mn exposure in 46 male welders (mean age = 37.4, sd = 11.7 years). Each welders’ cumulative Mn exposure indices (Mn-CEI) for the past 12 months and total work history Mn exposure were constructed based on air Mn measurements and work histories. The association between these exposure indices and performance on cognitive, motor control, and psychological tests was examined. In addition, among a subset of welders (n=24) who completed the tests both before and after a work shift, we examined the association between cross-shift Mn exposure assessed from personal monitoring and acute changes in test scores. Mn exposures in this study (median = 12.9 μg/m3) were much lower, as compared to those observed in other similar studies. Increasing total Mn-CEI was significantly associated with slower reaction time on the continuous performance test (CPT; p<0.01), as well as worse mood for several scales on the Profile of Mood States (POMS; confused, tired, and a composite of tired and energetic, all p≤0.03). Increasing Mn-CEI over the previous 12 months was significantly associated with worse mood on the sad, tense, and confused POMS scales (all p≤0.03) and the association with worse CPT performance approached significance (p=0.10). Higher Mn exposure over the course of a workday was associated with worse performance on the CPT test across the day (p=0.06) as well as declines in fine motor control over the work-shift (p=0.04), adjusting for age and time between the 2 tests. Our study suggests that even at relatively low Mn exposure levels neuropsychological effects may manifest particularly with respect to attention, mood, and fine motor control. PMID:21192973

Aggregate-level lead exposure, gun violence, homicide, and rape

PubMed Central

Nelson, Erik J.; Qian, Zhengmin; Vaughn, Michael G.; Wright, John P.; Beaver, Kevin M.; Barnes, J. C.; Petkovsek, Melissa; Lewis, Roger; Schootman, Mario; Rosenfeld, Richard

2017-01-01

Context An increasing body of research has linked the geographic distribution of lead with various indicators of criminal and antisocial behavior. Objective The current study, using data from an ongoing project related to lead exposure in St. Louis City, MO, analyzed the association between aggregate blood lead levels and specific indicators violent crime within the city. Design Ecological study. Setting St. Louis, Missouri. Exposure measure Blood lead levels. Main outcome measure Official reports of violent crimes were categorized as 1) crimes involving a firearm (yes/no), 2) assault crimes (with or without a firearm), 3) robbery crimes (with or without a firearm), 4) homicides and 5) rape. Results With the exception of rape, aggregate blood-lead levels were statistically significant predictors of violent crime at the census tract level. The risk ratios for each of the outcome measures were as follows: firearm crimes 1.03 (1.03–1.04), assault crimes 1.03 (1.02–1.03), robbery crimes 1.03 (1.02–1.04), homicide 1.03 (1.01, 1.04), and rape 1.01 (0.99–1.03). Conclusions Extending prior research in St. Louis, results suggest that aggregated lead exposure at the census tract level predicted crime outcomes, even after accounting for important sociological variables. Moving forward, a more developed understanding of aggregate level crime may necessitate a shift toward studying the synergy between sociological and biological risk factors such as lead exposure. PMID:29176826

Ambient and at-the-ear occupational noise exposure and serum lipid levels.

PubMed

Arlien-Søborg, Mai C; Schmedes, Astrid S; Stokholm, Z A; Grynderup, M B; Bonde, J P; Jensen, C S; Hansen, Å M; Frederiksen, T W; Kristiansen, J; Christensen, K L; Vestergaard, J M; Lund, S P; Kolstad, H A

2016-10-01

Occupational and residential noise exposure has been related to increased risk of cardiovascular disease. Alteration of serum lipid levels has been proposed as a possible causal pathway. The objective of this study was to investigate the relation between ambient and at-the-ear occupational noise exposure and serum levels of total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, and triglycerides when accounting for well-established predictors of lipid levels. This cross-sectional study included 424 industrial workers and 84 financial workers to obtain contrast in noise exposure levels. They provided a serum sample and wore portable dosimeters that every 5-s recorded ambient noise exposure levels during a 24-h period. We extracted measurements obtained during work and calculated the full-shift mean ambient noise level. For 331 workers who kept a diary on the use of a hearing protection device (HPD), we subtracted 10 dB from every noise recording obtained during HPD use and estimated the mean full-shift noise exposure level at the ear. Mean ambient noise level was 79.9 dB (A) [range 55.0-98.9] and the mean estimated level at the ear 77.8 dB (A) [range 55.0-94.2]. Ambient and at-the-ear noise levels were strongly associated with increasing levels of triglycerides, cholesterol-HDL ratio, and decreasing levels of HDL-cholesterol, but only in unadjusted analyses that did not account for HPD use and other risk factors. No associations between ambient or at-the-ear occupational noise exposure and serum lipid levels were observed. This indicates that a causal pathway between occupational and residential noise exposure and cardiovascular disease does not include alteration of lipid levels.

[Lead exposure in the ceramic tile industry: time trends and current exposure levels].

PubMed

Candela, S; Ferri, F; Olmi, M

1998-01-01

There is a high density of industries for the production of ceramic tiles in the District of Scandiano (province of Reggio Emilia, Emilia Romagna region). In this area, since the beginning of 1970s, the time trend of Pb exposure in ceramic tile plants has been evaluated by means of biological monitoring (BM) data collected at the Service of Prevention and Safety in the Work Environment and its associated Toxicology Laboratory. From these data, a clear decreasing time trend of exposure levels is documented, the reduction being more evident during the seventies and in 1985-88. During the seventies BM was introduced systematically in all ceramic tile plants with the determination of delta-aminolevulinic acid in urine (ALA-U). As a consequence of the BM programme, hygienic measures for the abatement of pollution inside the plants were implemented, and a reduction, from 20.6% to 2%, of ALA-U values exceeding 10 mg/l, was observed. In 1985, the determination of lead in blood (PbB) replaced that of ALA-U in the BM programmes and highlighted the persistence of high level of exposure to Pb, which could not be outlined by means of ALA-U because of its lower sensitivity. PbB levels were 36.1 micrograms/100 ml and 25.7 micrograms/100 ml in male and female workers, respectively. These results required the implementation, within the plants, of additional hygienic measures and a significant reduction of PbB was obtained in the following three years. In 1988 PbB levels were 26.0 +/- 10.7 and 21.6 +/- 10.3 micrograms/100 ml in male and female workers, respectively. In 1993-95 Pb levels were obtained from 1328 male and 771 female workers of 56 plants, accounting for about 40% of the total number of workers in the ceramic industry, in the zones of Sassuolo and Scandiano. Exposure levels are not different from those observed in the preceding years, with PbB levels of 25.3 +/- 11.1 and 19.1 +/- 9.2 micrograms/100 ml in male and female workers, respectively.

Maize miRNA and target regulation in response to hormone depletion and light exposure during somatic embryogenesis

PubMed Central

Chávez-Hernández, Elva C.; Alejandri-Ramírez, Naholi D.; Juárez-González, Vasti T.; Dinkova, Tzvetanka D.

2015-01-01

Maize somatic embryogenesis (SE) is induced from the immature zygotic embryo in darkness and under the appropriate hormones' levels. Small RNA expression is reprogrammed and certain miRNAs become particularly enriched during induction while others, characteristic to the zygotic embryo, decrease. To explore the impact of different environmental cues on miRNA regulation in maize SE, we tested specific miRNA abundance and their target gene expression in response to photoperiod and hormone depletion for two different maize cultivars (VS-535 and H-565). The expression levels of miR156, miR159, miR164, miR168, miR397, miR398, miR408, miR528, and some predicted targets (SBP23, GA-MYB, CUC2, AGO1c, LAC2, SOD9, GR1, SOD1A, PLC) were examined upon staged hormone depletion in the presence of light photoperiod or darkness. Almost all examined miRNA, except miR159, increased upon hormone depletion, regardless photoperiod absence/presence. miR528, miR408, and miR398 changed the most. On the other hand, expression of miRNA target genes was strongly regulated by the photoperiod exposure. Stress-related miRNA targets showed greater differences between cultivars than development-related targets. miRNA/target inverse relationship was more frequently observed in darkness than light. Interestingly, miR528, but not miR159, miR168 or miR398, was located on polyribosome fractions suggesting a role for this miRNA at the level of translation. Overall our results demonstrate that hormone depletion exerts a great influence on specific miRNA expression during plant regeneration independently of light. However, their targets are additionally influenced by the presence of photoperiod. The reproducibility or differences observed for particular miRNA-target regulation between two different highly embryogenic genotypes provide clues for conserved miRNA roles within the SE process. PMID:26257760

Population-Level Exposure to Particulate Air Pollution during Active Travel: Planning for Low-Exposure, Health-Promoting Cities

PubMed Central

Hankey, Steve; Lindsey, Greg; Marshall, Julian D.

2016-01-01

Background: Providing infrastructure and land uses to encourage active travel (i.e., bicycling and walking) are promising strategies for designing health-promoting cities. Population-level exposure to air pollution during active travel is understudied. Objectives: Our goals were a) to investigate population-level patterns in exposure during active travel, based on spatial estimates of bicycle traffic, pedestrian traffic, and particulate concentrations; and b) to assess how those exposure patterns are associated with the built environment. Methods: We employed facility–demand models (active travel) and land use regression models (particulate concentrations) to estimate block-level (n = 13,604) exposure during rush-hour (1600–1800 hours) in Minneapolis, Minnesota. We used the model-derived estimates to identify land use patterns and characteristics of the street network that are health promoting. We also assessed how exposure is correlated with indicators of health disparities (e.g., household income, proportion of nonwhite residents). Our work uses population-level rates of active travel (i.e., traffic flows) rather than the probability of walking or biking (i.e., “walkability” or “bikeability”) to assess exposure. Results: Active travel often occurs on high-traffic streets or near activity centers where particulate concentrations are highest (i.e., 20–42% of active travel occurs on blocks with high population-level exposure). Only 2–3% of blocks (3–8% of total active travel) are “sweet spots” (i.e., high active travel, low particulate concentrations); sweet spots are located a) near but slightly removed from the city-center or b) on off-street trails. We identified 1,721 blocks (~ 20% of local roads) where shifting active travel from high-traffic roads to adjacent low-traffic roads would reduce exposure by ~ 15%. Active travel is correlated with population density, land use mix, open space, and retail area; particulate concentrations were

Evaluation of noise pollution level based upon community exposure and response data

NASA Technical Reports Server (NTRS)

Edmiston, R. D.

1972-01-01

The results and procedures are reported from an evaluation of noise pollution level as a predictor of annoyance, based on aircraft noise exposure and community response data. The measures of noise exposure presented include composite noise rating, noise exposure forecast, noise and number index. A proposed measure as a universal noise exposure measure for noise pollution level (L sub NP) is discussed.

Low levels of exposure to libby amphibole asbestos and localized pleural thickening.

PubMed

Christensen, Krista Yorita; Bateson, Thomas F; Kopylev, Leonid

2013-11-01

To explore the relationship between low levels of exposure to Libby amphibole asbestos (LAA) and pleural abnormalities, specifically localized pleural thickening (LPT). Three studies presenting the risks associated with quantitative LAA exposure estimates were reviewed, paying particular attention to lower exposure ranges. Studies reviewed were conducted among workers exposed to LAA at mining and milling operations in Libby, Montana, at a vermiculite processing facility in Marysville, Ohio, and community residents exposed to LAA from a vermiculite processing facility in Minneapolis, Minnesota. Pleural abnormalities were evaluated using radiographs. Despite differences in study populations and design, each study found that cumulative inhalation LAA exposure was associated with increased risk of LPT even at low levels of exposure. Inhalation exposure to LAA is associated with increased risk of LPT even at the lowest levels of exposure in each study.

Prediction of intracellular exposure bridges the gap between target- and cell-based drug discovery

PubMed Central

Gordon, Laurie J.; Wayne, Gareth J.; Almqvist, Helena; Axelsson, Hanna; Seashore-Ludlow, Brinton; Treyer, Andrea; Lundbäck, Thomas; West, Andy; Hann, Michael M.; Artursson, Per

2017-01-01

Inadequate target exposure is a major cause of high attrition in drug discovery. Here, we show that a label-free method for quantifying the intracellular bioavailability (Fic) of drug molecules predicts drug access to intracellular targets and hence, pharmacological effect. We determined Fic in multiple cellular assays and cell types representing different targets from a number of therapeutic areas, including cancer, inflammation, and dementia. Both cytosolic targets and targets localized in subcellular compartments were investigated. Fic gives insights on membrane-permeable compounds in terms of cellular potency and intracellular target engagement, compared with biochemical potency measurements alone. Knowledge of the amount of drug that is locally available to bind intracellular targets provides a powerful tool for compound selection in early drug discovery. PMID:28701380

Effects of a powered air-purifying respirator intervention on indium exposure reduction and indium related biomarkers among ITO sputter target manufacturing workers.

PubMed

Liu, Hung-Hsin; Chen, Chang-Yuh; Lan, Cheng-Hang; Chang, Cheng-Ping; Peng, Chiung-Yu

2016-01-01

This study aimed to evaluate the efficacy of powered air-purifying respirators (PAPRs) worn by the workers, and to investigate the effect of this application on exposure and preclinical effects in terms of workplace measuring and biomarker monitoring in ITO sputter target manufacturing plants and workers, respectively. Fifty-four workers were recruited and investigated from 2010-2012, during which PAPRs were provided to on-site workers in September 2011. Each worker completed questionnaires and provided blood and urine samples for analysis of biomarkers of indium exposure and preclinical effects. Area and personal indium air samples were randomly collected from selected worksites and from participants. The penetration percentage of the respirator (concentration inside respirator divided by concentration outside respirator) was 6.6%. Some biomarkers, such as S-In, SOD, GPx, GST, MDA, and TMOM, reflected the decrease in exposure and showed lower levels, after implementation of PAPRs. This study is the first to investigate the efficacy of PAPRs for reducing indium exposure. The measurement results clearly showed that the implementation of PAPRs reduces levels of indium-related biomarkers. These findings have practical applications for minimizing occupational exposure to indium and for managing the health of workers exposed to indium.

Personal carbon monoxide exposures of preschool children in Helsinki, Finland: levels and determinants

NASA Astrophysics Data System (ADS)

Alm, S.; Mukala, K.; Jantunen, M. J.

Personal CO exposures of 194 preschool children were measured with personal exposure monitors during a 24 week sampling period from fall 1990 to spring 1991 in Helsinki, Finland. Arithmetic mean of the maximum 1 and 8 h exposure levels were 6.0 and 3.3 mg m -3. The then Finnish ambient air quality guideline values for 1/8 h maximum CO level (30/10 mg m -3) were exceeded in 2/4% of the children's daily maximum 1/8 h exposure levels. Gas stove at home, parents, especially mother, smoking in the home, and living in high rise buildings — reflecting higher local population and traffic density — increased the children's CO exposures. The presence of a fireplace in the home was associated with decreased CO exposures. Father's high education reduced the children's CO exposure while mother's education level had no significant effect. The peak (15 min) exposure levels of the children commuting to day care center by car or bus were higher than those of the children who walked or came by bike.

Population-Level Exposure to Particulate Air Pollution during Active Travel: Planning for Low-Exposure, Health-Promoting Cities.

PubMed

Hankey, Steve; Lindsey, Greg; Marshall, Julian D

2017-04-01

Providing infrastructure and land uses to encourage active travel (i.e., bicycling and walking) are promising strategies for designing health-promoting cities. Population-level exposure to air pollution during active travel is understudied. Our goals were a ) to investigate population-level patterns in exposure during active travel, based on spatial estimates of bicycle traffic, pedestrian traffic, and particulate concentrations; and b ) to assess how those exposure patterns are associated with the built environment. We employed facility-demand models (active travel) and land use regression models (particulate concentrations) to estimate block-level ( n = 13,604) exposure during rush-hour (1600-1800 hours) in Minneapolis, Minnesota. We used the model-derived estimates to identify land use patterns and characteristics of the street network that are health promoting. We also assessed how exposure is correlated with indicators of health disparities (e.g., household income, proportion of nonwhite residents). Our work uses population-level rates of active travel (i.e., traffic flows) rather than the probability of walking or biking (i.e., "walkability" or "bikeability") to assess exposure. Active travel often occurs on high-traffic streets or near activity centers where particulate concentrations are highest (i.e., 20-42% of active travel occurs on blocks with high population-level exposure). Only 2-3% of blocks (3-8% of total active travel) are "sweet spots" (i.e., high active travel, low particulate concentrations); sweet spots are located a ) near but slightly removed from the city-center or b ) on off-street trails. We identified 1,721 blocks (~ 20% of local roads) where shifting active travel from high-traffic roads to adjacent low-traffic roads would reduce exposure by ~ 15%. Active travel is correlated with population density, land use mix, open space, and retail area; particulate concentrations were mostly unchanged with land use. Public health officials and

Decreased Anxiety in Juvenile Rats Following Exposure to Low Levels of Chlorpyrifos During Development

PubMed Central

Carr, Russell L.; Armstrong, Nathan H.; Buchanan, Alenda T.; Eells, Jeffrey B.; Mohammed, Afzaal N.; Ross, Matthew K.; Nail, Carole A.

2016-01-01

Exposure to chlorpyrifos (CPF) during the late preweanling period in rats inhibits the endocannabinoid metabolizing enzymes fatty acid hydrolase (FAAH) and monoacylglycerol lipase (MAGL), resulting in accumulation of their respective substrates anandamide (AEA) and 2-arachidonylglycerol (2-AG). This occurs at 1.0 mg/kg, but at a lower dosage (0.5 mg/kg) only FAAH and AEA are affected with no measurable inhibition of either cholinesterase (ChE) or MAGL. The endocannabinoid system plays a vital role in nervous system development and may be an important developmental target for CPF. The endocannabinoid system plays an important role in the regulation of anxiety and, at higher dosages, developmental exposure to CPF alters anxiety-like behavior. However, it is not clear whether exposure to low dosages of CPF that do not inhibit ChE will cause any persistent effects on anxiety-like behavior. To determine if this occurs, 10-day old rat pups were exposed daily for 7 days to either corn oil or 0.5, 0.75, or 1.0 mg/kg CPF by oral gavage. At 12 h following the last CPF administration, 1.0 mg/kg resulted in significant inhibition of FAAH, MAGL, and ChE, whereas 0.5 and 0.75 mg/kg resulted in significant inhibition of only FAAH. AEA levels were significantly elevated in all three treatment groups as were palmitoylethanolamide and oleoylethanolamide, which are also substrates for FAAH. 2-AG levels were significantly elevated by 0.75 and 1.0 mg/kg but not 0.5 mg/kg. On day 25, the latency to emerge from a dark container into a highly illuminated novel open field was measured as an indicator of anxiety. All three CPF treatment groups spent significantly less time in the dark container prior to emerging as compared to the control group, suggesting a decreased level of anxiety. This demonstrates that repeated preweanling exposure to dosages of CPF that do not inhibit brain ChE can induce a decline in the level of anxiety that is detectable during the early postweanling period. PMID

MicroRNA-155 targets cyb561d2 in zebrafish in response to fipronil exposure.

PubMed

Huang, Hannian; Zhang, Kai; Zhou, Yongyong; Ding, Xianfeng; Yu, Liang; Zhu, Guonian; Guo, Jiangfeng

2016-07-01

MicroRNAs (miRNAs), which are a class of small noncoding RNAs, can modulate the expression of many protein-coding genes when an organism is exposed to an environmental chemical. We previously demonstrated that miR-155 was significantly downregulated in adult zebrafish (Danio rerio) in response to fipronil (5-amino-1-[2,6-dichloro-4-(trifluoromethyl) phenyl]-4-[(trifluoromethyl) sulphinyl]-1H-pyrazole-3-carbonitrile) exposure. However, the regulation of this miRNA's predicted target gene cyb561d2, which is a member of the cytochrome b561 (cyt b561) family involved in electron transfer, cell defence, and chemical stress, has not been experimentally validated to date. In this study, we evaluated the effects of fipronil on miR-155 and cyb561d2 in zebrafish. The expression of miR-155 was downregulated, whereas cyb561d2 was upregulated in both mRNA and protein level in a dose-dependent manner upon stimulation of fipronil. The dual luciferase report assay demonstrated that miR-155 interacted with cyb561d2 3'-untranslated regions (3'-UTR). The expression of cyb561d2 was reduced in both mRNA and protein levels when ZF4 cells were transfected with an miR-155 mimic, whereas its expression levels of both mRNA and protein were increased when endogenous miR-155 was inhibited by transfection with an miR-155 inhibitor. The results improved our understanding of molecular mechanism of toxicity upon fipronil exposure, and presents miR-155 as a potential novel toxicological biomarker for chemical exposure. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 877-886, 2016. © 2014 Wiley Periodicals, Inc.

Street-level noise in an urban setting: assessment and contribution to personal exposure.

PubMed

McAlexander, Tara P; Gershon, Robyn R M; Neitzel, Richard L

2015-02-28

The urban soundscape, which represents the totality of noise in the urban setting, is formed from a wide range of sources. One of the most ubiquitous and least studied of these is street-level (i.e., sidewalk) noise. Mainly associated with vehicular traffic, street level noise is hard to ignore and hard to escape. It is also potentially dangerous, as excessive noise from any source is an important risk factor for adverse health effects. This study was conducted to better characterize the urban soundscape and the role of street level noise on overall personal noise exposure in an urban setting. Street-level noise measures were obtained at 99 street sites located throughout New York City (NYC), along with data on time, location, and sources of environmental noise. The relationship between street-level noise measures and potential predictors of noise was analyzed using linear and logistic regression models, and geospatial modeling was used to evaluate spatial trends in noise. Daily durations of street-level activities (time spent standing, sitting, walking and running on streets) were estimated via survey from a sample of NYC community members recruited at NYC street fairs. Street-level noise measurements were then combined with daily exposure durations for each member of the sample to estimate exposure to street noise, as well as exposure to other sources of noise. The mean street noise level was 73.4 dBA, with substantial spatial variation (range 55.8-95.0 dBA). Density of vehicular (road) traffic was significantly associated with excessive street level noise levels. Exposure duration data for street-level noise and other common sources of noise were collected from 1894 NYC community members. Based on individual street-level exposure estimates, and in consideration of all other sources of noise exposure in an urban population, we estimated that street noise exposure contributes approximately 4% to an average individual's annual noise dose. Street-level noise

Low-level carbon monoxide exposure and work capacity at 1600 meters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weiser, P.C.; Cropp, G.J.A.; Morrill, C.G.

At sea level, low-level carbon monoxide (CO) exposure impairs exercise performance. To determine if altitude residence at 1600 m augments this CO effect, two studies of graded treadmill work capacity were done. The Initial Study investigated nine, non-smoking male subjects breathing either filtered air (FA) or 28 ppm CO in filtered air. End-exercise carboxyhemoglobin (HbCO) levels averaged 0.9 %HbCO breathing FA and 4.7 %HbCO breathing CO. Total work performance and aerobic work capacity were reduced. Work heart rate was elevated, and post-exercise left ventricular ejection time breathing CO did not shorten to the same degree as with FA exposure. COmore » exposure resulted in a lower anaerobic threshold, and a greater minute ventilation occurred at work rates heavier than the anaerobic threshold due to an increased blood lactate level. The Dose-Response Study exposed twelve subjects to FA or CO such that the end-exercise HbCO levels were 0.7, 3.5, 5.4 and 8.7 %HbCO. Exercise performance and aerobic work capacity were impaired in proportion to the CO exposure. In both studies, maximal cardio-pulmonary responses were not different, but submaximal exercise changes were elevated breathing CO. Thus, in healthy young men residing near 1600 m, an increase in low-level CO exposure produced a linear decrement in maximal aerobic performance similar to that reported at sea level.« less

Derivation of an occupational exposure level for manganese in welding fumes.

PubMed

Bailey, Lisa A; Kerper, Laura E; Goodman, Julie E

2018-01-01

Exposure to high levels of manganese (Mn) in occupational settings is known to lead to adverse neurological effects. Since Mn is an essential nutrient, there are mechanisms that maintain its homeostatic control in the body, and there is some level of Mn in air that does not perturb Mn homeostasis. However, the Mn exposure concentrations at which no adverse effects are expected in occupational settings vary considerably across regulatory agencies. We set out to derive a Mn Occupational Exposure Level (OEL) for welders based on a review of studies that evaluated Mn exposure concentrations from welding fumes and: (1) neurological effects in welders; (2) levels of Mn in the brains of welders (via pallidal index [PI] estimated from magnetic resonance imaging [MRI]); (3) other biomarkers of Mn exposure in welders (i.e., blood and urine); and (4) Mn brain concentrations, PI, and corresponding neurological effects in non-human primates. Our analysis suggests uncertainty in quantifying dose-response associations for Mn from many of the occupational welding studies. The few welding studies that adequately estimate exposure suggest a possible OEL of 100-140μg/m 3 for respirable Mn. This range is consistent with other epidemiology studies, studies of biomarkers of Mn exposure in welders, and with studies in non-human primates, though future studies could provide a stronger basis for deriving a Mn occupational guideline for welders. Copyright © 2017 Elsevier B.V. All rights reserved.

Aggregate-level lead exposure, gun violence, homicide, and rape.

PubMed

Boutwell, Brian B; Nelson, Erik J; Qian, Zhengmin; Vaughn, Michael G; Wright, John P; Beaver, Kevin M; Barnes, J C; Petkovsek, Melissa; Lewis, Roger; Schootman, Mario; Rosenfeld, Richard

2017-01-01

An increasing body of research has linked the geographic distribution of lead with various indicators of criminal and antisocial behavior. The current study, using data from an ongoing project related to lead exposure in St. Louis City, MO, analyzed the association between aggregate blood lead levels and specific indicators violent crime within the city. Ecological study. St. Louis, Missouri. Blood lead levels. Official reports of violent crimes were categorized as 1) crimes involving a firearm (yes/no), 2) assault crimes (with or without a firearm), 3) robbery crimes (with or without a firearm), 4) homicides and 5) rape. With the exception of rape, aggregate blood-lead levels were statistically significant predictors of violent crime at the census tract level. The risk ratios for each of the outcome measures were as follows: firearm crimes 1.03 (1.03-1.04), assault crimes 1.03 (1.02-1.03), robbery crimes 1.03 (1.02-1.04), homicide 1.03 (1.01, 1.04), and rape 1.01 (0.99-1.03). Extending prior research in St. Louis, results suggest that aggregated lead exposure at the census tract level predicted crime outcomes, even after accounting for important sociological variables. Moving forward, a more developed understanding of aggregate level crime may necessitate a shift toward studying the synergy between sociological and biological risk factors such as lead exposure.

Televised antismoking advertising: effects of level and duration of exposure.

PubMed

Dunlop, Sally; Cotter, Trish; Perez, Donna; Wakefield, Melanie

2013-08-01

We assessed the effects of levels and duration of exposure to televised antismoking advertising on cognitive and behavioral changes. We used data from a serial cross-sectional telephone survey with weekly interviews of adult smokers and recent quitters in New South Wales, Australia (n = 13,301), between April 2005 and December 2010. We merged survey data with commercial TV ratings data to estimate individuals' exposure to antismoking advertising. Logistic regression analyses indicated that after adjustment for a wide range of potential confounders, exposure to antismoking advertising at levels between 100 and 200 gross rating points per week on average over 6 to 9 weeks was associated with an increased likelihood of having (1) salient quitting thoughts and (2) recent quit attempts. Associations between exposure for shorter periods and these outcomes were not significant. Broadcasting schedules may affect the success of antismoking ads. Campaign planners should ensure advertising exposure at adequate frequency over relatively sustained periods to maximize impact.

Televised Antismoking Advertising: Effects of Level and Duration of Exposure

PubMed Central

Cotter, Trish; Perez, Donna; Wakefield, Melanie

2013-01-01

Objectives. We assessed the effects of levels and duration of exposure to televised antismoking advertising on cognitive and behavioral changes. Methods. We used data from a serial cross-sectional telephone survey with weekly interviews of adult smokers and recent quitters in New South Wales, Australia (n = 13 301), between April 2005 and December 2010. We merged survey data with commercial TV ratings data to estimate individuals’ exposure to antismoking advertising. Results. Logistic regression analyses indicated that after adjustment for a wide range of potential confounders, exposure to antismoking advertising at levels between 100 and 200 gross rating points per week on average over 6 to 9 weeks was associated with an increased likelihood of having (1) salient quitting thoughts and (2) recent quit attempts. Associations between exposure for shorter periods and these outcomes were not significant. Conclusions. Broadcasting schedules may affect the success of antismoking ads. Campaign planners should ensure advertising exposure at adequate frequency over relatively sustained periods to maximize impact. PMID:23763419

Is There a Critical Period for the Developmental Neurotoxicity of Low-Level Tobacco Smoke Exposure?

PubMed

Slotkin, Theodore A; Stadler, Ashley; Skavicus, Samantha; Card, Jennifer; Ruff, Jonathan; Levin, Edward D; Seidler, Frederic J

2017-01-01

Secondhand tobacco smoke exposure in pregnancy increases the risk of neurodevelopmental disorders. We evaluated in rats whether there is a critical period during which tobacco smoke extract (TSE) affects the development of acetylcholine and serotonin systems, prominent targets for adverse effects of nicotine and tobacco smoke. We simulated secondhand smoke exposure by administering TSE so as to produce nicotine concentrations one-tenth those in active smoking, with 3 distinct, 10-day windows: premating, early gestation or late gestation. We conducted longitudinal evaluations in multiple brain regions, starting in early adolescence (postnatal day 30) and continued to full adulthood (day 150). TSE exposure in any of the 3 windows impaired presynaptic cholinergic activity, exacerbated by a decrement in nicotinic cholinergic receptor concentrations. Although the adverse effects were seen for all 3 treatment windows, there was a distinct progression, with lowest sensitivity for premating exposure and higher sensitivity for gestational exposures. Serotonin receptors were also reduced by TSE exposure with the same profile: little effect with premating exposure, intermediate effect with early gestational exposure and large effect with late gestational exposure. As serotonergic circuits can offset the neurobehavioral impact of cholinergic deficits, these receptor changes were maladaptive. Thus, there is no single 'critical period' for effects of low-level tobacco smoke but there is differential sensitivity dependent upon the developmental stage at the time of exposure. Our findings reinforce the need to avoid secondhand smoke exposure not only during pregnancy, but also in the period prior to conception, or generally for women of childbearing age. © The Author 2016. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Child-targeted fast-food television advertising exposure is linked with fast-food intake among pre-school children.

PubMed

Dalton, Madeline A; Longacre, Meghan R; Drake, Keith M; Cleveland, Lauren P; Harris, Jennifer L; Hendricks, Kristy; Titus, Linda J

2017-06-01

To determine whether exposure to child-targeted fast-food (FF) television (TV) advertising is associated with children's FF intake in a non-experimental setting. Cross-sectional survey conducted April-December 2013. Parents reported their pre-school child's TV viewing time, channels watched and past-week FF consumption. Responses were combined with a list of FF commercials (ads) aired on children's TV channels during the same period to calculate children's exposure to child-targeted TV ads for the following chain FF restaurants: McDonald's, Subway and Wendy's (MSW). Paediatric and Women, Infants, and Children (WIC) clinics in New Hampshire, USA. Parents (n 548) with a child of pre-school age. Children's mean age was 4·4 years; 43·2 % ate MSW in the past week. Among the 40·8 % exposed to MSW ads, 23·3 % had low, 34·2 % moderate and 42·5 % high exposure. McDonald's accounted for over 70 % of children's MSW ad exposure and consumption. Children's MSW consumption was significantly associated with their ad exposure, but not overall TV viewing time. After adjusting for demographics, socio-economic status and other screen time, moderate MSW ad exposure was associated with a 31 % (95 % CI 1·12, 1·53) increase and high MSW ad exposure with a 26 % (95 % CI 1·13, 1·41) increase in the likelihood of consuming MSW in the past week. Further adjustment for parent FF consumption did not change the findings substantially. Exposure to child-targeted FF TV advertising is positively associated with FF consumption among children of pre-school age, highlighting the vulnerability of young children to persuasive advertising and supporting recommendations to limit child-directed FF marketing.

Child-targeted fast-food television advertising exposure is linked with fast-food intake among pre-school children

PubMed Central

Dalton, Madeline A; Longacre, Meghan R; Drake, Keith M; Cleveland, Lauren P; Harris, Jennifer L; Hendricks, Kristy; Titus, Linda J

2017-01-01

Objective To determine whether exposure to child-targeted fast-food (FF) television (TV) advertising is associated with children’s FF intake in a non-experimental setting. Design Cross-sectional survey conducted April–December 2013. Parents reported their pre-school child’s TV viewing time, channels watched and past-week FF consumption. Responses were combined with a list of FF commercials (ads) aired on children’s TV channels during the same period to calculate children’s exposure to child-targeted TV ads for the following chain FF restaurants: McDonald’s, Subway and Wendy’s (MSW). Setting Paediatric and Women, Infants, and Children (WIC) clinics in New Hampshire, USA. Subjects Parents (n 548) with a child of pre-school age. Results Children’s mean age was 4·4 years; 43·2 % ate MSW in the past week. Among the 40·8 % exposed to MSW ads, 23·3 % had low, 34·2 % moderate and 42·5 % high exposure. McDonald’s accounted for over 70 % of children’s MSW ad exposure and consumption. Children’s MSW consumption was significantly associated with their ad exposure, but not overall TV viewing time. After adjusting for demographics, socio-economic status and other screen time, moderate MSW ad exposure was associated with a 31 % (95 % CI 1·12, 1·53) increase and high MSW ad exposure with a 26 % (95 % CI 1·13, 1·41) increase in the likelihood of consuming MSW in the past week. Further adjustment for parent FF consumption did not change the findings substantially. Conclusions Exposure to child-targeted FF TV advertising is positively associated with FF consumption among children of pre-school age, highlighting the vulnerability of young children to persuasive advertising and supporting recommendations to limit child-directed FF marketing. PMID:28416041

Level of In Utero Cocaine Exposure and Neonatal Ultrasound Findings

PubMed Central

Frank, Deborah A.; McCarten, Kathleen M.; Robson, Caroline D.; Mirochnick, Mark; Cabral, Howard; Park, Henry; Zuckerman, Barry

2008-01-01

Objective To assess whether there is an association between the level of in utero cocaine exposure and findings on neonatal cranial ultrasound, controlling for potentially confounding variables. Study Design In a prospective longitudinal study, three cocaine exposure groups were defined by maternal report and infant meconium assay: unexposed, heavier cocaine exposure (>75th percentile self-reported days of use or of meconium benzoylecogonine concentration) or lighter cocaine exposure (all others). Neonatal ultrasounds from 241 well, term infants were read by a single radiologist who was masked to the exposure group. Results Infants with lighter cocaine exposure did not differ from the unexposed infants on any ultrasound findings. After controlling for infant gender, gestational age, and birth weight z scores and for maternal parity, blood pressure in labor, ethnicity, and use of cigarettes, alcohol, and marijuana during pregnancy, the more heavily cocaine-exposed infants were more likely than the unexposed infants to show subependymal hemorrhage in the caudothalamic groove (covariate adjusted odds ratio: 3.88; 95% confidence interval: 1.45, 10.35). Conclusions This is the first study to demonstrate that ultrasound findings suggestive of vascular injury to the neonatal central nervous system are related to the level of prenatal cocaine exposure. Inconsistency in previous research in identifying an association between prenatal cocaine exposure and neonatal cranial ultrasound findings may reflect failure to consider dose effects. PMID:10545554

Orbit targeting specialist function: Level C formulation requirements

NASA Technical Reports Server (NTRS)

Dupont, A.; Mcadoo, S.; Jones, H.; Jones, A. K.; Pearson, D.

1978-01-01

A definition of the level C requirements for onboard maneuver targeting software is provided. Included are revisions of the level C software requirements delineated in JSC IN 78-FM-27, Proximity Operations Software; Level C Requirements, dated May 1978. The software supports the terminal phase midcourse (TPM) maneuver, braking and close-in operations as well as supporting computation of the rendezvous corrective combination maneuver (NCC), and the terminal phase initiation (TPI). Specific formulation is contained here for the orbit targeting specialist function including the processing logic, linkage, and data base definitions for all modules. The crew interface with the software is through the keyboard and the ORBIT-TGT display.

Occupational noise exposure and hearing levels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ambasankaran, M.; Brahmachari, D.; Chadda, V.K.

1981-07-01

A study was made at the Bhabha Atomic Research Center to measure the hearing levels of persons working in a noise environment. Two different workplaces, central air-conditioning plant and glass blowing shops, where a number of persons were exposed to noise levels exceeding 85 dB(A) were chosen. The occupational exposure to noise was determined using a sound level meter, an octave band filter and a personal noise dose meter. The hearing levels of persons exposed to these high levels of noise and a control group not exposed to occupational noise were measured by means of a pure-tone audiometer in amore » specially-built booth. These persons, aged between 20 to 60 years, were divided into four age groups for the study. The low ambient noise levels in the booth were measured using correlation technique since such low signals cannot be detected by an ordinary sound level meter. The audiometric findings and the results of the noise level survey are discussed in this paper.« less

Endogenous cortisol levels influence exposure therapy in spider phobia.

PubMed

Lass-Hennemann, Johanna; Michael, Tanja

2014-09-01

Previous research in patients with phobia showed that the administration of glucocorticoids reduces fear in phobic situations and enhances exposure therapy. Glucocorticoids underlie a daily cycle with a peak in the morning and low levels during the evening and night. The aim of the present study was to investigate whether exposure is more effective when conducted in the morning when endogenous cortisol levels are high. Sixty patients meeting DSM IV criteria for specific phobia (animal type) were randomly assigned to one-session exposure treatment either at 08.00 a.m. (high cortisol group) or at 06.00 p.m. (low cortisol group). Participants returned for a posttreatment assessment one week after therapy and a follow-up assessment three months after therapy. Both groups showed good outcome, but patients treated in the morning exhibited significantly less fear of spiders in the behavioral approach test (BAT) and a trend for lower scores on the Fear of Spiders Questionnaire (FSQ) than patients treated in the evening. This effect was present at posttreatment and follow-up. Our findings indicate that exposure therapy is more effective in the morning than in the evening. We suggest that this may be due to higher endogenous cortisol levels in the morning group that enhance extinction memory. Copyright © 2014 Elsevier Ltd. All rights reserved.

Numeral size, spacing between targets, and exposure time in discrimination by elderly people using an lcd monitor.

PubMed

Huang, Kuo-Chen; Yeh, Po-Chan

2007-04-01

The present study investigated the effects of numeral size, spacing between targets, and exposure time on the discrimination performance by elderly and younger people using a liquid crystal display screen. Analysis showed size of numerals significantly affected discrimination, which increased with increasing numeral size. Spacing between targets also had a significant effect on discrimination, i.e., the larger the space between numerals, the better their discrimination. When the spacing between numerals increased to 4 or 5 points, however, discrimination did not increase beyond that for 3-point spacing. Although performance increased with increasing exposure time, the difference in discrimination at an exposure time of 0.8 vs 1.0 sec. was not significant. The accuracy by the elderly group was less than that by younger subjects.

Survey of RF exposure levels from mobile telephone base stations in Australia.

PubMed

Henderson, S I; Bangay, M J

2006-01-01

This paper reports the results of an exposure level survey of radiofrequency electromagnetic energy originating from mobile telephone base station antennas. Measurements of CDMA800, GSM900, GSM1800, and 3G(UMTS) signals were performed at distances ranging over 50 to 500 m from 60 base stations in five Australian cities. The exposure levels from these mobile telecommunications base stations were found to be well below the general public exposure limits of the ICNIRP guidelines and the Australian radiofrequency standard (ARPANSA RPS3). The highest recorded level from a single base station was 7.8 x 10(-3) W/m(2), which translates to 0.2% of the general public exposure limit.

Mapping of radio frequency electromagnetic field exposure levels in outdoor environment and comparing with reference levels for general public health.

PubMed

Cansiz, Mustafa; Abbasov, Teymuraz; Kurt, M Bahattin; Celik, A Recai

2018-03-01

In this study, radio frequency electromagnetic field exposure levels were measured on the main streets in the city center of Diyarbakır, Turkey. Measured electric field levels were plotted on satellite imagery of Diyarbakır and were compared with exposure guidelines published by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). Exposure measurements were performed in dense urban, urban and suburban areas each day for 7 consecutive days. The measurement system consisted of high precision and portable spectrum analyzer, three-axis electric field antenna, connection cable and a laptop which was used to record the measurement samples as a data logger. The highest exposure levels were detected for two places, which are called Diclekent and Batıkent. It was observed that the highest instantaneous electric field strength value for Batıkent was 7.18 V/m and for Diclekent was 5.81 V/m. It was statistically determined that the main contributor band to the total exposure levels was Universal Mobile Telecommunications System band. Finally, it was concluded that all measured exposure levels were lower than the reference levels recommended by ICNIRP for general public health.

Feedback on Measured Dust Concentrations Reduces Exposure Levels Among Farmers.

PubMed

Basinas, Ioannis; Sigsgaard, Torben; Bønløkke, Jakob Hjort; Andersen, Nils Testrup; Omland, Øyvind; Kromhout, Hans; Schlünssen, Vivi

2016-08-01

The high burden of exposure to organic dust among livestock farmers warrants the establishment of effective preventive and exposure control strategies for these workers. The number of intervention studies exploring the effectiveness of exposure reduction strategies through the use of objective measurements has been limited. To examine whether dust exposure can be reduced by providing feedback to the farmers concerning measurements of the exposure to dust in their farm. The personal dust levels of farmers in 54 pig and 26 dairy cattle farms were evaluated in two measurement series performed approximately 6 months apart. Detailed information on work tasks and farm characteristics during the measurements were registered. Participating farms were randomized a priori to a control (n = 40) and an intervention group (n = 40). Shortly after the first visit, owners of intervention farms only received a letter with information on the measured dust concentrations in the farm together with some general advises on exposure reduction strategies (e.g. use of respirators during certain tasks). Relationships between measured dust concentrations and intervention status were quantified by means of linear mixed effect analysis with farm and worker id as random effects. Season, type of farming, and work tasks were treated as fixed effects. Changes in exposure over time were explored primarily at a farm level in models combined, as well as separate for pig and cattle farmers. After adjustment for fixed effects, an overall reduction of 23% in personal dust exposures was estimated as a result of the intervention (P = 0.02). Exposure reductions attributable to the intervention were similar across pig and cattle farmers, but statistically significant only for pig farmers. Intervention effects among pig farmers did not depend on the individuals' information status; but among cattle farmers a significant 48% reduction in exposure was found only among individuals that reported to have been

Extremely low-level microwaves attenuate immune imbalance induced by inhalation exposure to low-level toluene in mice.

PubMed

Novoselova, Elena G; Glushkova, Olga V; Khrenov, Maxim O; Novoselova, Tatyana V; Lunin, Sergey M; Fesenko, Eugeny E

2017-05-01

To clarify whether extremely low-level microwaves (MW) alone or in combination with p38 inhibitor affect immune cell responses to inhalation exposure of mice to low-level toluene. The cytokine profile, heat shock proteins expression, and the activity of several signal cascades, namely, NF-κB, SAPK/JNK, IRF-3, p38 MAPK, and TLR4 were measured in spleen lymphocytes of mice treated to air-delivered toluene (0.6 mg/m 3 ) or extremely low-level microwaves (8.15-18 GHz, 1μW/cm 2 , 1 Hz swinging frequency) or combined action of these two factors. A single exposure to air-delivered low-level toluene induced activation of NF-κB, SAPK/JNK, IFR-3, p38 MAPK and TLR4 pathways. Furthermore, air toluene induced the expression of Hsp72 and enhanced IL-1, IL-6, and TNF-α in blood plasma, which is indicative of a pro-inflammatory response. Exposure to MW alone also resulted in the enhancement of the plasma cytokine values (e.g. IL-6, TNF-α, and IFN-γ) and activation of the NF-κB, MAPK p38, and especially the TLR4 pathways in splenic lymphocytes. Paradoxically, pre-exposure to MW partially recovered or normalized the lymphocyte parameters in the toluene-exposed mice, while the p38 inhibitor XI additionally increased protective activity of microwaves by down regulating MAPKs (JNK and p38), IKK, as well as expression of TLR4 and Hsp90-α. The results suggest that exposure to low-intensity MW at specific conditions may recover immune parameters in mice undergoing inhalation exposure to low-level toluene via mechanisms involving cellular signaling.

In vitro atrazine-exposure inhibits human natural killer cell lytic granule release

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rowe, Alexander M.; Brundage, Kathleen M.; Center for Immunopathology and Microbial Pathogenesis, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26506

2007-06-01

The herbicide atrazine is a known immunotoxicant and an inhibitor of human natural killer (NK) cell lytic function. The precise changes in NK cell lytic function following atrazine exposure have not been fully elucidated. The current study identifies the point at which atrazine exerts its affect on the stepwise process of human NK cell-mediated lyses of the K562 target cell line. Using intracellular staining of human peripheral blood lymphocytes, it was determined that a 24-h in vitro exposure to atrazine did not decrease the level of NK cell lytic proteins granzyme A, granzyme B or perforin. Thus, it was hypothesizedmore » that atrazine exposure was inhibiting the ability of the NK cells to bind to the target cell and subsequently inhibit the release of lytic protein from the NK cell. To test this hypothesis, flow cytometry and fluorescent microscopy were employed to analyze NK cell-target cell co-cultures following atrazine exposure. These assays demonstrated no significant decrease in the level of target cell binding. However, the levels of NK intracellular lytic protein retained and the amount of lytic protein released were assessed following a 4-h incubation with K562 target cells. The relative level of intracellular lytic protein was 25-50% higher, and the amount of lytic protein released was 55-65% less in atrazine-treated cells than vehicle-treated cells following incubation with the target cells. These results indicate that ATR exposure inhibits the ability of NK cells to lyse target cells by blocking lytic granule release without affecting the ability of the NK cell to form stable conjugates with target cells.« less

Associations between cadmium exposure and circulating levels of sex hormones in postmenopausal women

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ali, Imran; Engström, Annette; Vahter, Marie

Recent epidemiological as well as in vivo and in vitro studies collectively suggest that the metalloestrogen cadmium (Cd) could be a potential risk factor for hormone-related cancers in particularly breast cancer. Assessment of the association between Cd exposure and levels of endogenous sex hormones is of pivotal importance, as increased levels of such have been associated with a higher risk of breast cancer in postmenopausal women. The present study investigated the perceived relationship (multivariable-adjusted linear regression analyses) between Cd exposure [blood Cd (B-Cd) and urinary Cd (U-Cd)], and serum levels of androstenedione, testosterone, estradiol, and sex-hormone binding globulin (SHBG), inmore » 438 postmenopausal Swedish women without hormone replacement therapy (HRT). A significant positive association between B-Cd (median 3.4 nmol/L) and serum testosterone levels, as well as a significant inverse association between B-Cd and serum estradiol levels and with the estradiol/testosterone ratio were encountered. However, U-Cd (median 0.69 nmol/mmol creatinine) was inversely associated with serum estradiol levels only. Our data may suggest that Cd interferes with the levels of testosterone and estradiol in postmenopausal women, which might have implications for breast cancer risk. - Highlights: • Low level cadmium exposure may interfere with the levels of steroid hormones. • Cadmium exposure was associated with increased serum testosterone concentrations. • Cadmium exposure was associated with decreased estradiol/testosterone ratio. • Cadmium exposure may have implications for breast-cancer promotion.« less

Lack of effect of menthol level and type on smokers' estimated mouth level exposures to tar and nicotine and perceived sensory characteristics of cigarette smoke.

PubMed

Ashley, Madeleine; Dixon, Mike; Sisodiya, Ajit; Prasad, Krishna

2012-08-01

Menthol can reduce sensory irritation and it has been hypothesised that this could result in smokers of mentholated cigarettes taking larger puffs and deeper post-puff inhalations thereby obtaining higher exposures to smoke constituents than smokers of non-mentholated cigarettes. The aim of our study was to use part-filter analysis methodology to assess the effects of cigarette menthol loading on regular and occasional smokers of mentholated cigarettes. We measured mouth level exposure to tar and nicotine and investigated the effects of mentholation on smokers' sensory perceptions such as cooling and irritation. Test cigarettes were produced containing no menthol and different loadings of synthetic and natural l-menthol at 1 and 4mg ISO tar yields. A target of 100 smokers of menthol cigarettes and 100 smokers who predominantly smoked non-menthol cigarettes from both 1 and 4mg ISO tar yield categories were recruited in Poland and Japan. Each subject was required to smoke the test cigarette types of their usual ISO tar yield. There were positive relationships between menthol loading and the perceived 'strength of menthol taste' and 'cooling' effect. However, we did not see marked menthol-induced reductions in perceived irritation or menthol-induced increases in mouth level exposure to tar and nicotine. Copyright © 2012 Elsevier Inc. All rights reserved.

Decreased anxiety in juvenile rats following exposure to low levels of chlorpyrifos during development.

PubMed

Carr, Russell L; Armstrong, Nathan H; Buchanan, Alenda T; Eells, Jeffrey B; Mohammed, Afzaal N; Ross, Matthew K; Nail, Carole A

2017-03-01

Exposure to chlorpyrifos (CPF) during the late preweanling period in rats inhibits the endocannabinoid metabolizing enzymes fatty acid hydrolase (FAAH) and monoacylglycerol lipase (MAGL), resulting in accumulation of their respective substrates anandamide (AEA) and 2-arachidonylglycerol (2-AG). This occurs at 1.0mg/kg, but at a lower dosage (0.5mg/kg) only FAAH and AEA are affected with no measurable inhibition of either cholinesterase (ChE) or MAGL. The endocannabinoid system plays a vital role in nervous system development and may be an important developmental target for CPF. The endocannabinoid system plays an important role in the regulation of anxiety and, at higher dosages, developmental exposure to CPF alters anxiety-like behavior. However, it is not clear whether exposure to low dosages of CPF that do not inhibit ChE will cause any persistent effects on anxiety-like behavior. To determine if this occurs, 10-day old rat pups were exposed daily for 7 days to either corn oil or 0.5, 0.75, or 1.0mg/kg CPF by oral gavage. At 12h following the last CPF administration, 1.0mg/kg resulted in significant inhibition of FAAH, MAGL, and ChE, whereas 0.5 and 0.75mg/kg resulted in significant inhibition of only FAAH. AEA levels were significantly elevated in all three treatment groups as were palmitoylethanolamide and oleoylethanolamide, which are also substrates for FAAH. 2-AG levels were significantly elevated by 0.75 and 1.0mg/kg but not 0.5mg/kg. On day 25, the latency to emerge from a dark container into a highly illuminated novel open field was measured as an indicator of anxiety. All three CPF treatment groups spent significantly less time in the dark container prior to emerging as compared to the control group, suggesting a decreased level of anxiety. This demonstrates that repeated preweanling exposure to dosages of CPF that do not inhibit brain ChE can induce a decline in the level of anxiety that is detectable during the early postweanling period. Copyright �

Biomonitoring of organophosphate exposure of pesticide sprayers and comparison of exposure levels with other population groups in Thessaly (Greece).

PubMed

Koureas, Michalis; Tsakalof, Andreas; Tzatzarakis, Manolis; Vakonaki, Elena; Tsatsakis, Aristidis; Hadjichristodoulou, Christos

2014-02-01

To evaluate the exposure of different population groups in Thessaly (Greece) to organophosphate pesticides (OPs) and investigate the dependence of exposure levels on pesticide application practices, personal protective and hygienic measures taken. For the exposure assessment, four dialkyl phosphate (DAP) metabolites of organophosphate pesticides were quantified in spot urine samples of 77 pesticide sprayers, 75 residents of the studied agricultural area non-involved in agricultural activities and 112 urban residents who served as a control group. Structured questionnaires were used to record demographic characteristics, pesticide application parameters and protective measures taken. Univariate and multivariate analysis of the obtained cross-sectional data was performed to identify potential risk factors associated with biomarker levels. It was found that total DAP median level in the sprayers' group was 24.9 μg/g creatinine (IQR: 13.0-42.1), while the rural and urban residents had significantly lower (p<0.001) levels of 11.3 μg/g creatinine (IQR: 5.3-18.7) and 11.9 μg/g creatinine (IQR: 6.3-20.3), respectively. In sprayers who had recently applied an OP pesticide (n=28), the median levels of DAP metabolites were 31.8 μg/g creatinine (IQR: 22.3-117.2). Logistic regression analysis showed that the use of full body coveralls while handling and spraying pesticides was significantly associated with lower DAP levels (OR 4.05, 95% CI 1.22 to 13.46). Also, changing clothes immediately after accidental contamination of clothing with pesticide amounts was found to be significantly associated with lower exposure levels (OR 4.04, CI 1.05 to 15.57). Our study findings confirm the increased exposure to OPs in pesticide sprayers and underline the importance of protective measures especially those that focus on dermal exposure mitigation.

Is There a Safe Level of Exposure to a Carcinogen?

ERIC Educational Resources Information Center

Hrudey, Steve E.; Krewski, Daniel

1995-01-01

Presents an approach to estimating the "safe" levels of low-dose exposure to carcinogens that involves working upward from the smallest conceivable chronic dose instead of extrapolating downward from high exposures. Discusses expert and public opinion and other issues related to quantitative cancer risk assessment. (LZ)

Nickel exposure and plasma levels of biomarkers for assessing oxidative stress in nickel electroplating workers.

PubMed

Tsao, Yu-Chung; Gu, Po-Wen; Liu, Su-Hsun; Tzeng, I-Shiang; Chen, Jau-Yuan; Luo, Jiin-Chyuan John

2017-07-01

The mechanism of nickel-induced pathogenesis remains elusive. To examine effects of nickel exposure on plasma oxidative and anti-oxidative biomarkers. Biomarker data were collected from 154 workers with various levels of nickel exposure and from 73 controls. Correlations between nickel exposure and oxidative and anti-oxidative biomarkers were determined using linear regression models. Workers with a exposure to high nickel levels had significantly lower levels of anti-oxidants (glutathione and catalase) than those with a lower exposure to nickel; however, only glutathione showed an independent association after multivariable adjustment. Exposure to high levels of nickel may reduce serum anti-oxidative capacity.

Radiation exposure levels within timber industries in Calabar, Nigeria

PubMed Central

Inyang, S. O.; Inyang, I. S.; Egbe, N. O.

2009-01-01

The UNSCEAR (2000) observed that there could be some exposure at work which would require regulatory control but is not really considered. This study was, therefore, set up to evaluate the effective dose in timber industries in Calabar, Nigeria to determine if the evaluated dose levels could lead to any radiological health effect in the workers, and also determine if the industries require regulatory control. The gamma ray exposure at four timber industries measured using an exposure meter were converted to effective dose and compared with the public and occupational values. The evaluated effective dose values in the timber industries were below public and occupational exposure limits and may not necessarily result in any radiological health hazard. Therefore, they may not require regulatory control. PMID:20098544

Modification of otoacoustic emissions following ear-level exposure to MP3 player music.

PubMed

Bhagat, Shaum P; Davis, Anne M

2008-12-01

The purpose of this study was to examine if a pre-determined exposure level and duration of MP3 player music would result in significant changes in cochlear function when measured with audiometric and physiological methods. Distortion-product otoacoustic emissions (DPOAEs), synchronized spontaneous otoacoustic emissions (SSOAEs), and hearing thresholds were measured in 20 normal-hearing adults before and after a 30-minute MP3 player music exposure. DPOAEs were acquired with 65/45 dB SPL primary tones (f(2)=0.842-7.996 kHz) with a frequency resolution of 8 points/octave. A probe microphone system recorded ear-canal music levels and was used to equalize levels at approximately 85 dBC across individuals during the music presentation. Comparison of pre- and post-exposure measurements revealed no significant differences in hearing thresholds, but DPOAE levels in half-octave bands centered from 1.4-6.0 kHz were significantly reduced following the music exposure. Post-exposure shifts in SSOAE frequency and level were highly variable in individuals identified with SSOAEs. The results for the exposure conditions explored in this study indicate that changes in otoacoustic emissions may precede the development of music-induced hearing threshold shifts.

30 CFR 57.5042 - Revised exposure levels.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Revised exposure levels. 57.5042 Section 57.5042 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Air Quality, Radiation, Physical Agents, and Diesel Particulate...

30 CFR 57.5042 - Revised exposure levels.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Revised exposure levels. 57.5042 Section 57.5042 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Air Quality, Radiation, Physical Agents, and Diesel Particulate...

30 CFR 57.5042 - Revised exposure levels.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Revised exposure levels. 57.5042 Section 57.5042 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Air Quality, Radiation, Physical Agents, and Diesel Particulate...

30 CFR 57.5042 - Revised exposure levels.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Revised exposure levels. 57.5042 Section 57.5042 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Air Quality, Radiation, Physical Agents, and Diesel Particulate...

30 CFR 57.5042 - Revised exposure levels.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Revised exposure levels. 57.5042 Section 57.5042 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Air Quality, Radiation, Physical Agents, and Diesel Particulate...

Environmental Enrichment Alters Neurotrophin Levels After Fetal Alcohol Exposure in Rats

PubMed Central

Parks, Elizabeth A.; McMechan, Andrew P.; Hannigan, John H.; Berman, Robert F.

2014-01-01

Background Prenatal alcohol exposure causes abnormal brain development, leading to behavioral deficits, some of which can be ameliorated by environmental enrichment. As both environmental enrichment and prenatal alcohol exposure can individually alter neurotrophin expression, we studied the interaction of prenatal alcohol and postweaning environmental enrichment on brain neurotrophin levels in rats. Methods Pregnant rats received alcohol by gavage, 0, 4, or 6 g / kg / d (Zero, Low, or High groups), or no treatment (Naïve group), on gestational days 8 to 20. After weaning on postnatal day 21, offspring were housed for 6 weeks in Isolated, Social, or Enriched conditions. Levels of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3) were then measured in frontal cortex, occipital cortex, hippocampus, and cerebellar vermis. Results Prenatal alcohol exposure increased NGF levels in frontal cortex (High-dose group) and cerebellar vermis (High- and Low-dose groups); increased BDNF in frontal cortex, occipital cortex and hippocampus (Low-dose groups), and increased NT-3 in hippocampus and cerebellar vermis (High-dose). Environmental enrichment resulted in lower NGF, BDNF, and NT-3 levels in occipital cortex and lower NGF in frontal cortex. The only significant interaction between prenatal alcohol treatment and environment was in cerebellar vermis where NT-3 levels were higher for enriched animals after prenatal alcohol exposure, but not for animals housed under Isolated or Social conditions. Conclusions Both prenatal alcohol exposure and postweaning housing conditions alter brain neurotrophin levels, but the effects appear to be largely independent. Although environmental enrichment can improve functional outcomes, these results do not provide strong support for the hypothesis that rearing in a complex environment ameliorates prenatal alcohol effects on brain neurotrophin levels in rats. PMID:18652597

Occupational exposure levels of bioaerosol components are associated with serum levels of the acute phase protein Serum Amyloid A in greenhouse workers.

PubMed

Madsen, Anne Mette; Thilsing, Trine; Bælum, Jesper; Garde, Anne Helene; Vogel, Ulla

2016-01-20

Occupational exposure to particles may be associated with increased inflammation of the airways. Animal experiments suggest that inhaled particles also induce a pulmonary acute phase response, leading to systemic circulation of acute phase proteins. Greenhouse workers are exposed to elevated levels of bioaerosols. The objective of this study is to assess whether greenhouse workers personal exposure to bioaerosol components was associated with serum levels of the acute phase proteins Serum Amyloid A (SAA) and C-reactive protein (CRP). SAA and CRP levels were determined in serum sampled repeatedly from 33 greenhouse workers. Blood was drawn repeatedly on Mondays and Thursdays during work weeks. Acute phase protein levels were compared to levels in a comparison group of 42 people and related to individual exposure levels to endotoxin, dust, bacteria, fungi and β-glucan. Serum levels of SAA and CRP were not significantly different in greenhouse workers and a reference group, or on the two work days. In a mixed model, SAA levels were positively associated with endotoxin exposure levels (p = 0.0007). Results for fungi were not clear. CRP levels were positively associated with endotoxin exposures (p = 0.022). Furthermore, when workers were categorized into three groups based on SAA and CRP serum levels endotoxin exposure was highest in the group with the highest SAA levels and in the group with middle and highest CRP levels. SAA and CRP levels were elevated in workers with asthma. Greenhouse workers did not have elevated serum levels of SAA and CRP compared to a reference group. However, occupational exposure to endotoxin was positively associated with serum levels of the acute phase proteins SAA and CRP. Preventive measures to reduce endotoxin exposure may be beneficial.

Association between multi-level inorganic arsenic exposure from drinking water and skin lesions in China.

PubMed

Guo, Xiaojuan; Fujino, Yoshihisa; Ye, Xiaolei; Liu, Jun; Yoshimura, Takesumi

2006-09-01

Arsenic is one of the most important toxicants in the environment. In Inner Mongolia of China, 300,000 residents are believed to be drinking water containing >50 microg/liter. Skin lesions have been known as the most common consequences resulting from chronic exposure to arsenic. To clarify the prevalence of arsenic-induced skin lesions, it is important to assess the impact of this problem among the target population, and to make future planning. We evaluated the association between multi-levels inorganic arsenic exposure from drinking water and skin lesions in an arsenic-affected area in Inner Mongolia, China. One hundred nine and 32 subjects in high (>50 microg/liter) and low (<50 microg/liter) arsenic-affected villages were recruited and had the detailed physical examination with special emphasis on arsenic-related skin lesions. Arsenic exposure was measured for each participant with respect to iAs concentration of primary well and the duration using the well. Arsenic-induced skin lesions including keratosis, pigmentation, and/or depigmentation were diagnosed in 56 and 3 subjects in the two villages, respectively. Logistic regression was conducted to calculate odd ratios of skin lesions associated with arsenic exposure with adjustments for sex, age group, smoking and duration of exposure. A consistent dose-response relationship between arsenic exposure level and skin lesion risk was observed. Compared to those with iAs concentration <50 microg/liter, the adjusted odds ratios of skin lesions for the subjects with 51-99, 100-149 and >150 microg/liter were 33.3% (OR =15.50, 95% CI: 1.53-248.70), 46.7% (OR =16.10, 95% CI: 3.73-69.63) and 55.7% (OR= 25.70, 95% CI: 6.43-102.87), respectively. Duration of using well was not associated with increased risk of skin lesions in this population; (OR =1.68, 95% CI: 0.40-6.91 for 6-15 years, OR = 2.30, 95% CI: 0.58-9.14 for over 15 years) compared with the duration of less than 5 years.

A hybrid modeling with data assimilation to evaluate human exposure level

NASA Astrophysics Data System (ADS)

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.

Individual-level exposure to disaster, neighborhood environmental characteristics, and their independent and combined associations with depressive symptoms in women.

PubMed

Gaston, Symielle A; Volaufova, Julia; Peters, Edward S; Ferguson, Tekeda F; Robinson, William T; Nugent, Nicole; Trapido, Edward J; Rung, Ariane L

2017-09-01

The severity of the stress response to experiencing disaster depends on individual exposure and background stress prior to the event. To date, there is limited research on the interaction between neighborhood environmental stress and experiencing an oil spill, and their effects on depression. The objective of the current study was to assess if the association between exposure to the Deepwater Horizon Oil Spill (DHOS) and depressive symptoms varied by neighborhood characteristics. US Census data (2010) and longitudinal data collected in two waves (2012-2014 and 2014-2016) from female residents [N = 889 (Wave I), 737 (Wave II)] of an area highly affected by the DHOS were analyzed. Multilevel and individual-level negative binomial regressions were performed to estimate associations with depressive symptoms in both waves. An interaction term was included to estimate effect modification of the association between DHOS exposure and depressive symptoms by neighborhood characteristics. Generalized estimating equations were applied to the negative binomial regression testing longitudinal associations. Census tract-level neighborhood characteristics were not associated with depressive symptoms. Exposure to the DHOS and neighborhood physical disorder were associated with depressive symptoms cross-sectionally. There was no evidence of effect modification; however, physical/environmental exposure to the DHOS was associated with increased depressive symptoms only among women living in areas with physical disorder. Exposure to the DHOS remained associated with depressive symptoms over time. Findings support the enduring consequences of disaster exposure on depressive symptoms in women and identify potential targets for post-disaster intervention based on residential characteristics.

ENVIRONMENTAL MANGANESE: GUIDELINE EXPOSURE LEVELS, EVIDENCE OF HEALTH EFFECTS AND RESEARCH NEEDS.

EPA Science Inventory

Introduction. The ubiquitous element, manganese (Mn), is an essential nutrient, but toxic at excessive exposure levels. The US EPA, therefore, set guideline levels for Mn exposure through inhalation (reference concentration-RfC=0.05 g/m3) and ingestion (reference dose-RfD=0.14 m...

Low Level Chlorpyrifos Exposure Increases Anandamide Accumulation in Juvenile Rat Brain in the Absence of Brain Cholinesterase Inhibition

PubMed Central

Carr, Russell L.; Graves, Casey A.; Mangum, Lee C.; Nail, Carole A.; Ross, Matthew K.

2014-01-01

The prevailing dogma is that chlorpyrifos (CPF) mediates its toxicity through inhibition of cholinesterase (ChE). However, in recent years, the toxicological effects of developmental CPF exposure have been attributed to an unknown non-cholinergic mechanism of action. We hypothesize that the endocannabinoid system may be an important target because of its vital role in nervous system development. We have previously reported that repeated exposure to CPF results in greater inhibition of fatty acid amide hydrolase (FAAH), the enzyme that metabolizes the endocannabinoid anandamide (AEA), than inhibition of either forebrain ChE or monoacylglycerol lipase (MAGL), the enzyme that metabolizes the endocannabinoid 2-arachidonylglycerol (2-AG). This exposure resulted in the accumulation of 2-AG and AEA in the forebrain of juvenile rats; however, even at the lowest dosage level used (1.0 mg/kg), forebrain ChE inhibition was still present. Thus, it is not clear if FAAH activity would be inhibited at dosage levels that do not inhibit ChE. To determine this, 10 day old rat pups were exposed daily for 7 days to either corn oil or 0.5 mg/kg CPF by oral gavage. At 4 and 12 h post-exposure on the last day of administration, the activities of serum ChE and carboxylesterase (CES) and forebrain ChE, MAGL, and FAAH were determined as well as the forebrain AEA and 2-AG levels. Significant inhibition of serum ChE and CES was present at both 4 and 12 h. There was no significant inhibition of the activities of forebrain ChE or MAGL and no significant change in the amount of 2-AG at either time point. On the other hand, while no statistically significant effects were observed at 4 h, FAAH activity was significantly inhibited at 12 h resulting in a significant accumulation of AEA. Although it is not clear if this level of accumulation impacts brain maturation, this study demonstrates that developmental CPF exposure at a level that does not inhibit brain ChE can alter components of

Occupational exposure to beryllium in French enterprises: a survey of airborne exposure and surface levels.

PubMed

Vincent, Raymond; Catani, Jacques; Créau, Yvon; Frocaut, Anne-Marie; Good, Andrée; Goutet, Pierre; Hou, Alain; Leray, Fabrice; André-Lesage, Marie-Ange; Soyez, Alain

2009-06-01

An assessment survey of occupational exposure to beryllium (Be) was conducted in France between late 2004 and the end of 2006. Exposure estimates were based on the analytical results of samples collected from workplace air and from work surfaces in 95 facilities belonging to 37 sectors of activity. The results of this study indicated airborne Be concentrations in excess of the occupational exposure limit value of 2 microg m(-3) recommended in France. Metallurgy and electronic component manufacturing represented the activities and occupations where workers had the highest arithmetic mean exposures to Be. Surface contamination levels were also high and frequently exceeded thresholds recommended by different bodies. These results should prompt the development of prevention programmes that include Be substitution, process control and surface decontamination, in conjunction with suitable medical surveillance.

Radiation-induced taste aversion: effects of radiation exposure level and the exposure-taste interval

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spector, A.C.; Smith, J.C.; Hollander, G.R.

1986-05-01

Radiation-induced taste aversion has been suggested to possibly play a role in the dietary difficulties observed in some radiotherapy patients. In rats, these aversions can still be formed even when the radiation exposure precedes the taste experience by several hours. This study was conducted to examine whether increasing the radiation exposure level could extend the range of the exposure-taste interval that would still support the formation of a taste aversion. Separate groups of rats received either a 100 or 300 R gamma-ray exposure followed 1, 3, 6, or 24 h later by a 10-min saccharin (0.1% w/v) presentation. A controlmore » group received a sham exposure followed 1 h later by a 10-min saccharin presentation. Twenty-four hours following the saccharin presentation all rats received a series of twelve 23-h two-bottle preference tests between saccharin and water. The results indicated that the duration of the exposure-taste interval plays an increasingly more important role in determining the initial extent of the aversion as the dose decreases. The course of recovery from taste aversion seems more affected by dose than by the temporal parameters of the conditioning trial.« less

Recent Developments in Low-Level Lead Exposure and Intellectual Impairment in Children

PubMed Central

Koller, Karin; Brown, Terry; Spurgeon, Anne; Levy, Len

2004-01-01

In the last decade children’s blood lead levels have fallen significantly in a number of countries, and current mean levels in developed countries are in the region of 3 μg/dL. Despite this reduction, childhood lead poisoning continues to be a major public health problem for certain at-risk groups of children, and concerns remain over the effects of lead on intellectual development in infants and children. The evidence for lowered cognitive ability in children exposed to lead has come largely from prospective epidemiologic studies. The current World Health Organization/Centers for Disease Control and Prevention blood level of concern reflects this and stands at 10 μg/dL. However, a recent study on a cohort of children whose lifetime peak blood levels were consistently < 10 μg/dL has extended the association of blood lead and intellectual impairment to lower levels of lead exposure and suggests there is no safety margin at existing exposures. Because of the importance of this finding, we reviewed this study in detail along with other recent developments in the field of low-level lead exposure and children’s cognitive development. We conclude that these findings are important scientifically, and efforts should continue to reduce childhood exposure. However, from a public health perspective, exposure to lead should be seen within the many other risk factors impacting on normal childhood development, in particular the influence of the learning environment itself. Current lead exposure accounts for a very small amount of variance in cognitive ability (1–4%), whereas social and parenting factors account for 40% or more. PMID:15198918

Cognitive development and low-level lead exposure in poly-drug exposed children.

PubMed

Min, Meeyoung O; Singer, Lynn T; Kirchner, H Lester; Minnes, Sonia; Short, Elizabeth; Hussain, Zehra; Nelson, Suchitra

2009-01-01

The impact of early postnatal lead exposure measured at age 4 on children's IQ and academic achievement at and 11 years of age was examined. The sample consisted of 278 inner-city, primarily African American children who were polydrug exposed prenatally. Regression analyses indicated a linear effect of lead exposure on outcomes and no moderating effects of polydrug exposure. An IQ loss of about 4.1-5.4 Full Scale IQ points was estimated for each 10 microg/dL increase in blood lead level at ages 4, 9, and 11 years as a function of blood lead level at age 4. Decrements in scores on tests of non-verbal reasoning were consistently associated with higher lead levels at age 4, while verbal decrements became apparent only at age 11. Lower reading summary scores at 9 and 11 years were consistently associated with higher lead exposure, while decrements in mathematics were not apparent until 11 years. Subgroup analyses on children with blood lead levels <10 microg/dL showed detrimental lead effects even at the 5 microg/dL level, providing additional evidence of adverse effects occurring at blood lead levels below the current 10 microg/dL public health blood lead action level.

Cognitive Development and Low-Level Lead Exposure in Poly-Drug Exposed Children

PubMed Central

Min, Meeyoung O.; Singer, Lynn T.; Kirchner, H. Lester; Minnes, Sonia; Short, Elizabeth; Hussain, Zehra; Nelson, Suchitra

2009-01-01

The impact of early postnatal lead exposure measured at age 4 on children’s IQ and academic achievement at 4, 9, and 11 years of age was examined. The sample consisted of 278 inner-city, primarily African American children who were polydrug exposed prenatally. Regression analyses indicated a linear effect of lead exposure on outcomes and no moderating effects of polydrug exposure. An IQ loss of about 4.1–5.4 Full Scale IQ points was estimated for each 10 ug/dl increase in blood lead level at ages 4, 9, and 11 years as a function of blood lead level at age 4. Decrements in scores on tests of non-verbal reasoning were consistently associated with higher lead levels at age 4, while verbal decrements became apparent only at age 11. Lower reading summary scores at 9 and 11 years were consistently associated with higher lead exposure, while decrements in mathematics were not apparent until 11 years. Subgroup analyses on children with blood lead levels < 10 μg/dL showed detrimental lead effects even at the 5 μg/dL level, providing additional evidence of adverse effects occurring at blood lead levels below the current 10 μg/dL public health blood lead action level. PMID:19345261

Estimation of Particulate Mass and Manganese Exposure Levels among Welders

PubMed Central

Hobson, Angela; Seixas, Noah; Sterling, David; Racette, Brad A.

2011-01-01

Background: Welders are frequently exposed to Manganese (Mn), which may increase the risk of neurological impairment. Historical exposure estimates for welding-exposed workers are needed for epidemiological studies evaluating the relationship between welding and neurological or other health outcomes. The objective of this study was to develop and validate a multivariate model to estimate quantitative levels of welding fume exposures based on welding particulate mass and Mn concentrations reported in the published literature. Methods: Articles that described welding particulate and Mn exposures during field welding activities were identified through a comprehensive literature search. Summary measures of exposure and related determinants such as year of sampling, welding process performed, type of ventilation used, degree of enclosure, base metal, and location of sampling filter were extracted from each article. The natural log of the reported arithmetic mean exposure level was used as the dependent variable in model building, while the independent variables included the exposure determinants. Cross-validation was performed to aid in model selection and to evaluate the generalizability of the models. Results: A total of 33 particulate and 27 Mn means were included in the regression analysis. The final model explained 76% of the variability in the mean exposures and included welding process and degree of enclosure as predictors. There was very little change in the explained variability and root mean squared error between the final model and its cross-validation model indicating the final model is robust given the available data. Conclusions: This model may be improved with more detailed exposure determinants; however, the relatively large amount of variance explained by the final model along with the positive generalizability results of the cross-validation increases the confidence that the estimates derived from this model can be used for estimating welder exposures

Accommodating brightness and exposure levels in densitometry of stained polyacrylamide electrophoresis gels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tan, Han Yen; Ng, Tuck Wah; Liew, Oi Wah

2010-03-20

Flatbed scanner densitometers can be operated under various illumination and recording exposure levels. In this work, we show that optical density measurement accuracy, sensitivity, and stability of stained polyacrylamide electrophoresis gel densitometry are crucially dependent on these two factors (brightness and exposure level), notwithstanding that the source is monochromatic, spatially uniform, and the measurements are made using an accurately calibrated step wedge in tandem. We further outline a method to accommodate the intensity deviations over a range of illumination and exposure levels in order to maintain sensitivity and repeatability in the computed optical densities. Comparisons were also made with resultsmore » from a commercial densitometer.« less

Effect of Short-term 900 MHz low level electromagnetic radiation exposure on blood serotonin and glutamate levels.

PubMed

Eris, A H; Kiziltan, H S; Meral, I; Genc, H; Trabzon, M; Seyithanoglu, H; Yagci, B; Uysal, O

2015-01-01

Long term exposure to low level electromagnetic radiation (LLER) by using cellular phones causes serious health problems. Ten male Wistar Albino rats were anesthetized 30 min before the LLER exposure, 0.5 ml blood was taken from the tail vein of rats in order to determine control values. Rats were grouped by three and placed on a plexi-glass flat. A fixed equivalent frequency emitter device was used. A sign to be an electromagnetic field 15.14 V/m (608 mW/m(2)) in strength in the head region with 100 kHz FM modulation at 900 MHz was applied to the animals. After calculating the ideal position for the device, electromagnetic LLER energy was applied for 45 minutes from a distance to be equal with energy transmitted by a mobile phone from a 0.5-1 cm distance to their head regions. After 1.5 hours and before the rats awoke, 0.5 ml of blood was taken from the tail veins in order to determine the treatment values. Plasma 5-HT and glutamate levels were measured by enzyme immunoassay (EIA) using commercial kits. It was found that a single 45 min of LLER exposure increased the blood 5-HT level significantly, but did not change the glutamate level of rats. It was concluded that even a single 45 min of LLER exposure may produce an increase in 5-HT level without changing the blood glutamate level. Increased 5-HT level may lead to a retarded learning and a deficit in spatial memory (Tab. 2, Fig. 2, Ref. 24).

Occupational exposure to diesel engine exhaust and serum cytokine levels.

PubMed

Dai, Yufei; Ren, Dianzhi; Bassig, Bryan A; Vermeulen, Roel; Hu, Wei; Niu, Yong; Duan, Huawei; Ye, Meng; Meng, Tao; Xu, Jun; Bin, Ping; Shen, Meili; Yang, Jufang; Fu, Wei; Meliefste, Kees; Silverman, Debra; Rothman, Nathaniel; Lan, Qing; Zheng, Yuxin

2018-03-01

The International Agency for Research on Cancer has classified diesel engine exhaust (DEE) as a human lung carcinogen. Given that inflammation is suspected to be an important underlying mechanism of lung carcinogenesis, we evaluated the relationship between DEE exposure and the inflammatory response using data from a cross-sectional molecular epidemiology study of 41 diesel engine testing workers and 46 unexposed controls. Repeated personal exposure measurements of PM 2.5 and other DEE constituents were taken for the diesel engine testing workers before blood collection. Serum levels of six inflammatory biomarkers including interleukin (IL)-1, IL-6, IL-8, tumor necrosis factor (TNF)-α, macrophage inflammatory protein (MIP)-1β, and monocyte chemotactic protein (MCP)-1 were analyzed in all subjects. Compared to unexposed controls, concentrations of MIP-1β were significantly reduced by ∼37% in DEE exposed workers (P < 0.001) and showed a strong decreasing trend with increasing PM 2.5 concentrations in all subjects (P trend  < 0.001) as well as in exposed subjects only (P trend  = 0.001). Levels of IL-8 and MIP-1β were significantly lower in workers in the highest exposure tertile of PM 2.5 (>397 µg/m 3 ) compared to unexposed controls. Further, significant inverse exposure-response relationships for IL-8 and MCP-1 were also found in relation to increasing PM 2.5 levels among the DEE exposed workers. Given that IL-8, MIP-1β, and MCP-1 are chemokines that play important roles in recruitment of immunocompetent cells for immune defense and tumor cell clearance, the observed lower levels of these markers with increasing PM 2.5 exposure may provide insight into the mechanism by which DEE promotes lung cancer. Environ. Mol. Mutagen. 59:144-150, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Assessment of personal airborne exposures and surface contamination from x-ray vaporization of beryllium targets at the National Ignition Facility.

PubMed

Paik, Samuel Y; Epperson, Patrick M; Kasper, Kenneth M

2017-06-01

This article presents air and surface sampling data collected over the first two years since beryllium was introduced as a target material at the National Ignition Facility. Over this time, 101 experiments with beryllium-containing targets were executed. The data provides an assessment of current conditions in the facility and a baseline for future impacts as new, reduced regulatory limits for beryllium are being proposed by both the Occupational Safety and Health Administration and Department of Energy. This study also investigates how beryllium deposits onto exposed surfaces as a result of x-ray vaporization and the effectiveness of simple decontamination measures in reducing the amount of removable beryllium from a surface. Based on 1,961 surface wipe samples collected from entrant components (equipment directly exposed to target debris) and their surrounding work areas during routine reconfiguration activities, only one result was above the beryllium release limit of 0.2 µg/100 cm 2 and 27 results were above the analytical reporting limit of 0.01 µg/100 cm 2 , for a beryllium detection rate of 1.4%. Surface wipe samples collected from the internal walls of the NIF target chamber, however, showed higher levels of beryllium, with beryllium detected on 73% and 87% of the samples during the first and second target chamber entries (performed annually), respectively, with 23% of the samples above the beryllium release limit during the second target chamber entry. The analysis of a target chamber wall panel exposed during the first 30 beryllium-containing experiments (cumulatively) indicated that 87% of the beryllium contamination remains fixed onto the surface after wet wiping the surface and 92% of the non-fixed contamination was removed by decontaminating the surface using a dry wipe followed by a wet wipe. Personal airborne exposures assessed during access to entrant components and during target chamber entry indicated that airborne beryllium was not present

Benzene metabolite levels in blood and bone marrow of B6C3F{sub 1} mice after low-level exposure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bechtold, W.E.; Strunk, M.R.; Thornton-Manning, J.R.

1995-12-01

Studies at the Inhalation Toxicology Research Institute (ITRI) have explored the species-specific uptake and metabolism of benzene. Results have shown that metabolism is dependent on both dose and route of administration. Of particular interest were shifts in the major metabolic pathways as a function of exposure concentration. In these studies, B6C3F{sub 1} mice were exposed to increasing levels of benzene by either gavage or inhalation. As benzene internal dose increased, the relative amounts of muconic acid and hydroquinone decreased. In contrast, the relative amount of catechol increased with increasing exposure. These results show that the relative levels of toxic metabolitesmore » are a function of exposure level. Based on these results and assuming a linear relationship between exposure concentration and levels of bone marrow metabolites, it would be difficult to detect an elevation of any phenolic metabolites above background after occupational exposures to the OSHA Permissible Exposure Limit of 1 ppm benzene.« less

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

PubMed

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.

Individual schooling and women's community-level media exposure: a multilevel analysis of normative influences associated with women's justification of wife beating in Bangladesh.

PubMed

Krause, Kathleen H; Haardörfer, Regine; Yount, Kathryn M

2017-02-01

Our objective was to examine the multilevel correlates of women's justification of wife beating in Bangladesh, a form of intimate partner violence (IPV). We focus on individual-level schooling, community-level media exposure among women and their interaction. A cross-sectional study using data from the 2011 Bangladesh Demographic and Health Survey. Our sample included 17 749 ever-married women 15-49 years in 600 communities. We fit 6 multilevel logistic regression models to examine factors associated with justifying IPV; focusing on a woman's completed grades of schooling; frequent (at least once weekly) community-level media exposure among women via newspaper/magazine, television and radio; and their cross-level interaction. At the individual level, completing more grades of schooling than the community average was negatively associated with justifying IPV (0.95, 95% CI 0.94 to 0.97). The main effects of women's community-level media exposure were not significant, but suggested that frequent exposure to newspaper/magazine or television was negatively associated with justifying IPV, while exposure to radio was positively associated. In cross-level interactions, a woman's completed grades of schooling above the community average was protective against justifying IPV, even in communities where women's exposure to radio would otherwise increase the odds of justifying IPV. Different forms of media likely send different messages about gender and IPV. Girls' schooling should remain a priority, given its protective effect against justifying wife beating. Targeting girls and women who do not receive any schooling for intervention may yield the most benefit in terms of normative change regarding IPV against women. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Gestational exposure to high perchlorate concentrations in drinking water and neonatal thyroxine levels.

PubMed

Amitai, Yona; Winston, Gary; Sack, Joseph; Wasser, Janice; Lewis, Matthew; Blount, Benjamin C; Valentin-Blasini, Liza; Fisher, Nirah; Israeli, Avi; Leventhal, Alex

2007-09-01

To assess the effect of gestational perchlorate exposure through drinking water on neonatal thyroxine (T(4)). T(4) values were compared among newborns in Ramat Hasharon, Israel, whose mothers resided in suburbs where drinking water contained perchlorate < or = 340 microg/L (very high exposure, n = 97), 42-94 microg/L (high exposure, n = 216), and < 3 microg/L (low exposure, n = 843). In the very high and high exposure areas, T(4) values in newborns whose mothers drank tap water exclusively (as determined by a telephone interview) were analyzed as a subset. Serum perchlorate levels in blood from donors residing in the area were used as proxy indicators of exposure. Neonatal T(4) values (mean +/- SD) in the very high, high, and low exposure groups were 13.9 +/- 3.8, 13.9 +/- 3.4, and 14.0 +/- 3.5 microg/dL, respectively (p = NS). Serum perchlorate concentrations in blood from donors residing in areas corresponding to these groups were 5.99 +/- 3.89, 1.19 +/- 1.37, and 0.44 +/- 0.55 microg/L, respectively. T(4) levels of neonates with putative gestational exposure to perchlorate in drinking water were not statistically different from controls. This study finds no change in neonatal T(4) levels despite maternal consumption of drinking water that contains perchlorate at levels in excess of the Environmental Protection Agency (EPA) drinking water equivalent level (24.5 microg/L) based on the National Research Council reference dose (RfD) [0.7 microg/(kg.day)]. Therefore the perchlorate RfD is likely to be protective of thyroid function in neonates of mothers with adequate iodide intake.

Low-level exposure to radiofrequency electromagnetic fields: health effects and research needs.

PubMed

Repacholi, M H

1998-01-01

The World Health Organization (WHO), the International Commission on Non-Ionizing Radiation Protection (ICNIRP), and the German and Austrian Governments jointly sponsored an international seminar in November of 1996 on the biological effects of low-level radiofrequency (RF) electromagnetic fields. For purposes of this seminar, RF fields having frequencies only in the range of about 10 MHz to 300 GHz were considered. This is one of a series of scientific review seminars held under the International Electromagnetic Field (EMF) Project to identify any health hazards from EMF exposure. The scientific literature was reviewed during the seminar and expert working groups formed to provide a status report on possible health effects from exposure to low-level RF fields and identify gaps in knowledge requiring more research to improve health risk assessments. It was concluded that, although hazards from exposure to high-level (thermal) RF fields were established, no known health hazards were associated with exposure to RF sources emitting fields too low to cause a significant temperature rise in tissue. Biological effects from low-level RF exposure were identified needing replication and further study. These included in vitro studies of cell kinetics and proliferation effects, effects on genes, signal transduction effects and alterations in membrane structure and function, and biophysical and biochemical mechanisms for RF field effects. In vivo studies should focus on the potential for cancer promotion, co-promotion and progression, as well as possible synergistic, genotoxic, immunological, and carcinogenic effects associated with chronic low-level RF exposure. Research is needed to determine whether low-level RF exposure causes DNA damage or influences central nervous system function, melatonin synthesis, permeability of the blood brain barrier (BBB), or reaction to neurotropic drugs. Reported RF-induced changes to eye structure and function should also be investigated

Company-level, semi-quantitative assessment of occupational styrene exposure when individual data are not available.

PubMed

Kolstad, Henrik A; Sønderskov, Jette; Burstyn, Igor

2005-03-01

In epidemiological research, self-reported information about determinants and levels of occupational exposures is difficult to obtain, especially if the disease under study has a high mortality rate or follow-up has exceeded several years. In this paper, we present a semi-quantitative exposure assessment strategy for nested case-control studies of styrene exposure among workers of the Danish reinforced plastics industry when no information on job title, task or other indicators of individual exposure were readily available from cases and controls. The strategy takes advantage of the variability in styrene exposure level and styrene exposure probability across companies. The study comprised 1522 cases of selected malignancies and neurodegenerative diseases and controls employed in 230 reinforced plastics companies and other related industries. Between 1960 and 1996, 3057 measurements of styrene exposure level obtained from 191 companies, were identified. Mixed effects models were used to estimate expected styrene exposure levels by production characteristics for all companies. Styrene exposure probability within each company was estimated for all but three cases and controls from the fraction of laminators, which was reported by a sample of 945 living colleagues of the cases and controls and by employers and dealers of plastic raw materials. The estimates were validated from a subset of 427 living cases and controls that reported their own work as laminators in the industry. We computed styrene exposure scores that integrated estimated styrene exposure level and styrene exposure probability. Product (boats), process (hand and spray lamination) and calendar year period were the major determinants of styrene exposure level. Within-company styrene exposure variability increased by calendar year and was accounted for when computing the styrene exposure scores. Exposure probability estimates based on colleagues' reports showed the highest predictive values in the

Lead Levels in Landfill Areas and Childhood Exposure: An Integrative Review.

PubMed

Kim, M Angela; Williams, Kimberly A

2017-01-01

Landfills are high-risk areas for environmental lead exposure for children living in poverty stricken areas in many countries. This review examines landfills and lead toxicity in children. The review discusses the effects of lead toxicity, provides evidenced based recommendations to reduce lead exposure, and identify gaps in the evidence. A database search was conducted of articles in English from 1985 to 2014. Ten articles met the inclusion criteria. The Whittemore and Knafl framework and the John Hopkins Research Evidence Appraisal Tool © were used for reviewing the data. Elevated blood lead levels (BLLs) of children living near landfills were related to increased soil lead levels. Toxic effects of lead included adverse outcomes such as encephalopathy or death for children. Different approaches to decrease lead level include environmental surveillance, BLL screening, and soil abatement which are costly. Increased BLL through environmental exposure is connected with poor health outcomes and death among children. Evidence-based prevention included monitoring and screening and costly soil abatement. It is recommended that future studies focus on community education for exposure avoidance for children living near landfill areas. © 2016 Wiley Periodicals, Inc.

Respiratory health effects of exposure to low levels of airborne endotoxin - a systematic review.

PubMed

Farokhi, Azadèh; Heederik, Dick; Smit, Lidwien A M

2018-02-08

Elevated endotoxin levels have been measured in ambient air around livestock farms, which is a cause of concern for neighbouring residents. There is clear evidence that occupational exposure to high concentrations of airborne endotoxin causes respiratory inflammation, respiratory symptoms and lung function decline. However, health effects of exposure to low levels of endotoxin are less well described. The aim of this systematic review is to summarize published associations between exposure to relatively low levels of airborne endotoxin and respiratory health endpoints. Studies investigating respiratory effects of measured or modelled exposure to low levels of airborne endotoxin (average < 100 EU/m 3 ) were eligible for inclusion. In total, 1362 articles were identified through a Pubmed database search, of which 31 articles were included in this review. Studies were included up to February 2017. Overview tables and forest plots were created, and study quality was assessed. Twenty-two included studies had a cross-sectional design, others were designed as longitudinal observational (n = 7) or experimental (n = 2) studies. Most studies (n = 23) were conducted in an occupational setting, some involved domestic or experimental exposure. Several studies reported statistically significant effects of exposure to low levels of endotoxin on respiratory symptoms and lung function. However, considerable heterogeneity existed in the outcomes of the included studies and no overall estimate could be provided by meta-analysis to quantify the possible relationship. Instead, a best evidence synthesis was performed among studies examining the exposure-response relationship between endotoxin and respiratory outcomes. Significant exposure-response relationships between endotoxin and symptoms and FEV 1 were shown in several studies, with no conflicting findings in the studies included in the best evidence synthesis. Significantly different effects of endotoxin exposure

Exposure to volatile organic compounds for individuals with occupations associated with potential exposure to motor vehicle exhaust and/or gasoline vapor emissions.

PubMed

Jo, W K; Song, K B

2001-03-26

Workers who work near volatile organic compounds (VOCs) source(s), motor vehicle exhausts and/or gasoline vapor emissions, are suspected to be exposed to highly-elevated VOC levels during their work-time. This study confirmed this suspicion and evaluated the work-time exposure VOCs for traffic police officers, parking garage attendants, service station attendants, roadside storekeepers and underground storekeepers, by measuring the concentrations of six aromatic VOCs in workplace air, or personal air and breath samples. For nearly all target VOCs, the post-work breath concentrations of the workers were slightly or significantly higher than the pre-work breath concentrations, depending on the compound and occupation. Furthermore, both the pre- and post-work breath concentrations of the workers showed elevated levels compared with a control group of college students. The post-work breath concentrations were significantly correlated with the personal air concentrations, while the pre-work breath concentrations were not. Smoking workers were not always exposed to higher aromatic VOC levels than non-smoking workers. The breath and personal air concentrations for all the target compounds were both higher for underground parking garage attendants than for ground-level parking attendants. For all the target compounds except toluene, storekeepers exhibited similar levels of exposure for all store types. Print shopkeepers recorded the highest toluene exposure.

Elevated blood lead levels from exposure via a radiator workshop.

PubMed

Treble, R G; Thompson, T S; Morton, D N

1998-04-01

Elevated lead levels were discovered in blood samples collected from family members where both the father and the mother worked in a radiator repair workshop. The father and mother were found to have blood lead levels of 2.0 and 0.5 mumol/L (41.7 and 10.4 micrograms/dL), respectively. The father's blood lead level was just below the Canadian occupational health and safety intervention level (2.5 mumol/L or 52.1 micrograms/dL). The two children had blood lead levels of 1.0 and 0.8 mumol/L (20.8 and 16.7 micrograms/dL), both of which are in excess of the recommended guideline for intervention in the case of children (0.5 mumol/L or 10.4 micrograms/dL). The exposure of the two children was possibly due to a combination of pathways including exposure at the workshop itself during visits and also the transportation of lead-containing dust to the home environment.

Targeting pre-exposure prophylaxis among men who have sex with men in the United States and Peru: partnership types, contact rates, and sexual role

PubMed Central

Carnegie, Nicole Bohme; Goodreau, Steven M.; Liu, Albert; Vittinghoff, Eric; Sanchez, Jorge; Lama, Javier R.; Buchbinder, Susan

2015-01-01

Background We aim to identify optimal strategies for deploying pre-exposure prophylaxis among men who have sex with men in the US and Peru to maximize population-level effectiveness in an efficient manner. We use epidemic models to simulate the impact of targeting strategies. Most studies have focused on targeting either the general population or high-risk MSM. Alternative strategies, including serodiscordant couples, may better balance effectiveness and efficiency. Methods We use dynamic, stochastic sexual network models based in exponential-family random graph modeling, parameterized from behavioral surveys of MSM in the US and Peru. These models represent main partnerships and casual contacts separately, permitting modeling of interventions targeting men whose risk derives from combinations of relational types. We also model varying rates of uptake and adherence to PrEP. We assess sensitivity of results to risk compensation via increases in condomless casual contacts and condomless sex in main partnerships. Results Targeting all men who are not exclusively insertive has the largest impact on HIV incidence, but targeting only those with high levels of casual activity yields comparable results using fewer person-years on PrEP. The effect is robust to risk compensation in the US, but less so in Peru. Targeting serodiscordant main partnerships does not significantly impact incidence, but requires fewer person-years on PrEP per infection averted than other strategies. Conclusions PrEP could be effective in reducing new infections at the population level in both settings. Serodiscordant partnerships are an attractive component of a targeting program, but targeting should include other high-risk men. PMID:25942463

Reexamining the Correlates of Adolescent Violent Victimization: The Importance of Exposure, Guardianship, and Target Characteristics

ERIC Educational Resources Information Center

Tillyer, Marie Skubak; Tillyer, Rob; Miller, Holly Ventura; Pangrac, Rebekah

2011-01-01

The present study examines the relative contributions of various theoretical constructs to violent victimization by operationalizing multiple measures of exposure to motivated offenders, guardianship, and target characteristics. Using a nationally representative sample of American adolescents, we conducted principal components factor analysis and…

Ultraviolet B exposure activates Stat3 signaling via phosphorylation at tyrosine705 in skin of SKH1 hairless mouse: a target for the management of skin cancer?

PubMed

Ahsan, Haseeb; Aziz, Moammir Hasan; Ahmad, Nihal

2005-07-22

Understanding the molecular determinants of ultraviolet (UV) response may lead to the development of novel targets; and therefore, better approaches for the management of cancers, which mainly arise due to the exposure of skin to UV (particularly its UVB spectrum). Signal transducer and activator of transcription (Stat) proteins have been shown to activate multiple signaling pathways to contribute to oncogenesis. Here, we studied the regulation of Stat3 during UVB exposure-mediated responses in the skin of SKH-1 hairless mouse, a model regarded to possess relevance to human situations. Our data demonstrated that a single UVB (180 mJ/cm(2)) exposure to the skin of SKH-1 hairless mice resulted in significant upregulation in (i) protein levels of Stat3 and (ii) phosphorylation of Stat3 at tyrosine(705). Further, the activation of Stat3 was found to be associated with a decrease in apoptotic response of UVB and a gradual time-dependent increase in leukocyte infiltration and hyperplasia. In conclusion, we have demonstrated, for the first time, that UVB exposure to skin resulted in an activation of pro-survival protein Stat3. Based on our observation, we suggest that Stat3 could serve as a target for the management of UVB exposure-mediated damages including skin cancer.

Glutathione level after long-term occupational elemental mercury exposure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kobal, Alfred Bogomir; Prezelj, Marija; Horvat, Milena

2008-05-15

Many in vitro and in vivo studies have elucidated the interaction of inorganic mercury (Hg) and glutathione. However, human studies are limited. In this study, we investigated the potential effects of remote long-term intermittent occupational elemental Hg vapour (Hg{sup o}) exposure on erythrocyte glutathione levels and some antioxidative enzyme activities in ex-mercury miners in the period after exposure. The study included 49 ex-mercury miners divided into subgroups of 28 still active, Hg{sup o}-not-exposed miners and 21 elderly retired miners, and 41 controls, age-matched to the miners subgroup. The control workers were taken from 'mercury-free works'. Reduced glutathione (GSH) and oxidizedmore » disulphide glutathione (GSSG) concentrations in haemolysed erythrocytes were determined by capillary electrophoresis, while total glutathione (total GSH) and the GSH/GSSG ratio were calculated from the determined values. Catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) activities in erythrocytes were measured using commercially available reagent kits, while urine Hg (U-Hg) concentrations were determined by cold vapour atomic absorption (CVAAS). No correlation of present U-Hg levels, GSH, GSSG, and antioxidative enzymes with remote occupational biological exposure indices were found. The mean CAT activity in miners and retired miners was significantly higher (p<0.05) than in the controls. No differences in mean GPx activity among the three groups were found, whereas the mean GR activity was significantly higher (p<0.05) in miners than in retired miners. The mean concentrations of GSH (mmol/g Hb) in miners (13.03{+-}3.71) were significantly higher (p<0.05) than in the control group (11.68{+-}2.66). No differences in mean total GSH, GSSG levels, and GSH/GSSG ratio between miners and controls were found. A positive correlation between GSSG and present U-Hg excretion (r=0.41, p=0.001) in the whole group of ex-mercury miners was observed. The

Understanding Environmental Tobacco Smoke Exposure and Effects in Asthmatic Children through Determination of Urinary Cotinine and Targeted Metabolomics of Plasma

EPA Science Inventory

Understanding Environmental Tobacco Smoke Exposure and Effects in Asthmatic Children through Determination of Urinary Cotinine and Targeted Metabolomics of Plasma Introduction Asthma is a complex disease with multiple triggers and causal factors, Exposure to environmental tob...

Schistosoma mansoni P-glycoprotein levels increase in response to praziquantel exposure and correlate with reduced praziquantel susceptibility.

PubMed

Messerli, Shanta M; Kasinathan, Ravi S; Morgan, William; Spranger, Stefani; Greenberg, Robert M

2009-09-01

One potential physiological target for new antischistosomals is the parasite's system for excretion of wastes and xenobiotics. P-glycoprotein (Pgp), a member of the ATP-binding-cassette superfamily of proteins, is an ATP-dependent efflux pump involved in transport of toxins and xenobiotics from cells. In vertebrates, increased expression of Pgp is associated with multidrug resistance in tumor cells. Pgp may also play a role in drug resistance in helminths. In this report, we examine the relationship between praziquantel (PZQ), the current drug of choice against schistosomiasis, and Pgp expression in Schistosoma mansoni. We show that levels of RNA for SMDR2, a Pgp homolog from S. mansoni, increase transiently in adult male worms following exposure to sub-lethal concentrations (100-500 nM) of PZQ. A corresponding, though delayed, increase in anti-Pgp immunoreactive protein expression occurs in adult males following exposure to PZQ. The level of anti-Pgp immunoreactivity in particular regions of adult worms also increases in response to PZQ. Adult worms from an Egyptian S. mansoni isolate with reduced sensitivity to PZQ express increased levels of SMDR2 RNA and anti-Pgp-immunoreactive protein, perhaps indicating a role for multidrug resistance proteins in development or maintenance of PZQ resistance.

Schistosoma mansoni P-glycoprotein levels increase in response to praziquantel exposure and correlate with reduced praziquantel susceptibility

PubMed Central

Messerli, Shanta M.; Kasinathan, Ravi S.; Morgan, William; Spranger, Stefani; Greenberg, Robert M.

2009-01-01

One potential physiological target for new antischistosomals is the parasite’s system for excretion of wastes and xenobiotics. P-glycoprotein (Pgp), a member of the ATP-binding cassette superfamily of proteins, is an ATP-dependent efflux pump involved in transport of toxins and xenobiotics from cells. In vertebrates, increased expression of Pgp is associated with multidrug resistance in tumor cells. Pgp may also play a role in drug resistance in helminths. In this report, we examine the relationship between praziquantel (PZQ), the current drug of choice against schistosomiasis, and Pgp expression in Schistosoma mansoni. We show that levels of RNA for SMDR2, a Pgp homolog from S. mansoni, increase transiently in adult male worms following exposure to sublethal concentrations (100 – 500 nM) of PZQ. A corresponding, though delayed, increase in anti-Pgp immunoreactive protein expression occurs in adult males following exposure to PZQ. The level of anti-Pgp immunoreactivity in particular regions of adult worms also increases in response to PZQ. Adult worms from an Egyptian S. mansoni isolate with reduced sensitivity to PZQ express increased levels of SMDR2 RNA and anti-Pgp-immunoreactive protein, perhaps indicating a role for multidrug resistance proteins in development or maintenance of PZQ resistance. PMID:19406169

Exposure levels for chemical threat compounds: information to facilitate chemical incident response.

PubMed

Hauschild, Veronique D; Watson, Annetta

2013-01-01

Although not widely known, a robust set of peer-reviewed public health and occupational exposure levels presently exist for key chemical warfare agents (CWAs) and certain acutely toxic industrial chemicals (TICs) identified as terrorist attack threats. Familiarity with these CWA and TIC exposure levels and their historic applications has facilitated emergency management decision-making by public and environmental health decision-makers. Specifically, multiple air, soil, and water exposure levels for CWAs and TICs summarized here have been extensively peer-reviewed and published; many have been recognized and are in use by federal and state health agencies as criteria for hazard zone prediction and assessment, occupational safety, and "how clean is clean enough" decisions. The key, however, is to know which criteria are most appropriate for specific decisions. While public safety is critical, high levels of concern often associated with perceived or actual proximity to extremely toxic chemical agents could result in overly cautious decisions that generate excessive delays, expenditure of scarce resources, and technological difficulties. Rapid selection of the most appropriate chemical exposure criteria is recommended to avoid such problems and expedite all phases of chemical incident response and recovery.

Butyltin exposure causes a rapid decrease in cyclic AMP levels in human lymphocytes.

PubMed

Whalen, M M; Loganathan, B G

2001-03-15

Natural killer (NK) cells are a subset of lymphocytes that are capable of killing tumor cells, virally infected cells, and antibody-coated cells. Butyltins (BTs) are used in a variety of consumer products and industrial applications. Tributyltin (TBT) is found in dairy products, meat, and fish. Dibutyltin (DBT) is found in plastic products, beverages stored in PVC pipes during manufacturing, and poultry products. BTs appear to increase the risk of cancer and viral infections in exposed individuals. This increased risk may be due in part to the inhibitory effect of these compounds on the cytotoxic function of NK cells. A 24-h exposure of NK cells to 200 nM TBT or 1.5 microM DBT decreased the cytotoxic function of NK cells by greater than 90%. Higher concentrations of TBT and DBT decreased the cytotoxic function of NK cells (by greater than 90%) after only a 1-h exposure. A 24-h exposure to either TBT or DBT decreased intracellular ATP levels by about 30%. However, as much as a 1-h exposure to either 300 nM TBT or 10 microM DBT caused no significant decrease in ATP levels. Thus, a decrease in ATP levels is a longer-term consequence of BT exposure. Intracellular levels of cAMP are decreased by as much as 80% within 5 min of exposure to either TBT or DBT. This rapid decline in cAMP levels in NK cells may be a consequence of BT exposure that is related to the rapid decrease in the cytotoxic function of NK cells. Copyright 2001 Academic Press.

HELLE: Health Effects of Low Level Exposures/ Gezondheidseffecten van lage blootstellingniveaus [International workshop: Influence of low level exposures to chemicals and radiation on human and ecological health

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schoten, Eert

1998-11-26

The Health Council is closely involved in establishing the scientific foundation of exposure limits for substances and radiation in order to protect public health. Through the years, the Council has contributed to the formulation of principles and procedures, both for carcinogenic and for noncarcinogenic agents. As a rule, the discussion with regard to the derivation of health-based recommended exposure limits centers around the appropriateness of extrapolation methods (What can be inferred from data on high exposure levels and on experimental animals?). Generally speaking, there is a lack of direct information on the health effects of low levels of exposure. Effectsmore » at these levels cannot usually be detected by means of traditional animal experiments or epidemiological research. The capacity of these analytical instruments to distinguish between ''signal'' and ''noise'' is inadequate in most cases. Annex B of this report contains a brief outline of the difficulties and the established methods for tackling this problem. In spite of this, the hope exists that the posited weak signals, if they are indeed present, can be detected by other means. The search will have to take place on a deeper level. In other words, effort must be made to discover what occurs at underlying levels of biological organization when organisms are exposed to low doses of radiation or substances. Molecular and cell biology provide various methods and techniques which give an insight into the processes within the cell. This results in an increase in the knowledge about the molecular and cellular effects of exposure to agents, or stated differently, the working mechanisms which form the basis of the health effects. Last year, the Health Council considered that the time was ripe to take stock of the state of knowledge in this field. To this end, an international working conference was held from 19 to 21 October 1997, entitled ''Health Effects of Low Level Exposures: Scientific

Combined pesticide exposure severely affects individual- and colony-level traits in bees

PubMed Central

Gill, Richard J.; Ramos-Rodriguez, Oscar; Raine, Nigel E.

2012-01-01

Reported widespread declines of wild and managed insect pollinators have serious consequences for global ecosystem services and agricultural production1-3. Bees contribute around 80% of insect pollination, so it is imperative we understand and mitigate the causes of current declines4-6. Recent studies have implicated the role of pesticides as exposure to these chemicals has been associated with changes in bee behaviour7-11 and reductions in colony queen production12. However the key link between changes in individual behaviour and consequent impact at the colony level has not been shown. Social bee colonies depend on the collective performance of numerous individual workers. So whilst field-level pesticide concentrations can have a subtle/sublethal effect at the individual level8, it is not known whether bee societies can buffer such effects or if it results in a severe cumulative effect at the colony level. Furthermore, widespread agricultural intensification means bees are exposed to numerous pesticides when foraging13-15, yet the possible combinatorial effects of pesticide exposure have rarely been investigated16,17. Here we show that chronic exposure of bumblebees to two pesticides (neonicotinoid and pyrethroid) at concentrations that could approximate field-level exposure impairs natural foraging behaviour and increases worker mortality leading to significant reductions in brood development and colony success. We found worker foraging performance, particularly pollen collecting efficiency, was significantly reduced with observed knock-on effects for forager recruitment, worker losses and overall worker productivity. Moreover, we provide evidence that combinatorial exposure to pesticides increases the propensity of colonies to fail. PMID:23086150

Exposure Cessation During Adulthood Did Not Prevent Immunotoxicity Caused by Developmental Exposure to Low-Level Trichloroethylene in Drinking Water.

PubMed

Gilbert, Kathleen M; Bai, Shasha; Barnette, Dustyn; Blossom, Sarah J

2017-06-01

Exposure to the water pollutant trichloroethylene (TCE) can promote autoimmunity in both humans and rodents. Using a mouse model we have shown that chronic adult exposure to TCE at 500 μg/ml in drinking water generates autoimmune hepatitis in female MRL+/+ mice. There is increasing evidence that developmental exposure to certain chemicals can be more toxic than adult exposure. This study was designed to test whether exposure to a much lower level of TCE (0.05 μg/ml) during gestation, lactation, and early life generated autoimmunity similar to that found following adult exposure to higher concentrations of TCE. When female MRL+/+ mice were examined at postnatal day (PND) 259 we found that developmental/early life exposure [gestational day 0 to PND 154] to TCE at a concentration 10 000 fold lower than that shown to be effective for adult exposure triggered autoimmune hepatitis. This effect was observed despite exposure cessation at PND 154. In concordance with the liver pathology, female MRL+/+ exposed during development and early life to TCE (0.05 or 500 μg/ml) generated a range of antiliver antibodies detected by Western blotting. Expression of proinflammatory cytokines by CD4+ T cells was also similarly observed at PND 259 in the TCE-exposed mice regardless of concentration. Thus, exposure to TCE at approximately environmental levels from gestational day 0 to PND 154 generated tissue pathology and CD4+ T cell alterations that required higher concentrations if exposure was limited to adulthood. TCE exposure cessation at PND 154 did not prevent the immunotoxicity. © The Author 2017. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Consumer product exposures associated with urinary phthalate levels in pregnant women

PubMed Central

Buckley, Jessie P.; Palmieri, Rachel T.; Matuszewski, Jeanine M.; Herring, Amy H.; Baird, Donna D.; Hartmann, Katherine E.; Hoppin, Jane A.

2012-01-01

Human phthalate exposure is ubiquitous, but little is known regarding predictors of urinary phthalate levels. To explore this, 50 pregnant women aged 18–38 years completed two questionnaires on potential phthalate exposures and provided a first morning void. Urine samples were analyzed for 12 phthalate metabolites. Associations with questionnaire items were evaluated via Wilcoxon tests and t-tests, and r-squared values were calculated in multiple linear regression models. Few measured factors were statistically significantly associated with phthalate levels. Individuals who used nail polish had higher levels of mono-butyl phthalate (p=0.048) than non-users. Mono-benzyl phthalate levels were higher among women who used eye makeup (p=0.034) or used makeup on a regular basis (p=0.004). Women who used cologne or perfume had higher levels of di-(2-ethylhexyl) phthalate metabolites. Household products, home flooring or paneling, and other personal care products were also associated with urinary phthalates. The proportion of variance in metabolite concentrations explained by questionnaire items ranged between 0.31 for mono-ethyl phthalate and 0.42 for mono-n-methyl phthalate. Although personal care product use may be an important predictor of urinary phthalate levels, most of the variability in phthalate exposure was not captured by our relatively comprehensive set of questionnaire items. PMID:22760436

Assessment of personal airborne exposures and surface contamination from x-ray vaporization of beryllium targets at the National Ignition Facility

DOE PAGES

Paik, Samuel Y.; Epperson, Patrick M.; Kasper, Kenneth M.

2017-02-28

Here, this article presents air and surface sampling data collected over the first two years since beryllium was introduced as a target material at the National Ignition Facility. Over this time, 101 experiments with beryllium-containing targets were executed. The data provides an assessment of current conditions in the facility and a baseline for future impacts as new, reduced regulatory limits for beryllium are being proposed by both the Occupational Safety and Health Administration and Department of Energy. This study also investigates how beryllium deposits onto exposed surfaces as a result of x-ray vaporization and the effectiveness of simple decontamination measuresmore » in reducing the amount of removable beryllium from a surface. Based on 1,961 surface wipe samples collected from entrant components (equipment directly exposed to target debris) and their surrounding work areas during routine reconfiguration activities, only one result was above the beryllium release limit of 0.2 µg/100 cm 2 and 27 results were above the analytical reporting limit of 0.01 µg/100 cm 2, for a beryllium detection rate of 1.4%. Surface wipe samples collected from the internal walls of the NIF target chamber, however, showed higher levels of beryllium, with beryllium detected on 73% and 87% of the samples during the first and second target chamber entries (performed annually), respectively, with 23% of the samples above the beryllium release limit during the second target chamber entry. The analysis of a target chamber wall panel exposed during the first 30 beryllium-containing experiments (cumulatively) indicated that 87% of the beryllium contamination remains fixed onto the surface after wet wiping the surface and 92% of the non-fixed contamination was removed by decontaminating the surface using a dry wipe followed by a wet wipe. Personal airborne exposures assessed during access to entrant components and during target chamber entry indicated that airborne beryllium was

Statistical modelling of formaldehyde occupational exposure levels in French industries, 1986-2003.

PubMed

Lavoué, Jérôme; Vincent, Raymond; Gérin, Michel

2006-04-01

Occupational exposure databanks (OEDBs) have been cited as sources of exposure data for exposure surveillance and exposure assessment in epidemiology. In 2003, an extract was made from COLCHIC, the French national OEDB, of all concentrations of formaldehyde. The data were analysed with extended linear mixed-effects models in order to identify influent variables and elaborate a multi-sector picture of formaldehyde exposures. Respectively, 1401 and 1448 personal and area concentrations were available for the analysis. The fixed effects of the personal and area models explained, respectively, 57 and 53% of the total variance. Personal concentrations were related to the sampling duration (short-term higher than TWA levels), decreased with the year of sampling (-9% per year) and were higher when local exhaust ventilation was present. Personal levels taken during planned visits and for occupational illness notification purpose were consistently lower than those taken during ventilation modification programmes or because the hygienist suspected the presence of significant risk or exposure. Area concentrations were related to the sampling duration (short-term higher than TWA levels), and decreased with the year of sampling (-7% per year) and when the measurement sampling flow increased. Significant within-facility (correlation coefficient 0.4-0.5) and within-sampling campaign correlation (correlation coefficient 0.8) was found for both area and personal data. The industry/task classification appeared to have the greatest influence on exposure variability while the sample duration and the sampling flow were significant in some cases. Estimates made from the models for year 2002 showed elevated formaldehyde exposure in the fields of anatomopathological and biological analyses, operation of gluing machinery in the wood industry, operation and monitoring of mixers in the pharmaceutical industry, and garages and warehouses in urban transit authorities.

The Impact of Different Permissible Exposure Limits on Hearing Threshold Levels Beyond 25 dBA

PubMed Central

Sayapathi, Balachandar S; Su, Anselm Ting; Koh, David

2014-01-01

Background: Development of noise-induced hearing loss is reliant on a few factors such as frequency, intensity, and duration of noise exposure. The occurrence of this occupational malady has doubled from 120 million to 250 million in a decade. Countries such as Malaysia, India, and the US have adopted 90 dBA as the permissible exposure limit. According to the US Occupational Safety and Health Administration (OSHA), the exposure limit for noise is 90 dBA, while that of the US National Institute of Occupational Safety and Health (NIOSH) is 85 dBA for 8 hours of noise exposure. Objectives: This study aimed to assess the development of hearing threshold levels beyond 25 dBA on adoption of 85 dBA as the permissible exposure limit compared to 90 dBA. Patients and Methods: This is an intervention study done on two automobile factories. There were 203 employees exposed to noise levels beyond the action level. Hearing protection devices were distributed to reduce noise levels to a level between the permissible exposure limit and action level. The permissible exposure limits were 90 and 85 dBA in factories 1 and 2, respectively, while the action levels were 85 and 80 dBA, respectively. The hearing threshold levels of participants were measured at baseline and at first month of postshift exposure of noise. The outcome was measured by a manual audiometer. McNemar and chi-square tests were used in the statistical analysis. Results: We found that hearing threshold levels of more than 25 dBA has changed significantly from pre-intervention to post-intervention among participants from both factories (3000 Hz for the right ear and 2000 Hz for the left ear). There was a statistically significant association between participants at 3000 Hz on the right ear at ‘deteriorated’ level ( χ² (1) = 4.08, φ = - 0.142, P = 0.043), whereas there was worsening of hearing threshold beyond 25 dBA among those embraced 90 dBA. Conclusions: The adoption of 85 dBA as the permissible exposure

The Impact of Different Permissible Exposure Limits on Hearing Threshold Levels Beyond 25 dBA.

PubMed

Sayapathi, Balachandar S; Su, Anselm Ting; Koh, David

2014-10-01

Development of noise-induced hearing loss is reliant on a few factors such as frequency, intensity, and duration of noise exposure. The occurrence of this occupational malady has doubled from 120 million to 250 million in a decade. Countries such as Malaysia, India, and the US have adopted 90 dBA as the permissible exposure limit. According to the US Occupational Safety and Health Administration (OSHA), the exposure limit for noise is 90 dBA, while that of the US National Institute of Occupational Safety and Health (NIOSH) is 85 dBA for 8 hours of noise exposure. This study aimed to assess the development of hearing threshold levels beyond 25 dBA on adoption of 85 dBA as the permissible exposure limit compared to 90 dBA. This is an intervention study done on two automobile factories. There were 203 employees exposed to noise levels beyond the action level. Hearing protection devices were distributed to reduce noise levels to a level between the permissible exposure limit and action level. The permissible exposure limits were 90 and 85 dBA in factories 1 and 2, respectively, while the action levels were 85 and 80 dBA, respectively. The hearing threshold levels of participants were measured at baseline and at first month of postshift exposure of noise. The outcome was measured by a manual audiometer. McNemar and chi-square tests were used in the statistical analysis. We found that hearing threshold levels of more than 25 dBA has changed significantly from pre-intervention to post-intervention among participants from both factories (3000 Hz for the right ear and 2000 Hz for the left ear). There was a statistically significant association between participants at 3000 Hz on the right ear at 'deteriorated' level ( χ² (1) = 4.08, φ = - 0.142, P = 0.043), whereas there was worsening of hearing threshold beyond 25 dBA among those embraced 90 dBA. The adoption of 85 dBA as the permissible exposure limit has preserved hearing threshold level among participants at 3000 Hz

EPA’s Non-Targeted Analysis Research Program: Expanding public data resources in support of exposure science

EPA Science Inventory

Suspect screening (SSA) and non-targeted analysis (NTA) methods using high-resolution mass spectrometry (HRMS) offer new approaches to efficiently generate exposure data for chemicals in a variety of environmental and biological media. These techniques aid characterization of the...

Acute Exposure to Low-to-Moderate Carbon Dioxide Levels and Submariner Decision Making.

PubMed

Rodeheffer, Christopher D; Chabal, Sarah; Clarke, John M; Fothergill, David M

2018-06-01

Submarines routinely operate with higher levels of ambient carbon dioxide (CO2) (i.e., 2000 - 5000 ppm) than what is typically considered normal (i.e., 400 - 600 ppm). Although significant cognitive impairments are rarely reported at these elevated CO2 levels, recent studies using the Strategic Management Simulation (SMS) test have found impairments in decision-making performance during acute CO2 exposure at levels as low as 1000 ppm. This is a potential concern for submarine operations, as personnel regularly make mission-critical decisions that affect the safety and efficiency of the vessel and its crew while exposed to similar levels of CO2. The objective of this study was to determine if submariner decision-making performance is impacted by acute exposure to levels of CO2 routinely present in the submarine atmosphere during sea patrols. Using a subject-blinded balanced design, 36 submarine-qualified sailors were randomly assigned to receive 1 of 3 CO2 exposure conditions (600, 2500, or 15,000 ppm). After a 45-min atmospheric acclimation period, participants completed an 80-min computer-administered SMS test as a measure of decision making. There were no significant differences for any of the nine SMS measures of decision making between the CO2 exposure conditions. In contrast to recent research demonstrating cognitive deficits on the SMS test in students and professional-grade office workers, we were unable to replicate this effect in a submariner population-even with acute CO2 exposures more than an order of magnitude greater than those used in previous studies that demonstrated such effects.Rodeheffer CD, Chabal S, Clarke JM, Fothergill DM. Acute exposure to low-to-moderate carbon dioxide levels and submariner decision making. Aerosp Med Hum Perform. 2018; 89(6):520-525.

The availability of state-level highway accident exposure information

DOT National Transportation Integrated Search

1982-09-30

The purpose of the investigation desaibed in this report is to ascertain the : availability and accuracy of highway accident exposure data at both the Federal : and state levels. The ultimate aim is to develop a computer file of generally : available...

miRNA-216 and miRNA-499 target cyb561d2 in zebrafish in response to fipronil exposure.

PubMed

Zhou, Yongyong; Huang, Hannian; Zhang, Kai; Ding, Xianfeng; Jia, Longlue; Yu, Liang; Zhu, Guonian; Guo, Jiangfeng

2016-07-01

MicroRNA (miRNA) can regulate the expression of its target gene by mediating mRNA cleavage or by translational repression at a post-transcriptional level. Usually, one miRNA may regulate many genes as its targets, while one gene may also be targeted by many miRNAs. We previously demonstrated that cyb561d2, whose protein product is involved in cell defense, and chemical stress, is targeted by miR-155 in adult zebrafish (Danio rerio) when exposed to fipronil (5-amino-1-[2,6-dichloro-4-(trifluoromethyl) phenyl]-4-[(trifluoromethyl) sulphinyl]-1H-pyrazole-3-carbonitrile). Microcosm Targets prediction showed that the cyb561d2 gene is also highly possibly targeted by miR-194a, miR-216b, miR-429, and miR-499. These interactions need to be further validated experimentally. In this study, we evaluated the effects of fipronil on miR-194a, miR-216b, miR-429, miR-499 and cyb561d2 in zebrafish and investigated whether these four miRNAs could regulate the expression of cyb561d2 in both mRNA and protein levels. The expression of cyb561d2 was upregulated in both mRNA and protein level in a dose-dependent manner upon stimulation of fipronil, and miR-216b and miR-499 were downregulated concurrently, whereas there was no significant changes were observed in the expression level of miR-194a and miR-429. The dual luciferase report assay demonstrated that miR-216b and miR-499 interacted with cyb561d2 3'-untranslated regions (3'-UTR), miR-194a and miR-429 did not stimulate degradation of cyb561d2 mRNA. The expression of cyb561d2 was reduced in both mRNA and protein level when ZF4 cells were transfected with miR-499 mimic, whereas expression level of both mRNA and protein was increased when endogenous miR-499 was inhibited by transfection with miR-499 inhibitor. Likewise, the mRNA and protein level of cyb561d2 was affected by treatment with the mimics and the inhibitor of miR-216b. In contrast, when ZF4 cells were transfected with a mimic of miR-194a or miR-429, the expression of cyb561d2

Effect of Direct Exposure to Foreign Target Groups on Descriptive Stereotypes Held by American Students

ERIC Educational Resources Information Center

McCrady, Richard E.; McCrady, Jean B.

1976-01-01

American college students (N=77) enrolled in a semester-at-sea program rated four target groups before and after exposure in their own national settings, on a rating instrument designed to discriminate between descriptive and evaluative judgments in stereotyping. The greatest change was in the stereotypic profile of the English. (Author)

The Effects of Repeated Low-Level Blast Exposure on Hearing in Marines

PubMed Central

Kubli, Lina R.; Pinto, Robin L.; Burrows, Holly L.; Littlefield, Philip D.; Brungart, Douglas S.

2017-01-01

Background: The study evaluates a group of Military Service Members specialized in blast explosive training called “Breachers” who are routinely exposed to multiple low-level blasts while teaching breaching at the U.S. Marine Corps in Quantico Virginia. The objective of this study was to determine if there are any acute or long-term auditory changes due to repeated low-level blast exposures used in training. The performance of the instructor group “Breachers” was compared to a control group, “Engineers”. Methods: A total of 11 Breachers and four engineers were evaluated in the study. The participants received comprehensive auditory tests, including pure-tone testing, speech-in-noise (SIN) measures, and central auditory behavioral and objective tests using early and late (P300) auditory evoked potentials over a period of 17 months. They also received shorter assessments immediately following the blast-exposure onsite at Quantico. Results: No acute or longitudinal effects were identified. However, there were some interesting baseline effects found in both groups. Contrary to the expected, the onsite hearing thresholds and distortion product otoacoustic emissions were slightly better at a few frequencies immediately after blast-exposure than measurements obtained with the same equipment weeks to months after each blast-exposure. Conclusions: To date, the current study is the most comprehensive study that evaluates the long-term effects of blast-exposure on hearing. Despite extensive testing to assess changes, the findings of this study suggest that the levels of current exposures used in this military training environment do not seem to have an obvious deleterious effect on hearing. PMID:28937017

[Myocardial ultrastructural changes in rats following different levels of acute +Gz exposure].

PubMed

Zheng, Jun; Liu, Cheng-gang; Ren, Li; Xiao, Xiao-guang; Xu, Shu-xuan; Wang, Ping; Ji, Gui-ying

2004-06-01

To observe the effects of different levels of acute +Gz exposure on myocardial ultrastructure of rats and provide experimental basis for further development of anti-G measures. Twenty male Wistar rats were randomly divided into 4 groups (n=5): normal control group, +20 Gz group, +10 Gz group and +5 Gz group. Profile of the centrifuge +Gz exposure was trapezoidal, in which +20 Gz lasted for 30 s, +10 Gz for 1.5 min. +5 Gz exposure was repeated for 3 times with 30 min interval and each for 1.5 min. Myocardial tissue of left ventricle was sampled for transmission electron microscopy 5 h after exposure. +20 Gz and +10 Gz exposure caused obvious edema of myocardial and endothelial cells, myofibril disorder and injuries of mitochondria and nucleus. Breaks of myocardial fiber, formation of contraction bands and rupture of mitochondria were also observed in +20 Gz group. In +5 Gz group, there was still slight edema of myocardial and endothelial cells, while organic changes of myocardial ultrastructure were not observed. High +Gz exposure can cause myocardial ultrastructural injury in rats. Slight reversible injured response can also be observed in myocardial cell after repeated moderate level of +Gz exposure. This indicates that attention should be paid to the study of the effect of high +Gz on heart in pilots.

Olfactory recognition memory is disrupted in young mice with chronic low-level lead exposure

PubMed Central

Flores-Montoya, Mayra Gisel; Alvarez, Juan Manuel; Sobin, Christina

2015-01-01

Chronic developmental lead exposure yielding very low blood lead burden is an unresolved child public health problem. Few studies have attempted to model neurobehavioral changes in young animals following very low level exposure, and studies are needed to identify tests that are sensitive to the neurobehavioral changes that may occur. Mechanisms of action are not yet known however results have suggested that hippocampus/dentate gyrus may be uniquely vulnerable to early chronic low-level lead exposure. This study examined the sensitivity of a novel odor recognition task to differences in pre-adolescent C57BL/6J mice chronically exposed from birth to PND 28, to 0 ppm (control), 30 ppm (low-dose), or 330 ppm (higher-dose) lead acetate (N = 33). Blood lead levels (BLLs) determined by ICP-MS ranged from 0.02 to 20.31 µg/dL. Generalized linear mixed model analyses with litter as a random effect showed a significant interaction of BLL × sex. As BLLs increased olfactory recognition memory decreased in males. Among females, non-linear effects were observed at lower but not higher levels of lead exposure. The novel odor detection task is sensitive to effects associated with early chronic low-level lead exposure in young C57BL/6J mice. PMID:25936521

Neurobehavioral effects of combined prenatal exposure to low-level mercury vapor and methylmercury.

PubMed

Yoshida, Minoru; Suzuki, Megumi; Satoh, Masahiko; Yasutake, Akira; Watanabe, Chiho

2011-01-01

We evaluated the effects of prenatal exposure to low-level mercury (Hg(0)) or methylmercury (MeHg) as well as combined exposure (Hg(0) + MeHg exposure) on the neurobehavioral function of mice. The Hg(0) exposure group was exposed to Hg(0) at a mean concentration of 0.030 mg/m(3) for 6 hr/day during gestation period. The MeHg exposure was supplied with food containing 5 ppm of MeHg from gestational day 1 to postnatal day 10. The combined exposure group was exposed to both Hg(0) vapor and MeHg according to above described procedure. After delivery, when their offspring reached the age of 8 weeks, behavioral analysis was performed. Open field (OPF) tests of the offspring showed an increase and decrease in voluntary activity in male and female mice, respectively, in the MeHg exposure group. In addition, the rate of central entries was significantly higher in this group than in the control group. The results of OPF tests in the Hg(0) + MeHg exposure group were similar to those in the MeHg exposure group in both males and females. The results in the Hg(0) exposure group did not significantly differ from those in the control group in males or females. Passive avoidance response (PA) tests revealed no significant differences in avoidance latency in the retention trial between the Hg(0), MeHg, or Hg(0) + MeHg exposure group and the control group in males or females. Morris water maze tests showed a delay in the latency to reach the platform in the MeHg and Hg(0) + MeHg exposure groups compared with the control group in males but no significant differences between the Hg(0), MeHg, or Hg(0) + MeHg exposure group and the control group in females. The results of OPF tests revealed only slight effects of prenatal low-level Hg(0) exposure (0.03 mg/m(3)), close to the no-observable-effect level (NOEL) stated by the WHO (0.025 mg/m(3)), on the subsequent neurobehavioral function. However, prenatal exposure to 5 ppm of MeHg affected exploratory activity in the OPF test, and, in

A Behavioral Intervention to Reduce Child Exposure to Indoor Air Pollution: Identifying Possible Target Behaviors

ERIC Educational Resources Information Center

Barnes, Brendon R.; Mathee, Angela; Shafritz, Lonna B.; Krieger, Laurie; Zimicki, Susan

2004-01-01

Indoor air pollution has been causally linked to acute lower respiratory infections in children younger than 5. The aim of this study was to identify target behaviors for a behavioral intervention to reduce child exposure to indoor air pollution by attempting to answer two research questions: Which behaviors are protective of child respiratory…

Epigenetic marker (LINE-1 promoter) methylation level was associated with occupational lead exposure.

PubMed

Li, Chunping; Yang, Xiaolin; Xu, Ming; Zhang, Jinlong; Sun, Na

2013-05-01

Occupational and environmental exposures to lead (Pb) are a worldwide concern. DNA methylation plays an important role in the development of Pb toxicity. Here, we try to find out the evidence to prove that the methylation of the LINE-1 promoter may be involved in Pb toxicity. To determine whether the methylation level of the LINE-1 is associated with the risk of Pb poisoning, we first constructed a Pb acetate-treated cell model to detect the association between LINE-1 methylation and Pb exposure. A case-control study involving 53 workers from a battery plant and 57 healthy volunteers with matching age and gender distribution was carried out. We employed methylation-specific real-time PCR to determine the relationship between LINE-1 methylation level and Pb exposure. In the cell model, Pb exposure significantly decreased the level of LINE-1 methylation (p = 0.009). Significant difference in methylation frequencies was found between the exposed and control samples (p < 0.001). We also found a decreasing trend of LINE-1 methylation level with increasing blood Pb level (p < 0.001). Therefore, the LINE-1 promoter methylation might contribute to the risk of Pb poisoning and identified a possible epigenetic biomarker for Pb toxicity, especially in individuals occupationally exposed to Pb.

76 FR 12942 - Proposed Information Collection; Comment Request; Defining Target Levels for Ecosystem Components...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-09

... Collection; Comment Request; Defining Target Levels for Ecosystem Components: A Socio-Ecological Approach... numerous species, and a mean level of species placement within a predator/prey chain or food web can serve...-based Management, when target levels for indicators exist. Because targets are an expression of the...

Prediction of Exposure Level of Energetic Solar Particle Events

NASA Astrophysics Data System (ADS)

Kim, M. H. Y.; Blattnig, S.

2016-12-01

The potential for exposure to large solar particle events (SPEs) with fluxes that extend to high energies is a major concern during interplanetary transfer and extravehicular activities (EVAs) on the lunar and Martian surfaces. Prediction of sporadic occurrence of SPEs is not accurate for near or long-term scales, while the expected frequency of such events is strongly influenced by solar cycle activity. In the development of NASA's operational strategies real-time estimation of exposure to SPEs has been considered so that adequate responses can be applied in a timely manner to reduce exposures to well below the exposure limits. Previously, the organ doses of large historical SPEs had been calculated by using the complete energy spectra of each event and then developing a prediction model for blood-forming organ (BFO) dose based solely on an assumed value of integrated fluence above 30 MeV (Φ30) for an otherwise unspecified future SPE. While BFO dose is determined primarily by solar protons with high energies, it was reasoned that more accurate BFO dose prediction models could be developed using integrated fluence above 60 MeV (Φ60) and above 100 MeV (Φ100) as predictors instead of Φ30. In the current study, re-analysis of major SPEs (in which the proton spectra of the ground level enhancement [GLE] events since 1956 are correctly described by Band functions) has been used in evaluation of exposure levels. More accurate prediction models for BFO dose and NASA effective dose are then developed using integrated fluence above 200 MeV (Φ200), which by far have the most weight in the calculation of doses for deep-seated organs from exposure to extreme SPEs (GLEs or sub-GLEs). The unconditional probability of a BFO dose exceeding a pre-specified BFO dose limit is simultaneously calculated by taking into account the distribution of the predictor (Φ30, Φ60, Φ100, or Φ200) as estimated from historical SPEs. These results can be applied to the development of

Assessing multimedia/multipathway exposures to inorganic arsenic at population and individual level using MERLIN-Expo.

PubMed

Van Holderbeke, Mirja; Fierens, Tine; Standaert, Arnout; Cornelis, Christa; Brochot, Céline; Ciffroy, Philippe; Johansson, Erik; Bierkens, Johan

2016-10-15

In this study, we report on model simulations performed using the newly developed exposure tool, MERLIN-Expo, in order to assess inorganic arsenic (iAs) exposure to adults resulting from past emissions by non-ferrous smelters in Belgium (Northern Campine area). Exposure scenarios were constructed to estimate external iAs exposure as well as the toxicologically relevant As (tAs, i.e., iAs, MMA and DMA) body burden in adults living in the vicinity of the former industrial sites as compared to adults living in adjacent areas and a reference area. Two scenarios are discussed: a first scenario studying exposure to iAs at the aggregated population level and a second scenario studying exposure at the individual level for a random sub-sample of subjects in each of the three different study areas. These two scenarios only differ in the type of human related input data (i.e., time-activity data, ingestion rates and consumption patterns) that were used, namely averages (incl. probability density functions, PDFs) in the simulation at population level and subject-specific values in the simulation at individual level. The model predictions are shown to be lower than the corresponding biomonitoring data from the monitoring campaign. Urinary tAs levels in adults, irrespective of the area they lived in, were under-predicted by MERLIN-Expo by 40% on average. The model predictions for individual adults, by contrast, under-predict the biomonitoring data by 7% on average, but with more important under-predictions for subjects at the upper end of exposure. Still, average predicted urinary tAs levels from the simulations at population level and at individual level overlap, and, at least for the current case, lead to similar conclusions. These results constitute a first and partial verification of the model performance of MERLIN-Expo when dealing with iAs in a complex site-specific exposure scenario, and demonstrate the robustness of the modelling tool for these situations. Copyright �

LOW-LEVEL CARBON MONOXIDE EXPOSURE AND WORK CAPACITY AT 1600 METERS

EPA Science Inventory

At sea level, low-level carbon monoxide (CO) exposure impairs exercise performance. To determine if altitude residence at 1600 m augments this CO effect, two studies of graded treadmill work capacity were done. The Initial Study investigated nine, non-smoking male subjects breath...

Lifetime Exposure to Intimate Partner Violence and Proinflammatory Cytokine Levels Across the Perinatal Period.

PubMed

Robertson Blackmore, Emma; Mittal, Mona; Cai, Xueya; Moynihan, Jan A; Matthieu, Monica M; O'Connor, Thomas G

2016-10-01

Intimate partner violence (IPV) is a public health concern, affecting one-third of US women. Prior research suggests an association between exposure to IPV and poor maternal perinatal health, but the underlying biological correlates are not well understood. This study examined the relationship between exposure to IPV and proinflammatory cytokine levels, a candidate mechanism accounting for poor psychiatric and obstetric outcomes, across the perinatal period. Data were obtained from a prospective, longitudinal cohort study of 171 women receiving obstetrical care from a hospital-based practice serving a predominantly low-income minority population. Participants completed questionnaires on IPV exposure, psychiatric symptoms, and psychosocial and obstetric factors and provided blood samples at 18 and 32 weeks of gestation and 6 weeks and 6 months postpartum. Serum levels of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) were assayed via enzyme-linked immunosorbent assay. Thirty-five (20.5%) women reported lifetime exposure to IPV and 7 (4.1%) reported being physically hurt in the preceding 12 months (4 while pregnant). Lifetime exposure to IPV was associated with increased likelihood of experiencing perinatal depression and smoking during pregnancy. Women with a history of IPV had significantly higher levels of TNF-α at 18 weeks (z = -2.29, p < 0.05), but significantly smaller changes in levels of IL-6 (β = -0.36, p = 0.04) across time. Lifetime exposure to IPV was associated with a range of adverse mental health outcomes and may affect proinflammatory cytokine levels in pregnancy.

Investigations of internal noise levels for different target sizes, contrasts, and noise structures

NASA Astrophysics Data System (ADS)

Han, Minah; Choi, Shinkook; Baek, Jongduk

2014-03-01

To describe internal noise levels for different target sizes, contrasts, and noise structures, Gaussian targets with four different sizes (i.e., standard deviation of 2,4,6 and 8) and three different noise structures(i.e., white, low-pass, and highpass) were generated. The generated noise images were scaled to have standard deviation of 0.15. For each noise type, target contrasts were adjusted to have the same detectability based on NPW, and the detectability of CHO was calculated accordingly. For human observer study, 3 trained observers performed 2AFC detection tasks, and correction rate, Pc, was calculated for each task. By adding proper internal noise level to numerical observer (i.e., NPW and CHO), detectability of human observer was matched with that of numerical observers. Even though target contrasts were adjusted to have the same detectability of NPW observer, detectability of human observer decreases as the target size increases. The internal noise level varies for different target sizes, contrasts, and noise structures, demonstrating different internal noise levels should be considered in numerical observer to predict the detection performance of human observer.

Olfactory recognition memory is disrupted in young mice with chronic low-level lead exposure.

PubMed

Flores-Montoya, Mayra Gisel; Alvarez, Juan Manuel; Sobin, Christina

2015-07-02

Chronic developmental lead exposure yielding very low blood lead burden is an unresolved child public health problem. Few studies have attempted to model neurobehavioral changes in young animals following very low level exposure, and studies are needed to identify tests that are sensitive to the neurobehavioral changes that may occur. Mechanisms of action are not yet known however results have suggested that hippocampus/dentate gyrus may be uniquely vulnerable to early chronic low-level lead exposure. This study examined the sensitivity of a novel odor recognition task to differences in pre-adolescent C57BL/6J mice chronically exposed from birth to PND 28, to 0 ppm (control), 30 ppm (low-dose), or 330 ppm (higher-dose) lead acetate (N=33). Blood lead levels (BLLs) determined by ICP-MS ranged from 0.02 to 20.31 μg/dL. Generalized linear mixed model analyses with litter as a random effect showed a significant interaction of BLL×sex. As BLLs increased olfactory recognition memory decreased in males. Among females, non-linear effects were observed at lower but not higher levels of lead exposure. The novel odor detection task is sensitive to effects associated with early chronic low-level lead exposure in young C57BL/6J mice. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Exposure to meat-derived carcinogens and bulky DNA adduct levels in normal-appearing colon mucosa.

PubMed

Ho, Vikki; Brunetti, Vanessa; Peacock, Sarah; Massey, Thomas E; Godschalk, Roger W L; van Schooten, Frederik J; Ashbury, Janet E; Vanner, Stephen J; King, Will D

2017-09-01

Meat consumption is a risk factor for colorectal cancer. This research investigated the relationship between meat-derived carcinogen exposure and bulky DNA adduct levels, a biomarker of DNA damage, in colon mucosa. Least squares regression was used to examine the relationship between meat-derived carcinogen exposure (PhIP and meat mutagenicity) and bulky DNA adduct levels in normal-appearing colon tissue measured using 32 P-postlabelling among 202 patients undergoing a screening colonoscopy. Gene-diet interactions between carcinogen exposure and genetic factors relevant to biotransformation and DNA repair were also examined. Genotyping was conducting using the MassARRAY ® iPLEX ® Gold SNP Genotyping assay. PhIP and higher meat mutagenicity exposures were not associated with levels of bulky DNA adducts in colon mucosa. The XPC polymorphism (rs2228001) was found to associate with bulky DNA adduct levels, whereby genotypes conferring lower DNA repair activity were associated with higher DNA adduct levels than the normal activity genotype. Among individuals with genotypes associated with lower DNA repair (XPD, rs13181 and rs1799179) or detoxification activity (GSTP1, rs1695), higher PhIP or meat mutagenicity exposures were associated with higher DNA adduct levels. Significant interactions between the XPC polymorphism (rs2228000) and both dietary PhIP and meat mutagenicity on DNA adduct levels was observed, but associations were inconsistent with the a priori hypothesized direction of effect. Exposure to meat-derived carcinogens may be associated with increased DNA damage occurring directly in the colon among genetically susceptible individuals. Copyright © 2017 Elsevier B.V. All rights reserved.

Joint sparsity based heterogeneous data-level fusion for target detection and estimation

NASA Astrophysics Data System (ADS)

Niu, Ruixin; Zulch, Peter; Distasio, Marcello; Blasch, Erik; Shen, Dan; Chen, Genshe

2017-05-01

Typical surveillance systems employ decision- or feature-level fusion approaches to integrate heterogeneous sensor data, which are sub-optimal and incur information loss. In this paper, we investigate data-level heterogeneous sensor fusion. Since the sensors monitor the common targets of interest, whose states can be determined by only a few parameters, it is reasonable to assume that the measurement domain has a low intrinsic dimensionality. For heterogeneous sensor data, we develop a joint-sparse data-level fusion (JSDLF) approach based on the emerging joint sparse signal recovery techniques by discretizing the target state space. This approach is applied to fuse signals from multiple distributed radio frequency (RF) signal sensors and a video camera for joint target detection and state estimation. The JSDLF approach is data-driven and requires minimum prior information, since there is no need to know the time-varying RF signal amplitudes, or the image intensity of the targets. It can handle non-linearity in the sensor data due to state space discretization and the use of frequency/pixel selection matrices. Furthermore, for a multi-target case with J targets, the JSDLF approach only requires discretization in a single-target state space, instead of discretization in a J-target state space, as in the case of the generalized likelihood ratio test (GLRT) or the maximum likelihood estimator (MLE). Numerical examples are provided to demonstrate that the proposed JSDLF approach achieves excellent performance with near real-time accurate target position and velocity estimates.

The relationship between the level of exposure to stress factors and cannabis in recent onset psychosis.

PubMed

Arranz, Sara; Monferrer, Nuria; Jose Algora, M; Cabezas, Angel; Sole, Montse; Vilella, E; Labad, J; Sanchez-Gistau, Vanessa

2018-05-06

There is a lack of studies investigating the dose-response effect of childhood trauma, recent events and cannabis use on recent psychosis. This study aims to determine the relationship between the level of exposure to stress factors and cannabis use with psychosis and to determine the combination effect among these factors in predicting a psychotic disorder. 146 recent onset psychotic (ROP) patients and 61 healthy controls were included. Childhood trauma was evaluated using the childhood trauma questionnaire (CTQ) and recent events using the Holmes-Rahe social readjustment scale. The pattern of cannabis use was assessed by a detailed interview. A hierarchical multiple regression was run in order to determine both the cumulative and independent contribution of each factor in predicting a psychotic disorder. The highest levels of exposure to childhood trauma and cannabis were associated with psychosis while neither low nor high recent event exposure was associated. The combined effect of risk factors yielded a significant association with psychosis (× 2  = 86.76, p < .001) explaining the 49% of its variation. ROP were more likely to be exposed to one, two or three environmental factors than HC. Exposed to two or all factors were 7.5-fold and 26.7-fold more likely to have a diagnosis of psychosis, respectively. Our study provides evidence for a cumulative and a dose-response effect of environmental factors on recent psychosis. Considering that cannabis use and stress are highly prevalent in the population with psychosis, investigations of their relationships are needed to implement targeted prevention and treatment strategies. Copyright © 2018 Elsevier B.V. All rights reserved.

Affective and behavioral changes following exposure to traumatic events: the moderating effect of religiosity on avoidance behavior among students studying under a high level of terror event exposure.

PubMed

Korn, Liat; Zukerman, Gil

2011-12-01

The goals of this study were to examine the development of affective and behavioral changes following exposure to traumatic events among Israeli students studying under a high level of terror event exposure and to assess the effects of religiosity on those changes development. A questionnaire was administered to 770 students in the Ariel University Center in Judea and Samaria. Higher levels of terror exposure were associated with higher levels of avoidance behavior, subjective feelings of insecurity, and emotional distress. Higher religiosity moderated avoidance behavior, even when controlling for the level of objective exposure to terror events exposure, but had no influence on subjective sense of insecurity, or the level of emotional distress. These findings suggest that religiosity moderates behavioral changes development after traumatic event exposure mainly by reducing avoidance behavior.

28 CFR 79.44 - Proof of working level month exposure to radiation.

Code of Federal Regulations, 2014 CFR

2014-07-01

... radiation. 79.44 Section 79.44 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) CLAIMS UNDER THE RADIATION EXPOSURE COMPENSATION ACT Eligibility Criteria for Claims by Uranium Miners § 79.44 Proof of working level month exposure to radiation. (a) If one or more of the sources in § 79.43(a) contain a...

Chronic exposure to environmental levels of tribromophenol impairs zebrafish reproduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deng Jun; Graduate School of the Chinese Academy of Sciences, Beijing 100039; Liu Chunsheng

Tribromophenol (2,4,6-TBP) is ubiquitously found in aquatic environments and biota. In this study, we exposed zebrafish embryos (F{sub 0}; 2'''' days post-fertilization, dpf) to environmental concentration (0.3 mug/L) and a higher concentration (3.0 mug/L) of TBP and assessed the impact of chronic exposure (120 dpf) on reproduction. TBP exposure did not cause a significant increase in the malformation and reduction in the survival in the F{sub 0}-generation fish. After TBP exposure, the plasma testosterone and estradiol levels significantly increased in males and decreased in females. The transcription of steroidogenic genes (3beta-HSD, 17beta-HSD, CYP17, CYP19A, CYP19B) was significantly upregulated in themore » brain and testes in males and downregulated in the brain and ovary in females. TBP exposure significantly downregulated and upregulated the expression of VTG in the liver of female and male fish, respectively. Meanwhile, TBP exposure altered the sex ratio toward a male-dominant state. The F{sub 1}-generation larvae exhibited increased malformation, reduced survival, and retarded growth, suggesting that TBP in the aquatic environment has significant adverse effects on fish population.« less

Human amygdala engagement moderated by early life stress exposure is a biobehavioral target for predicting recovery on antidepressants.

PubMed

Goldstein-Piekarski, Andrea N; Korgaonkar, Mayuresh S; Green, Erin; Suppes, Trisha; Schatzberg, Alan F; Hastie, Trevor; Nemeroff, Charles B; Williams, Leanne M

2016-10-18

Amygdala circuitry and early life stress (ELS) are both strongly and independently implicated in the neurobiology of depression. Importantly, animal models have revealed that the contribution of ELS to the development and maintenance of depression is likely a consequence of structural and physiological changes in amygdala circuitry in response to stress hormones. Despite these mechanistic foundations, amygdala engagement and ELS have not been investigated as biobehavioral targets for predicting functional remission in translational human studies of depression. Addressing this question, we integrated human neuroimaging and measurement of ELS within a controlled trial of antidepressant outcomes. Here we demonstrate that the interaction between amygdala activation engaged by emotional stimuli and ELS predicts functional remission on antidepressants with a greater than 80% cross-validated accuracy. Our model suggests that in depressed people with high ELS, the likelihood of remission is highest with greater amygdala reactivity to socially rewarding stimuli, whereas for those with low-ELS exposure, remission is associated with lower amygdala reactivity to both rewarding and threat-related stimuli. This full model predicted functional remission over and above the contribution of demographics, symptom severity, ELS, and amygdala reactivity alone. These findings identify a human target for elucidating the mechanisms of antidepressant functional remission and offer a target for developing novel therapeutics. The results also offer a proof-of-concept for using neuroimaging as a target for guiding neuroscience-informed intervention decisions at the level of the individual person.

Improved inhalation technology for setting safe exposure levels for workplace chemicals

NASA Technical Reports Server (NTRS)

Stuart, Bruce O.

1993-01-01

Threshold Limit Values recommended as allowable air concentrations of a chemical in the workplace are often based upon a no-observable-effect-level (NOEL) determined by experimental inhalation studies using rodents. A 'safe level' for human exposure must then be estimated by the use of generalized safety factors in attempts to extrapolate from experimental rodents to man. The recent development of chemical-specific physiologically-based toxicokinetics makes use of measured physiological, biochemical, and metabolic parameters to construct a validated model that is able to 'scale-up' rodent response data to predict the behavior of the chemical in man. This procedure is made possible by recent advances in personal computer software and the emergence of appropriate biological data, and provides an analytical tool for much more reliable risk evaluation and airborne chemical exposure level setting for humans.

Does methodology matter in eyewitness identification research? The effect of live versus video exposure on eyewitness identification accuracy.

PubMed

Pozzulo, Joanna D; Crescini, Charmagne; Panton, Tasha

2008-01-01

The present study examined the effect of mode of target exposure (live versus video) on eyewitness identification accuracy. Adult participants (N=104) were exposed to a staged crime that they witnessed either live or on videotape. Participants were then asked to rate their stress and arousal levels prior to being presented with either a target-present or -absent simultaneous lineup. Across target-present and -absent lineups, mode of target exposure did not have a significant effect on identification accuracy. However, mode of target exposure was found to have a significant effect on stress and arousal levels. Participants who witnessed the crime live had higher levels of stress and arousal than those who were exposed to the videotaped crime. A higher level of arousal was significantly related to poorer identification accuracy for those in the video condition. For participants in the live condition however, stress and arousal had no effect on eyewitness identification accuracy. Implications of these findings in regards to the generalizability of laboratory-based research on eyewitness testimony to real-life crime are discussed.

Perinatal alcohol exposure enhances nocistatin levels in adulthood.

PubMed

Tekes, Kornélia; Hantos, Mónika; Gyenge, Melinda; Csaba, Gyorgy

2007-06-01

In earlier experiments perinatal hormonal imprinting by alcohol decreased the hormone content of immune cells for life. In the present study, both a single day (15% on the third postnatal day) and a long-term treatment schedule of alcohol exposure (3% for 21 days) of dams during lactation significantly (P < 0.01) enhanced endogenous levels of nocistatin in the blood plasma as well as in the cerebrospinal fluid of the offspring, measured in 3-month-old rats. Our data suggest that alcohol consumption during lactation can cause a life-long influence on nocistatin levels in the offspring and most likely modify nocistatin-related functions such as pain tolerance.

Mechanisms Underlying Endothelin-1 Level Elevations Caused by Excessive Fluoride Exposure.

PubMed

Sun, Liyan; Gao, Yanhui; Zhang, Wei; Liu, Xiaona; Li, Bingyun; Cui, Xiaohui; Sun, Dianjun

2016-01-01

To explore the mechanisms underlying endothelin-1 (ET-1) elevations induced by excessive fluoride exposure. We measured serum and bone fluoride ion content and plasma ET-1 levels and compared these parameters among different groups in an animal model. We also observed morphological changes in the aorta and endothelium of rabbits. In cell experiments, human umbilical vein endothelial cells (HUVECs) were treated with varying concentrations of NaF for 24h, with or without 10 µM U0126 pretreatment for 1 h. ET-1 levels in culture fluid and intracellular reactive oxygen species (ROS) levels, as well as ET1 gene, endothelin-converting enzyme-1 (ECE-1), extracellular signal-regulating kinase 1/2 (ERK1/2), pERK1/2 expression levels and RAS activation were measured and compared among the groups. Plasma ET-1 levels of rabbits increased significantly in fluorinated groups compared with those in the control group. The rabbit thoracic aortas became slightly hardened in fluorinated groups compared with those in the control group, and some vacuoles were present in the endothelial cell cytoplasm of the rabbits in fluorinated groups. In our cell experiments, ET1 gene and ECE-1 expression levels in HUVECs and ET-1 expression levels in the cell culture supernatants increased significantly in some experimental groups compared with those in the control group. These trends paralleled the changes in intracellular ROS levels, RAS activation, and the pERK1/2-to-ERK1/2 ratio. After U0126 was added, ECE-1 expression and ET-1 levels decreased significantly. Excessive fluoride exposure leads to characteristic endothelial damage (vacuoles), thoracic aorta hardening, and plasma ET-1 level elevations in rabbits. In addition, the ROS-RAS-MEK1/2-pERK1/2/ERK1/2 pathway plays a crucial-and at least partial-role in ET-1 over-expression, which is promoted by excessive fluoride exposure. © 2016 The Author(s) Published by S. Karger AG, Basel.

Lifetime Exposure to Intimate Partner Violence and Proinflammatory Cytokine Levels Across the Perinatal Period

PubMed Central

Mittal, Mona; Cai, Xueya; Moynihan, Jan A.; Matthieu, Monica M.; O'Connor, Thomas G.

2016-01-01

Abstract Background: Intimate partner violence (IPV) is a public health concern, affecting one-third of US women. Prior research suggests an association between exposure to IPV and poor maternal perinatal health, but the underlying biological correlates are not well understood. This study examined the relationship between exposure to IPV and proinflammatory cytokine levels, a candidate mechanism accounting for poor psychiatric and obstetric outcomes, across the perinatal period. Materials and Methods: Data were obtained from a prospective, longitudinal cohort study of 171 women receiving obstetrical care from a hospital-based practice serving a predominantly low-income minority population. Participants completed questionnaires on IPV exposure, psychiatric symptoms, and psychosocial and obstetric factors and provided blood samples at 18 and 32 weeks of gestation and 6 weeks and 6 months postpartum. Serum levels of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) were assayed via enzyme-linked immunosorbent assay. Results: Thirty-five (20.5%) women reported lifetime exposure to IPV and 7 (4.1%) reported being physically hurt in the preceding 12 months (4 while pregnant). Lifetime exposure to IPV was associated with increased likelihood of experiencing perinatal depression and smoking during pregnancy. Women with a history of IPV had significantly higher levels of TNF-α at 18 weeks (z = −2.29, p < 0.05), but significantly smaller changes in levels of IL-6 (β = −0.36, p = 0.04) across time. Conclusion: Lifetime exposure to IPV was associated with a range of adverse mental health outcomes and may affect proinflammatory cytokine levels in pregnancy. PMID:26744816

Reasons for testing and exposure sources among women of childbearing age with moderate blood lead levels.

PubMed

Fletcher, A M; Gelberg, K H; Marshall, E G

1999-06-01

The purpose of this study was to examine the circumstances under which women receive blood lead tests in New York State and to characterize the sources of lead exposure among women of childbearing age with moderate blood lead levels. Telephone interviews were conducted with 135 women between the ages of 18 and 45, with blood lead levels from 10 through 25 micrograms/dl, were used to collect information on the reason for their blood lead test and possible sources of lead exposure. It was found that the two most common reasons to be tested for blood lead were workplace screening (47%) and pregnancy (27%). Occupational exposure was the primary source of lead exposure in this population (46%). Another common source of lead exposure was home renovation (24%). A significant proportion (31%) of women with blood lead levels from 10 through 25 micrograms/dl had no known current source of lead exposure. Based on New York's sample, there are a significant number of women of reproductive age with potentially fetotoxic blood lead levels.

Chronic exposure to low frequency noise at moderate levels causes impaired balance in mice.

PubMed

Tamura, Haruka; Ohgami, Nobutaka; Yajima, Ichiro; Iida, Machiko; Ohgami, Kyoko; Fujii, Noriko; Itabe, Hiroyuki; Kusudo, Tastuya; Yamashita, Hitoshi; Kato, Masashi

2012-01-01

We are routinely exposed to low frequency noise (LFN; below 0.5 kHz) at moderate levels of 60-70 dB sound pressure level (SPL) generated from various sources in occupational and daily environments. LFN has been reported to affect balance in humans. However, there is limited information about the influence of chronic exposure to LFN at moderate levels for balance. In this study, we investigated whether chronic exposure to LFN at a moderate level of 70 dB SPL affects the vestibule, which is one of the organs responsible for balance in mice. Wild-type ICR mice were exposed for 1 month to LFN (0.1 kHz) and high frequency noise (HFN; 16 kHz) at 70 dB SPL at a distance of approximately 10-20 cm. Behavior analyses including rotarod, beam-crossing and footprint analyses showed impairments of balance in LFN-exposed mice but not in non-exposed mice or HFN-exposed mice. Immunohistochemical analysis showed a decreased number of vestibular hair cells and increased levels of oxidative stress in LFN-exposed mice compared to those in non-exposed mice. Our results suggest that chronic exposure to LFN at moderate levels causes impaired balance involving morphological impairments of the vestibule with enhanced levels of oxidative stress. Thus, the results of this study indicate the importance of considering the risk of chronic exposure to LFN at a moderate level for imbalance.

Chronic Exposure to Low Frequency Noise at Moderate Levels Causes Impaired Balance in Mice

PubMed Central

Tamura, Haruka; Ohgami, Nobutaka; Yajima, Ichiro; Iida, Machiko; Ohgami, Kyoko; Fujii, Noriko; Itabe, Hiroyuki; Kusudo, Tastuya; Yamashita, Hitoshi; Kato, Masashi

2012-01-01

We are routinely exposed to low frequency noise (LFN; below 0.5 kHz) at moderate levels of 60–70 dB sound pressure level (SPL) generated from various sources in occupational and daily environments. LFN has been reported to affect balance in humans. However, there is limited information about the influence of chronic exposure to LFN at moderate levels for balance. In this study, we investigated whether chronic exposure to LFN at a moderate level of 70 dB SPL affects the vestibule, which is one of the organs responsible for balance in mice. Wild-type ICR mice were exposed for 1 month to LFN (0.1 kHz) and high frequency noise (HFN; 16 kHz) at 70 dB SPL at a distance of approximately 10–20 cm. Behavior analyses including rotarod, beam-crossing and footprint analyses showed impairments of balance in LFN-exposed mice but not in non-exposed mice or HFN-exposed mice. Immunohistochemical analysis showed a decreased number of vestibular hair cells and increased levels of oxidative stress in LFN-exposed mice compared to those in non-exposed mice. Our results suggest that chronic exposure to LFN at moderate levels causes impaired balance involving morphological impairments of the vestibule with enhanced levels of oxidative stress. Thus, the results of this study indicate the importance of considering the risk of chronic exposure to LFN at a moderate level for imbalance. PMID:22768129

Exposure to pyrethroids insecticides and serum levels of thyroid-related measures in pregnant women

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Jie; Hisada, Aya; Yoshinaga, Jun, E-mail: junyosh@k.u-tokyo.ac.jp

Possible association between environmental exposure to pyrethroid insecticides and serum thyroid-related measures was explored in 231 pregnant women of 10–12 gestational weeks recruited at a university hospital in Tokyo during 2009–2011. Serum levels of free thyroxine (fT4), thyroid stimulating hormone (TSH) and thyroid biding globulin (TBG) and urinary pyrethroid insecticide metabolite (3-phenoxybenzoic acid, 3-PBA) were measured. Obstetrical information was obtained from medical records and dietary and lifestyle information was collected by self-administered questionnaire. Geometric mean concentration of creatinine-adjusted urinary 3-PBA was 0.363 (geometric standard deviation: 3.06) μg/g cre, which was consistent with the previously reported levels for non-exposed Japanese adultmore » females. The range of serum fT4, TSH and TBG level was 0.83–3.41 ng/dL, 0.01–27.4 μIU/mL and 16.4–54.4 μg/mL, respectively. Multiple regression analysis was carried out by using either one of serum levels of thyroid-related measures as a dependent variable and urinary 3-PBA as well as other potential covariates (age, pre-pregnancy BMI, parity, urinary iodine, smoking and drinking status) as independent variables: 3-PBA was not found as a significant predictor of serum level of thyroid-related measures. Lack of association may be due to lower pyrethroid insecticide exposure level of the present subjects. Taking the ability of pyrethroid insecticides and their metabolite to bind to nuclear thyroid hormone (TH) receptor, as well as their ability of placental transfer, into consideration, it is warranted to investigate if pyrethroid pesticides do not have any effect on TH actions in fetus brain even though maternal circulating TH level is not affected. -- Highlights: • Pyrethroid exposure and thyroid hormone status was examined in pregnant women. • Urinary 3-phenoxybenzoic acid was used as a biomarker of exposure. • Iodine nutrition, age and other covariates were

Exposure of Female Rats to an Environmentally Relevant Mixture of Brominated Flame Retardants Targets the Ovary, Affecting Folliculogenesis and Steroidogenesis1

PubMed Central

Lefèvre, Pavine L.C.; Berger, Robert G.; Ernest, Sheila R.; Gaertner, Dean W.; Rawn, Dorothea F.K.; Wade, Michael G.; Robaire, Bernard; Hales, Barbara F.

2015-01-01

Brominated flame retardants (BFRs) are incorporated into various consumer products to prevent flame propagation. These compounds leach into the domestic environment, resulting in chronic exposure and contamination. Pregnancy failure is associated with high levels of BFRs in human follicular fluid, raising serious questions regarding their impact on female reproductive health. The goal of this study is to elucidate the effects of an environmentally relevant BFR mixture on female rat ovarian functions (i.e., folliculogenesis and steroidogenesis). A BFR dietary mixture formulated to mimic the relative BFR congener levels in North American house dust was administered to adult female Sprague-Dawley rats from 2 to 3 wk before mating until Gestational Day 20; these diets were designed to deliver nominal doses of 0, 0.06, 20, or 60 mg/kg/day of the BFR mixture. Exposure to BFRs triggered an approximately 50% increase in the numbers of preantral and antral follicles and an enlargement of the antral follicles in the ovaries of the dams. A significant reduction in the expression of catalase, an antioxidant enzyme, and downregulation of the expression of insulin-like factor 3 (Insl3) and 17alpha-hydroxylase (Cyp17a1) were observed in the ovary. In addition, BFR exposure affected steroidogenesis; we observed a significant decrease in circulating 17-hydroxypregnenolone and an increase in testosterone concentrations in BFR-exposed dams. Thus, BFRs target ovarian function in the rat, adversely affecting both folliculogenesis and steroidogenesis. PMID:26607716

Associations between community-level disaster exposure and individual-level changes in disability and risk of death for older Americans

PubMed Central

Brilleman, Samuel L.; Wolfe, Rory; Moreno-Betancur, Margarita; Sales, Anne E.; Langa, Kenneth M.; Li, Yun; Daugherty Biddison, Elizabeth L.; Rubinson, Lewis; Iwashyna, Theodore J.

2016-01-01

Disasters occur frequently in the United States (US) and their impact on acute morbidity, mortality and short-term increased health needs has been well described. However, barring mental health, little is known about the medium or longer-term health impacts of disasters. This study sought to determine if there is an association between community-level disaster exposure and individual-level changes in disability and/or the risk of death for older Americans. Using the US Federal Emergency Management Agency’s database of disaster declarations, 602 disasters occurred between August 1998 and December 2010 and were characterized by their presence, intensity, duration and type. Repeated measurements of a disability score (based on activities of daily living) and dates of death were observed between January 2000 and November 2010 for 18,102 American individuals aged 50 to 89 years, who were participating in the national longitudinal Health and Retirement Study. Longitudinal (disability) and time-to-event (death) data were modelled simultaneously using a ‘joint modelling’ approach. There was no evidence of an association between community-level disaster exposure and individual-level changes in disability or the risk of death. Our results suggest that future research should focus on individual-level disaster exposures, moderate to severe disaster events, or higher-risk groups of individuals. PMID:27960126

High-level dietary cadmium exposure is associated with global DNA hypermethylation in the gastropod hepatopancreas

PubMed Central

Popescu, Cristina; Draghici, George A.; Andrica, Florina-Maria; Privistirescu, Ionela A.; Gergen, Iosif I.; Stöger, Reinhard

2017-01-01

5-methylcytosine (5mC) is a key epigenetic mark which influences gene expression and phenotype. In vertebrates, this epigenetic mark is sensitive to Cd exposure, but there is no information linking such an event with changes in global 5mC levels in terrestrial gastropods despite their importance as excellentecotoxicological bioindicators of metal contamination. Therefore, we first evaluated total 5mC content in DNA of the hepatopancreas of adult Cantareus aspersus with the aim to determine whether this epigenetic mark is responsive to Cd exposure. The experiment was conducted under laboratory conditions and involved a continuous exposure, multiple dose- and time-point (14, 28, and 56 days) study design. Hepatopancreas cadmium levels were measured using Flame Atomic Absorption Spectrometry and the percentage of 5-mC in samples using an ELISA-based colorimetric assay. Snail death rates were also assessed. Our results, for the first time, reveal the presence of 5mC in C. aspersus and provide evidence for Cd-induced changes in global 5mC levels in DNA of gastropods and mollusks. Although less sensitive than tissue accumulation, DNA methylation levels responded in a dose- and time-dependent manner to dietary cadmium, with exposure dose having a much stronger effect than exposure duration. An obvious trend of increasing 5mC levels was observed starting at 28 days of exposure to the second highest dose and this trend persisted at the two highest treatments for close to one month, when the experiment was terminated after 56 days. Moreover, a strong association was identified between Cd concentrations in the hepatopancreas and DNA methylation levels in this organ. These data indicate an overall trend towards DNA hypermethylation with elevated Cd exposure. No consistent lethal effect was observed, irrespective of time point and Cd-dosage. Overall, our findings suggest that the total 5mC content in DNA of the hepatopancreas of land snails is responsive to sublethal Cd

Association Between Arsenic Exposure From Drinking Water and Plasma Levels of Cardiovascular Markers

PubMed Central

Wu, Fen; Jasmine, Farzana; Kibriya, Muhammad G.; Liu, Mengling; Wójcik, Oktawia; Parvez, Faruque; Rahaman, Ronald; Roy, Shantanu; Paul-Brutus, Rachelle; Segers, Stephanie; Slavkovich, Vesna; Islam, Tariqul; Levy, Diane; Mey, Jacob L.; van Geen, Alexander; Graziano, Joseph H.; Ahsan, Habibul; Chen, Yu

2012-01-01

The authors conducted a cross-sectional study to assess the relation between arsenic exposure from drinking water and plasma levels of markers of systemic inflammation and endothelial dysfunction (matrix metalloproteinase-9, myeloperoxidase, plasminogen activator inhibitor-1, soluble E-selectin, soluble intercellular adhesion molecule-1 (ICAM-1), and soluble vascular adhesion molecule-1 (VCAM-1)) using baseline data from 668 participants (age, >30 years) in the Health Effects of Arsenic Longitudinal Study in Bangladesh (2007–2008). Both well water arsenic and urinary arsenic were positively associated with plasma levels of soluble VCAM-1. For every 1-unit increase in log-transformed well water arsenic (ln μg/L) and urinary arsenic (ln μg/g creatinine), plasma soluble VCAM-1 was 1.02 (95% confidence interval: 1.01, 1.03) and 1.04 (95% confidence interval: 1.01, 1.07) times greater, respectively. There was a significant interaction between arsenic exposure and higher body mass index, such that the increased levels of plasminogen activator inhibitor-1 and soluble VCAM-1 associated with arsenic exposure were stronger among people with higher body mass index. The findings indicate an effect of chronic arsenic exposure from drinking water on vascular inflammation and endothelial dysfunction that could be modified by body mass index and also suggest a potential mechanism underlying the association between arsenic exposure and cardiovascular disease. PMID:22534204

Association between arsenic exposure from drinking water and plasma levels of cardiovascular markers.

PubMed

Wu, Fen; Jasmine, Farzana; Kibriya, Muhammad G; Liu, Mengling; Wójcik, Oktawia; Parvez, Faruque; Rahaman, Ronald; Roy, Shantanu; Paul-Brutus, Rachelle; Segers, Stephanie; Slavkovich, Vesna; Islam, Tariqul; Levy, Diane; Mey, Jacob L; van Geen, Alexander; Graziano, Joseph H; Ahsan, Habibul; Chen, Yu

2012-06-15

The authors conducted a cross-sectional study to assess the relation between arsenic exposure from drinking water and plasma levels of markers of systemic inflammation and endothelial dysfunction (matrix metalloproteinase-9, myeloperoxidase, plasminogen activator inhibitor-1, soluble E-selectin, soluble intercellular adhesion molecule-1 (ICAM-1), and soluble vascular adhesion molecule-1 (VCAM-1)) using baseline data from 668 participants (age, >30 years) in the Health Effects of Arsenic Longitudinal Study in Bangladesh (2007-2008). Both well water arsenic and urinary arsenic were positively associated with plasma levels of soluble VCAM-1. For every 1-unit increase in log-transformed well water arsenic (ln μg/L) and urinary arsenic (ln μg/g creatinine), plasma soluble VCAM-1 was 1.02 (95% confidence interval: 1.01, 1.03) and 1.04 (95% confidence interval: 1.01, 1.07) times greater, respectively. There was a significant interaction between arsenic exposure and higher body mass index, such that the increased levels of plasminogen activator inhibitor-1 and soluble VCAM-1 associated with arsenic exposure were stronger among people with higher body mass index. The findings indicate an effect of chronic arsenic exposure from drinking water on vascular inflammation and endothelial dysfunction that could be modified by body mass index and also suggest a potential mechanism underlying the association between arsenic exposure and cardiovascular disease.

Exposure of Female Rats to an Environmentally Relevant Mixture of Brominated Flame Retardants Targets the Ovary, Affecting Folliculogenesis and Steroidogenesis.

PubMed

Lefèvre, Pavine L C; Berger, Robert G; Ernest, Sheila R; Gaertner, Dean W; Rawn, Dorothea F K; Wade, Michael G; Robaire, Bernard; Hales, Barbara F

2016-01-01

Brominated flame retardants (BFRs) are incorporated into various consumer products to prevent flame propagation. These compounds leach into the domestic environment, resulting in chronic exposure and contamination. Pregnancy failure is associated with high levels of BFRs in human follicular fluid, raising serious questions regarding their impact on female reproductive health. The goal of this study is to elucidate the effects of an environmentally relevant BFR mixture on female rat ovarian functions (i.e., folliculogenesis and steroidogenesis). A BFR dietary mixture formulated to mimic the relative BFR congener levels in North American house dust was administered to adult female Sprague-Dawley rats from 2 to 3 wk before mating until Gestational Day 20; these diets were designed to deliver nominal doses of 0, 0.06, 20, or 60 mg/kg/day of the BFR mixture. Exposure to BFRs triggered an approximately 50% increase in the numbers of preantral and antral follicles and an enlargement of the antral follicles in the ovaries of the dams. A significant reduction in the expression of catalase, an antioxidant enzyme, and downregulation of the expression of insulin-like factor 3 (Insl3) and 17alpha-hydroxylase (Cyp17a1) were observed in the ovary. In addition, BFR exposure affected steroidogenesis; we observed a significant decrease in circulating 17-hydroxypregnenolone and an increase in testosterone concentrations in BFR-exposed dams. Thus, BFRs target ovarian function in the rat, adversely affecting both folliculogenesis and steroidogenesis. © 2016 by the Society for the Study of Reproduction, Inc.

Physiological response of juvenile rainbow trout to chronic low level exposures of waterborne silver.

PubMed

Galvez, F; Hogstrand, C; Wood, C M

1998-02-01

The physiological effects of chronic exposure to AgNO3 in moderately hard freshwater were investigated in juvenile rainbow trout (Oncorhynchus mykiss Walbaum). Two separate 28-day exposures were performed at silver concentrations of 0.5 and 2.0 micrograms/L in flowing Hamilton dechlorinated tap water. Exposure to 0.5 microgram/L Ag resulted in a slight increase (approximately 14.9%) in food consumption, whereas growth rates remained unaltered. Both plasma Na+ and Cl- levels were significantly decreased by 11.8% and 9.3%, respectively at day 16 of the exposure. Hepatic Ag concentrations were elevated approximately 4-fold in 0.5 microgram/L Ag-exposed fish. However, no significant increases in liver metallothionein (MT) concentrations were noted. No mortalities were observed during this 28-day exposure. In comparison, chronic exposure to 2.0 micrograms/L Ag resulted in a 28.8% decrease in food consumption and a 43.0% reduction in growth rate. Plasma [Na+] was decreased by 18.3%, whereas plasma [Cl-] was reduced by 12.2% at day 7. At both concentrations of silver, plasma ion concentrations appeared to recover thereafter. Silver accumulated steadily in the liver up until day 15 when concentrations were 39.7 micrograms/g wet weight (285-fold increase) above control levels. In addition, MT levels were increased by 81.2% at day 7. Silver exposure at 2.0 micrograms/L resulted in approximately 15.0% mortality over the 28-day period.

Developing, implementing, and evaluating a condom promotion program targeting sexually active adolescents.

PubMed

Alstead, M; Campsmith, M; Halley, C S; Hartfield, K; Goldbaum, G; Wood, R W

1999-12-01

This article describes the development, implementation, and evaluation of the Condom Campaign, a 1995 HIV prevention program promoting condom use among sexually active adolescents in three King County, Washington, urban communities. This program employed three main strategies: (a) mobilizing all levels of the target communities to support and guide program development and implementation; (b) creating and implementing a mass media campaign targeting sexually active teenagers that promoted correct condom use and favorable attitudes toward condoms; and (c) recruiting public agencies, community organizations, and businesses to distribute condoms from bins and vending machines. We evaluated the program through a series of cross-sectional interviews conducted in the three communities chosen for their elevated levels of adolescent sexual risk behavior. Overall, 73% of target youth reported exposure to the Condom Campaign; exposure did not differ by age, gender, race, or level of sexual experience. Levels of sexual activity remained stable throughout the media campaign.

The levels of kerosene components in biological samples after repeated dermal exposure to kerosene in rats.

PubMed

Fujihara, Junko; Hieda, Yoko; Tsujino, Yoshio; Xue, Yuying; Takayama, Koji; Kimura, Kojiro; Dekio, Satoshi

2004-04-01

The current study was experimentally investigated using rats whether or not kerosene components are accumulated from daily repeated dermal exposure. Rats received daily 1h-exposure to kerosene for 5 days (5K), daily 1h-exposure for 4 days and left for 1 day (4KL), a single 1h-exposure (1K), a single 1h-exposure and left for 1 day (1KL), or a single 1h-exposure, sacrificed and left dead for 1 day (1KLD). Kerosene components, trimethylbenzenes (TMBs) and aliphatic hydrocarbons (AHCs) in blood and tissues were determined by GC-MS. In blood, almost the same concentrations of TMBs were detected in the rats sacrificed immediately after exposure (5K, 1K and 1KLD), and only trace levels were detected in the rats sacrificed 1 day after exposure (4 and 1KL). Almost the same levels of AHCs in blood were detected among groups except for the rats sacrificed 1 day after a single exposure (1KL), in which AHCs were slightly lower. These results suggest that (1) AHCs tend to be accumulated from daily exposure, while TMBs do not, (2) the proportions of detected kerosene components in blood can be an indicator of whether the last exposure occurred just before death or not, (3) the kerosene levels last at least 1 day without blood circulation.

Should there be a target level of docosahexaenoic acid in breast milk?

PubMed

Jackson, Kristina Harris; Harris, William S

2016-03-01

This article examines the evidence for and against establishing a target level of docosahexaenoic acid (DHA) in breast milk. Two target levels for milk DHA have been recently proposed. One (∼0.3% of milk fatty acids) was based on milk DHA levels achieved in women consuming the amount of DHA recommended by the American Academy of Pediatrics for pregnant and lactating women (at least 200 mg DHA/day). Another (∼1.0%) was based on biomarker studies of populations with differing lifelong intakes of fish. Populations or research cohorts with milk DHA levels of 1.0% are associated with intakes that allow both the mother and infant to maintain relatively high DHA levels throughout lactation. Lower milk DHA levels may signal suboptimal maternal stores and possibly suboptimal infant intakes. Based on the current data, a reasonable milk DHA target appears to be approximately 0.3%, which is about the worldwide average. Although this may not be the 'optimal' level (which remains to be defined), it is clearly an improvement over the currently low milk DHA levels (∼0.2%) seen in many Western populations.

Rat lung metallothionein and heme oxygenase gene expression following ozone and zinc oxide exposure.

PubMed

Cosma, G; Fulton, H; DeFeo, T; Gordon, T

1992-11-01

We have conducted exposures in rats to determine pulmonary responses following inhalation of two common components of welding fumes, zinc oxide and ozone. To examine their effects on target-inducible gene expression, we measured mRNA levels of two metal-responsive genes, metallothionein (MT) and heme oxygenase (HO), in lung tissue by RNA slot-blot analysis. A 3-hr exposure to ZnO fume via a combustion furnace caused a substantial elevation in lung MT mRNA at all concentrations tested. Exposures to 5 and 2.5 mg/m3 ZnO resulted in peak 8-fold increases in MT mRNA levels (compared to air-exposed control animal values) immediately after exposure, while 1 mg/m3 ZnO exposure caused a 3.5-fold elevation in MT mRNA. These levels returned to approximate control gene expression values 24 hr after exposure. In addition, ZnO exposure caused an immediate elevation in lung HO gene expression levels, with 8-, 11-, and 5-fold increases observed after the same ZnO exposure levels (p < 0.05). Like MT gene induction, HO mRNA values returned to approximate control levels 24 hr after exposure. In striking contrast to the induction of MT and HO gene expression after ZnO exposures, there was no elevation in gene expression following a 6-hr exposure to 0.5 and 1 ppm ozone, even when lungs were examined as late as 72 hr after exposure. Our results demonstrate the induction of target gene expression following the inhalation of ZnO at concentrations equal to, and below, the current recommended threshold limit value of 5 mg/m3 ZnO. Furthermore, the lack of effect of ozone exposure on MT and HO gene expression suggests no involvement of these genes in the acute respiratory response to this oxidant compound.

Assessment of Environmental Cockroach Allergen Exposure

PubMed Central

Chew, Ginger L.

2016-01-01

In the past, cockroach allergen exposure assessment mainly focused on settled dust in homes in low-income urban cities in the United States. That choice was not wrong; without measureable levels of cockroach allergen, it is difficult to show associations with any home characteristics much less with health outcomes (e.g., allergy, asthma). However, recent studies in other suburban areas, schools, and other countries have elucidated the importance of cockroach allergen in these environments too. In addition, characterizing the underlying factors that give rise to cockroach allergen exposure (or protect against it) can lead to more targeted public health interventions. This review discusses different approaches to sampling indoor environments, interprets recent asthma and allergy studies, compares cockroach allergen levels from past studies with those of recent studies, and describes strategies to decrease exposures. PMID:22825884

Exposure to potential occupational asthmogens: prevalence data from the National Occupational Exposure Survey.

PubMed

de la Hoz, R E; Young, R O; Pedersen, D H

1997-02-01

Few data are available about the prevalence of occupational exposures to agents which can cause occupational asthma or aggravate preexisting asthma (asthmogens). Using potential occupational exposure data from the National Occupational Exposure Survey (NOES) of 1980-1983, we investigated the number of asthmogen exposures, asthmogen-exposure(s) per production worker, and unprotected occupational asthmogen exposures in different industries and occupations. Data for the entire United States were used to generate estimates of occupational exposure at two selected state and local levels. It was estimated that 7,864,000 workers in the surveyed industries were potentially exposed to one or more occupational asthmogen(s) in the United States. The average number of observed potential exposures per asthmogen-exposed worker was 4.4, and varied from 11.9, in the Water Transportation industry, to 1.2 in Local and Suburban transportation. The largest number of observed potential exposures was recorded in the Apparel and Other Finished Products (garment) industry. This work and further analyses using this approach are expected to contribute to a better understanding of the epidemiology of occupational asthma, and to serve as a guide to target future occupational asthma surveillance efforts.

Evaluation of the Stryker S2 IM Nail Distal Targeting Device for reduction of radiation exposure: a case series study.

PubMed

Anastopoulos, George; Ntagiopoulos, Panagiotis G; Chissas, Dionisios; Loupasis, George; Asimakopoulos, Antonios; Athanaselis, Eustratios; Megas, Panagiotis

2008-10-01

Distal locking is one challenging step during intramedullary nailing of femoral shaft fractures that can lead to an increase of radiation exposure. In the present study, the authors describe a technique for the distal locking of femoral nails, implementing a new targeting device in an attempt to reduce radiation exposure and operational time. Over a 2-year period, 127 consecutive cases of femoral shaft fractures were included in the study. All cases were treated with nailing of femoral shaft fractures with an unslotted reamed antegrade femoral nail and distal locking was performed with the use of a proximally mounted aiming device. Mean duration of the procedure was 63.5 18.1 min while the duration for distal locking was 6.6 +/- 2.6 min. In all successful cases, exposure from intraoperative fluoroscopy was 17.2 +/- 7.4 s for the whole operative procedure, and for distal locking was 2 shots, 1.35 s (range, 0.9-2.2 s) and 1.9 mGy (range, 1.1-2.9 mGy). Five cases (3.9%) were unsuccessful, but overall no intraoperative complications were encountered from the application of this technique. The ability of the device to correspond to the level of nail deformation and to properly identify the distal holes, reduced exposure to radiation compared to other published reports, and should be considered as a valuable tool for distal locking of femoral fractures.

Pesticide Exposure and Cholinesterase Levels in Migrant Farm Workers in Thailand.

PubMed

Thetkathuek, Anamai; Yenjai, Pornthip; Jaidee, Wanlop; Jaidee, Patchana; Sriprapat, Poonsak

2017-01-01

In this study, we examined the effects of pesticides in migrant farm workers from Cambodia after workplace exposure on fruit plantations in eastern Thailand. We studied 891 migrant farm workers employed on pineapple, durian, and rambutan plantations in Thailand. Data were collected via a detailed questionnaire survey and measurements of serum cholinesterase level (SChE). The majority of subjects was male (57.7%), with an average age of 30.3 years. Most subjects (76.8%) were moderately aware of good industrial hygiene practices. SChE level was divided into four groups based on the results. Only 4.4% had normal levels of cholinesterase activity, 20.5% had slightly reduced levels, 58.5% had markedly reduced levels and were "at risk," and 16.6% who had highest levels of cholinesterase inhibition were deemed to be in an "unsafe" range. SChE was classified into two groups, SChE value of 87.5 was "normal" and <87.5 units/mL "abnormal." For the multiple logistic regression analysis of the abnormal SChE levels, the variables entered in the model included gender, period of insecticide use, the total area of plantation, frequency of spraying, period of daily insecticide spraying, and insecticide spraying method. The results indicated that the aOR (adjust odds ratio) for male migrant farm workers (95% confidence interval [CI]) was 1.58 (1.14, 2.17). The OR for farm migrant workers who worked on larger plantations of more than 39.5 acres (95% CI) was 2.69 (1.51, 4.82). Finally, the OR for the migrant farm workers who used a backpack sprayer (95% CI) was 2.07 (1.28, 3.34). These results suggest that health screening should be provided to migrant farm workers, especially those who spray pesticides on plantations of >39 acres, use a backpack sprayer, or have a low level of compliance with accepted industrial hygiene practices. These three classes of workers are at increased risk of chemical exposures and developing acute or chronic illness from pesticide exposures.

Proposal for single and mixture biological exposure limits for sevoflurane and nitrous oxide at low occupational exposure levels.

PubMed

Accorsi, Antonio; Valenti, Simona; Barbieri, Anna; Raffi, Giovanni Battista; Violante, Francesco Saverio

2003-03-01

Assessment of individual exposures to sevoflurane plus nitrous oxide (N(2)O) by biological monitoring of unmodified analytes in post-shift urine of exposed personnel. Anaesthetics in urine and breathing area were monitored in 124 subjects in 11 operating theatres. Passive samplers were collected after 2.5-7 h of exposure, at the same time as post-shift urinary samples, to evaluate the individual time-weighted average (TWA) exposures to sevoflurane and N(2)O. A static headspace sampler coupled with a gas chromatograph mass spectrometer was used for analytical determinations (sensitivity sufficient to reveal biological/environmental exposures of 0.1 microg/l(urine) and 50 ppb for sevoflurane, and 1 microg/l(urine) and 80 ppb for N(2)O). Median (range) post-shift urinary and environmental values were 1.2 microg/l(urine) (0.1-5.0) and 0.4 ppm (0.05-3.0) for sevoflurane ( n=107) and 10.9 microg/l(urine) (0.5-74.9) and 8.6 ppm (0.2-123.4) for N(2)O ( n=121) (all low-exposure range). At log-log regression, urinary levels closely correlated with environmental data (sevoflurane, r(2)=0.7538; N(2)O, r(2)=0.8749). Biological equivalent limits (BELs) based on National Institute for Occupational Safety and Health (NIOSH) TWA exposure limits, calculated as means of regression slope and y-intercept, were 3.6 microg/l(urine) for sevoflurane (corresponding to 2 ppm) and 22.3 microg/l(urine) for N(2)O (corresponding to 25 ppm). Individual "mixture BELs", which we calculated by applying the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV) mix formula to biomarker values and using the obtained NIOSH-based BELs as a reference, closely correlated with mixture TLVs (rho=0.816, Lin's concordance test). CONCLUSIONS. We propose urinary sevoflurane as a new, specific, internal dose biomarker for routine biological monitoring of personal exposures among operating-theatre personnel, and use of reliable "mixture BELs" to provide safer levels of

Request for a Test Exposure of OPERA Targets in the NuMI Beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kodama, K.; /Aichi U.; Tzanakos, G.

2004-11-01

We request to use the Fermilab NuMI neutrino beam in the MINOS Near Detector Hall to produce neutrino interactions in two separate detector arrangements using prototype target bricks designed for the OPERA experiment. OPERA is scheduled to to begin taking data in the CERN Neutrinos to Gran Sasso (CNGS) beam in 2006. The proposed test set up would be located just upstream of the MINOS Near Detector. The data will be used to validate the OPERA analysis scheme and to study backward particle production in neutrino interactions, which is of interest to the OPERA collaboration as well as the neutrinomore » community in general. In addition, we contend that the data taken in this exposure may also be useful to the MINOS collaboration as additional input to the understanding of the initial composition of the neutrino beam. Ideally, this exposure could take place in early to mid-2005, providing timely feedback to both the OPERA and MINOS collaborations.« less

Common sole larvae survive high levels of pile-driving sound in controlled exposure experiments.

PubMed

Bolle, Loes J; de Jong, Christ A F; Bierman, Stijn M; van Beek, Pieter J G; van Keeken, Olvin A; Wessels, Peter W; van Damme, Cindy J G; Winter, Hendrik V; de Haan, Dick; Dekeling, René P A

2012-01-01

In view of the rapid extension of offshore wind farms, there is an urgent need to improve our knowledge on possible adverse effects of underwater sound generated by pile-driving. Mortality and injuries have been observed in fish exposed to loud impulse sounds, but knowledge on the sound levels at which (sub-)lethal effects occur is limited for juvenile and adult fish, and virtually non-existent for fish eggs and larvae. A device was developed in which fish larvae can be exposed to underwater sound. It consists of a rigid-walled cylindrical chamber driven by an electro-dynamical sound projector. Samples of up to 100 larvae can be exposed simultaneously to a homogeneously distributed sound pressure and particle velocity field. Recorded pile-driving sounds could be reproduced accurately in the frequency range between 50 and 1000 Hz, at zero to peak pressure levels up to 210 dB re 1µPa(2) (zero to peak pressures up to 32 kPa) and single pulse sound exposure levels up to 186 dB re 1µPa(2)s. The device was used to examine lethal effects of sound exposure in common sole (Solea solea) larvae. Different developmental stages were exposed to various levels and durations of pile-driving sound. The highest cumulative sound exposure level applied was 206 dB re 1µPa(2)s, which corresponds to 100 strikes at a distance of 100 m from a typical North Sea pile-driving site. The results showed no statistically significant differences in mortality between exposure and control groups at sound exposure levels which were well above the US interim criteria for non-auditory tissue damage in fish. Although our findings cannot be extrapolated to fish larvae in general, as interspecific differences in vulnerability to sound exposure may occur, they do indicate that previous assumptions and criteria may need to be revised.

Common Sole Larvae Survive High Levels of Pile-Driving Sound in Controlled Exposure Experiments

PubMed Central

Bolle, Loes J.; de Jong, Christ A. F.; Bierman, Stijn M.; van Beek, Pieter J. G.; van Keeken, Olvin A.; Wessels, Peter W.; van Damme, Cindy J. G.; Winter, Hendrik V.; de Haan, Dick; Dekeling, René P. A.

2012-01-01

In view of the rapid extension of offshore wind farms, there is an urgent need to improve our knowledge on possible adverse effects of underwater sound generated by pile-driving. Mortality and injuries have been observed in fish exposed to loud impulse sounds, but knowledge on the sound levels at which (sub-)lethal effects occur is limited for juvenile and adult fish, and virtually non-existent for fish eggs and larvae. A device was developed in which fish larvae can be exposed to underwater sound. It consists of a rigid-walled cylindrical chamber driven by an electro-dynamical sound projector. Samples of up to 100 larvae can be exposed simultaneously to a homogeneously distributed sound pressure and particle velocity field. Recorded pile-driving sounds could be reproduced accurately in the frequency range between 50 and 1000 Hz, at zero to peak pressure levels up to 210 dB re 1µPa2 (zero to peak pressures up to 32 kPa) and single pulse sound exposure levels up to 186 dB re 1µPa2s. The device was used to examine lethal effects of sound exposure in common sole (Solea solea) larvae. Different developmental stages were exposed to various levels and durations of pile-driving sound. The highest cumulative sound exposure level applied was 206 dB re 1µPa2s, which corresponds to 100 strikes at a distance of 100 m from a typical North Sea pile-driving site. The results showed no statistically significant differences in mortality between exposure and control groups at sound exposure levels which were well above the US interim criteria for non-auditory tissue damage in fish. Although our findings cannot be extrapolated to fish larvae in general, as interspecific differences in vulnerability to sound exposure may occur, they do indicate that previous assumptions and criteria may need to be revised. PMID:22431996

20180311 - EPA’s Non-Targeted Analysis Research Program: Expanding public data resources in support of exposure science (SOT)

EPA Science Inventory

Suspect screening (SSA) and non-targeted analysis (NTA) methods using high-resolution mass spectrometry (HRMS) offer new approaches to efficiently generate exposure data for chemicals in a variety of environmental and biological media. These techniques aid characterization of the...

Influence of gestation, regular bleeding and intermittent exposure on blood perfluorooctane sulfonate levels in mice: potential factors inducing sex difference and affecting exposure evaluation.

PubMed

Liu, Wei; Li, Xiao; Xu, Lei; Liu, Li; Jin, Yihe; Sato, Itaru; Tsuda, Shuji

2010-06-01

Higher blood levels of perfluorooctane sulfonate (PFOS) in males than the females have been observed in many human biomonitoring studies, which is not well explained yet. The effects of gestation and regular bleeding on blood PFOS level in mice were investigated to evaluate the potential factors that could result in the sex difference. The mice were exposed to PFOS via drinking water at a concentration of 50 mug/l. After 6 weeks of pre-exposure and the gestation period, the blood PFOS concentrations in the gestagenic mice were significantly lower than the control non-gestagenic mice with a ratio of 0.45. Significant lower blood PFOS concentrations in the male mice treated by regular artificial bleeding were observed compared with those from the control male. However, such difference was not observed for the females. The sex difference in the effect of regular artificial bleeding on the blood PFOS level may be caused by the different accumulation and elimination rate in the female and male mice. In addition, the effect of intermittent exposure to PFOS on blood level was evaluated. Each single exposure caused a significant increase in blood PFOS level in both females and males, suggesting the acute exposure to PFOS occurred before the blood sampling, e.g. exposure to PFOS-contaminated foods or drinks, would affect the biomonitoring data to some extent depending on the background blood level. Thus serial blood monitoring is required to obtain accurate body burden.

Effects of combined radiofrequency radiation exposure on levels of reactive oxygen species in neuronal cells

PubMed Central

Kang, Kyoung Ah; Lee, Hyung Chul; Lee, Je-Jung; Hong, Mi-Na; Park, Myung-Jin; Lee, Yun-Sil; Choi, Hyung-Do; Kim, Nam; Ko, Young-Gyu; Lee, Jae-Seon

2014-01-01

The objective of this study was to investigate the effects of the combined RF radiation (837 MHz CDMA plus 1950 MHz WCDMA) signal on levels of intracellular reactive oxygen species (ROS) in neuronal cells. Exposure of the combined RF signal was conducted at specific absorption rate values of 2 W/kg of CDMA plus 2 W/kg of WCDMA for 2 h. Co-exposure to combined RF radiation with either H2O2 or menadione was also performed. The experimental exposure groups were incubator control, sham-exposed, combined RF radiation-exposed with or without either H2O2 or menadione groups. The intracellular ROS level was measured by flow cytometry using the fluorescent probe dichlorofluorescein diacetate. Intracellular ROS levels were not consistently affected by combined RF radiation exposure alone in a time-dependent manner in U87, PC12 or SH-SY5Y cells. In neuronal cells exposed to combined RF radiation with either H2O2 or menadione, intracellular ROS levels showed no statically significant alteration compared with exposure to menadione or H2O2 alone. These findings indicate that neither combined RF radiation alone nor combined RF radiation with menadione or H2O2 influences the intracellular ROS level in neuronal cells such as U87, PC12 or SH-SY5Y. PMID:24105709

A comparison of individual exposure, perception, and acceptable levels of PM2.5 with air pollution policy objectives in China.

PubMed

Huang, Lei; Rao, Chao; van der Kuijp, Tsering Jan; Bi, Jun; Liu, Yang

2017-08-01

Atmospheric pollution has emerged as a major public health issue in China. Public perception and acceptable risk levels of air pollution can prompt individual behavioral changes and play a major role in the public's response to health risks. Therefore, to explore these responses and evaluate what constitutes publicly acceptable concentrations of fine particulate matter (PM 2.5 ), questionnaire surveys were conducted in three representative cities of China: Beijing, Nanjing, and Guangzhou. Great differences in public risk perception were revealed. Public perception of the health effects of air pollution (Effect) and familiarity with it (Familiarity) were significantly higher in the winter than in the summer, and also during severe haze days compared with typical days. The public perception of trust in the government (Trust) was consistent across all conditions. Exposure to severe haze pollution and experiencing harms from it were key factors influencing public willingness to respond to haze. These results reflected individual exposure levels correlating closely with risk perception and acceptance of PM 2.5 . However, a crucial gap exists between public acceptable risk levels (PARL) of air pollution and the policy objectives of the State Council's Action Plan. Thus, policymakers can utilize this study to develop more targeted measures to combat air pollution. Copyright © 2017 Elsevier Inc. All rights reserved.

Global gene expression profiles in brain regions reflecting abnormal neuronal and glial functions targeting myelin sheaths after 28-day exposure to cuprizone in rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abe, Hajime

Both developmental and postpubertal cuprizone (CPZ) exposure impairs hippocampal neurogenesis in rats. We previously found that developmental CPZ exposure alters the expression of genes related to neurogenesis, myelination, and synaptic transmission in specific brain regions of offspring. Here, we examined neuronal and glial toxicity profiles in response to postpubertal CPZ exposure by using expression microarray analysis in the hippocampal dentate gyrus, corpus callosum, cerebral cortex, and cerebellar vermis of 5-week-old male rats exposed to 0, 120, and 600 mg/kg CPZ for 28 days. Genes showing transcript upregulation were subjected to immunohistochemical analysis. We found transcript expression alterations at 600 mg/kgmore » for genes related to synaptic transmission, Ache and Prima1, and cell cycle regulation, Tfap4 and Cdkn1a, in the dentate gyrus, which showed aberrant neurogenesis in the subgranular zone. This dose downregulated myelination-related genes in multiple brain regions, whereas KLOTHO{sup +} oligodendrocyte density was decreased only in the corpus callosum. The corpus callosum showed an increase in transcript levels for inflammatory response-related genes and in the number of CD68{sup +} microglia, MT{sup +} astrocytes, and TUNEL{sup +} apoptotic cells. These results suggest that postpubertal CPZ exposure targets synaptic transmission and cell cycle regulation to affect neurogenesis in the dentate gyrus. CPZ suppressed myelination in multiple brain regions and KLOTHO-mediated oligodendrocyte maturation only in the corpus callosum. The increased number of CD68{sup +} microglia, MT{sup +} astrocytes, and TUNEL{sup +} apoptotic cells in the corpus callosum may be involved in the induction of KLOTHO{sup +} oligodendrocyte death and be a protective mechanism against myelin damage following CPZ exposure. - Highlights: • Target gene expression profiles were examined in rats after 28-day CPZ exposure. • Multiple brain region-specific global gene

GENE EXPRESSION PROFILING OF ACCESSIBLE SURROGATE TISSUES TO MONITOR MOLECULAR CHANGES IN INACCESSIBLE TARGET TISSUES FOLLOWING TOXICANT EXPOSURE

EPA Science Inventory

Gene Expression Profiling Of Accessible Surrogate Tissues To Monitor Molecular Changes In Inaccessible Target Tissues Following Toxicant Exposure
John C. Rockett, Chad R. Blystone, Amber K. Goetz, Rachel N. Murrell, Judith E. Schmid and David J. Dix
Reproductive Toxicology ...

Patient dose, gray level and exposure index with a computed radiography system

NASA Astrophysics Data System (ADS)

Silva, T. R.; Yoshimura, E. M.

2014-02-01

Computed radiography (CR) is gradually replacing conventional screen-film system in Brazil. To assess image quality, manufactures provide the calculation of an exposure index through the acquisition software of the CR system. The objective of this study is to verify if the CR image can be used as an evaluator of patient absorbed dose too, through a relationship between the entrance skin dose and the exposure index or the gray level values obtained in the image. The CR system used for this study (Agfa model 30-X with NX acquisition software) calculates an exposure index called Log of the Median (lgM), related to the absorbed dose to the IP. The lgM value depends on the average gray level (called Scan Average Level (SAL)) of the segmented pixel value histogram of the whole image. A Rando male phantom was used to simulate a human body (chest and head), and was irradiated with an X-ray equipment, using usual radiologic techniques for chest exams. Thermoluminescent dosimeters (LiF, TLD100) were used to evaluate entrance skin dose and exit dose. The results showed a logarithm relation between entrance dose and SAL in the image center, regardless of the beam filtration. The exposure index varies linearly with the entrance dose, but the angular coefficient is beam quality dependent. We conclude that, with an adequate calibration, the CR system can be used to evaluate the patient absorbed dose.

Low-Level Environmental Phthalate Exposure Associates with Urine Metabolome Alteration in a Chinese Male Cohort.

PubMed

Zhang, Jie; Liu, Liangpo; Wang, Xiaofei; Huang, Qingyu; Tian, Meiping; Shen, Heqing

2016-06-07

The general population is exposed to phthalates through various sources and routes. Integration of omics data and epidemiological data is a key step toward directly linking phthalate biomonitoring data with biological response. Urine metabolomics is a powerful tool to identify exposure biomarkers and delineate the modes of action of environmental stressors. The objectives of this study are to investigate the association between low-level environmental phthalate exposure and urine metabolome alteration in male population, and to unveil the metabolic pathways involved in the mechanisms of phthalate toxicity. In this retrospective cross-sectional study, we studied the urine metabolomic profiles of 364 male subjects exposed to low-level environmental phthalates. Di(2-ethylhexyl) phthalate (DEHP) and dibutyl phthalate (DBP) are the most widely used phthalates. ∑DEHP and MBP (the major metabolite of DBP) were associated with significant alteration of global urine metabolome in the male population. We observed significant increase in the levels of acetylneuraminic acid, carnitine C8:1, carnitine C18:0, cystine, phenylglycine, phenylpyruvic acid and glutamylphenylalanine; and meanwhile, decrease in the levels of carnitine C16:2, diacetylspermine, alanine, taurine, tryptophan, ornithine, methylglutaconic acid, hydroxyl-PEG2 and keto-PGE2 in high exposure group. The observations indicated that low-level environmental phthalate exposure associated with increased oxidative stress and fatty acid oxidation and decreased prostaglandin metabolism. Urea cycle, tryptophan and phenylalanine metabolism disruption was also observed. The urine metabolome disruption effects associated with ∑DEHP and MBP were similar, but not identical. The multibiomarker models presented AUC values of 0.845 and 0.834 for ∑DEHP and MBP, respectively. The predictive accuracy rates of established models were 81% for ΣDEHP and 73% for MBP. Our results suggest that low-level environmental phthalate

Estimating the dose response relationship for occupational radiation exposure measured with minimum detection level.

PubMed

Xue, Xiaonan; Shore, Roy E; Ye, Xiangyang; Kim, Mimi Y

2004-10-01

Occupational exposures are often recorded as zero when the exposure is below the minimum detection level (BMDL). This can lead to an underestimation of the doses received by individuals and can lead to biased estimates of risk in occupational epidemiologic studies. The extent of the exposure underestimation is increased with the magnitude of the minimum detection level (MDL) and the frequency of monitoring. This paper uses multiple imputation methods to impute values for the missing doses due to BMDL. A Gibbs sampling algorithm is developed to implement the method, which is applied to two distinct scenarios: when dose information is available for each measurement (but BMDL is recorded as zero or some other arbitrary value), or when the dose information available represents the summation of a series of measurements (e.g., only yearly cumulative exposure is available but based on, say, weekly measurements). Then the average of the multiple imputed exposure realizations for each individual is used to obtain an unbiased estimate of the relative risk associated with exposure. Simulation studies are used to evaluate the performance of the estimators. As an illustration, the method is applied to a sample of historical occupational radiation exposure data from the Oak Ridge National Laboratory.

Detection of low level benzene exposure in supermarket wrappers by urinary muconic acid.

PubMed

E S Johnson S Halabi G Netto G Lucier W Bechtold R Henderson

1999-01-01

Women who use the 'hot wire' and 'cool rod' machines to wrap meat in supermarkets are potentially exposed to low levels of benzene and polycyclic aromatic hydrocarbons present in fumes emitted during the thermal decomposition of the plastic used to wrap meat. In order to evaluate whether the benzene metabolite trans, trans-muconic acid (MA) can be used to monitor these low levels, we collected urine samples from supermarket workers, and assayed the urine for MA. Geometric mean after-shift MA levels were highest for subjects who used the 'hot wire' machine, i.e. > 300 ng mg-1 creatinine (Cr). The corresponding levels for subjects who used the 'cool rod' machine were similar to those for subjects who did not use either type of machine, and were much lower. These results indicate that urinary muconic acid has some potential for use in monitoring benzene exposures of less than 1 part per million (ppm). The study detected very high background MA levels (exceeding 2000 ng mg-1 Cr) in some subjects, suggesting that individuals in the general population without occupational exposure to benzene may have urinary MA levels equivalent to exposure to up to 2 ppm benzene in ambient air. However, since non-benzene sources of the metabolite cannot be completely ruled out as partially responsible for these high levels, the public health significance of this finding is not known at the moment.

Is beryllium-induced lung cancer caused only by soluble forms and high exposure levels?

PubMed

Schubauer-Berigan, Mary K; Couch, James R; Deddens, James A

2017-08-01

The US Occupational Safety and Health Administration (OSHA) recently proposed a permissible exposure limit of 0.2 µg/m 3 for beryllium, based partly on extrapolated estimates of lung cancer risk from a pooled occupational cohort. The purpose of the present analysis was to evaluate whether cohort members exposed at lower levels to mainly insoluble forms of beryllium exhibit increased risk of lung cancer. We conducted Cox proportional hazards regression analyses among 75 lung cancer cases in age-based risk sets within two lower exposure plants in the pooled cohort followed from 1940 to 2005. We used categorical and power models to evaluate exposure-response patterns for mean and cumulative beryllium exposures in the two-plant cohort, comparing findings with the full pooled cohort. We also evaluated the distribution of exposure-years in each cohort by solubility class (soluble, insoluble and mixed). 98% of workers in the two-plant cohort were hired between 1955 and 1969. The mean beryllium exposure averaged 1.3 µg/m 3 and the predominant form was insoluble. Adjusting for confounders, we observed a monotonic increase in lung cancer mortality across exposure categories in the two-plant cohort. The exposure-response coefficients (per unit ln exposure) were 0.270 (p=0.061) for mean exposure and 0.170 (p=0.033) for cumulative exposure, compared with 0.155 and 0.094 (respectively) in the full cohort. The low-exposure levels at these two plants and the predominance of insoluble beryllium suggest that the overall pooled cohort findings on which OSHA's lung cancer risk assessment is based are relevant for current workers exposed to any form of beryllium. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Clusters of community exposure to coastal flooding hazards based on storm and sea level rise scenarios—implications for adaptation networks in the San Francisco Bay region

USGS Publications Warehouse

Hummel, Michelle; Wood, Nathan J.; Schweikert, Amy; Stacey, Mark T.; Jones, Jeanne; Barnard, Patrick L.; Erikson, Li H.

2018-01-01

Sea level is projected to rise over the coming decades, further increasing the extent of flooding hazards in coastal communities. Efforts to address potential impacts from climate-driven coastal hazards have called for collaboration among communities to strengthen the application of best practices. However, communities currently lack practical tools for identifying potential partner communities based on similar hazard exposure characteristics. This study uses statistical cluster analysis to identify similarities in community exposure to flooding hazards for a suite of sea level rise and storm scenarios. We demonstrate this approach using 63 jurisdictions in the San Francisco Bay region of California (USA) and compare 21 distinct exposure variables related to residents, employees, and structures for six hazard scenario combinations of sea level rise and storms. Results indicate that cluster analysis can provide an effective mechanism for identifying community groupings. Cluster compositions changed based on the selected societal variables and sea level rise scenarios, suggesting that a community could participate in multiple networks to target specific issues or policy interventions. The proposed clustering approach can serve as a data-driven foundation to help communities identify other communities with similar adaptation challenges and to enhance regional efforts that aim to facilitate adaptation planning and investment prioritization.

Low-level arsenic exposure from drinking water is associated with prostate cancer in Iowa.

PubMed

Roh, Taehyun; Lynch, Charles F; Weyer, Peter; Wang, Kai; Kelly, Kevin M; Ludewig, Gabriele

2017-11-01

Inorganic arsenic is a toxic naturally occurring element in soil and water in many regions of the US including the Midwest. Prostate cancer is the second most common type of cancer in men in Iowa, surpassed only by non-melanotic skin cancer. Epidemiology studies have evaluated arsenic exposure from drinking water and prostate cancer, but most have focused on high-level exposures outside the US. As drinking water from groundwater sources is a major source of arsenic exposure, we conducted an ecologic study to evaluate prostate cancer and arsenic in drinking water from public water sources and private wells in Iowa, where exposure levels are low, but duration of exposure can be long. Arsenic data from public water systems were obtained from the Iowa Safe Drinking Water Information System for the years 1994-2003 and for private wells from two Iowa Well Water Studies, the Iowa Community Private Well Study (ICPWS, 2002-2003) and Iowa Statewide Rural Well Water Survey Phase 2 (SWIRL2, 2006-2008) that provided data for 87 Iowa counties. Prostate cancer incidence data from 2009 to 2013 for Iowa were obtained from Surveillance, Epidemiology and End Results' SEER*Stat software. County averages of water arsenic levels varied from 1.08 to 18.6 ppb, with three counties above the current 10 ppb limit. Based on the tertiles of arsenic levels, counties were divided into three groups: low (1.08-2.06 ppb), medium (2.07-2.98 ppb), and high (2.99-18.6 ppb). Spatial Poisson regression modeling was conducted to estimate the risk ratios (RR) of prostate cancer by tertiles of arsenic level at a county level, adjusted for demographic and risk factors. The RR of prostate cancer were 1.23 (95% CI, 1.16-1.30) and 1.28 (95% CI, 1.21-1.35) in the medium and high groups, respectively, compared to the low group after adjusting for risk factors. The RR increased to 1.36 (95% CI, 1.28-1.45) in the high group when analyses were restricted to aggressive prostate cancers (Gleason score ≥ 7). This

[Effects of mere subliminal exposure on trait judgments and the role of stereotyped knowledge].

PubMed

Yamada, Ayumi

2004-06-01

This study investigated the effects of repeated exposures to male and female targets on trait impressions and the role of stereotyped knowledge for the target's social category in impression formation process. The participants were repeatedly exposed to slides of male and female faces for subliminal durations. For each of 12 pairs containing both previously presented slide and newly presented slide, the participants made forced-choice liking judgments (Experiment 1), trait judgments (Experiment 2) and recognition judgments (Experiments 1 and 2). It was found that participants' attitude toward the targets became more positive, even though target recognition was not significantly greater than the chance level. Yet, when the dimension of judgment was stereotypically associated with the target's social category, exposure effects were obtained for the targets whose social category and its dimension were inferentially matched, but not obtained for the targets whose social category and its dimension were not inferentially matched. Some theoretical implications of the role of social category information in the mere exposure phenomenon are discussed.

[Exposure degree of important non-target arthropods to Cry2Aa in Bt rice fields].

PubMed

Zhang, Qing-Ling; Li, Yun-He; Hua, Hong-Xia; Yang, Chang-Ju; Wu, Hong-Jin; Peng, Yu-Fa

2013-06-01

Based on the principle of "risk = hazard x exposure", the selected representative nontarget organisms in the assessment of the potential effects of insect-resistant genetically modified (GM) crops on non-target arthropods in laboratory are generally the arthropod species highly exposed to the insecticidal proteins expressed by the GM crops in farmland ecosystem. In order to understand the exposure degree of the important arthropod species to Cry proteins in Bt rice fields, and to select the appropriate non-target arthropods in the risk assessment of insect-resistant GM crops, the enzyme-linked immunosorbent assay (ELISA) was conducted to measure the Cry2Aa protein concentration in the arthropods collected from the cry2Aa rice fields at different rice growth stages. The results showed that there was a significant difference in the Cry2Aa content protein concentration in different arthropod species. Some species did not contain Cry2Aa protein, while some species contained larger amounts of Cry2Aa protein. Relative to the arthropods colleted after rice anthesis, the arthropods colleted in rice anthesis contained relative higher concentrations of Cry2Aa protein, especially for the predacious arthropods. No Cry proteins were detected in parasitic arthropods. This study provided references for the laboratory assessment of the effects of GM rice on nontarget arthropods.

Anxiety and depression following cumulative low-level exposure to organophosphate pesticides.

PubMed

Harrison, Virginia; Mackenzie Ross, Sarah

2016-11-01

Previous research suggests that individuals with a prior history of pesticide poisoning are at increased risk of psychiatric disorder (Freire and Koifman, 2013), but findings regarding the impact of cumulative low-level exposure are inconsistent. The aim of the current study was to investigate whether sheep farmers with a history of low-level exposure to organophosphate pesticides (1) report a higher level of psychological distress on subjective symptom questionnaires, compared to unexposed controls (2) also meet internationally agreed diagnostic criteria for a psychiatric disorder more often than unexposed controls. 127sheep farmers were evaluated and compared to 78 unexposed controls, matched in terms of gender, education, level of intelligence, working status and area of residence. Both self-report measures and structured clinical interviews were used to assess mental health. The exposed cohort reported significantly higher rates of anxiety and depression when self-report questionnaires were used to evaluate mood, even when stressful life events, demographic and physical health factors were taken into account. However, when diagnostic interviews were used to assess mood, this pattern only held true for anxiety. Copyright © 2016 Elsevier Inc. All rights reserved.

Impact of 900 MHz electromagnetic field exposure on main male reproductive hormone levels: a Rattus norvegicus model

NASA Astrophysics Data System (ADS)

Sepehrimanesh, Masood; Saeb, Mehdi; Nazifi, Saeed; Kazemipour, Nasrin; Jelodar, Gholamali; Saeb, Saeedeh

2014-09-01

This work analyzes the effects of radiofrequency-electromagnetic field (RF-EMF) exposure on the reproductive system of male rats, assessed by measuring circulating levels of FSH, LH, inhibin B, activin B, prolactin, and testosterone. Twenty adult male Sprague-Dawley rats (180 ± 10 g) were exposed to 900 MHz RF-EMF in four equal separated groups. The duration of exposure was 1, 2, and 4 h/day over a period of 30 days and sham-exposed animals were kept under the same environmental conditions as the exposed group except with no RF-EMF exposure. Before the exposure, at 15 and 30 days of exposure, determination of the abovementioned hormone levels was performed using ELISA. At the end of the experiment, FSH and LH values of the long time exposure (LTE) group were significantly higher than the sham-exposed group ( p < 0.05). Serum activin B and prolactin in the LTE group showed significant increase and inhibin B showed significant decrease than sham and short time exposed (STE) groups after 30 days RF-EMF exposure ( p < 0.05). Also, a significant decrease in serum testosterone levels in the LTE group was found compared to short and moderate time exposed (MTE) groups after 30 days RF-EMF exposure ( p < 0.05). Results suggest that reproductive hormone levels are disturbed as a result of RF-EMF exposure and it may possibly affect reproductive functions. However, testosterone and inhibin B concentrations as a fertility marker and spermatogenesis were decreased significantly.

Decision-level fusion of SAR and IR sensor information for automatic target detection

NASA Astrophysics Data System (ADS)

Cho, Young-Rae; Yim, Sung-Hyuk; Cho, Hyun-Woong; Won, Jin-Ju; Song, Woo-Jin; Kim, So-Hyeon

2017-05-01

We propose a decision-level architecture that combines synthetic aperture radar (SAR) and an infrared (IR) sensor for automatic target detection. We present a new size-based feature, called target-silhouette to reduce the number of false alarms produced by the conventional target-detection algorithm. Boolean Map Visual Theory is used to combine a pair of SAR and IR images to generate the target-enhanced map. Then basic belief assignment is used to transform this map into a belief map. The detection results of sensors are combined to build the target-silhouette map. We integrate the fusion mass and the target-silhouette map on the decision level to exclude false alarms. The proposed algorithm is evaluated using a SAR and IR synthetic database generated by SE-WORKBENCH simulator, and compared with conventional algorithms. The proposed fusion scheme achieves higher detection rate and lower false alarm rate than the conventional algorithms.

A computational study suggests that replacing PEG with PMOZ may increase exposure of hydrophobic targeting moiety.

PubMed

Magarkar, Aniket; Róg, Tomasz; Bunker, Alex

2017-05-30

In a previous study we showed that the cause of failure of a new, proposed, targeting ligand, the AETP moiety, when attached to a PEGylated liposome, was occlusion by the poly(ethylene glycol) (PEG) layer due to its hydrophobic nature, given that PEG is not entirely hydrophilic. At the time we proposed that possible replacement with a more hydrophilic protective polymer could alleviate this problem. In this study we have used computational molecular dynamics modelling, using a model with all atom resolution, to suggest that a specific alternative protective polymer, poly(2-methyloxazoline) (PMOZ), would perform exactly this function. Our results show that when PEG is replaced by PMOZ the relative exposure to the solvent of AETP is increased to a level even greater than that we found in previous simulations for the RGD peptide, a targeting moiety that has previously been used successfully in PEGylated liposome based therapies. While the AETP moiety itself is no longer under consideration, the results of this computational study have broader significance: the use of PMOZ as an alternative polymer coating to PEG could be efficacious in the context of more hydrophobic targeting ligands. In addition to PMOZ we studied another polyoxazoline, poly(2-ethyloxazoline) (PEOZ), that has also been mooted as a possible alternate protective polymer. It was also found that the RDG peptide occlusion was significantly greater for the case of both oxazolines as opposed to PEG and that, unlike PEG, neither oxazoline entered the membrane. As far as we are aware this is the first time that polyoxazolines have been studied using molecular dynamics simulation with all atom resolution. Copyright © 2017 Elsevier B.V. All rights reserved.

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

NASA Technical Reports Server (NTRS)

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.

Low levels of vitamin D poorly responsive to daylight exposure in patients with therapy-resistant schizophrenia.

PubMed

Bogers, Jan P.A.M.; Bostoen, Tijmen; Broekman, Theo G.

2016-01-01

Low vitamin D levels are associated with schizophrenia, but the possible association between vitamin D levels and illness severity or duration of exposure to daylight has barely been investigated. To compare vitamin D levels in therapy-refractory severely ill schizophrenia patients and members of staff. To investigate the influence of daylight exposure on vitamin D levels in patients. Vitamin D was measured in patients with therapy-resistant schizophrenia in April, after the winter, and in patients and staff members in June, after an exceptionally sunny spring. Vitamin D levels in April and June were compared in patients, and levels in June were compared in patients and staff. The influence of daylight was taken into account by comparing the time patients spent outdoors during the day with the recommended minimum time for adequate vitamin D synthesis, and by comparing time spent outdoors in patients and staff. Patients had high rates of vitamin D deficiency (79-90%) and lower levels of vitamin D than staff members (p < 0.001), independent of skin pigmentation. In patients, vitamin D levels did not normalize, despite the considerably longer than recommended exposure of the skin to daylight (p < 0.001) and the longer exposure in patients than in staff members (p = 0.003). The vitamin D deficiency of therapy-resistant schizophrenia patients is pronounced and cannot be explained by differences in skin pigmentation or by an inactive, indoor lifestyle on the ward. Even theoretically sufficient exposure of the patients to daylight did not ameliorate the low vitamin D levels. While vitamin D deficiency probably plays a role in somatic health problems, it may also play a role in schizophrenia. Interestingly, exposure to daylight during an unusually sunny spring was not sufficient to correct the vitamin D deficiency seen in the patients. This emphasizes the need to measure and correct vitamin D levels in these patients.

Protocol adherence and the ability to achieve target haemoglobin levels in haemodialysis patients.

PubMed

Chan, Kevin; Moran, John; Hlatky, Mark; Lafayette, Richard

2009-06-01

Anemia management remains complicated in patients with endstage renal disease on hemodialysis. We wished to evaluate the effect of protocol adherence to EPO and intravenous iron dosing on achieving the desired range of hemoglobin levels. A cohort of hemodialysis patients was studied to evaluate the rate of adherence to EPO and iron dosing protocols over a 5 month period. A database was completed to evaluate all known comorbidities, demographic factors, and facility issues that might affect hemoglobin levels. A logistic regression model was employed to evaluate the effect of adherence to the anemia protocols on the probability of achieving a hemoglobin level below, within or above the targeted range of 11-12.5 g/dl. Among 2114 patients, we found that adherence to both the EPO and iron dosing protocol resulted in the greatest probability of achieving the target hemoglobin range (56 +/- 5% in anemia protocol adherent patients versus 42 +/- 7% in non adherent patients). This was predominantly due to a lowered risk of having above target hemoglobin levels rather than below. The use of the anemia protocols was associated with lower rates of hospitalization (9 +/- 0.7 visits/100 months in adherent group vs 15 +/- 2 in non adherent group) and lower utilization of both EPO and intravenous iron. Furthermore, patients in the adherent groups had less variability of their hemoglobin levels month by month, at least as judged by standard deviation. Adherence to anemia protocols, as practiced in the dialysis units included in this cohort, may improve hemodialysis patients' ability to achieve target hemoglobin levels, and by avoiding above target hemoglobin values, lower drug utilization and reduce variability of hemoglobin levels.

Prenatal exposure to lead in Spain: cord blood levels and associated factors.

PubMed

Llop, Sabrina; Aguinagalde, Xabier; Vioque, Jesus; Ibarluzea, Jesús; Guxens, Mònica; Casas, Maribel; Murcia, Mario; Ruiz, María; Amurrio, Ascensión; Rebagliato, Marisa; Marina, Loreto Santa; Fernandez-Somoano, Ana; Tardon, Adonina; Ballester, Ferran

2011-05-01

Lead is a known neurotoxic. Fetuses and infants are very vulnerable to lead exposure, since their blood-brain barrier is not completely formed. Hence, there is an importance for monitoring of blood lead levels prenatally and during early infancy. The aim of this study is to evaluate the prenatal exposure to lead and its association with maternal factors in four population based mother-child cohorts in Spain. The present research was carried out within the framework of the INMA project INfancia y Medio Ambiente (Environment and Childhood). A total of 1462 pregnant women were recruited between 2004 and 2008. Lead was analyzed in a sample of cord blood by thermal decomposition, amalgation, and Atomic Absorption Spectrometry. Maternal sociodemographic, lifestyle and dietary factors were obtained by questionnaires during pregnancy. A multivariate logistic regression model was constructed. The dependent variable was a dichotomous lead level variable (detected vs no detected, i.e. ≥ vs < 2μg/dL). A low percentage of cord blood samples with lead levels ≥ 2μg/dL were found (5.9%). Geometric mean and maximum were 1.06μg/dL and 19μg/dL, respectively. Smoking at the beginning of pregnancy, age, social class, weight gain during pregnancy, gravidity, and place of residence were the maternal factors associated with detectable cord blood lead levels. Mother's diet does not appear to be a determining factor of lead exposure. Nevertheless, daily intake of iron and zinc may act as a protective factor against having cord blood lead levels ≥ 2μg/dL. In the different regions of Spain taking part in this study, lead levels to which newborns are exposed are low. Mobilization of lead from bones may be the main contributor to the cord blood levels. Copyright © 2011 Elsevier B.V. All rights reserved.

Tributyltin exposure alters cytokine levels in mouse serum.

PubMed

Lawrence, Shanieek; Pellom, Samuel T; Shanker, Anil; Whalen, Margaret M

2016-11-01

Tributyltin (TBT), a toxic environmental contaminant, has been widely utilized for various industrial, agricultural and household purposes. Its usage has led to a global contamination and its bioaccumulation in aquatic organisms and terrestrial mammals. Previous studies suggest that TBT has debilitating effects on the overall immune function of animals, rendering them more vulnerable to diseases. TBT (at concentrations that have been detected in human blood) alters secretion of inflammatory cytokines from human lymphocytes ex vivo. Thus, it is important to determine if specified levels of TBT can alter levels of cytokines in an in vivo system. Mice were exposed to biologically relevant concentrations of TBT (200, 100 or 25 nM final concentrations). The quantitative determination of interferon (IFN)-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL2, IL5, IL7, IL12βp40, IL13, IL15, keratinocyte chemoattractant (KC), macrophage inflammatory protein 1β (MIP), MIP2 and regulated on activation normal T-cell-expressed and secreted (RANTES) was performed in mouse sera by MAGPIX analysis and Western blot. Results indicated alterations (both decreases and increases) in several cytokines. The pro-inflammatory cytokines IFNγ, TNFα, IL-1β, IL-2, IL5, IL12βp40 and IL-15 were altered as were the chemokines MIP-1 and RANTES and the anti-inflammatory cytokine IL-13. Increases in IFNγ and TNFα were seen in the serum of mice exposed to TBT for less than 24 h. Levels of IL1β, IL-12 βp40, IL-5 and IL-15 were also modulated in mouse serum, depending on the specific experiment and exposure level. IL-2 was consistently decreased in mouse serum when animals were exposed to TBT. There were also TBT-induced increases in MIP-1β, RANTES and IL-13. These results from human and murine samples clearly suggest that TBT exposures modulate the secretion inflammatory cytokines.

Radon levels in Romanian caves: an occupational exposure survey.

PubMed

Cucoş Dinu, Alexandra; Călugăr, Monica I; Burghele, Bety D; Dumitru, Oana A; Cosma, Constantin; Onac, Bogdan P

2017-10-01

A comprehensive radon survey has been carried out in seven caves located in the western half of Romania's most significant karst regions. Touristic and non-touristic caves were investigated with the aim to provide a reliable distribution of their radon levels and evaluate the occupational exposure and associated effective doses. Radon gas concentrations were measured with long-term diffusion-type detectors during two consecutive seasons (warm and cold). All investigated caves exceed the European Union reference level of radon gas at workplaces (300 Bq/m 3 ). The radon concentration in these caves ranges between 53 and 2866 Bq/m 3 , reflecting particular cave topography, season-related cave ventilation, and complex tectonic and geological settings surrounding each location. Relatively homogeneous high radon levels occur in all investigated touristic caves and in Tăuşoare and Vântului along their main galleries. Except for Muierii, in all the other caves radon levels are higher during the warm season, compared to the cold one. This suggests that natural cave ventilation largely controls the underground accumulation of radon. The results reported here reveal that the occupational exposure in Urşilor, Vadu Crişului, Tăuşoare, Vântului, and Muierii caves needs to be carefully monitored. The effective doses to workers vary between an average of 0.25 and 4.39 mSv/year depending on the measuring season. The highest values were recorded in show caves, ranging from 1.15 to 6.15 mSv/year, well above the European recommended limit, thus posing a potential health hazard upon cave guides, cavers, and scientists.

Low-level maternal exposure to nicotine associates with significant metabolic perturbations in second-trimester amniotic fluid.

PubMed

Fischer, S Taylor; Lili, Loukia N; Li, Shuzhao; Tran, ViLinh T; Stewart, Kim B; Schwartz, Charles E; Jones, Dean P; Sherman, Stephanie L; Fridovich-Keil, Judith L

2017-10-01

Decades of public health research have documented that smoking in pregnancy poses significant health risks to both mother and child. More recent studies have shown that even passive maternal exposure to secondhand smoke associates with negative birth outcomes. However, the mechanisms linking exposure to outcomes have remained obscure. As a first step toward defining the metabolic consequence of low-level nicotine exposure on fetal development, we conducted an untargeted metabolomic analysis of 81 paired samples of maternal serum and amniotic fluid collected from karyotypically normal pregnancies in the second trimester. By comparing the m/z and retention times of our mass spectral features with confirmed standards, we identified cotinine, a nicotine derivative, and used the calculated cotinine concentrations to classify our maternal serum samples into exposure groups using previously defined cut-offs. We found that cotinine levels consistent with low-level maternal exposure to nicotine associated with distinct metabolic perturbations, particularly in amniotic fluid. In fact, the metabolic effects in amniotic fluid of ostensibly low-level exposed mothers showed greater overlap with perturbations previously observed in the sera of adult smokers than did the perturbations observed in the corresponding maternal sera. Dysregulated fetal pathways included aspartate and asparagine metabolism, pyrimidine metabolism, and metabolism of other amino acids. We also observed a strong negative association between level of maternal serum cotinine and acetylated polyamines in the amniotic fluid. Combined, these results confirm that low-level maternal nicotine exposure, indicated by a maternal serum cotinine level of 2-10ng/mL, is associated with striking metabolic consequences in the fetal compartment, and that the affected pathways overlap those perturbed in the sera of adult smokers. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of the lipid regulating drug clofibric acid on PPARα-regulated gene transcript levels in common carp (Cyprinus carpio) at pharmacological and environmental exposure levels.

PubMed

Corcoran, Jenna; Winter, Matthew J; Lange, Anke; Cumming, Rob; Owen, Stewart F; Tyler, Charles R

2015-04-01

In mammals, the peroxisome proliferator-activated receptor α (PPARα) plays a key role in regulating various genes involved in lipid metabolism, bile acid synthesis and cholesterol homeostasis, and is activated by a diverse group of compounds collectively termed peroxisome proliferators (PPs). Specific PPs have been detected in the aquatic environment; however little is known on their pharmacological activity in fish. We investigated the bioavailability and persistence of the human PPARα ligand clofibric acid (CFA) in carp, together with various relevant endpoints, at a concentration similar to therapeutic levels in humans (20mg/L) and for an environmentally relevant concentration (4μg/L). Exposure to pharmacologically-relevant concentrations of CFA resulted in increased transcript levels of a number of known PPARα target genes together with increased acyl-coA oxidase (Acox1) activity, supporting stimulation of lipid metabolism pathways in carp which are known to be similarly activated in mammals. Although Cu,Zn-superoxide dismutase (Sod1) activity was not affected, mRNA levels of several biotransformation genes were also increased, paralleling previous reports in mammals and indicating a potential role in hepatic detoxification for PPARα in carp. Importantly, transcription of some of these genes (and Acox1 activity) were affected at exposure concentrations comparable with those reported in effluent discharges. Collectively, these data suggest that CFA is pharmacologically active in carp and has the potential to invoke PPARα-related responses in fish exposed in the environment, particularly considering that CFA may represent just one of a number of PPAR-active compounds present to which wild fish may be exposed. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Effects of the lipid regulating drug clofibric acid on PPARα-regulated gene transcript levels in common carp (Cyprinus carpio) at pharmacological and environmental exposure levels

PubMed Central

Corcoran, Jenna; Winter, Matthew J.; Lange, Anke; Cumming, Rob; Owen, Stewart F.; Tyler, Charles R.

2015-01-01

In mammals, the peroxisome proliferator-activated receptor α (PPARα) plays a key role in regulating various genes involved in lipid metabolism, bile acid synthesis and cholesterol homeostasis, and is activated by a diverse group of compounds collectively termed peroxisome proliferators (PPs). Specific PPs have been detected in the aquatic environment; however little is known on their pharmacological activity in fish. We investigated the bioavailability and persistence of the human PPARα ligand clofibric acid (CFA) in carp, together with various relevant endpoints, at a concentration similar to therapeutic levels in humans (20 mg/L) and for an environmentally relevant concentration (4 μg/L). Exposure to pharmacologically-relevant concentrations of CFA resulted in increased transcript levels of a number of known PPARα target genes together with increased acyl-coA oxidase (Acox1) activity, supporting stimulation of lipid metabolism pathways in carp which are known to be similarly activated in mammals. Although Cu,Zn-superoxide dismutase (Sod1) activity was not affected, mRNA levels of several biotransformation genes were also increased, paralleling previous reports in mammals and indicating a potential role in hepatic detoxification for PPARα in carp. Importantly, transcription of some of these genes (and Acox1 activity) were affected at exposure concentrations comparable with those reported in effluent discharges. Collectively, these data suggest that CFA is pharmacologically active in carp and has the potential to invoke PPARα-related responses in fish exposed in the environment, particularly considering that CFA may represent just one of a number of PPAR-active compounds present to which wild fish may be exposed. PMID:25749508

Exposure setup to study potential adverse effects at GSM 1800 and UMTS frequencies on the auditory systems of rats.

PubMed

Lopresto, V; Pinto, R; De Vita, A; Mancini, S; Galloni, P; Marino, C; Ravazzani, P; Lovisolo, G A

2007-01-01

To investigate possible biological effects of exposure to electromagnetic (EM) fields at the frequencies of global system for mobile communication (GSM) 1800 system and universal mobile telecommunication system (UMTS) on the auditory system of rats, an exposure setup for in vivo experiments is presented. The study was carried out in the framework of two European research projects. The target of the investigation was the cochlea. A dosimetric study was performed, both numerically and through direct measurements, to assess the interaction of the radiated fields and the dose distribution in the biological target. For the local exposure of rats, a loop antenna operating at the frequency bands of interest was designed, realised and characterised through numerical and experimental dosimetric procedures. Moreover, an exposure apparatus was set up, consisting of three arrays of four loop antennas, placed on three levels, thus allowing simultaneous exposure of 12 rats to give statistical power to the experiments. To isolate the exposure arrays, the setup was assembled by a wooden rack with EM field absorbing panels, inserted among the levels and at the four sides of the rack. Isolation was verified by direct measurements. Two exposure arrays were simultaneously supplied, whereas the third one was used for sham exposure. Blind exposure was achieved through a black box, hiding physical connections to the microwave power supply. During exposure sessions, rats were restrained in special plastic jigs for repeatable positioning, thus assuring the fixed level of dose in the target.

Intra‐Target Microdosing – A Novel Drug Development Approach: Proof of Concept, Safety, and Feasibility Study in Humans

PubMed Central

MacLeod, D; Lee, K; Santoro, A; DeMasi, DK; Hawk, T; Feinglos, M; Rowland, M; Noveck, RJ

2017-01-01

Abstract Intra‐Target Microdosing (ITM) is a novel drug development approach aimed at increasing the efficiency of first‐in‐human (FIH) testing of new molecular entities (NMEs). ITM combines intra‐target drug delivery and “microdosing,” the subpharmacological systemic exposure. We hypothesized that when the target tissue is small (about 1/100th of total body mass), ITM can lead to target therapeutic‐level exposure with minimal (microdose) systemic exposure. Each of five healthy male volunteers received insulin microdose into the radial artery or full therapeutic dose intravenously in separate visits. Insulin and glucose levels were similar between systemic administration and ITM administration in the ipsilateral hand, and glucose levels demonstrated a reduction in the ipsilateral hand but not in the contralateral hand. Positron emission tomography (PET) imaging of 18F‐fluorodeoxyglucose (FDG) uptake demonstrated differences between the ipsilateral and contralateral arms. The procedures were safe and well‐tolerated. Results are consistent with ITM proof‐of‐concept (POC) and demonstrate the ethical, regulatory, and logistical feasibility of the approach. PMID:28689370

Global climate targets and future consumption level: an evaluation of the required GHG intensity

NASA Astrophysics Data System (ADS)

Girod, Bastien; van Vuuren, Detlef Peter; Hertwich, Edgar G.

2013-03-01

Discussion and analysis on international climate policy often focuses on the rather abstract level of total national and regional greenhouse gas (GHG) emissions. At some point, however, emission reductions need to be translated to consumption level. In this article, we evaluate the implications of the strictest IPCC representative concentration pathway for key consumption categories (food, travel, shelter, goods, services). We use IPAT style identities to account for possible growth in global consumption levels and indicate the required change in GHG emission intensity for each category (i.e. GHG emission per calorie, person kilometer, square meter, kilogram, US dollar). The proposed concept provides guidance for product developers, consumers and policymakers. To reach the 2 °C climate target (2.1 tCO2-eq. per capita in 2050), the GHG emission intensity of consumption has to be reduced by a factor of 5 in 2050. The climate targets on consumption level allow discussion of the feasibility of this climate target at product and consumption level. In most consumption categories products in line with this climate target are available. For animal food and air travel, reaching the GHG intensity targets with product modifications alone will be challenging and therefore structural changes in consumption patterns might be needed. The concept opens up possibilities for further research on potential solutions on the consumption and product level to global climate mitigation.

Effects of Low-Level Blast Exposure on the Nervous System: Is There Really a Controversy?

PubMed Central

Elder, Gregory A.; Stone, James R.; Ahlers, Stephen T.

2014-01-01

High-pressure blast waves can cause extensive CNS injury in human beings. However, in combat settings, such as Iraq and Afghanistan, lower level exposures associated with mild traumatic brain injury (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 human beings 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 human beings 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

Validation of Aircraft Noise Prediction Models at Low Levels of Exposure

NASA Technical Reports Server (NTRS)

Page, Juliet A.; Hobbs, Christopher M.; Plotkin, Kenneth J.; Stusnick, Eric; Shepherd, Kevin P. (Technical Monitor)

2000-01-01

Aircraft noise measurements were made at Denver International Airport for a period of four weeks. Detailed operational information was provided by airline operators which enabled noise levels to be predicted using the FAA's Integrated Noise Model. Several thrust prediction techniques were evaluated. Measured sound exposure levels for departure operations were found to be 4 to 10 dB higher than predicted, depending on the thrust prediction technique employed. Differences between measured and predicted levels are shown to be related to atmospheric conditions present at the aircraft altitude.

METHODOLOGICAL ISSUES IN HUMAN EXPOSURE STUDIES OF LOW LEVEL SOLVENT MIXTURES

EPA Science Inventory

The design of appropriate studies to assess the sensory irritant and neurobehavioral-effects of exposure to complex VOC mixtures poses a variety of methodological challenges, particularly at the low levels found in new buildings. or instance, Otto et al (1989) exposed subjects to...

Changes in the emission properties of metallic targets upon exposure to repetitively pulsed laser radiation

NASA Astrophysics Data System (ADS)

Konov, V. I.; Pimenov, S. M.; Prokhorov, A. M.; Chapliev, N. I.

1988-02-01

A scanning electron microscope and a repetitively pulsed CO2 laser are used to reveal the relationships which govern the correlation of the transforming metal surface microrelief with the emission of charged particles and the surface luminescence upon exposure to multipulse laser focusing. It is shown that the effect of sorption and laser-stimulated desorption on the emission signals can manifest itself in different ways depending on the current oscillation mode in the target-vacuum chamber circuit.

Asphalt fume exposure levels in North American asphalt production and roofing manufacturing operations.

PubMed

Axten, Charles W; Fayerweather, William E; Trumbore, David C; Mueller, Dennis J; Sampson, Arthur F

2012-01-01

This study extends by 8 years (1998-2005) a previous survey of asphalt fume exposures within North American asphalt processing and roofing product manufacturing workers. It focuses on characterizing personal, full-shift samples and seeks to address several limitations of the previous survey. Five major roofing manufacturers with established occupational health programs submitted workplace asphalt fume sampling results to a central repository for review and analysis. A certified industrial hygienist-led quality assurance team oversaw the data collection, consolidation, and analysis efforts. The analysis dataset consisted of 1261 personal exposure samples analyzed for total particulate (TP) and benzene soluble fraction (BSF) using existing NIOSH methods. For BSF, the survey's arithmetic (0.25 mg/m(3), SD = 0.62) and geometric (0.12 mg/m(3), GSD = 2.88) means indicate that the industry has sustained the control levels achieved in the late 1980s, early 1990s. Similar results were found for TP. The survey-wide summary statistics are consistent with other post-1990 multi-company exposure studies. Although these findings indicate that currently available controls are capable of achieving substantial (95%) compliance with the current threshold limit value in asphalt processing and inorganic shingle and roll plants, they also show that the majority of plants are not achieving this level of exposure control, and that exposures are significantly higher in plants making other product lines, particularly organic felt products. The current retrospective survey of existing company exposure data, like its predecessor, has several important limitations. These include lack of data on smaller manufacturers and on several commercially important product lines; insufficient information on the prevalence and effectiveness of engineering controls; no standard criteria by which to define and assess exposures in non-routine operations; and a paucity of exposure data collected as part of a

Occupational exposure to Cr(VI): comparison between chromium levels in lymphocytes, erythrocytes, and urine.

PubMed

Lukanova, A; Toniolo, P; Zhitkovich, A; Nikolova, V; Panev, T; Popov, T; Taioli, E; Costa, M

1996-01-01

The relationships between chromium (Cr) levels in lymphocytes, erythrocytes, urine, and ambient air were compared among 14 chrome-platers from a metallurgic plant in Bulgaria and two groups of local controls, one from the same heavily polluted industrial town as the chrome-platers (n = 11) and one from a seaside resort town 100 km away (n = 6). Among the chrome-platers, the Cr concentration in peripheral lymphocytes was positively correlated with total Cr and Cr(VI) levels in ambient air and with Cr excretion in urine. As compared to the controls, the chrome-platers had mean Cr levels in lymphocytes twice as high, in erythrocytes ninefold higher, and in urine fourfold to eightfold higher. Although Cr levels in urine and lymphocytes were similar between the two control groups, levels in erythrocytes were 3 times higher among subjects from the industrial area than among those from the seaside town. The study suggests that lymphocyte Cr could be a good indicator of the Cr body burden caused by high exposures to Cr(VI), such as in electroplating operations. In these conditions, erythrocyte Cr may be less useful, possibly owing to increased toxicity due to the high affinity of erythrocytes for Cr. However, when exposure is lower, such as in most environmental situations, erythrocyte Cr should provide a better and more sensitive index than lymphocyte Cr. By contrast, urinary Cr, which provides information on total Cr exposure, including Cr(III) from dietary and environmental sources, does not seem to be of value for studying occupational exposure to Cr(VI).

Short-term effects of subchronic low-level hydrogen sulfide exposure on oil field workers.

PubMed

Mousa, Haider Abdul-Lateef

2015-01-01

To investigate the short-term effects of low-level hydrogen sulfide (H2S) exposure on oil field workers. Observational study included 34 patients who work at an oil field. All patients were males with age range of 22-60 years (mean 37 years). The data were collected by systematic questionnaire about symptoms. The inclusion criteria of patients were symptoms related to inhalation of H2S gas in the oil field. The complaints should be frequent and relapsed after each gas exposure and disappeared when there was no gas exposure. Exclusion criteria were the symptoms which experienced with or without H2S exposure. The presence of H2S gas was confirmed by valid gas detector devices. The most frequent presenting symptom was nasal bleeding. It was revealed in 18 patients (52.9%). This followed by pharyngeal bleeding, gum bleeding, and bloody saliva (mouth bleeding) which were encountered in five cases for each complaint (14.7%). Other less frequent presenting symptoms were tongue bleeding, bloody sputum, headache, abdominal colic, pharyngeal soreness, fatigue, and sleepiness. Nasal mucosa was the most vulnerable part to H2S effect. Inhalation of H2S produced upper respiratory tract epithelial damage that led to bleeding from nose, pharynx, gum, tongue, trachea, and bronchi. There were no complaints of asthmatic attack upon exposure to low level of H2S. Sunlight had a significant role in reduction of ambient air H2S level.

Does apartment's distance to an in-built transformer room predict magnetic field exposure levels?

PubMed

Huss, Anke; Goris, Kelly; Vermeulen, Roel; Kromhout, Hans

2013-01-01

It has been shown that magnetic field exposure in apartments located directly on top or adjacent to transformer rooms is higher compared with exposure in apartments located further away from the transformer rooms. It is unclear whether this also translates into exposure contrast among individuals living in these apartments. We performed spot measurements of magnetic fields in 35 apartments in 14 apartment buildings with an in-built transformer and additionally performed 24-h personal measurements in a subsample of 24 individuals. Apartments placed directly on top of or adjacent to a transformer room had on average exposures of 0.42 μT, apartments on the second floor on top of a transformer room, or sharing a corner or edge with the transformer room had 0.11 μT, and apartments located further away from the transformer room had levels of 0.06 μT. Personal exposure levels were approximately a factor 2 lower compared with apartment averages, but still showed exposure contrasts, but only for those individuals who live in the apartments directly on top or adjacent to a transformer room compared with those living further away, with 0.23 versus 0.06 μT for personal exposure when indoors, respectively. A classification of individuals into 'high' and 'low' exposed based on the location of their apartment within a building with an in-built transformer is possible and could be applied in future epidemiological studies.

Health effects of subchronic exposure to environmental levels of diesel exhaust.

PubMed

Reed, M D; Gigliotti, A P; McDonald, J D; Seagrave, J C; Seilkop, S K; Mauderly, J L

2004-04-01

Diesel exhaust is a public health concern and contributor to both ambient and occupational air pollution. As part of a general health assessment of multiple anthropogenic source emissions conducted by the National Environmental Respiratory Center (NERC), a series of health assays was conducted on rats and mice exposed to environmentally relevant levels of diesel exhaust. This article summarizes the study design and exposures, and reports findings on several general indicators of toxicity and carcinogenic potential. Diesel exhaust was generated from a commonly used 2000 model 5.9-L, 6-cylinder turbo diesel engine operated on a variable-load heavy-duty test cycle burning national average certification fuel. Animals were exposed to clean air (control) or four dilutions of whole emissions based on particulate matter concentration (30, 100, 300, and 1000 microg/m(3)). Male and female F344 rats and A/J mice were exposed by whole-body inhalation 6 h/day, 7 days/wk, for either 1 wk or 6 mo. Exposures were characterized in detail. Effects of exposure on clinical observations, body and organ weights, serum chemistry, hematology, histopathology, bronchoalveolar lavage, and serum clotting factors were mild. Significant exposure-related effects occurring in both male and female rats included decreases in serum cholesterol and clotting Factor VII and slight increases in serum gamma-glutamyl transferase. Several other responses met screening criteria for significant exposure effects but were not consistent between genders or exposure times and were not corroborated by related parameters. Carcinogenic potential as determined by micronucleated reticulocyte counts and proliferation of adenomas in A/J mice were unaffected by 6 mo of exposure. Parallel studies demonstrated effects on cardiac function and resistance to viral infection; however, the results reported here show few and only modest health hazards from subchronic or shorter exposures to realistic concentrations of

Exposure to low levels of hydrogen sulfide elevates circulating glucose in maternal rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hayden, L.J.; Goeden, H.; Roth, S.H.

1990-09-01

Although the lethal effect of hydrogen sulfide (H{sub 2}S) has long been known, the results of exposure to low levels of H{sub 2}S have not been well documented. Rat dams and pups were exposed to low levels of H{sub 2}S (less than or equal to 75 ppm) from d 1 of gestation until d 21 postpartum and analyzed for changes in circulating enzymatic activity and metabolites. Blood glucose was significantly elevated in maternal blood on d 21 postpartum at all exposure levels. This increase in glucose was accompanied by a possible decrease in serum triglyceride in the pups and inmore » the dams on d 21 postpartum. There was no evidence of alterations in serum alkaline phosphatase, lactate dehydrogenase, or serum glutamate oxaloacetate transaminase.« less

Effect of occupational EMF exposure from radar at two different frequency bands on plasma melatonin and serotonin levels.

PubMed

Singh, Sarika; Mani, Kumar Vyonkesh; Kapoor, Neeru

2015-05-01

To delineate the effect of chronic electromagnetic field (EMF) exposure from radar on plasma melatonin and serotonin levels in occupationally exposed military personnel. A total of 166 male military personnel participated in the study out of which only 155 joined for blood draw. They were divided into three sets: Control group (n = 68), exposure group I (n = 40) exposed to 8-12 GHz and exposure group II (n = 58) working with radar at 12.5-18 GHz frequency. The three groups were further split into two groups according to their years of service (up to 10 years and > 10 years) in order to investigate the effect of years of exposure from radar. Melatonin and serotonin levels were estimated by enzyme immunoassay in fasting blood samples collected from 06:00-07:00 h. EMF measurements were recorded at different locations using Satimo EME Guard 'Personal Exposure Meter' and Narda 'Broad Band Field Meter'. The group I exposed population registered a minor though not significant decrease in plasma melatonin concentration while the other group II exposed population registered statistically significant decline in melatonin concentration when compared with controls. Highly significant increase in plasma serotonin levels was found in exposure group II when compared to control whereas marginal non-significant rise was also registered in exposure group I in comparison to control. Exposure in terms of length of service up to 10 years did not produce any significant effect in the indoleamine levels in both the exposure groups when they were compared with their respective control groups. Whereas, length of service greater than 10 years was observed to decrease and increase respectively the melatonin and serotonin concentration significantly in exposure group II but not in exposure group I. However, correlation test did not yield any significant association between years of service and melatonin or serotonin levels respectively in both the exposure sets I and II. No significant

Continuous activation of Nrf2 and its target antioxidant enzymes leads to arsenite-induced malignant transformation of human bronchial epithelial cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Xu; Wang, Dapeng; Department of Toxicology, School of Public Health, Guizhou Medical University, Guiyang, Guizhou

Long-term exposure to arsenite leads to human lung cancer, but the underlying mechanisms of carcinogenesis remain obscure. The transcription factor of nuclear factor-erythroid-2 p45-related factor (Nrf2)-mediated antioxidant response represents a critical cellular defense mechanism and protection against various diseases. Paradoxically, emerging data suggest that the constitutive activation of Nrf2 is associated with cancer development, progression and chemotherapy resistance. However, the role of Nrf2 in the occurrence of cancer induced by long-term arsenite exposure remains to be fully understood. By establishing transformed human bronchial epithelial (HBE) cells via chronic low-dose arsenite treatment, we showed that, in acquiring this malignant phenotype, continuousmore » low level of ROS and sustained enhancement of Nrf2 and its target antioxidant enzyme levels were observed in the later-stage of arsenite-induced cell transformation. The downregulation of Keap1 level may be responsible for the over-activation of Nrf2 and its target enzymes. To validate these observations, Nrf2 was knocked down in arsenite-transformed HBE cells by SiRNA transfection, and the levels of Nrf2 and its target antioxidant enzymes, ROS, cell proliferation, migration, and colony formation were determined following these treatments. Results showed that blocked Nrf2 expression significantly reduced Nrf2 and its target antioxidant enzyme levels, restored ROS levels, and eventually suppressed cell proliferation, migration, and colony formation of the transformed cells. In summary, the results of the study strongly suggested that the continuous activation of Nrf2 and its target antioxidant enzymes led to the over-depletion of intracellular ROS levels, which contributed to arsenite-induced HBE cell transformation. - Highlights: • Low level, long term arsenite exposure induces malignant transformation in vitro. • Long term arsenite exposure reduces ROS and MDA levels. • Long term

Urinary DAP metabolite levels in Thai farmers and their families and exposure to pesticides from agricultural pesticide spraying.

PubMed

Hanchenlaksh, Chalalai; Povey, Andrew; O'Brien, Sarah; de Vocht, Frank

2011-08-01

We conducted a biomarker study to characterise exposure to pesticides among farmers and their families in Thailand to assess the relative importance of the dermal exposure route and to identify important factors that determine exposure levels within farmers' families. Sixteen farmers' families (eight vegetable and eight fruit farmers) participated in the study. Three morning spot urine samples were collected during a pesticide spraying week. Spot samples were grouped by individual and analysed for dialkylphosphate (DAP) metabolites and creatinine. Additional information on exposure and lifestyle was collected by means of questionnaires. Dermal exposure was assessed using a semi-quantitative observational method (DREAM). Urinary DAP levels varied 20-fold between farmers, with average (geometric mean) levels of 51.1 μg/g for vegetable and 122.2 μg/g for fruit farmers. A moderate correlation (r(s)∼0.45) was found between log(e)-transformed DREAM scores and DAP levels. Farmers' urinary metabolite levels were not correlated with those of their spouses (r(s)∼-0.30) or children (r(s)∼-0.00) collected on the same days. Detectable spouses' DAP levels were on average (geometric mean) 13.0 μg/g and those of children 7.6 μg/g. Farmers in Thailand as well as their families are exposed to pesticides in the spraying season and dermal exposure is an important route. The main route of exposure for farmers' families seems to be through transfer from the farmer to family members or contamination of the home environment, rather than family members helping or playing on the farm. Showering or washing immediately after pesticide spraying greatly reduces the potential exposure of family members to pesticide residues.

Occupational EMF exposure from radar at X and Ku frequency band and plasma catecholamine levels.

PubMed

Singh, Sarika; Kapoor, Neeru

2015-09-01

Workers in certain occupations such as the military may be exposed to technical radiofrequency radiation exposure above current limits, which may pose a health risk. The present investigation intended to find the effect of chronic electromagnetic field (EMF) exposure from radar on plasma catecholamines in the military workforce. In the study, 166 male personnel selected randomly were categorized into three groups: control (n = 68), exposure group-I (X-band, 8-12 GHz, n = 40), and exposure group-II (Ku-band, 12.5-18 GHz, n = 58). The three clusters were further divided into two groups according to their years of service (YOS) (up to 9 years and ≥10 years) to study the effect of years of radar exposure. Enzyme immunoassay was employed to assess catecholamine concentrations. EMF levels were recorded at different occupational distances from radar. Significant adrenaline diminution was registered in exposure group-II with no significant difference in exposure group-I when both groups were weighed against control. Nor-adrenaline and dopamine levels did not vary significantly in both exposure groups when compared to controls. Exposure in terms of YOS also did not yield any significant alteration in any of the catecholamines and in any of the exposure groups when compared with their respective control groups. The shift from baseline catecholamine values due to stress has immense significance for health and well-being. Their continual alteration may prove harmful in due course. Suitable follow-up studies are needed to further strengthen these preliminary observations and for now, exposures should be limited as much as possible with essential safeguards. © 2015 Wiley Periodicals, Inc.

Outdoor exposure and vitamin D levels in urban children with asthma.

PubMed

Bose, Sonali; Breysse, Patrick N; McCormack, Meredith C; Hansel, Nadia N; Rusher, Robert R; Matsui, Elizabeth; Peng, Roger; Curtin-Brosnan, Jean; Diette, Gregory B

2013-06-12

The inner-city pediatric population in the United States has a disproportionate burden of asthma. Recent attention has focused on the immunomodulatory role of vitamin D, which may be protective against disease morbidity. As the primary determinant of vitamin D status in humans is exposure to sunlight, we aimed to determine if 25-OH vitamin D levels in urban preschool children with asthma were low, influenced by time spent outdoors, and associated with asthma morbidity. Serum 25-OH vitamin D levels were measured at baseline in a cohort of 121 inner-city children ages 2-6 years with asthma in Baltimore, MD. Participants were followed longitudinally at 3 and 6 months to assess time spent outdoors, asthma symptoms through questionnaires and daily diaries, and allergic markers. In a predominantly black population of preschool children, the median 25-OH vitamin D level was 28 ng/mL (IQR 21.2-36.9), with 54% of the children below the traditionally sufficient level of 30 ng/mL and 7.4% in the range associated with risk of rickets (< 15 ng/mL). The median time spent outdoors was 3 hours/day (IQR 2-4), and greater time spent outdoors was not associated with higher vitamin D levels. 25-OH vitamin D did not show seasonal variation in our cohort (p = 0.66). Lower 25-OH levels were correlated with higher IgE levels. Urban African-American preschool children with asthma have high rates of vitamin D insufficiency, and increased outdoor exposure is unlikely to correct these low 25-OH vitamin D levels. Repletion in this population may require dietary supplementation.

Elevated lead levels from e-waste exposure are linked to decreased olfactory memory in children.

PubMed

Zhang, Bo; Huo, Xia; Xu, Long; Cheng, Zhiheng; Cong, Xiaowei; Lu, Xueling; Xu, Xijin

2017-12-01

Lead (Pb) is a developmental neurotoxicant and can cause abnormal development of the nervous system in children. Hence, the aim of this study was to investigate the effect of Pb exposure on child olfactory memory by correlating the blood Pb levels of children in Guiyu with olfactory memory tests. We recruited 61 preschool children, 4- to 7-years of age, from Guiyu and 57 children from Haojiang. The mean blood Pb level of Guiyu children was 9.40 μg/dL, significantly higher than the 5.04 μg/dL mean blood Pb level of Haojiang children. In addition, approximately 23% of Guiyu children had blood Pb levels exceeding 10.00 μg/dL. The correlation analysis showed that blood Pb levels in children highly correlated with e-waste contact (r s  = 0.393). Moreover, the mean concentration of serum BDNF in Guiyu children (35.91 ng/ml) was higher than for Haojiang (28.10 ng/ml) and was positively correlated with blood Pb levels. Both item and source olfactory memory tests at 15 min, 5 h and 24 h after odor exposure showed that scores were lower in Guiyu children indicative of reduced olfactory memory in Guiyu children. Olfactory memory tests scores negatively correlated with blood Pb and serum BDNF levels, but were positively associated with parental education levels. At the same time, scores of both tests on children in the high blood Pb level group (blood Pb levels > 5.00 μg/dL) were lower than those in the low blood Pb level group (blood Pb levels ≤ 5.00 μg/dL), implying that Pb exposure decreases olfactory memory in children. Our findings suggest that Pb exposure in e-waste recycling and dismantling areas could result in an increase in serum BDNF level and a decrease in child olfactory memory, in addition, BDNF might be involved in olfactory memory impairment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects from environmental Mn exposures: a review of the evidence from non-occupational exposure studies.

PubMed

Hudnell, H K

1999-01-01

The risk posed to human health by environmental manganese exposure is unknown. Occupational-exposure outcomes may not extrapolate to environmental exposures due to the healthy worker effect and differences in dosage parameters which may affect the biological response. This paper attempts to combine the existing literature on non-occupational Mn exposures with results from our current study in SW Quebec on environmental Mn exposure (Mergler et al., this issue) within the framework of a biologically-based, dose-response (BBDR) model. BBDR MODEL: The basic BBDR model consists of seven stages relating exposure to health effects. The stages are: 1) sources, 2) applied dose, 3) absorbed dose, 4) target-site dose, 5) toxic event, 6) measurable change, and 7) health outcome. Several air monitoring programs, such as the PTEAM study (Riverside, CA, 1990, mean PM10 Mn outdoor-airborne 24 h average = 0.045 microgram/m3), provided data relevant to the estimation of Mn applied dose, but did not include measures of body burden. Data from the SW Quebec study showed a mean total-particulate airborne Mn concentration of 0.022 microgram/m3 with a range of 0.009 to 0.035 microgram/m3 across four sampling sites, whereas the EPA reference concentration (RfC) is 0.05 microgram/m3. EPA has considered tap water levels to be safe below 200 micrograms/l Mn, and mean Mn tap-water (MnW) level in the participants' homes was 6.38 +/- 11.95 micrograms/l with a range from 0.1 to 158.9 micrograms/l Mn. A previous study of MnW exposure in Greece reported Mn levels in areas with low, medium and high MnW ranging from 4 to 2,300 micrograms/l and a significant association with Mn in hair but not Mn in blood (MnB). The mean absorbed dose of the SW Quebec study participants, as indicated by MnB, was 7.5 +/- 2.3 micrograms/l with a range of 2.5 to 15.9 micrograms/l. Our study and others on environmental Mn exposure did not provide an estimate of target-site dose. However, a significant correlation (r = 0

Estimation of mouth level exposure to smoke constituents of cigarettes with different tar levels using filter analysis.

PubMed

Hyodo, T; Minagawa, K; Inoue, T; Fujimoto, J; Minami, N; Bito, R; Mikita, A

2013-12-01

A nicotine part-filter method can be applied to estimate smokers' mouth level exposure (MLE) to smoke constituents. The objectives of this study were (1) to generate calibration curves for 47 smoke constituents, (2) to estimate MLE to selected smoke constituents using Japanese smokers of commercially available cigarettes covering a wide range of International Organization for Standardization tar yields (1-21mg/cigarette), and (3) to investigate relationships between MLE estimates and various machine-smoking yields. Five cigarette brands were machine-smoked under 7 different smoking regimes and smoke constituents and nicotine content in part-filters were measured. Calibration curves were then generated. Spent cigarette filters were collected from a target of 50 smokers for each of the 15 brands and a total of 780 filters were obtained. Nicotine content in part-filters was then measured and MLE to each smoke constituent was estimated. Strong correlations were identified between nicotine content in part-filters and 41 out of the 47 smoke constituent yields. Estimates of MLE to acetaldehyde, acrolein, 1,3-butadiene, benzene, benzo[a]pyrene, carbon monoxide, and tar showed significant negative correlations with corresponding constituent yields per mg nicotine under the Health Canada Intense smoking regime, whereas significant positive correlations were observed for N-nitrosonornicotine and (4-methylnitrosoamino)-1-(3-pyridyl)-1-butanone. Copyright © 2013 Elsevier Inc. All rights reserved.

Assessment of ultrafine particles in Portuguese preschools: levels and exposure doses.

PubMed

Fonseca, J; Slezakova, K; Morais, S; Pereira, M C

2014-12-01

The aim of this work was to assess ultrafine particles (UFP) number concentrations in different microenvironments of Portuguese preschools and to estimate the respective exposure doses of UFP for 3-5-year-old children (in comparison with adults). UFP were sampled both indoors and outdoors in two urban (US1, US2) and one rural (RS1) preschool located in north of Portugal for 31 days. Total levels of indoor UFP were significantly higher at the urban preschools (mean of 1.82 × 10(4) and 1.32 × 10(4) particles/cm(3) at US1 an US2, respectively) than at the rural one (1.15 × 10(4) particles/cm(3) ). Canteens were the indoor microenvironment with the highest UFP (mean of 5.17 × 10(4) , 3.28 × 10(4) , and 4.09 × 10(4) particles/cm(3) at US1, US2, and RS1), whereas the lowest concentrations were observed in classrooms (9.31 × 10(3) , 11.3 × 10(3) , and 7.14 × 10(3) particles/cm(3) at US1, US2, and RS1). Mean indoor/outdoor ratios (I/O) of UFP at three preschools were lower than 1 (0.54-0.93), indicating that outdoor emissions significantly contributed to UFP indoors. Significant correlations were obtained between temperature, wind speed, relative humidity, solar radiation, and ambient UFP number concentrations. The estimated exposure doses were higher in children attending urban preschools; 3-5-year-old children were exposed to 4-6 times higher UFP doses than adults with similar daily schedules. This study reports information on ultrafine particles (UFPs) in various indoor and outdoor microenvironments (canteens, classrooms, gymnasiums, and outdoor) of urban and rural preschools. It identifies the potential sources and origins, characterizes the influence of meteorological parameters on UFP levels, and performs a comparison with other existing international studies. To this date, relatively few studies have investigated UFP in preschools (none in Portugal) and none assessed exposure dose for different age-groups. The obtained findings showed that levels of UFP in

Staphylococcus aureus methicillin resistance detected by HPLC-MS/MS targeted metabolic profiling.

PubMed

Schelli, Katie; Rutowski, Joshua; Roubidoux, Julia; Zhu, Jiangjiang

2017-03-15

Recently, novel bioanalytical methods, such as NMR and mass spectrometry based metabolomics approaches, have started to show promise in providing rapid, sensitive and reproducible detection of Staphylococcus aureus antibiotic resistance. Here we performed a proof-of-concept study focused on the application of HPLC-MS/MS based targeted metabolic profiling for detecting and monitoring the bacterial metabolic profile changes in response to sub-lethal levels of methicillin exposure. One hundred seventy-seven targeted metabolites from over 20 metabolic pathways were specifically screened and one hundred and thirty metabolites from in vitro bacterial tests were confidently detected from both methicillin susceptible and methicillin resistant Staphylococcus aureus (MSSA and MRSA, respectively). The metabolic profiles can be used to distinguish the isogenic pairs of MSSA strains from MRSA strains, without or with sub-lethal levels of methicillin exposure. In addition, better separation between MSSA and MRSA strains can be achieved in the latter case using principal component analysis (PCA). Metabolite data from isogenic pairs of MSSA and MRSA strains were further compared without and with sub-lethal levels of methicillin exposure, with metabolic pathway analyses additionally performed. Both analyses suggested that the metabolic activities of MSSA strains were more susceptible to the perturbation of the sub-lethal levels of methicillin exposure compared to the MRSA strains. Copyright © 2016 Elsevier B.V. All rights reserved.

Association of hypothyroidism with low-level arsenic exposure in rural West Texas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gong, Gordon, E-mail: gordon.gong@ttuhsc.edu; Basom, Janet; Department of Family and Community Medicine, Texas Tech University Health Sciences Center, Lubbock, TX

It has been reported recently that a higher airborne arsenic level was correlated with higher urinary arsenic concentration and lower serum thyroxin level among urban policemen and rural highway workmen in Italy. The current study was to determine whether exposure to low-level arsenic groundwater (2–22 µg/L) is associated with hypothyroidism among 723 participants (118 male and 267 female Hispanics; 108 male and 230 female non-Hispanic whites, NHW) living in rural West Texas counties. Arsenic and iodine levels in their groundwater used for drinking and or cooking were estimated by the inverse distance weighted (IDW) interpolation technique. Groundwater arsenic was ≥8more » µg/L in 36% of the subjects' wells while iodine concentration was <1 µg/L in 91% of their wells. Logistic regression analysis showed that arsenic in groundwater ≥8 µg/L and cumulative arsenic exposure (groundwater arsenic concentration multiplied by the number of years living in the current address) but not groundwater iodine concentration were significant predictors for hypothyroidism among Hispanics (p<0.05) but not NHW after adjusting for covariates such as age, gender, annual household income and health insurance coverage. The ethnic difference may be due to a marginally higher percentage of Hispanics (p=0.0622) who lived in areas with groundwater arsenic ≥8 µg/L compared with NHW. The prevalence of hypothyroidism was significantly higher in Hispanics or NHW of this rural cohort than the national prevalence. Measures should be taken to reduce arsenic in drinking water in order to prevent hypothyroidism in rural areas. - Highlights: • We determined if arsenic exposure is associated with hypothyroidism in rural Texas. • Groundwater arsenic level is associated with hypothyroidism among Hispanics only. • The rate of hypothyroidism in rural Texas was higher than the US general population.« less

Integrated toxic evaluation of sulfamethazine on zebrafish: Including two lifespan stages (embryo-larval and adult) and three exposure periods (exposure, post-exposure and re-exposure).

PubMed

Yan, Zhengyu; Yang, Qiulian; Jiang, Weili; Lu, Jilai; Xiang, Zhongrun; Guo, Ruixin; Chen, Jianqiu

2018-03-01

Persistence of antibiotics in aquatic environment may pose a risk to the non-target aquatic organisms. This study provided an integrated evaluation to analyze the toxic stress of sulfamethazine (SMZ) on zebrafish in two lifespan stages (embryo-larval and adult) and three exposure periods (exposure, post-exposure and re-exposure). Zebrafish embryos and adult zebrafish were exposed to SMZ at 0.2, 20 and 2000 μg/L, respectively. The results showed that SMZ at any given concentration inhibited the hatching of embryos at 58-96 hpf (hours post-fertilization). Our result also indicated that two major kinds of the malformation, which was induced by the antibiotic, were edema and spinal curvature. Additionally, the antibiotic stimulated the heartbeat while reduced the body length of the embryo at 72 hpf. Superoxide dismutase (SOD) activities and malondialdehyde (MDA) contents significantly increased at 120 hpf when the embryos were exposed to the lowest concentration (0.2 μg/L) of the antibiotic. On the other hand, the antibiotic induced SOD activities and MDA contents in adult zebrafish in the exposure and re-exposure periods. The MDA contents could recover while SOD activities still increased in 2 d after the exposure. Both SOD activities and MDA contents could recover in 7 d after the exposure. Levels of SOD and MDA in the re-exposure were higher than those in the first exposure. Our results suggested that SMZ had toxic effects on both embryos and adult zebrafish, and provided an integrated evaluation of the toxic effects of SMZ on zebrafish at a new perspective. Copyright © 2017 Elsevier Ltd. All rights reserved.

Multiple context mere exposure: Examining the limits of liking.

PubMed

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

2016-01-01

Recent evidence suggests that increased liking of exposed stimuli-a phenomenon known as the mere exposure effect-is dependent on experiencing the stimuli in the same context at exposure and test. Three experiments extended this work by examining the effect of presenting target stimuli in single and multiple exposure contexts. Target face stimuli were repeatedly paired with nonsense words, which took the role of contexts, across exposure. On test, the mere exposure effect was found only when the target face stimuli were presented with nonsense word cues (contexts) with which they had been repeatedly paired. The mere exposure effect was eliminated when exposure to target face stimuli with the nonsense word cues (contexts) was minimal, despite the overall number of exposures to the target face being equated across single- and multiple-context exposure conditions. The results suggest that familiarity of the relationship between stimuli and their context, not simply familiarity of the stimuli themselves, leads to liking. The finding supports a broader framework, which suggests that liking is partly a function of the consistency between past and present experiences with a target stimulus.

Exposure-dependent variation in cryolite induced lethality in the non-target insect, Drosophila melanogaster

PubMed Central

Podder, Sayanti

2014-01-01

The starting point of toxicity testing of any chemical in an organism is the determination of its Lethal Concentration 50 (LC50). In the present study, LC50 of a fluorinated insecticide cryolite is determined in a non-target insect model, Drosophila melanogaster. Interestingly, the result shows that acute LC50 of cryolite was much greater in comparison to the chronic one in case of Drosophila larvae. Larvae which were exposed to 65,000 to 70,000 µg/ml cryolite through food showed 50% mortality after 18 hours of acute exposure, whereas only 150 to 160 µg/ml cryolite was sufficient to cause 50% mortality in case of chronic exposure. Thus cryolite in a small amount when applied once cannot produce noticeable changes in Drosophila, whereas the same amount when used continuously can be fatal. The non-feeding pupal stage was also seen to be affected by chemical treatment. This suggests that the test chemical affects the developmental fate and results in failure of adult emergence. Absence of chemical-induced mortality in adults assumes that the toxicity of cryolite might be restricted to the preimaginal stages of the organism. Reduction in body size of larvae after ingestion of cryolite (with food) in acute treatment schedule is another interesting finding of this study. Some individuals consuming cryolite containing food cannot survive whereas the few survivors manifest a significant growth retardation which might be due to a tendency of refusal in feeding. Hence the present findings provide a scope of assessment of risk of other similar non-target groups. PMID:26038671

The Variation of Work Productivity and Muscle Activities at Different Levels of Production Target

NASA Astrophysics Data System (ADS)

Nur, Nurhayati Mohd; Dawal, Siti Zawiah Md; Dahari, Mahidzal; Zuhairah Mahmud Zuhudi, Nurul

2017-10-01

This paper aims to investigate the variation of work productivity and muscle activities among workers performing industrial repetitive tasks at four different levels of production target. The work productivity and muscle activities data were recorded from twenty workers at four levels of production target corresponding to “participative (PS1)”, “normal (PS2)”, “high (PS3)” and “very high (PS4)”. The results showed that worker productivity was found to increase at higher production target and there was a significant change (p < 0.005) in work productivity across the four different production targets. The muscle activities were found to increase at higher production target and correspond to more discomfort and a higher rate of muscle fatigue. The results indicated that working with a higher production target results in higher worker productivity, but could lead to higher risk of WMSDs.

The relationship between blood lead levels and occupational exposure in a pregnant population.

PubMed

La-Llave-León, Osmel; Salas Pacheco, José Manuel; Estrada Martínez, Sergio; Esquivel Rodríguez, Eloísa; Castellanos Juárez, Francisco X; Sandoval Carrillo, Ada; Lechuga Quiñones, Angélica María; Vázquez Alanís, Fernando; García Vargas, Gonzalo; Méndez Hernández, Edna Madai; Duarte Sustaita, Jaime

2016-12-07

Pregnant women exposed to lead are at risk of suffering reproductive damages, such as miscarriage, preeclampsia, premature delivery and low birth weight. Despite that the workplace offers the greatest potential for lead exposure, there is relatively little information about occupational exposure to lead during pregnancy. This study aims to assess the association between blood lead levels and occupational exposure in pregnant women from Durango, Mexico. A cross-sectional study was carried out in a population of 299 pregnant women. Blood lead was measured in 31 women who worked in jobs where lead is used (exposed group) and 268 who did not work in those places (control group). Chi-square test was applied to compare exposed and control groups with regard to blood lead levels. Odds ratio (OR) and 95% confidence intervals (CI) were calculated. Multivariable regression analysis was applied to determine significant predictors of blood lead concentrations in the exposed group. Exposed women had higher blood lead levels than those in the control group (4.00 ± 4.08 μg/dL vs 2.65 ± 1.75 μg/dL, p = 0.002). Furthermore, women in the exposed group had 3.82 times higher probability of having blood lead levels ≥ 5 μg/dL than those in the control group. Wearing of special workwear, changing clothes after work, living near a painting store, printing office, junkyard or rubbish dump, and washing the workwear together with other clothes resulted as significant predictors of elevated blood lead levels in the exposed group. Pregnant working women may be at risk of lead poisoning because of occupational and environmental exposure. The risk increases if they do not improve the use of protective equipment and their personal hygiene.

Postnatal odorant exposure induces peripheral olfactory plasticity at the cellular level.

PubMed

Cadiou, Hervé; Aoudé, Imad; Tazir, Bassim; Molinas, Adrien; Fenech, Claire; Meunier, Nicolas; Grosmaitre, Xavier

2014-04-02

Mammalian olfactory sensory neurons (OSNs) form the primary elements of the olfactory system. Inserted in the olfactory mucosa lining of the nasal cavity, they are exposed to the environment and their lifespan is brief. Several reports say that OSNs are regularly regenerated during the entire life and that odorant environment affects the olfactory epithelium. However, little is known about the impact of the odorant environment on OSNs at the cellular level and more precisely in the context of early postnatal olfactory exposure. Here we exposed MOR23-green fluorescent protein (GFP) and M71-GFP mice to lyral or acetophenone, ligands for MOR23 or M71, respectively. Daily postnatal exposure to lyral induces plasticity in the population of OSNs expressing MOR23. Their density decreases after odorant exposure, whereas the amount of MOR23 mRNA and protein remain stable in the whole epithelium. Meanwhile, quantitative PCR indicates that each MOR23 neuron has higher levels of olfactory receptor transcripts and also expresses more CNGA2 and phosphodiesterase 1C, fundamental olfactory transduction pathway proteins. Transcript levels return to baseline after 4 weeks recovery. Patch-clamp recordings reveal that exposed MOR23 neurons respond to lyral with higher sensitivity and broader dynamic range while the responses' kinetics were faster. These effects are specific to the odorant-receptor pair lyral-MOR23: there was no effect of acetophenone on MOR23 neurons and no effect of acetophenone and lyral on the M71 population. Together, our results clearly demonstrate that OSNs undergo specific anatomical, molecular, and functional adaptation when chronically exposed to odorants in the early stage of life.

Tadpole swimming performance and activity affected by acute exposure to sublethal levels of carbaryl

USGS Publications Warehouse

Bridges, C.M.

1997-01-01

General activity and swimming performance (i.e., sprint speed and distance) of plains leopard frog tadpoles (Rana blairi) were examined after acute exposure to three sublethal concentrations of carbaryl (3.5, 5.0, and 7.2 mg/L). Both swimming performance and spontaneous swimming activity are important for carrying out life history functions (e.g., growth and development) and for escaping from predators. Measured tadpole activity diminished by nearly 90% at 3.5 mg/L carbaryl and completely ceased at 7.2 mg/L. Sprint speed and sprint distance also decreased significantly following exposure. Carbaryl affected both swimming performance and activity after just 24 h, suggesting that 24 h may be an adequate length of exposure to determine behavioral effects on tadpoles. Slight recovery of activity levels was noted at 24 and 48 h post-exposure; no recovery of swimming performance was observed. Reduction in activity and swimming performance may result in increased predation rates and, because activity is closely associated with feeding, may result in slowed growth leading to a failure to emerge before pond drying or an indirect reduction in adult fitness. Acute exposure to sublethal toxicants such as carbaryl may not only affect immediate survival of tadpoles but also impact critical life history functions and generate changes at the local population level.

Antibiotic Effects on Methicillin-Resistant Staphylococcus aureus Cytoplasmic Peptidoglycan Intermediate Levels and Evidence for Potential Metabolite Level Regulatory Loops.

PubMed

Vemula, Harika; Ayon, Navid J; Burton, Alloch; Gutheil, William G

2017-06-01

Cytoplasmic peptidoglycan (PG) precursor levels were determined in methicillin-resistant Staphylococcus aureus (MRSA) after exposure to several cell wall-targeting antibiotics. Three experiments were performed: (i) exposure to 4× MIC levels (acute); (ii) exposure to sub-MIC levels (subacute); (iii) a time course experiment of the effect of vancomycin. In acute exposure experiments, fosfomycin increased UDP-GlcNAc, as expected, and resulted in substantially lower levels of total UDP-linked metabolite accumulation relative to other pathway inhibitors, indicating reduced entry into this pathway. Upstream inhibitors (fosfomycin, d-cycloserine, or d-boroalanine) reduced UDP-MurNAc-pentapeptide levels by more than fourfold. Alanine branch inhibitors (d-cycloserine and d-boroalanine) reduced d-Ala-d-Ala levels only modestly (up to 4-fold) but increased UDP-MurNAc-tripeptide levels up to 3,000-fold. Downstream pathway inhibitors (vancomycin, bacitracin, moenomycin, and oxacillin) increased UDP-MurNAc-pentapeptide levels up to 350-fold and UDP-MurNAc-l-Ala levels up to 80-fold, suggesting reduced MurD activity by downstream inhibitor action. Sub-MIC exposures demonstrated effects even at 1/8× MIC which strongly paralleled acute exposure changes. Time course data demonstrated that UDP-linked intermediate levels respond rapidly to vancomycin exposure, with several intermediates increasing three- to sixfold within minutes. UDP-linked intermediate level changes were also multiphasic, with some increasing, some decreasing, and some increasing and then decreasing. The total (summed) UDP-linked intermediate pool increased by 1,475 μM/min during the first 10 min after vancomycin exposure, providing a revised estimate of flux in this pathway during logarithmic growth. These observations outline the complexity of PG precursor response to antibiotic exposure in MRSA and indicate likely sites of regulation (entry and MurD). Copyright © 2017 American Society for Microbiology.

Age-specific fluoride exposure in drinking water and osteosarcoma (United States).

PubMed

Bassin, Elise B; Wypij, David; Davis, Roger B; Mittleman, Murray A

2006-05-01

We explored age-specific and gender-specific effects of fluoride level in drinking water and the incidence of osteosarcoma. We used data from a matched case-control study conducted through 11 hospitals in the United States that included a complete residential history for each patient and type of drinking water (public, private well, bottled) used at each address. Our analysis was limited to cases less than 20 years old. We standardized fluoride exposure estimates based on CDC-recommended target levels that take climate into account. We categorized exposure into three groups (<30%, 30-99%, >99% of target) and used conditional logistic regression to estimate odds ratios. Analysis is based on 103 cases under the age of 20 and 215 matched controls. For males, the unadjusted odds ratios for higher exposures were greater than 1.0 at each exposure age, reaching a peak of 4.07 (95% CI 1.43, 11.56) at age 7 years for the highest exposure. Adjusting for potential confounders produced similar results with an adjusted odds ratio for males of 5.46 (95% CI 1.50, 19.90) at age 7 years. This association was not apparent among females. Our exploratory analysis found an association between fluoride exposure in drinking water during childhood and the incidence of osteosarcoma among males but not consistently among females. Further research is required to confirm or refute this observation.

Effects of low-level exposure to xenobiotics present in paints on oxidative stress in workers.

PubMed

Moro, Angela M; Charão, Mariele; Brucker, Natália; Bulcão, Rachel; Freitas, Fernando; Guerreiro, Gilian; Baierle, Marília; Nascimento, Sabrina; Waechter, Fernanda; Hirakata, Vânia; Linden, Rafael; Thiesen, Flávia V; Garcia, Solange Cristina

2010-09-15

Paints are composed of an extensive variety of hazardous substances, such as organic solvents and heavy metals. Biomonitoring is an essential tool for assessing the risk to occupational health. Thus, this study analyzed the levels of biomarkers of exposure for toluene, xylene, styrene, ethylbenzene, and lead, as well as the oxidative stress biomarker alterations in painters of an industry. Lipid peroxidation biomarker (MDA), delta-aminolevulinate dehydratase (ALA-D), nonprotein thyol groups, superoxide dismutase and catalase (CAT) were analyzed in exposed and nonexposed subjects. We estimated which of the paint constituents have the greatest influence on the changes in the biomarkers of oxidative stress in this case of co-exposure. The results demonstrated that despite the fact that all the biomarkers of exposure were below the biological exposure limits, the MDA levels and antioxidant enzyme activities were increased, while nonprotein thyol groups and ALA-D levels were decreased in painters when compared with nonexposed subjects. After statistic test, toluene could be suggested as the principal factor responsible for increased lipid peroxidation and inhibition of ALA-D enzyme; however, further studies on the inhibition of ALA-D enzyme by toluene are necessary. Copyright 2010 Elsevier B.V. All rights reserved.

Prenatal exposure to cannabinoids evokes long-lasting functional alterations by targeting CB1 receptors on developing cortical neurons.

PubMed

de Salas-Quiroga, Adán; Díaz-Alonso, Javier; García-Rincón, Daniel; Remmers, Floortje; Vega, David; Gómez-Cañas, María; Lutz, Beat; Guzmán, Manuel; Galve-Roperh, Ismael

2015-11-03

The CB1 cannabinoid receptor, the main target of Δ(9)-tetrahydrocannabinol (THC), the most prominent psychoactive compound of marijuana, plays a crucial regulatory role in brain development as evidenced by the neurodevelopmental consequences of its manipulation in animal models. Likewise, recreational cannabis use during pregnancy affects brain structure and function of the progeny. However, the precise neurobiological substrates underlying the consequences of prenatal THC exposure remain unknown. As CB1 signaling is known to modulate long-range corticofugal connectivity, we analyzed the impact of THC exposure on cortical projection neuron development. THC administration to pregnant mice in a restricted time window interfered with subcerebral projection neuron generation, thereby altering corticospinal connectivity, and produced long-lasting alterations in the fine motor performance of the adult offspring. Consequences of THC exposure were reminiscent of those elicited by CB1 receptor genetic ablation, and CB1-null mice were resistant to THC-induced alterations. The identity of embryonic THC neuronal targets was determined by a Cre-mediated, lineage-specific, CB1 expression-rescue strategy in a CB1-null background. Early and selective CB1 reexpression in dorsal telencephalic glutamatergic neurons but not forebrain GABAergic neurons rescued the deficits in corticospinal motor neuron development of CB1-null mice and restored susceptibility to THC-induced motor alterations. In addition, THC administration induced an increase in seizure susceptibility that was mediated by its interference with CB1-dependent regulation of both glutamatergic and GABAergic neuron development. These findings demonstrate that prenatal exposure to THC has long-lasting deleterious consequences in the adult offspring solely mediated by its ability to disrupt the neurodevelopmental role of CB1 signaling.

Gestational exposure to urban air pollution related to a decrease in cord blood vitamin d levels.

PubMed

Baïz, Nour; Dargent-Molina, Patricia; Wark, John D; Souberbielle, Jean-Claude; Slama, Rémy; Annesi-Maesano, Isabella

2012-11-01

Vitamin D deficiency has been implicated in the increased risk of several diseases. Exposure to air pollution has been suggested as a contributor to vitamin D deficiency. However, studies that have examined the effects of air pollution on vitamin D status are few and have never focused on prenatal life as an exposure window. Our aim was to investigate the associations between gestational exposure to urban air pollutants and 25-hydroxyvitamin D [25(OH)D] cord blood serum level in 375 mother-child pairs of the EDEN birth cohort. The Atmospheric Dispersion Modelling System (ADMS-Urban) pollution model, a validated dispersion model combining data on traffic conditions, topography, meteorology, and background pollution, was used to assess the concentrations of two major urban pollutants, particulate matter less than 10 μm in diameter (PM(10)) and nitrogen dioxide (NO(2)), at the mother's home address during pregnancy. Cord blood samples were collected at birth and were analyzed for levels of 25(OH)D. Maternal exposure to ambient urban levels of NO(2) and PM(10) during the whole pregnancy was a strong predictor of low vitamin D status in newborns. After adjustment, log-transformed 25(OH)D decreased by 0.15 U (P = 0.05) and 0.41 U (P = 0.04) for a 10-μg/m(3) increase in NO(2) and PM(10) pregnancy levels, respectively. The association was strongest for third-trimester exposures (P = 0.0003 and P = 0.004 for NO(2) and PM(10), respectively). Gestational exposure to ambient urban air pollution, especially during late pregnancy, may contribute to lower vitamin D levels in offspring. This could affect the child's risk of developing diseases later in life.

Low-level cadmium exposure and effects on kidney function

PubMed Central

Wallin, Maria; Sallsten, Gerd; Lundh, Thomas; Barregard, Lars

2014-01-01

Objectives The nephrotoxicity of cadmium at low levels of exposure, measured by urinary cadmium, has recently been questioned since co-excretion of cadmium and proteins may have causes other than cadmium toxicity. The aim of this study was to explore the relation between kidney function and low or moderate cadmium levels, measured directly in kidney biopsies. Methods We analysed cadmium in kidney biopsies (K-Cd), blood (B-Cd) and urine (U-Cd) from 109 living kidney donors in a cross-sectional study. We measured glomerular filtration rate (GFR), cystatin C in serum, albumin, β-2-microglobulin (B2M), retinol-binding protein (RBP), α-1-microglobulin (A1M), N-acetyl-β-d-glucosaminidase and kidney injury molecule 1 (KIM-1) in 24 h and overnight urine. Results We found significant positive associations between A1M excretion and K-Cd in multiple regression models including age, sex, weight, smoking and urinary flow rate. This association was also present in never-smokers. A1M was also positively associated with B-Cd and U-Cd. GFR and the other biomarkers of kidney function were not associated with K-Cd. GFR estimated from serum cystatin C showed a very poor correlation with measured GFR. KIM-1, RBP and possibly albumin were positively associated with U-Cd, but only in overnight urine. No associations were found with B2M. Conclusions Our results suggest that A1M in urine is a sensitive biomarker for effects of low-level cadmium exposure. A few associations between other renal biomarkers and U-Cd, but not K-Cd, were probably caused by physiological co-excretion or chance. PMID:25286916

Estimation of quantitative levels of diesel exhaust exposure and the health impact in the contemporary Australian mining industry.

PubMed

Peters, Susan; de Klerk, Nicholas; Reid, Alison; Fritschi, Lin; Musk, Aw Bill; Vermeulen, Roel

2017-03-01

To estimate quantitative levels of exposure to diesel exhaust expressed by elemental carbon (EC) in the contemporary mining industry and to describe the excess risk of lung cancer that may result from those levels. EC exposure has been monitored in Western Australian miners since 2003. Mixed-effects models were used to estimate EC levels for five surface and five underground occupation groups (as a fixed effect) and specific jobs within each group (as a random effect). Further fixed effects included sampling year and duration, and mineral mined. On the basis of published risk functions, we estimated excess lifetime risk of lung cancer mortality for several employment scenarios. Personal EC measurements (n=8614) were available for 146 different jobs at 124 mine sites. The mean estimated EC exposure level for surface occupations in 2011 was 14 µg/m 3 for 12 hour shifts. Levels for underground occupation groups ranged from 18 to 44 µg/m 3 . Underground diesel loader operators had the highest exposed specific job: 59 µg/m 3 . A lifetime career (45 years) as a surface worker or underground miner, experiencing exposure levels as estimated for 2011 (14 and 44 µg/m 3 EC), was associated with 5.5 and 38 extra lung cancer deaths per 1000 males, respectively. EC exposure levels in the contemporary Australian mining industry are still substantial, particularly for underground workers. The estimated excess numbers of lung cancer deaths associated with these exposures support the need for implementation of stringent occupational exposure limits for diesel exhaust. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Personal formaldehyde exposure level in the gross anatomy dissecting room at College of Medicine King Saud University Riyadh.

PubMed

Vohra, Muhammad Saeed

2011-03-01

This study was conducted to correlate the personal formaldehyde (FA) exposure levels of instructors and students with the indoor FA concentrations in gross anatomy laboratory at King Saud University. The personal FA levels of instructors and students are higher than the indoor FA concentration in the gross anatomy laboratory. The gross anatomy laboratory at college of medicine, King Saud University Riyadh, was observed for indoor FA concentration and the personal exposure levels of instructors and the medical students during the 4th, 10th and 14th weeks of the dissection sessions. All air samples were collected by the diffusive sampling device and analyzed by using high performance liquid chromatography (HPLC). The personal exposure level of FA was higher than the indoor concentration, and the personal exposure levels of instructors were higher than that of the students. The concentration of FA was also higher in the center of the room than the corners and near the doors. Both the indoor FA concentrations and personal FA exposure levels are higher near the dissecting table than at locations away from it during the gross anatomy laboratory sessions. Thus, the instructors and students are exposed to the higher concentration of FA than the general population.

Air-liquid interface exposure to aerosols of poorly soluble nanomaterials induces different biological activation levels compared to exposure to suspensions.

PubMed

Loret, Thomas; Peyret, Emmanuel; Dubreuil, Marielle; Aguerre-Chariol, Olivier; Bressot, Christophe; le Bihan, Olivier; Amodeo, Tanguy; Trouiller, Bénédicte; Braun, Anne; Egles, Christophe; Lacroix, Ghislaine

2016-11-03

Recently, much progress has been made to develop more physiologic in vitro models of the respiratory system and improve in vitro simulation of particle exposure through inhalation. Nevertheless, the field of nanotoxicology still suffers from a lack of relevant in vitro models and exposure methods to predict accurately the effects observed in vivo, especially after respiratory exposure. In this context, the aim of our study was to evaluate if exposing pulmonary cells at the air-liquid interface to aerosols of inhalable and poorly soluble nanomaterials generates different toxicity patterns and/or biological activation levels compared to classic submerged exposures to suspensions. Three nano-TiO 2 and one nano-CeO 2 were used. An exposure system was set up using VitroCell® devices to expose pulmonary cells at the air-liquid interface to aerosols. A549 alveolar cells in monocultures or in co-cultures with THP-1 macrophages were exposed to aerosols in inserts or to suspensions in inserts and in plates. Submerged exposures in inserts were performed, using similar culture conditions and exposure kinetics to the air-liquid interface, to provide accurate comparisons between the methods. Exposure in plates using classical culture and exposure conditions was performed to provide comparable results with classical submerged exposure studies. The biological activity of the cells (inflammation, cell viability, oxidative stress) was assessed at 24 h and comparisons of the nanomaterial toxicities between exposure methods were performed. Deposited doses of nanomaterials achieved using our aerosol exposure system were sufficient to observe adverse effects. Co-cultures were more sensitive than monocultures and biological responses were usually observed at lower doses at the air-liquid interface than in submerged conditions. Nevertheless, the general ranking of the nanomaterials according to their toxicity was similar across the different exposure methods used. We showed that

Characteristics of functional enrichment and gene expression level of human putative transcriptional target genes.

PubMed

Osato, Naoki

2018-01-19

Transcriptional target genes show functional enrichment of genes. However, how many and how significantly transcriptional target genes include functional enrichments are still unclear. To address these issues, I predicted human transcriptional target genes using open chromatin regions, ChIP-seq data and DNA binding sequences of transcription factors in databases, and examined functional enrichment and gene expression level of putative transcriptional target genes. Gene Ontology annotations showed four times larger numbers of functional enrichments in putative transcriptional target genes than gene expression information alone, independent of transcriptional target genes. To compare the number of functional enrichments of putative transcriptional target genes between cells or search conditions, I normalized the number of functional enrichment by calculating its ratios in the total number of transcriptional target genes. With this analysis, native putative transcriptional target genes showed the largest normalized number of functional enrichments, compared with target genes including 5-60% of randomly selected genes. The normalized number of functional enrichments was changed according to the criteria of enhancer-promoter interactions such as distance from transcriptional start sites and orientation of CTCF-binding sites. Forward-reverse orientation of CTCF-binding sites showed significantly higher normalized number of functional enrichments than the other orientations. Journal papers showed that the top five frequent functional enrichments were related to the cellular functions in the three cell types. The median expression level of transcriptional target genes changed according to the criteria of enhancer-promoter assignments (i.e. interactions) and was correlated with the changes of the normalized number of functional enrichments of transcriptional target genes. Human putative transcriptional target genes showed significant functional enrichments. Functional

Interaction between air pollution exposure and genes in relation to levels of inflammatory markers and risk of myocardial infarction

PubMed Central

Panasevich, Sviatlana; Leander, Karin; Ljungman, Petter; Bellander, Tom; de Faire, Ulf; Pershagen, Göran; Nyberg, Fredrik

2013-01-01

Objectives Air pollution exposure induces cardiovascular effects, possibly via systemic inflammation and coagulation misbalance. Genetic variation may determine individual susceptibility. Our aim was to investigate effect modification by inflammation (Interleukin6 (IL6), tumour necrosis factor-α (TNF-α)) and coagulation (fibrinogen Bβ, plasminogen activator inhibitor-1 (PAI-1)) gene variants on the effect of long-term or short-term air pollution exposure on both blood marker levels and non-fatal myocardial infarction (MI) risk. Design Population-based case–control study with a nested case-crossover study. Gene-environment interactions for short-term and long-term air pollution on blood marker levels were studied in population controls, for long-term exposure on MI risk using case–control design, and for short-term exposure on MI onset using case-crossover design. Setting The Stockholm Heart Epidemiology Programme (SHEEP) conducted in 1992–1994 in Stockholm, Sweden. Spatial modelling was used to assess long-term (up to 30 years retrospectively) air pollution exposure to traffic-NO2 and heating-SO2 emissions at home addresses. Urban background NO2, SO2, PM10 and O3 measurements were used to estimate short-term (up to 5 days) air pollution exposure. Participants 1192 MI cases and 1506 population controls aged 45–70 years. Outcomes The levels of blood markers of inflammation (IL-6, TNF-α) and coagulation (fibrinogen, PAI-1) and MI risk. Results We observed gene–environment interaction for several IL6 and TNF SNPs in relation to inflammation blood marker levels. One-year traffic-NO2 exposure was associated with higher IL-6 levels with each additional IL6-174C allele, and 1-year heating-SO2 exposure with higher levels of TNF-α in TNF-308AA homozygotes versus −308G carriers. Short-term air pollution exposure also interacted with IL6 and TNF in relation to marker levels. The risk of MI followed the effect on blood markers in each genotype group

A mathematical model of exposure of non-target Lepidoptera to Bt-maize pollen expressing Cry1Ab within Europe.

PubMed

Perry, J N; Devos, Y; Arpaia, S; Bartsch, D; Gathmann, A; Hails, R S; Kiss, J; Lheureux, K; Manachini, B; Mestdagh, S; Neemann, G; Ortego, F; Schiemann, J; Sweet, J B

2010-05-07

Genetically modified (GM) maize MON810 expresses a Cry1Ab insecticidal protein, derived from Bacillus thuringiensis (Bt), toxic to lepidopteran target pests such as Ostrinia nubilalis. An environmental risk to non-target Lepidoptera from this GM crop is exposure to harmful amounts of Bt-containing pollen deposited on host plants in or near MON810 fields. An 11-parameter mathematical model analysed exposure of larvae of three non-target species: the butterflies Inachis io (L.), Vanessa atalanta (L.) and moth Plutella xylostella (L.), in 11 representative maize cultivation regions in four European countries. A mortality-dose relationship was integrated with a dose-distance relationship to estimate mortality both within the maize MON810 crop and within the field margin at varying distances from the crop edge. Mortality estimates were adjusted to allow for physical effects; the lack of temporal coincidence between the susceptible larval stage concerned and the period over which maize MON810 pollen is shed; and seven further parameters concerned with maize agronomy and host-plant ecology. Sublethal effects were estimated and allowance made for aggregated pollen deposition. Estimated environmental impact was low: in all regions, the calculated mortality rate for worst-case scenarios was less than one individual in every 1572 for the butterflies and one in 392 for the moth.

Evidence for changes in the transcription levels of two putative P-glycoprotein genes in sea lice (Lepeophtheirus salmonis) in response to emamectin benzoate exposure.

PubMed

Tribble, Nicholas D; Burka, John F; Kibenge, Frederick S B

2007-05-01

Overexpression of P-glycoproteins (Pgps) is assumed to be a principal mechanism of resistance of nematodes and arthropods to macrocyclic lactones. Quantitative RT-PCR (Q-RT-PCR) was used to demonstrate changes in transcription levels of two putative P-glycoprotein genes, designated here as SL0525 and SL-Pgp1, in sea lice (Lepeophtheirus salmonis) following exposure to emamectin benzoate (EMB). Pre-adult L. salmonis were challenged in an EMB bioassay for 24h and gene expression was studied from lice surviving EMB concentrations of 0, 10, and 30ppb. Gene expression was measured using Q-RT-PCR with elongation factor 1 (eEF1alpha) as an internal reference gene. The results show that both target genes, SL0525 and SL-Pgp1, had significantly increased levels of expression with exposure to 10ppb EMB (p=0.11 and p=0.17, respectively) whereas the group exposed to 30ppb was on the verge of being significant (p=0.053) only in the expression of SL-Pgp1. Gene expression for SL0525 and SL-Pgp1 were increased over five-fold at 10ppb EMB. Therefore, the upregulation of these target genes may offer protection by increasing Pgp expression when lice are exposed to EMB. Our optimized Q-RT-PCR can be used to determine if over-expression of these genes could be the basis for development of resistance in sea lice and thus allow suitable alternative chemotherapeutic options to be assessed.

[Internal Exposure Levels of PAHs of Primary School Students in Guangzhou].

PubMed

Su, Hui; Zhao, Bo; Zhang, Su-kun; Liu, Shan; Ren, Ming-zhong; Li, Jie; Shi, Xiao-xia

2015-12-01

In order to investigate the internal exposure levels of polycyclic aromatic hydrocarbons (PAHs) in primary school students of Guangzhou, the research collected urine of 78 and 86 primary school students from two primary schools in the summer of 2014, one school located in the ordinary residential area and the other in the industrial area. The contents of 10 kinds of OH-PAHs were tested by the rapid liquid chromatography coupled to triple quadruple tandem mass spectrometry. The results showed that the concentrations of total OH-PAHs in primary school students in the residential zone ranged from 0.83 µmol · mol⁻¹ to 80.63 µmol · mol⁻¹, while those in industrial area ranged from 1.06 µmol · mol⁻¹ to 72.47 µmol · mol⁻¹. The geometric average concentrations were 6.18 µmol · mol⁻¹ and 6.47 µmol · mol⁻¹, respectively, and there was no statistical significance between them (P > 0.05). Comparison of the exposure levels of different components of PAHs in the two areas found that all the OH-PAHs had no significant difference except for the levels of 1- OHP (P < 0.05). We should also pay attention to the higher exposure levels of PAHs in both areas when compared with other researches. In addition, the OH-PAHs in primary school students in the ordinary residential area had a good correlation between 0. 511 and 0.928 (P < 0.01), whereas there was no correlation between 1-OHP and 2-OHN, 1-OHN in the primary school students in the industrial area and other OH-PAHs had relatively weak correlation ranging from 0.338 to 0.855 (P < 0.01). This difference might indicate different pollution sources of PAHs in different functional areas, which was relatively single in the residential area, while the industrial area was polluted by multiple sources of industrial enterprises and logistics transportation emissions.

Cigarettes with different nicotine levels affect sensory perception and levels of biomarkers of exposure in adult smokers.

PubMed

McKinney, Diana L; Frost-Pineda, Kimberly; Oldham, Michael J; Fisher, Michael T; Wang, Jingzhu; Gogova, Maria; Kobal, Gerd

2014-07-01

Few clinical studies involving cigarettes have provided a comprehensive picture of smoke exposure, test article characterization, and insights into sensory properties combined. The purpose of these pilot studies was to determine whether cigarettes with different levels of nicotine but similar tar levels would affect sensory experience or smoking behavior so as to significantly alter levels of selected biomarkers of exposure (BOE). In 2 confined, double-blind studies, 120 adult smokers switched from Marlboro Gold cigarettes at baseline to either 1 of 2 lower nicotine cigarettes or 1 of 2 higher nicotine cigarettes and then to the other cigarette after 5 days. Urinary excretion of exposure biomarkers (nicotine equivalents [NE], total and free 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol [NNAL], 1-hydroxypyrene, and 3-hydroxypropyl mercapturic acid) as well as carboxyhemoglobin and plasma cotinine were measured at baseline, Day 5, and Day 10. Daily cigarette consumption was monitored and sensory characteristics were rated for each cigarette. With higher nicotine yield, urine NE, urine total NNAL, and plasma cotinine increased while nonnicotine BOE decreased without changes in cigarette consumption. In contrast, with lower nicotine yield, urine NE, urine total NNAL, and plasma cotinine dropped while nonnicotine BOE and cigarettes per day increased. Higher nicotine cigarettes were rated harsher and stronger than at baseline while lower nicotine cigarettes were less strong. All 4 test cigarettes were highly disliked. These studies demonstrate that abrupt increases or decreases in nicotine and the resulting sensory changes impact BOE through changes in intensity or frequency of smoking. © The Author 2014. 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.

A tissue dose-based comparative exposure assessment of manganese using physiologically based pharmacokinetic modeling—The importance of homeostatic control for an essential metal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gentry, P. Robinan, E-mail: rgentry@ramboll.com

A physiologically-based pharmacokinetic (PBPK) model (Schroeter et al., 2011) was applied to simulate target tissue manganese (Mn) concentrations following occupational and environmental exposures. These estimates of target tissue Mn concentrations were compared to determine margins of safety (MOS) and to evaluate the biological relevance of applying safety factors to derive acceptable Mn air concentrations. Mn blood concentrations measured in occupational studies permitted verification of the human PBPK models, increasing confidence in the resulting estimates. Mn exposure was determined based on measured ambient air Mn concentrations and dietary data in Canada and the United States (US). Incorporating dietary and inhalation exposuresmore » into the models indicated that increases in target tissue concentrations above endogenous levels only begin to occur when humans are exposed to levels of Mn in ambient air (i.e. > 10 μg/m{sup 3}) that are far higher than those currently measured in Canada or the US. A MOS greater than three orders of magnitude was observed, indicating that current Mn air concentrations are far below concentrations that would be required to produce the target tissue Mn concentrations associated with subclinical neurological effects. This application of PBPK modeling for an essential element clearly demonstrates that the conventional application of default factors to “convert” an occupational exposure to an equivalent continuous environmental exposure, followed by the application of safety factors, is not appropriate in the case of Mn. PBPK modeling demonstrates that the relationship between ambient Mn exposures and dose-to-target tissue is not linear due to normal tissue background levels and homeostatic controls. - Highlights: • Manganese is an essential nutrient, adding complexity to its risk assessment. • Nonlinearities in biological processes are important for manganese risk assessment. • A PBPK model was used to estimate target

Non-targeted and delayed effects of exposure to ionizing radiation: I. Radiation-induced genomic instability and bystander effects in vitro

NASA Technical Reports Server (NTRS)

Morgan, William F.

2003-01-01

A long-standing dogma in the radiation sciences is that energy from radiation must be deposited in the cell nucleus to elicit a biological effect. A number of non-targeted, delayed effects of ionizing radiation have been described that challenge this dogma and pose new challenges to evaluating potential hazards associated with radiation exposure. These effects include induced genomic instability and non-targeted bystander effects. The in vitro evidence for non-targeted effects in radiation biology will be reviewed, but the question as to how one extrapolates from these in vitro observations to the risk of radiation-induced adverse health effects such as cancer remains open.

Radiation exposure in the young level 1 trauma patient: a retrospective review.

PubMed

Gottschalk, Michael B; Bellaire, Laura L; Moore, Thomas

2015-01-01

Computed tomography (CT) has become an increasingly popular and powerful tool for clinicians managing trauma patients with life-threatening injuries, but the ramifications of increasing radiation burden on individual patients are not insignificant. This study examines a continuous series of 337 patients less than 40 years old admitted to a level 1 trauma center during a 4-month period. Primary outcome measures included number of scans; effective dose of radiation from radiographs and CT scans, respectively; and total effective dose from both sources over patients' hospital stays. Several variables, including hospital length of stay, initial Glasgow Coma Scale score, and Injury Severity Score, correlated with greater radiation exposure. Blunt trauma victims were more prone to higher doses than those with penetrating or combined penetrating and blunt trauma. Location and mechanism of injury were also found to correlate with radiation exposure. Trauma patients as a group are exposed to high levels of radiation from X-rays and CT scans, and CT scans contribute a very high proportion (91.3% ± 11.7%) of that radiation. Certain subgroups of patients are at a particularly high risk of exposure, and greater attention to cumulative radiation dose should be paid to patients with the above mentioned risk factors.

Design and Demonstration of a Material-Plasma Exposure Target Station for Neutron Irradiated Samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rapp, Juergen; Aaron, A. M.; Bell, Gary L.

2015-10-20

Fusion energy is the most promising energy source for the future, and one of the most important problems to be solved progressing to a commercial fusion reactor is the identification of plasma-facing materials compatible with the extreme conditions in the fusion reactor environment. The development of plasma–material interaction (PMI) science and the technology of plasma-facing components are key elements in the development of the next step fusion device in the United States, the so-called Fusion Nuclear Science Facility (FNSF). All of these PMI issues and the uncertain impact of the 14-MeV neutron irradiation have been identified in numerous expert panelmore » reports to the fusion community. The 2007 Greenwald report classifies reactor plasma-facing materials (PFCs) and materials as the only Tier 1 issues, requiring a “. . . major extrapolation from the current state of knowledge, need for qualitative improvements and substantial development for both the short and long term.” The Greenwald report goes on to list 19 gaps in understanding and performance related to the plasma–material interface for the technology facilities needed for DEMO-oriented R&D and DEMO itself. Of the 15 major gaps, six (G7, G9, G10, G12, G13) can possibly be addressed with ORNL’s proposal of an advanced Material Plasma Exposure eXperiment. Establishing this mid-scale plasma materials test facility at ORNL is a key element in ORNL’s strategy to secure a leadership role for decades of fusion R&D. That is to say, our end goal is to bring the “signature facility” FNSF home to ORNL. This project is related to the pre-conceptual design of an innovative target station for a future Material–Plasma Exposure eXperiment (MPEX). The target station will be designed to expose candidate fusion reactor plasma-facing materials and components (PFMs and PFCs) to conditions anticipated in fusion reactors, where PFCs will be exposed to dense high-temperature hydrogen plasmas providing

Application of physiologically based pharmacokinetic modeling in setting acute exposure guideline levels for methylene chloride.

PubMed

Bos, Peter Martinus Jozef; Zeilmaker, Marco Jacob; van Eijkeren, Jan Cornelis Henri

2006-06-01

Acute exposure guideline levels (AEGLs) are derived to protect the human population from adverse health effects in case of single exposure due to an accidental release of chemicals into the atmosphere. AEGLs are set at three different levels of increasing toxicity for exposure durations ranging from 10 min to 8 h. In the AEGL setting for methylene chloride, specific additional topics had to be addressed. This included a change of relevant toxicity endpoint within the 10-min to 8-h exposure time range from central nervous system depression caused by the parent compound to formation of carboxyhemoglobin (COHb) via biotransformation to carbon monoxide. Additionally, the biotransformation of methylene chloride includes both a saturable step as well as genetic polymorphism of the glutathione transferase involved. Physiologically based pharmacokinetic modeling was considered to be the appropriate tool to address all these topics in an adequate way. Two available PBPK models were combined and extended with additional algorithms for the estimation of the maximum COHb levels. The model was validated and verified with data obtained from volunteer studies. It was concluded that all the mentioned topics could be adequately accounted for by the PBPK model. The AEGL values as calculated with the model were substantiated by experimental data with volunteers and are concluded to be practically applicable.

Study of Parameters Affecting the Level of Ultrasound Exposure with In Vitro Set-Ups

NASA Astrophysics Data System (ADS)

Leskinen, Jarkko J.; Hynynen, Kullervo

2010-03-01

Ultrasound (US) exposures are widely used with in vitro cell systems e.g. in stem cell and tissue engineering research. However, without the knowledge of factors affecting the level of US exposure, the outcome of the biological result may vary from test to test or even be misinterpreted. Thereby, some of the factors affecting in vitro US exposures were studied. The level of US exposure was characterized in standard commercial cell culturing plates. The temperature distributions were measured inside the wells using infrared camera and fine wire thermocouples, and pressure and intensity distributions using a laser vibrometer and a schlieren system. The measurements were made at operating frequency of around 1 MHz with varying temporal parameters and powers (up to 2 W of acoustic power). Heat accumulation between the wells varied up to 40-50% depending on the location of the well on the plate. This well-to-well variation was be linked to the activity of reporter plasmid on osteoblastic cells. Similar temperature variations within the wells were also measured. Small sub-wavelength change in the exposure distance or, respectively, liquid volume inside the well was found to alter the acoustic field in both magnitude and shape due the standing waves. The gathered data reveals the complexity of the acoustic field in a typical in vitro set-up and gives new information about the environment of the in vitro cells during US exposures. This data may be especially useful when US set-ups are designed or characterized.

Exposure to extremely low frequency electromagnetic fields alters the behaviour, physiology and stress protein levels of desert locusts

PubMed Central

Wyszkowska, Joanna; Shepherd, Sebastian; Sharkh, Suleiman; Jackson, Christopher W.; Newland, Philip L.

2016-01-01

Electromagnetic fields (EMFs) are present throughout the modern world and are derived from many man-made sources including overhead transmission lines. The risks of extremely-low frequency (ELF) electromagnetic fields are particularly poorly understood especially at high field strengths as they are rarely encountered at ground level. Flying insects, however, can approach close to high field strength transmission lines prompting the question as to how these high levels of exposure affect behaviour and physiology. Here we utilise the accessible nervous system of the locust to ask how exposure to high levels of ELF EMF impact at multiple levels. We show that exposure to ELF EMFs above 4 mT leads to reduced walking. Moreover, intracellular recordings from an identified motor neuron, the fast extensor tibiae motor neuron, show increased spike latency and a broadening of its spike in exposed animals. In addition, hind leg kick force, produced by stimulating the extensor tibiae muscle, was reduced following exposure, while stress-protein levels (Hsp70) increased. Together these results suggest that ELF EMF exposure has the capacity to cause dramatic effects from behaviour to physiology and protein expression, and this study lays the foundation to explore the ecological significance of these effects in other flying insects. PMID:27808167

Lactobacillus rhamnosus ATCC 7469 exopolysaccharides synergizes with low level ionizing radiation to modulate signaling molecular targets in colorectal carcinogenesis in rats.

PubMed

Zahran, Walid E; Elsonbaty, Sawsan M; Moawed, Fatma S M

2017-08-01

Combination therapy that targets cellular signaling pathway represents an alternative therapy for the treatment of colon cancer (CRC). The present study was therefore aimed to investigate the probable interaction of Lactobacillus rhamnosus ATCC 7469 exopolysaccharides (EPS) with low level ionizing γ radiation (γ-R) exposure against dimethylhydrazine (DMH)- induced colorectal carcinogenesis in rats. Colon cancer was induced with 20mg DMH/kg BW. Rats received daily by gastric gavage 100mg EPS/Kg BW concomitant with 1Gy γ-R over two months. Colonic oxidative and inflammatory stresses were assessed. The change in the expression of p-p38 MAPK, p-STAT3, β-catenin, NF-kB, COX-2 and iNOS was evaluated by western blotting and q-PCR. It was found that DMH treatment significantly induced colon oxidative injury accompanied by inflammatory disturbance along with increased protein expression of the targeted signaling factors p-p38 MAPK, p-STAT3 and β-catenin. The mRNA gene expression of NF-kB, COX-2 and iNOS was significantly higher in DMH-treated animals. It's worthy to note that colon tissues with DMH treatment showed significant dysplasia and anaplasia of the glandular mucosal lining epithelium with loses of goblet cells formation, pleomorphism in the cells and hyperchromachia in nuclei. Interestingly, EPS treatment with γ-R exposure showed statistically significant amelioration of the oxidative and inflammatory biomarkers with modulated signaling molecular factors accompanied by improved histological structure against DMH-induced CRC. In conclusion, our findings showed that Lactobacillus rhamnosus ATCC 7469 EPS with low level γ-R in synergistic interaction are efficacious control against CRC progression throughout the modulation of key signaling growth factors associated with inflammation via antioxidant mediated anti-inflammatory and anti-proliferative activities. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

[A cohort study on association between the first trimester phthalates exposure and fasting blood glucose level in the third trimester].

PubMed

Zhang, Y W; Gao, H; Huang, K; Xu, Y Y; Sheng, J; Tao, F B

2017-03-10

Objective: To examine the association between the phthalate exposure in the first trimester and fasting blood glucose level or gestational diabetes mellitus (GDM) in the third trimester in pregnant women. Methods: A total of 3 474 pregnant women, receiving their prenatal examination in Ma' anshan Maternal and Child Health-Care Hospital of Anhui province, were selected from May 2013 to September 2014. Questionnaires were used to collect the information about their socio-demographic characteristics, clinical characteristics and GDM diagnostic results in the first, second and third trimesters. Urine samples and fasting venous blood samples were collected. Concentrations of 7 kinds of phthalate metabolites in urine samples were detected by solid phase extraction-high performance liquid chromatography-tandem mass spectrometry (SPE-HPLC-MS/MS), and multiple linear regression model was used for statistical analyses. Logistic regression analysis on the risk of the first trimester phthalate exposure for GDM in the third trimester was conducted. Results: The prevalence of GDM in this study was 12.8%, monomethyl phthalate (MMP), monoethyl phthalate (MEP), mono-n-butyl phthalate (MBP), monobenzyl phthalate (MBzP) and mono-(2-ethyl-5-oxohexyl) phthalate (MEHHP) exposure levels were positively correlated with the fasting blood glucose level in the third trimester ( P <0.05), but mono-(2-ethylhexyl) phthalate (MEHP) and mono-(2-ethyl-5-hydroxylhexyl) phthalate (MEOHP) exposure levels were negatively correlated with the fasting blood glucose level in the third trimester ( P <0.05). Stratified analysis showed a positive correlation between MEHHP exposure and the third trimester fasting blood glucose level in both normal group and GDM group. However, MMP, MEP, MBP, MBzP, MEHP and MEOHP exposure levels had influences on the third trimester fasting blood glucose level in normal group but not in GDM group. MMP and MBP exposure might increase the risk of GDM, but MEOHP exposure might

A Comparison of Two Methods Used for Ranking Task Exposure Levels Using Simulated Multi-Task Data

DTIC Science & Technology

1999-12-17

OF OKLAHOMA HEALTH SCIENCES CENTER GRADUATE COLLEGE A COMPARISON OF TWO METHODS USED FOR RANKING TASK EXPOSURE LEVELS USING SIMULATED MULTI-TASK...COSTANTINO Oklahoma City, Oklahoma 1999 ^ooo wx °^ A COMPARISON OF TWO METHODS USED FOR RANKING TASK EXPOSURE LEVELS USING SIMULATED MULTI-TASK DATA... METHODS AND MATERIALS 9 TV. RESULTS 14 V. DISCUSSION AND CONCLUSION 28 LIST OF REFERENCES 31 APPENDICES 33 Appendix A JJ -in Appendix B Dl IV

Tributyltin Exposure Alters Cytokine Levels in Mouse Serum

PubMed Central

Lawrence, Shanieek; Pellom, Samuel T.; Shanker, Anil; Whalen, Margaret M.

2016-01-01

Tributyltin (TBT), a toxic environmental contaminant, has been widely utilized for various industrial, agricultural and household purposes. Its usage has led to a global contamination and its bioaccumulation in aquatic organisms and terrestrial mammals. Previous studies suggest that TBT has debilitating effects on the overall immune function of animals, rendering them more vulnerable to diseases. TBT (at concentrations that have been detected in human blood) alters secretion of inflammatory cytokines from human lymphocytes ex vivo. Thus, it is important to determine if specified levels of TBT can alter levels of cytokines in an in vivo system. Mice were exposed to biologically relevant concentrations of TBT (200, 100 or 25 nM final concentrations). The quantitative determination of interferon (IFN)-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL2, IL5, IL7, IL12βp40, IL13, IL15, KC, MIP1β, MIP2 and RANTES was performed in mouse sera by MAGPIX analysis and Western blot. Results indicated alterations (both decreases and increases) in several cytokines. The pro-inflammatory cytokines IFNγ, TNFα, IL-1β, IL-2, IL5, IL12βp40, and IL-15 were altered as were the chemokines MIP-1 and RANTES and the anti-inflammatory cytokine IL-13. Increases in IFNγ and TNFα were seen in serum of mice exposed to TBT for less than 24 hr. IL1-β, IL-12βp40, IL-5 and IL-15 were also modulated in mouse serum depending on the specific experiment and the exposure concentration. IL-2 was consistently decreased in mouse serum when animals were exposed to TBT. There were also TBT-induced increases in MIP-1β, RANTES, and IL-13. These results from human and murine samples clearly suggest that TBT exposures modulate the secretion inflammatory cytokines. PMID:27602597

OPS MCC level B/C formulation requirements: Area targets and space volumes processor

NASA Technical Reports Server (NTRS)

Bishop, M. J., Jr.

1979-01-01

The level B/C mathematical specifications for the area targets and space volumes processor (ATSVP) are described. The processor is designed to compute the acquisition-of-signal (AOS) and loss-of-signal (LOS) times for area targets and space volumes. The characteristics of the area targets and space volumes are given. The mathematical equations necessary to determine whether the spacecraft lies within the area target or space volume are given. These equations provide a detailed model of the target geometry. A semianalytical technique for predicting the AOS and LOS time periods is disucssed. This technique was designed to bound the actual visibility period using a simplified target geometry model and unperturbed orbital motion. Functional overview of the ATSVP is presented and it's detailed logic flow is described.

Effects of the MAOA gene and levels of exposure to violence on antisocial outcomes.

PubMed

Ouellet-Morin, Isabelle; Côté, Sylvana M; Vitaro, Frank; Hébert, Martine; Carbonneau, René; Lacourse, Éric; Turecki, Gustavo; Tremblay, Richard E

2016-01-01

The monoamine oxidase A (MAOA) gene has been shown to moderate the impact of maltreatment on antisocial behaviour. Replication efforts have, however, yielded inconsistent results. To investigate whether the interaction between the MAOA gene and violence is present across the full distribution of violence or emerges at higher levels of exposure. Participants were 327 male members of the Québec Longitudinal Study of Kindergarten Children. Exposure to violence comprised retrospective reports of mother's and father's maltreatment, sexual and physical abuse. Conduct disorder and antisocial personality symptoms were assessed in semi-structured interviews and partner violence, property-violent crimes and arrest were self-reported. Non-linear interactions between the MAOA gene and violence were detected, suggesting that the genetic moderation may come about once a certain level of violence is experienced. Future studies should investigate the mechanisms translating substantial violence exposure, which could, subsequently, trigger the expression of genetically based differences in antisocial behaviour. © The Royal College of Psychiatrists 2016.

Music exposure improves spatial cognition by enhancing the BDNF level of dorsal hippocampal subregions in the developing rats.

PubMed

Xing, Yingshou; Chen, Wenxi; Wang, Yanran; Jing, Wei; Gao, Shan; Guo, Daqing; Xia, Yang; Yao, Dezhong

2016-03-01

Previous research has shown that dorsal hippocampus plays an important role in spatial memory process. Music exposure can enhance brain-derived neurotrophic factor (BDNF) expression level in dorsal hippocampus (DH) and thus enhance spatial cognition ability. But whether music experience may affect different subregions of DH in the same degree remains unclear. Here, we studied the effects of exposure to Mozart K.448 on learning behavior in developing rats using the classical Morris water maze task. The results showed that early music exposure could enhance significantly learning performance of the rats in the water maze test. Meanwhile, the BDNF/TrkB level of dorsal hippocampus CA3 (dCA3) and dentate gyrus (dDG) was significantly enhanced in rats exposed to Mozart music as compared to those without music exposure. In contrast, the BDNF/TrkB level of dorsal hippocampus CA1 (dCA1) was not affected. The results suggest that the spatial memory improvement by music exposure in rats may be associated with the enhanced BDNF/TrkB level of dCA3 and dDG. Copyright © 2016 Elsevier Inc. All rights reserved.

Blood and bronchoalveolar lavage fluid acetylcholinesterase levels following microinstillation inhalation exposure to sarin in Guinea pigs.

PubMed

Che, Magnus M; Conti, Michele; Boylan, Megan; Sciuto, Alfred M; Gordon, Richard K; Nambiar, Madhusoodana P

2008-07-01

We determined acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition in the bronchoalveolar lavage fluid (BALF) following inhalation exposure to chemical threat nerve agent (CTNA) sarin. Age- and weight-matched male guinea pigs were exposed to five different doses of sarin (169.3, 338.7, 508, 677.4, and 846.5 mg/m(3)) using a microinstillation inhalation exposure technique for 4 min. The technique involves aerosolization of the agent in the trachea using a microcatheter with a center hole that delivers the agent and multiple peripheral holes that pumps air to aerosolize the agent at the tip. Animals exposed to higher doses of sarin occasionally developed seizures and succumbed to death within 15 min after exposure. The LCt(50) for sarin using the microinstillation technique was determined to be close to 677.4 mg/m(3). Ear blood AChE activity showed a dose-dependent inhibition at 15 min postexposure. The inhibition of blood AChE remained constant over 35 and 55 min after sarin exposure indicating that there was no lung depot effect. Cardiac blood AChE and butyrylcholinesterase (BChE) activity in surviving animals euthanized at 24 h postexposure showed a dose-dependent inhibition with an inhibition of 60% at 677.4 and 846.5 mg/m(3) sarin exposure. AChE and BChE activity in bronchoalveolar lavage fluid (BALF) showed a slight increase at 338.7 to 677.4 mg/m(3) sarin exposure but a marginal inhibition at 169.3 mg/m(3). In contrast, the AChE protein levels determined by immunoblotting showed an increase at 169.3 mg/m(3) in the BALF. The BALF protein level, a biomarker of lung injury, was increased maximally at 338.7 mg/m(3) and that increase was dropped with an increase in the dose of sarin. The BALF protein levels correlated with the AChE and BChE activity. These data suggest that sarin microinstillation inhalation exposure results in respiratory toxicity and lung injury characterized by changes in lavage AChE, BChE, and protein levels.

Variability in electromagnetic field levels over time, and Monte-Carlo simulation of exposure parameters.

PubMed

Pachón-García, F T; Paniagua-Sánchez, J M; Rufo-Pérez, M; Jiménez-Barco, A

2014-12-01

This article analyses the electric field levels around medium-wave transmitters, delimiting the temporal variability of the levels received at a pre-established reception point. One extensively used dosimetric criterion is to consider historical levels of the field recorded over a certain period of time so as to provide an overall perspective of radio-frequency electric field exposure in a particular environment. This aspect is the focus of the present study, in which the measurements will be synthesised in the form of exposure coefficients. Two measurement campaigns were conducted: one short term (10 days) and the other long term (1 y). The short-term data were used to study which probability density functions best approximate the measured levels. The long-term data were used to compute the principal statistics that characterise the field values over a year. The data that form the focus of the study are the peak traces, since these are the most representative from the standpoint of exposure. The deviations found were around 6 % for short periods and 12 % for long periods. The information from the two campaigns was used to develop and implement a computer application based on the Monte Carlo method to simulate values of the field, allowing one to carry out robust statistics. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Classification of video sequences into chosen generalized use classes of target size and lighting level.

PubMed

Leszczuk, Mikołaj; Dudek, Łukasz; Witkowski, Marcin

The VQiPS (Video Quality in Public Safety) Working Group, supported by the U.S. Department of Homeland Security, has been developing a user guide for public safety video applications. According to VQiPS, five parameters have particular importance influencing the ability to achieve a recognition task. They are: usage time-frame, discrimination level, target size, lighting level, and level of motion. These parameters form what are referred to as Generalized Use Classes (GUCs). The aim of our research was to develop algorithms that would automatically assist classification of input sequences into one of the GUCs. Target size and lighting level parameters were approached. The experiment described reveals the experts' ambiguity and hesitation during the manual target size determination process. However, the automatic methods developed for target size classification make it possible to determine GUC parameters with 70 % compliance to the end-users' opinion. Lighting levels of the entire sequence can be classified with an efficiency reaching 93 %. To make the algorithms available for use, a test application has been developed. It is able to process video files and display classification results, the user interface being very simple and requiring only minimal user interaction.

Assessment of Tomato (Solanum lycopersicum L.) Producers' Exposure Level to Pesticides, in Kouka and Toussiana (Burkina Faso).

PubMed

Son, Diakalia; Zerbo, Fabrice K B; Bonzi, Schémaeza; Legreve, Anne; Somda, Irénée; Schiffers, Bruno

2018-01-25

To assess producers' exposure level to pesticides in vegetable production in Burkina Faso, a study was carried out in 2016 and 2017 among 30 tomato producers in the municipalities of Kouka and Toussiana. Eighteen (18) commercial formulations were identified, with more than 50% of pesticides destined for cotton production. Eleven active substances have been identified and the most frequently used are λ-cyhalothrin (35%), acetamiprid (22%) and profenofos (13%). The most commonly used chemical families are pyrethroids (28%) and organophosphates (18%). The study revealed a low level of training for producers, a high use of pesticides according to the Frequency Treatment Indicator, and a very low level of protection used by producers. The Health Risk Index shows that active substances such as methomyl, λ-cyhalothrin and profenofos present very high risk to operators' health. Based on the UK-POEM model, the predictive exposure levels obtained varied from 0.0105 mg/kg body weight/day to 1.7855 mg/kg body weight/day, which is several times higher than the Acceptable Operator Exposure Level. However, the study also shows that exposure can be greatly reduced if the required Personal Protective Equipment is worn. Producers' awareness and training on integrated pest management are necessary to reduce the risks linked to the pesticides use in Burkina Faso.

Exposure to ambient air pollution--does it affect semen quality and the level of reproductive hormones?

PubMed

Radwan, Michał; Jurewicz, Joanna; Polańska, Kinga; Sobala, Wojciech; Radwan, Paweł; Bochenek, Michał; Hanke, Wojciech

2016-01-01

Ambient air pollution has been associated with a variety of reproductive disorders. However, a limited amount of research has been conducted to examine the association between air pollution and male reproductive outcomes, specifically semen quality. The present study was designed to address the hypothesis that exposure to fluctuating levels of specific air pollutants adversely affects sperm parameters and the level of reproductive hormones. The study population consisted of 327 men who were attending an infertility clinic in Łodź, Poland for diagnostic purposes and who had normal semen concentration of 15-300 mln/ml. All participants were interviewed and provided a semen sample. Air quality data were obtained from AirBase database. The statistically significant association was observed between abnormalities in sperm morphology and exposure to all examined air pollutants (PM10, PM2.5, SO2, NOX, CO). Exposure to air pollutants (PM10, PM2.5, CO, NOx) was also negatively associated with the level of testosterone. Additional exposure to PM2.5, PM10 increase the percentage of cells with immature chromatin (HDS). The present study provides suggestive evidence of an association between ambient air pollution and sperm quality. Further research is needed to explore this association in more detail. Individual precise exposure assessment would be needed for more detailed risk characterization.

Racial/Ethnic Differences in Knowledge of Personal and Target Levels of Cardiovascular Health Indicators.

PubMed

Ma, Mindy; Ma, Alyson

2015-10-01

This study aimed to examine ethnic differences in knowledge of personal and target levels of cardiovascular health indicators between non-Hispanic whites and African Americans. A secondary objective was to evaluate the associations between knowledge of cardiovascular health indicators and health promotion behaviors. Participants (66.7% female) consisted of 265 whites and 428 African Americans, ages 18 and older recruited from primary care clinics and churches. Respondents completed a brief survey on blood pressure (BP), total cholesterol, blood glucose, body mass index (BMI), diet, and physical activity. Whites were more likely than African Americans to report knowing their personal and target levels of cardiovascular health indicators. Knowledge of personal BP and/or BMI was positively associated with actual physical activity, and awareness of personal blood glucose was positively associated with healthy dietary practices for participants in both groups. Among whites, awareness of personal BP and knowledge of target levels for BP, total cholesterol, and BMI were also associated with healthy diet. Results suggest there are racial/ethnic disparities in knowledge of personal and ideal levels of cardiovascular health indicators, and that this knowledge is related to health promotion behaviors. Targeted educational efforts are warranted to enhance knowledge of personal risk indicators among African Americans.

SHORT-TERM EXPOSURE TO ALCOHOL IN RATS AFFECTS BRAIN LEVELS OF ANANDAMIDE, OTHER N-ACYLETHANOLAMINES AND 2-ARACHIDONOYL-GLYCEROL

PubMed Central

Rubio, Marina; McHugh, Douglas; Fernández-Ruiz, Javier; Bradshaw, Heather; Walker, J. Michael

2010-01-01

Chronic alcohol exposure leads to significant changes in the levels of endocannabinoids and their receptors in the brains of humans and laboratory animals, as well as in cultured neuronal cells. However, little is known about the effects of short-term periods of alcohol exposure. In the present study, we examined the changes in endocannabinoid levels (anandamide and 2-arachidonoylglycerol), as well as four additional N-acylethanolamines, in four brain regions of rats exposed to alcohol through the liquid diet for a period of 24 hours. The levels of N-acylethanolamines were diminished 24 hours after the onset of alcohol exposure. This was particularly evident for anandamide in the hypothalamus, amygdala and caudate-putamen, for N-palmitoylethanolamine in the caudate-putamen, for N-oleoylethanolamine in the hypothalamus, caudate-putamen and prefrontal cortex, and for N-stearoylethanolamine in the amygdala. The only exception was N-linoleoylethanolamine for which the levels increased in the amygdala after the exposure to alcohol. The levels of the other major endocannabinoid, 2-arachidonoylglycerol, were also reduced with marked effects in the prefrontal cortex. These results support the notion that short-term alcohol exposure reduces endocannabinoid levels in the brain accompanied by a reduction in several related N-acylethanolamines. PMID:17574742

Cadmium, environmental exposure, and health outcomes

PubMed Central

Satarug, Soisungwan; Garrett, Scott H.; Sens, Mary Ann; Sens, Donald A.

2018-01-01

We provide an update of the issues surrounding health risk assessment of exposure to cadmium in food. Bioavailability of ingested cadmium has been confirmed in studies of persons with elevated dietary exposure, and the findings have been strengthened by the substantial amounts of cadmium accumulated in kidneys, eyes, and other tissues and organs of environmentally exposed individuals. We hypothesized that such accumulation results from the efficient absorption and systemic transport of cadmium, employing multiple transporters that are used for the body’s acquisition of calcium, iron, zinc, and manganese. Adverse effects of cadmium on kidney and bone have been observed in environmentally exposed populations at frequencies higher than those predicted from models of exposure. Population data raise concerns about the validity of the current safe intake level that uses the kidney as the sole target in assessing the health risk from ingested cadmium. The data also question the validity of incorporating the default 5% absorption rate in the threshold-type risk assessment model, known as the provisional tolerable weekly intake (PTWI), to derive a safe intake level for cadmium. PMID:21655733

Personalized Prediction of Glaucoma Progression Under Different Target Intraocular Pressure Levels Using Filtered Forecasting Methods.

PubMed

Kazemian, Pooyan; Lavieri, Mariel S; Van Oyen, Mark P; Andrews, Chris; Stein, Joshua D

2018-04-01

To generate personalized forecasts of how patients with open-angle glaucoma (OAG) experience disease progression at different intraocular pressure (IOP) levels to aid clinicians with setting personalized target IOPs. Secondary analyses using longitudinal data from 2 randomized controlled trials. Participants with moderate or advanced OAG from the Collaborative Initial Glaucoma Treatment Study (CIGTS) or the Advanced Glaucoma Intervention Study (AGIS). By using perimetric and tonometric data from trial participants, we developed and validated Kalman Filter (KF) models for fast-, slow-, and nonprogressing patients with OAG. The KF can generate personalized and dynamically updated forecasts of OAG progression under different target IOP levels. For each participant, we determined how mean deviation (MD) would change if the patient maintains his/her IOP at 1 of 7 levels (6, 9, 12, 15, 18, 21, or 24 mmHg) over the next 5 years. We also model and predict changes to MD over the same time horizon if IOP is increased or decreased by 3, 6, and 9 mmHg from the level attained in the trials. Personalized estimates of the change in MD under different target IOP levels. A total of 571 participants (mean age, 64.2 years; standard deviation, 10.9) were followed for a mean of 6.5 years (standard deviation, 2.8). Our models predicted that, on average, fast progressors would lose 2.1, 6.7, and 11.2 decibels (dB) MD under target IOPs of 6, 15, and 24 mmHg, respectively, over 5 years. In contrast, on average, slow progressors would lose 0.8, 2.1, and 4.1 dB MD under the same target IOPs and time frame. When using our tool to quantify the OAG progression dynamics for all 571 patients, we found no statistically significant differences over 5 years between progression for black versus white, male versus female, and CIGTS versus AGIS participants under different target IOPs (P > 0.05 for all). To our knowledge, this is the first clinical decision-making tool that generates personalized

DNA methylation levels and long-term trihalomethane exposure in drinking water: an epigenome-wide association study

PubMed Central

Salas, Lucas A; Bustamante, Mariona; Gonzalez, Juan R; Gracia-Lavedan, Esther; Moreno, Victor; Kogevinas, Manolis; Villanueva, Cristina M

2015-01-01

Trihalomethanes (THM) are undesired disinfection byproducts (DBPs) formed during water treatment. Mice exposed to DBPs showed global DNA hypomethylation and c-myc and c-jun gene-specific hypomethylation, while evidence of epigenetic effects in humans is scarce. We explored the association between lifetime THM exposure and DNA methylation through an epigenome-wide association study. We selected 138 population-based controls from a case-control study of colorectal cancer conducted in Barcelona, Spain, exposed to average lifetime THM levels ≤85 μg/L vs. >85 μg/L (N = 68 and N = 70, respectively). Mean age of participants was 70 years, and 54% were male. Average lifetime THM level in the exposure groups was 64 and 130 µg/L, respectively. DNA was extracted from whole blood and was bisulphite converted to measure DNA methylation levels using the Illumina HumanMethylation450 BeadChip. Data preprocessing was performed using RnBeads. Methylation was compared between exposure groups using empirical Bayes moderated linear regression for CpG sites and Gaussian kernel for CpG regions. ConsensusPathDB was used for gene set enrichment. Statistically significant differences in methylation between exposure groups was found in 140 CpG sites and 30 gene-related regions, after false discovery rate <0.05 and adjustment for age, sex, methylation first principal component, and blood cell proportion. The annotated genes were localized to several cancer pathways. Among them, 29 CpGs had methylation levels associated with THM levels (|Δβ|≥0.05) located in 11 genes associated with cancer in other studies. Our results suggest that THM exposure may affect DNA methylation in genes related to tumors, including colorectal and bladder cancers. Future confirmation studies are required. PMID:26039576

Chronic corticosterone exposure reduces hippocampal glycogen level and induces depression-like behavior in mice.

PubMed

Zhang, Hui-yu; Zhao, Yu-nan; Wang, Zhong-li; Huang, Yu-fang

2015-01-01

Long-term exposure to stress or high glucocorticoid levels leads to depression-like behavior in rodents; however, the cause remains unknown. Increasing evidence shows that astrocytes, the most abundant cells in the central nervous system (CNS), are important to the nervous system. Astrocytes nourish and protect the neurons, and serve as glycogen repositories for the brain. The metabolic process of glycogen, which is closely linked to neuronal activity, can supply sufficient energy substrates for neurons. The research team probed into the effects of chronic corticosterone (CORT) exposure on the glycogen level of astrocytes in the hippocampal tissues of male C57BL/6N mice in this study. The results showed that chronic CORT injection reduced hippocampal neurofilament light protein (NF-L) and synaptophysin (SYP) levels, induced depression-like behavior in male mice, reduced hippocampal glycogen level and glycogen synthase activity, and increased glycogen phosphorylase activity. The results suggested that the reduction of the hippocampal glycogen level may be the mechanism by which chronic CORT treatment damages hippocampal neurons and induces depression-like behavior in male mice.

A mathematical model of exposure of non-target Lepidoptera to Bt-maize pollen expressing Cry1Ab within Europe

PubMed Central

Perry, J. N.; Devos, Y.; Arpaia, S.; Bartsch, D.; Gathmann, A.; Hails, R. S.; Kiss, J.; Lheureux, K.; Manachini, B.; Mestdagh, S.; Neemann, G.; Ortego, F.; Schiemann, J.; Sweet, J. B.

2010-01-01

Genetically modified (GM) maize MON810 expresses a Cry1Ab insecticidal protein, derived from Bacillus thuringiensis (Bt), toxic to lepidopteran target pests such as Ostrinia nubilalis. An environmental risk to non-target Lepidoptera from this GM crop is exposure to harmful amounts of Bt-containing pollen deposited on host plants in or near MON810 fields. An 11-parameter mathematical model analysed exposure of larvae of three non-target species: the butterflies Inachis io (L.), Vanessa atalanta (L.) and moth Plutella xylostella (L.), in 11 representative maize cultivation regions in four European countries. A mortality–dose relationship was integrated with a dose–distance relationship to estimate mortality both within the maize MON810 crop and within the field margin at varying distances from the crop edge. Mortality estimates were adjusted to allow for physical effects; the lack of temporal coincidence between the susceptible larval stage concerned and the period over which maize MON810 pollen is shed; and seven further parameters concerned with maize agronomy and host-plant ecology. Sublethal effects were estimated and allowance made for aggregated pollen deposition. Estimated environmental impact was low: in all regions, the calculated mortality rate for worst-case scenarios was less than one individual in every 1572 for the butterflies and one in 392 for the moth. PMID:20053648

AMP-activated protein kinase-mediated glucose transport as a novel target of tributyltin in human embryonic carcinoma cells.

PubMed

Yamada, Shigeru; Kotake, Yaichiro; Sekino, Yuko; Kanda, Yasunari

2013-05-01

Organotin compounds such as tributyltin (TBT) are known to cause various forms of cytotoxicity, including developmental toxicity and neurotoxicity. However, the molecular target of the toxicity induced by nanomolar levels of TBT has not been identified. In the present study, we found that exposure to 100 nM TBT induced growth arrest in human pluripotent embryonic carcinoma cell line NT2/D1. Since glucose provides metabolic energy, we focused on the glycolytic system. We found that exposure to TBT reduced the levels of both glucose-6-phosphate and fructose-6-phosphate. To investigate the effect of TBT exposure on glycolysis, we examined glucose transporter (GLUT) activity. TBT exposure inhibited glucose uptake via a decrease in the level of cell surface-bound GLUT1. Furthermore, we examined the effect of AMP-activated protein kinase (AMPK), which is known to regulate glucose transport by facilitating GLUT translocation. Treatment with the potent AMPK activator, AICAR, restored the TBT-induced reduction in cell surface-bound GLUT1 and glucose uptake. In conclusion, these results suggest that exposure to nanomolar levels of TBT causes growth arrest by targeting glycolytic systems in human embryonic carcinoma cells. Thus, understanding the energy metabolism may provide new insights into the mechanisms of metal-induced cytotoxicity.

Long-term low-level arsenic exposure is associated with poorer neuropsychological functioning: a Project FRONTIER study.

PubMed

O'Bryant, Sid E; Edwards, Melissa; Menon, Chloe V; Gong, Gordon; Barber, Robert

2011-03-01

Exposure to elements in groundwater (toxic or beneficial) is commonplace yet, outside of lead and mercury, little research has examined the impact of many commonly occurring environmental exposures on mental abilities during the aging process. Inorganic arsenic is a known neurotoxin that has both neurodevelopmental and neurocognitive consequences. The aim of this study was to examine the potential association between current and long-term arsenic exposure and detailed neuropsychological functioning in a sample of rural-dwelling adults and elders. Data were analyzed from 434 participants (133 men and 301 women) of Project FRONTIER, a community-based participatory research study of the epidemiology of health issues of rural-dwelling adults and elders. The results of the study showed that GIS-based groundwater arsenic exposure (current and long-term) was significantly related to poorer scores in language, visuospatial skills, and executive functioning. Additionally, long-term low-level exposure to arsenic was significantly correlated to poorer scores in global cognition, processing speed and immediate memory. The finding of a correlation between arsenic and the domains of executive functioning and memory is of critical importance as these are cognitive domains that reflect the earliest manifestations of Alzheimer's disease. Additional work is warranted given the population health implications associated with long-term low-level arsenic exposure.

Effects of pre and postnatal exposure to low levels of polybromodiphenyl ethers on neurodevelopment and thyroid hormone levels at 4 years of age.

PubMed

Gascon, Mireia; Vrijheid, Martine; Martínez, David; Forns, Joan; Grimalt, Joan O; Torrent, Maties; Sunyer, Jordi

2011-04-01

There are at present very few studies of the effects of polybromodiphenyl ethers (PBDEs), used as flame retardants in consumer products, on neurodevelopment or thyroid hormone levels in humans. The present study aims to examine the association between pre and postnatal PBDE concentrations and neurodevelopment and thyroid hormone levels in children at age 4years and isolate the effects of PBDEs from those of PCBs, DDT, DDE and HCB. A prospective birth cohort in Menorca (Spain) enrolled 482 pregnant mothers between 1997 and 1998. At 4years, children were assessed for motor and cognitive function (McCarthy Scales of Children's Abilities), attention-deficit, hyperactivity and impulsivity (ADHD-DSM-IV) and social competence (California Preschool Social Competence Scale). PBDE concentrations were measured in cord blood (N=88) and in serum of 4years olds (N=244). Among all congeners analyzed only PBDE 47 was quantified in a reasonable number of samples (LOQ=0.002ng/ml). Exposure to PBDE 47 was analyzed as a dichotomous variable: concentrations above the LOQ (exposed) and concentrations below (referents). Scores for cognitive and motor functions were always lower in children pre and postnatally exposed to PBDE47 than in referents, but none of these associations was statistically significant (β coefficient (95%CI) of the total cognition score: -2.7 (-7.0, 1.6) for postnatal exposure, and -1.4 (-9.2, 6.5) for prenatal exposure). Postnatal exposure to PBDE 47 was statistically significantly related to an increased risk of symptoms on the attention deficit subscale of ADHD symptoms (RR (95%CI)=1.8 (1.0, 3.2)) but not to hyperactivity symptoms. A statistically significant higher risk of poor social competence symptoms was observed as a consequence of postnatal PBDE 47 exposure (RR (95%CI)=2.6 (1.2, 5.9)). Adjustment for other organochlorine compounds did not influence the results. Levels of thyroid hormones were not associated to PBDE exposure. This study highlights the

Secondhand Smoke Exposure Levels in Outdoor Hospitality Venues: A Qualitative and Quantitative Review of the Research Literature

PubMed Central

LICHT, ANDREA S; HYLAND, ANDREW; TRAVERS, MARK J; CHAPMAN, SIMON

2013-01-01

Objective This paper considers the evidence on whether outdoor secondhand smoke (SHS) is present in high enough levels of hospitality venues to potentially pose health risks, particularly among employees of such establishments. Data Sources Search strings in PubMed and Web of Science included combinations of environmental tobacco smoke, secondhand smoke, or passive smoke AND outdoor, yielding 217 and 5,199 results, respectively through June, 2012. Study Selection Sixteen studies were selected based on abstract review that either entirely or partly measured outdoor SHS exposures (particulate matter (PM) or other SHS indicators). Data Extraction The methods used to measure SHS indicators, particularly PM, were assessed for inclusion of extraneous variables that may affect such measurements or the corroboration of ambient levels with known standards. Data Synthesis The magnitude of SHS exposure (PM2.5) is dependent on the number of smokers present, proximity to the measuring device, outdoor enclosures, and wind. Under specific conditions, peak outdoor PM2.5 levels can be comparable to those recorded in indoor smoky environments. Using data from both observational and experimental studies, annual excess PM2.5 exposure of full-time waitstaff at outdoor smoking environments could average 4.0 to 12.2 μg/m3 under variable smoking conditions. Conclusions Although highly transitory, outdoor SHS exposures could occasionally exceed annual ambient air quality exposure guidelines. However, such exposures are likely to be higher for occupationally exposed individuals compared to patrons due to repeated and cumulative outdoor SHS exposures. Personal monitoring studies of waitstaff are warranted to corroborate these modeled estimates. PMID:23220937

10 CFR 20.2203 - Reports of exposures, radiation levels, and concentrations of radioactive material exceeding the...

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Reports of exposures, radiation levels, and concentrations of radioactive material exceeding the constraints or limits. 20.2203 Section 20.2203 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Reports § 20.2203 Reports of exposures...

10 CFR 20.2203 - Reports of exposures, radiation levels, and concentrations of radioactive material exceeding the...

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Reports of exposures, radiation levels, and concentrations of radioactive material exceeding the constraints or limits. 20.2203 Section 20.2203 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Reports § 20.2203 Reports of exposures...

10 CFR 20.2203 - Reports of exposures, radiation levels, and concentrations of radioactive material exceeding the...

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Reports of exposures, radiation levels, and concentrations of radioactive material exceeding the constraints or limits. 20.2203 Section 20.2203 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Reports § 20.2203 Reports of exposures...

10 CFR 20.2203 - Reports of exposures, radiation levels, and concentrations of radioactive material exceeding the...

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Reports of exposures, radiation levels, and concentrations of radioactive material exceeding the constraints or limits. 20.2203 Section 20.2203 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Reports § 20.2203 Reports of exposures...

10 CFR 20.2203 - Reports of exposures, radiation levels, and concentrations of radioactive material exceeding the...

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Reports of exposures, radiation levels, and concentrations of radioactive material exceeding the constraints or limits. 20.2203 Section 20.2203 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Reports § 20.2203 Reports of exposures...

Estimating individual-level exposure to airborne polycyclic aromatic hydrocarbons throughout the gestational period based on personal, indoor, and outdoor monitoring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, H.; Perera, F.; Pac, A.

2008-11-15

Current understanding on health effects of long-term polycyclic aromatic hydrocarbon (PAH) exposure is limited by lack of data on time-varying nature of the pollutants at an individual level. In a cohort of pregnant women in Krakow, Poland, we examined the contribution of temporal, spatial, and behavioral factors to prenatal exposure to airborne PAHs within each trimester and developed a predictive model of PAH exposure over the entire gestational period. The observed personal, indoor, and outdoor B(a)P levels we observed in Krakow far exceed the recommended Swedish guideline value for B(a)P of 0.1 ng/m{sup 3}. Based on simultaneously monitored levels, themore » outdoor PAH level alone accounts for 93% of total variability in personal exposure during the heating season. Living near the Krakow bus depot, a crossroad, and the city, center and time spent outdoors or commuting were not associated with higher personal exposure. During the nonheating season only, a 1-hr increase in environmental tobacco smoke (ETS) exposure was associated with a 10-16% increase in personal exposure to the nine measured PAHs. A 1{degree}C decrease in ambient temperature was associated with a 3-5% increase in exposure to benz(a)anthracene, benzo(k)fluoranthene, and dibenz(a,h)anthracene, after accounting for the outdoor concentration. A random effects model demonstrated that mean personal exposure at a given gestational period depends on the season, residence location, and ETS. Considering that most women reported spending < 3 hr/day outdoors, most women in the study were exposed to outdoor-originating PAHs within the indoor setting. Cross-sectional, longitudinal monitoring supplemented with questionnaire data allowed development of a gestation-length model of individual-level exposure with high precision and validity.« less

Exposure to carbon monoxide, methyl-tertiary butyl ether (MTBE), and benzene levels inside vehicles traveling on an urban area in Korea.

PubMed

Jo, W K; Park, K H

1998-01-01

This study was designed to allow systematic comparison of exposure on public (40-seater buses) and private (four passengers cars) transport modes for carbon monoxide (CO), methyl-tertiary butyl ether (MTBE), and benzene by carrying out simultaneous measurements along the same routes. There were statistically significant differences (p < 0.05) in the concentrations of all target compounds among the three microenvironments; inside autos; inside buses; and in ambient air. The target compounds were significantly correlated for all the three environments, with at least p < 0.05. The in-vehicle concentrations of MTBE and benzene were significantly higher (p < 0.0001), on the average 3.5 times higher, in the car with a carbureted engine than in the other three electronic fuel-injected cars. On the other hand, the CO concentrations were not significantly different among the four cars. The in-auto MTBE levels (48.5 micrograms/m3 as a median) measured during commutes in this study was 2-3 times higher than the New Jersey and Connecticut's results. The in-auto concentration of CO (4.8 ppm as a median) in this study was comparable with those in later studies in some American cities, but much lower than those in earlier studies in other American cities. The in-bus CO concentration was 3.6 ppm as a median. As a median, the in-auto concentration of benzene was 44.9 micrograms/m3, while the in-bus concentration 17.0 micrograms/m3. The in-auto/in-bus exposure ratios for all the target compounds was 31-40% higher than the corresponding concentration ratios, due to the higher travel speed on buses in the specified commute route as compared to the autos.

Environmental urban lead exposure and blood lead levels in children of Mexico City.

PubMed Central

Romieu, I; Carreon, T; Lopez, L; Palazuelos, E; Rios, C; Manuel, Y; Hernandez-Avila, M

1995-01-01

Lead contamination is now a leading public health problem in Mexico. However, there are few data on the lead content of various environmental sources, and little is known about the contribution of these sources to the total lead exposure in the population of children residing in Mexico City. We conducted a cross-sectional study in a random sample of 200 children younger than 5 years of age who lived in one of two areas of Mexico City. Environmental samples of floor, window, and street dust, paint, soil, water, and glazed ceramics were obtained from the participants' households, as well as blood samples and dirt from the hands of the children. Blood lead levels ranged from 1 to 31 micrograms/dl with a mean of 9.9 micrograms/dl (SD 5.8 micrograms/dl). Forty-four percent of the children 18 months of age or older had blood lead levels exceeding 10 micrograms/dl. The lead content of environmental samples was low, except in glazed ceramic. The major predictors of blood lead levels were the lead content of the glazed ceramics used to prepare children's food, exposure to airborne lead due to vehicular emission, and the lead content of the dirt from the children's hands. We conclude that the major sources of lead exposure in Mexico City could be controlled by adequate public health programs to reinforce the use of unleaded gasoline and to encourage production and use of unleaded cookware instead of lead-glazed ceramics. PMID:8605853

EPHECT II: Exposure assessment to household consumer products.

PubMed

Dimitroulopoulou, C; Trantallidi, M; Carrer, P; Efthimiou, G C; Bartzis, J G

2015-12-01

Within the framework of the EPHECT project (Emissions, exposure patterns and health effects of consumer products in the EU), irritative and respiratory health effects were assessed in relation to acute and long-term exposure to key and emerging indoor air pollutants emitted during household use of selected consumer products. In this context, inhalation exposure assessment was carried out for six selected 'target' compounds (acrolein, formaldehyde, benzene, naphthalene, d-limonene and α-pinene). This paper presents the methodology and the outcomes from the micro-environmental modelling of the 'target' pollutants following single or multiple use of selected consumer products and the subsequent exposure assessment. The results indicate that emissions from consumer products of benzene and α-pinene were not considered to contribute significantly to the EU indoor background levels, in contrast to some cases of formaldehyde and d-limonene emissions in Eastern Europe (mainly from cleaning products). The group of housekeepers in East Europe appears to experience the highest exposures to acrolein, formaldehyde and benzene, followed by the group of the retired people in North, who experiences the highest exposures to naphthalene and α-pinene. High exposure may be attributed to the scenarios developed within this project, which follow a 'most-representative worst-case scenario' strategy for exposure and health risk assessment. Despite the above limitations, this is the first comprehensive study that provides exposure estimates for 8 population groups across Europe exposed to 6 priority pollutants, as a result of the use of 15 consumer product classes in households, while accounting for regional differences in uses, use scenarios and ventilation conditions of each region. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

Exposure, infection, systemic cytokine levels and antibody responses in young children concurrently exposed to schistosomiasis and malaria

PubMed Central

IMAI, NATSUKO; RUJENI, NADINE; NAUSCH, NORMAN; BOURKE, CLAIRE D.; APPLEBY, LAURA J.; COWAN, GRAEME; GWISAI, REGGIS; MIDZI, NICHOLAS; CAVANAGH, DAVID; MDULUZA, TAKAFIRA; TAYLOR, DAVID; MUTAPI, FRANCISCA

2011-01-01

SUMMARY Despite the overlapping distribution of Schistosoma haematobium and Plasmodium falciparum infections, few studies have investigated early immune responses to both parasites in young children resident in areas co-endemic for the parasites. This study measures infection levels of both parasites and relates them to exposure and immune responses in young children. Levels of IgM, IgE, IgG4 directed against schistosome cercariae, egg and adult worm and IgM, IgG directed against P. falciparum schizonts and the merozoite surface proteins 1 and 2 together with the cytokines IFN-γ, IL-4, IL-5, IL-10 and TNF-α were measured by ELISA in 95 Zimbabwean children aged 1–5 years. Schistosome infection prevalence was 14·7% and that of Plasmodium infection was 0% in the children. 43. 4% of the children showed immunological evidence of exposure to schistosome parasites and 13% showed immunological evidence of exposure to Plasmodium parasites. Schistosome–specific responses, indicative of exposure to parasite antigens, were positively associated with cercariae-specific IgE responses, while Plasmodium-specific responses, indicative of exposure to parasite antigens, were negatively associated with responses associated with protective immunity against Plasmodium. There was no significant association between schistosome-specific and Plasmodium-specific responses. Systemic cytokine levels rose with age as well as with schistosome infection and exposure. Overall the results show that (1) significantly more children are exposed to schistosome and Plasmodium infection than those currently infected and; (2) the development of protective acquired immunity commences in early childhood, although its effects on infection levels and pathology may take many years to become apparent. PMID:21813042

Radio-frequency electromagnetic field (RF-EMF) exposure levels in different European outdoor urban environments in comparison with regulatory limits.

PubMed

Urbinello, Damiano; Joseph, Wout; Huss, Anke; Verloock, Leen; Beekhuizen, Johan; Vermeulen, Roel; Martens, Luc; Röösli, Martin

2014-07-01

Concerns of the general public about potential adverse health effects caused by radio-frequency electromagnetic fields (RF-EMFs) led authorities to introduce precautionary exposure limits, which vary considerably between regions. It may be speculated that precautionary limits affect the base station network in a manner that mean population exposure unintentionally increases. The objectives of this multicentre study were to compare mean exposure levels in outdoor areas across four different European cities and to compare with regulatory RF-EMF exposure levels in the corresponding areas. We performed measurements in the cities of Amsterdam (the Netherlands, regulatory limits for mobile phone base station frequency bands: 41-61 V/m), Basel (Switzerland, 4-6 V/m), Ghent (Belgium, 3-4.5 V/m) and Brussels (Belgium, 2.9-4.3 V/m) using a portable measurement device. Measurements were conducted in three different types of outdoor areas (central and non-central residential areas and downtown), between 2011 and 2012 at 12 different days. On each day, measurements were taken every 4s for approximately 15 to 30 min per area. Measurements per urban environment were repeated 12 times during 1 year. Arithmetic mean values for mobile phone base station exposure ranged between 0.22 V/m (Basel) and 0.41 V/m (Amsterdam) in all outdoor areas combined. The 95th percentile for total RF-EMF exposure varied between 0.46 V/m (Basel) and 0.82 V/m (Amsterdam) and the 99th percentile between 0.81 V/m (Basel) and 1.20 V/m (Brussels). All exposure levels were far below international reference levels proposed by ICNIRP (International Commission on Non-Ionizing Radiation Protection). Our study did not find indications that lowering the regulatory limit results in higher mobile phone base station exposure levels. Copyright © 2014 Elsevier Ltd. All rights reserved.

Analysis of radiation exposure for naval units of Operation Crossroads. Volume 2. (Appendix A) target ships. Technical report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weitz, R.; Thomas, C.; Klemm, J.

1982-03-03

External radiation doses are reconstructed for crews of support and target ships of Joint Task Force One at Operation CROSSROADS, 1946. Volume I describes the reconstruction methodology, which consists of modeling the radiation environment, to include the radioactivity of lagoon water, target ships, and support ship contamination; retracing ship paths through this environment; and calculating the doses to shipboard personnel. The USS RECLAIMER, a support ship, is selected as a representative ship to demonstrate this methodology. Doses for all other ships are summarized. Volume II (Appendix A) details the results for target ship personnel. Volume III (Appendix B) details themore » results for support ship personnel. Calculated doses for more than 36,000 personnel aboard support ships while at Bikini range from zero to 1.7 rem. Of those, approximately 34,000 are less than 0.5 rem. From the models provided, doses due to target ship reboarding and doses accrued after departure from Bikini can be calculated, based on the individual circumstances of exposure.« less

Assessment of Tomato (Solanum lycopersicum L.) Producers’ Exposure Level to Pesticides, in Kouka and Toussiana (Burkina Faso)

PubMed Central

Zerbo, Fabrice K. B.; Bonzi, Schémaeza; Legreve, Anne; Somda, Irénée; Schiffers, Bruno

2018-01-01

To assess producers’ exposure level to pesticides in vegetable production in Burkina Faso, a study was carried out in 2016 and 2017 among 30 tomato producers in the municipalities of Kouka and Toussiana. Eighteen (18) commercial formulations were identified, with more than 50% of pesticides destined for cotton production. Eleven active substances have been identified and the most frequently used are λ-cyhalothrin (35%), acetamiprid (22%) and profenofos (13%). The most commonly used chemical families are pyrethroids (28%) and organophosphates (18%). The study revealed a low level of training for producers, a high use of pesticides according to the Frequency Treatment Indicator, and a very low level of protection used by producers. The Health Risk Index shows that active substances such as methomyl, λ-cyhalothrin and profenofos present very high risk to operators’ health. Based on the UK-POEM model, the predictive exposure levels obtained varied from 0.0105 mg/kg body weight/day to 1.7855 mg/kg body weight/day, which is several times higher than the Acceptable Operator Exposure Level. However, the study also shows that exposure can be greatly reduced if the required Personal Protective Equipment is worn. Producers’ awareness and training on integrated pest management are necessary to reduce the risks linked to the pesticides use in Burkina Faso. PMID:29370136

Estimate of safe human exposure levels for lunar dust based on comparative benchmark dose modeling.

PubMed

James, John T; Lam, Chiu-Wing; Santana, Patricia A; Scully, Robert R

2013-04-01

Brief exposures of Apollo astronauts to lunar dust occasionally elicited upper respiratory irritation; however, no limits were ever set for prolonged exposure to lunar dust. The United States and other space faring nations intend to return to the moon for extensive exploration within a few decades. In the meantime, habitats for that exploration, whether mobile or fixed, must be designed to limit human exposure to lunar dust to safe levels. Herein we estimate safe exposure limits for lunar dust collected during the Apollo 14 mission. We instilled three respirable-sized (∼2 μ mass median diameter) lunar dusts (two ground and one unground) and two standard dusts of widely different toxicities (quartz and TiO₂) into the respiratory system of rats. Rats in groups of six were given 0, 1, 2.5 or 7.5 mg of the test dust in a saline-Survanta® vehicle, and biochemical and cellular biomarkers of toxicity in lung lavage fluid were assayed 1 week and one month after instillation. By comparing the dose--response curves of sensitive biomarkers, we estimated safe exposure levels for astronauts and concluded that unground lunar dust and dust ground by two different methods were not toxicologically distinguishable. The safe exposure estimates were 1.3 ± 0.4 mg/m³ (jet-milled dust), 1.0 ± 0.5 mg/m³ (ball-milled dust) and 0.9 ± 0.3 mg/m³ (unground, natural dust). We estimate that 0.5-1 mg/m³ of lunar dust is safe for periodic human exposures during long stays in habitats on the lunar surface.

Characterization of Changes in Gene Expression and Biochemical Pathways at Low Levels of Benzene Exposure

PubMed Central

Thomas, Reuben; Hubbard, Alan E.; McHale, Cliona M.; Zhang, Luoping; Rappaport, Stephen M.; Lan, Qing; Rothman, Nathaniel; Vermeulen, Roel; Guyton, Kathryn Z.; Jinot, Jennifer; Sonawane, Babasaheb R.; Smith, Martyn T.

2014-01-01

Benzene, a ubiquitous environmental pollutant, causes acute myeloid leukemia (AML). Recently, through transcriptome profiling of peripheral blood mononuclear cells (PBMC), we reported dose-dependent effects of benzene exposure on gene expression and biochemical pathways in 83 workers exposed across four airborne concentration ranges (from <1 ppm to >10 ppm) compared with 42 subjects with non-workplace ambient exposure levels. Here, we further characterize these dose-dependent effects with continuous benzene exposure in all 125 study subjects. We estimated air benzene exposure levels in the 42 environmentally-exposed subjects from their unmetabolized urinary benzene levels. We used a novel non-parametric, data-adaptive model selection method to estimate the change with dose in the expression of each gene. We describe non-parametric approaches to model pathway responses and used these to estimate the dose responses of the AML pathway and 4 other pathways of interest. The response patterns of majority of genes as captured by mean estimates of the first and second principal components of the dose-response for the five pathways and the profiles of 6 AML pathway response-representative genes (identified by clustering) exhibited similar apparent supra-linear responses. Responses at or below 0.1 ppm benzene were observed for altered expression of AML pathway genes and CYP2E1. Together, these data show that benzene alters disease-relevant pathways and genes in a dose-dependent manner, with effects apparent at doses as low as 100 ppb in air. Studies with extensive exposure assessment of subjects exposed in the low-dose range between 10 ppb and 1 ppm are needed to confirm these findings. PMID:24786086

Acute inhalative exposure assessment: derivation of guideline levels with special regard to sensitive subpopulations and time scaling.

PubMed

Mielke, Hans; Gundert, Anna; Abraham, Klaus; Gundert-Remy, Ursula

2005-10-30

Risk assessment for acute airborne exposure to volatile organic compounds (VOCs), including exposure to chemical warfare agents, requires consideration of local and systemic effects at high concentrations. The operating procedure developed by the US Acute Exposure Guideline Level (AEGL) committee has gained special attention, in part because of the international collaboration in the project. The procedure defines three levels (AEGL-1: discomfort; AEGL-2: irreversible or other serious, long-lasting adverse effects; AEGL-3: life-threatening effects or death) for different exposure times (10 and 30 min, and 1, 4 and 8 h). In this article, the methodology for deriving AEGL values is reported. Extending the areas covered by the existing AEGL methodology, sensitive subpopulations are dealt with in more detail. Sensitive persons are expected to suffer from stronger effects when exposed to a given external concentration. Using a kinetic model with the sample substance dichloromethane (DCM), the higher internal exposure of children is quantified and compared to a healthy, young adult. The difference is shown to depend on age, on dose, and on duration of exposure. Furthermore, several ways are presented to derive AEGL values for exposure times which differ from the exposure duration in animal studies ('time scaling'). In comparison to the conventional procedure, the alternative approaches are based on mechanistic models of the toxicodynamic effect. Use of these models results in AEGL values which are biologically justified.

Using a network-based approach and targeted maximum likelihood estimation to evaluate the effect of adding pre-exposure prophylaxis to an ongoing test-and-treat trial.

PubMed

Balzer, Laura; Staples, Patrick; Onnela, Jukka-Pekka; DeGruttola, Victor

2017-04-01

Several cluster-randomized trials are underway to investigate the implementation and effectiveness of a universal test-and-treat strategy on the HIV epidemic in sub-Saharan Africa. We consider nesting studies of pre-exposure prophylaxis within these trials. Pre-exposure prophylaxis is a general strategy where high-risk HIV- persons take antiretrovirals daily to reduce their risk of infection from exposure to HIV. We address how to target pre-exposure prophylaxis to high-risk groups and how to maximize power to detect the individual and combined effects of universal test-and-treat and pre-exposure prophylaxis strategies. We simulated 1000 trials, each consisting of 32 villages with 200 individuals per village. At baseline, we randomized the universal test-and-treat strategy. Then, after 3 years of follow-up, we considered four strategies for targeting pre-exposure prophylaxis: (1) all HIV- individuals who self-identify as high risk, (2) all HIV- individuals who are identified by their HIV+ partner (serodiscordant couples), (3) highly connected HIV- individuals, and (4) the HIV- contacts of a newly diagnosed HIV+ individual (a ring-based strategy). We explored two possible trial designs, and all villages were followed for a total of 7 years. For each village in a trial, we used a stochastic block model to generate bipartite (male-female) networks and simulated an agent-based epidemic process on these networks. We estimated the individual and combined intervention effects with a novel targeted maximum likelihood estimator, which used cross-validation to data-adaptively select from a pre-specified library the candidate estimator that maximized the efficiency of the analysis. The universal test-and-treat strategy reduced the 3-year cumulative HIV incidence by 4.0% on average. The impact of each pre-exposure prophylaxis strategy on the 4-year cumulative HIV incidence varied by the coverage of the universal test-and-treat strategy with lower coverage resulting in a larger

Acute myeloid and chronic lymphoid leukaemias and exposure to low-level benzene among petroleum workers

PubMed Central

Rushton, L; Schnatter, A R; Tang, G; Glass, D C

2014-01-01

Background: High benzene exposure causes acute myeloid leukaemia (AML). Three petroleum case–control studies identified 60 cases (241 matched controls) for AML and 80 cases (345 matched controls) for chronic lymphoid leukaemia (CLL). Methods: Cases were classified and scored regarding uncertainty by two haematologists using available diagnostic information. Blinded quantitative benzene exposure assessment used work histories and exposure measurements adjusted for era-specific circumstances. Statistical analyses included conditional logistic regression and penalised smoothing splines. Results: Benzene exposures were much lower than previous studies. Categorical analyses showed increased ORs for AML with several exposure metrics, although patterns were unclear; neither continuous exposure metrics nor spline analyses gave increased risks. ORs were highest in terminal workers, particularly for Tanker Drivers. No relationship was found between benzene exposure and risk of CLL, although the Australian study showed increased risks in refinery workers. Conclusion: Overall, this study does not persuasively demonstrate a risk between benzene and AML. A previously reported strong relationship between myelodysplastic syndrome (MDS) (potentially previously reported as AML) at our study's low benzene levels suggests that MDS may be the more relevant health risk for lower exposure. Higher CLL risks in refinery workers may be due to more diverse exposures than benzene alone. PMID:24357793

Internal exposure levels of typical POPs and their associations with childhood asthma in Shanghai, China.

PubMed

Meng, Ge; Feng, Yan; Nie, Zhiqing; Wu, Xiaomeng; Wei, Hongying; Wu, Shaowei; Yin, Yong; Wang, Yan

2016-04-01

Polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) are common persistent organic pollutants (POPs) that may be associated with childhood asthma. The concentrations of PBDEs, PCBs and OCPs were analyzed in pooled serum samples from both asthmatic and non-asthmatic children. The differences in the internal exposure levels between the case and control groups were tested (p value <0.0012). The associations between the internal exposure concentrations of the POPs and childhood asthma were estimated based on the odds ratios (ORs) calculated using logistic regression models. There were significant differences in three PBDEs, 26 PCBs and seven OCPs between the two groups, with significantly higher levels in the cases. The multiple logistic regression models demonstrated that the internal exposure concentrations of a number of the POPs (23 PCBs, p,p'-DDE and α-HCH) were positively associated with childhood asthma. Some synergistic effects were observed when the children were co-exposed to the chemicals. BDE-209 was positively associated with asthma aggravation. This study indicates the potential relationships between the internal exposure concentrations of particular POPs and the development of childhood asthma. Copyright © 2015 Elsevier Inc. All rights reserved.

[Assessment of occupational exposure to aromatic polycyclic hydrocarbons determining urinary levels of 1-pyrenol].

PubMed

Pavanello, S; Genova, A; Foà, V; Clonfero, E

2000-01-01

In conformity with Italian law 626/94, occupational exposure to Polycyclic Aromatic Hydrocarbons (PAH) in several types of work environments was assessed by analysing urinary levels of 1-pyrenol. A total of 231 non-smokers exposed to PAH (82 workers, employed in two different thermoelectric power plants using combustible oil (30 subjects from plant A and 52 from plant B), 18 subjects working for a company recovering exhausted oils, 12 working on rubber production, 10 on road surface asphalting operations, 22 working in the anodizing section of an aluminium plant, 27 chimney-sweeps, and 60 coke-oven workers (30 topside workers, and 30 doing other jobs)) were enrolled. There were also 53 non-smoker control subjects, not occupationally exposed to PAH. Current smokers were excluded, since smoking is an important confounding factor when occupational exposure to low PAH concentrations are monitored. Confounding factors, i.e., diet and passive smoking, were checked by means of a questionnaire which, in addition to personal data and habits, also requested specific details about the type of diet followed and possible exposure to passive smoking during the 24-hour period preceding urine collection. In controls, exposure to PAH in the diet significantly increased 1-pyrenol levels in urine: in subjects introducing > or = 1 microgram of pyrene with the diet, the mean urinary level of 1-pyrenol was significantly higher than that introduced with < 1 microgram (high versus low dietary intake, mean +/- SD, 0.08 +/- 0.13 and 0.04 +/- 0.06 1-pyrenol mumoles/mole of creatinine, respectively; Mann-Whitney U-test Z = 2.67, p < 0.01). Conversely, passive smoking did not influence 1-pyrenol levels. In the overall population (controls and exposed), multiple linear regression analysis showed that levels of urinary 1-pyrenol were significantly influenced by occupational exposure to PAH in asphalt workers, anodizing plant workers, chimney-sweeps, and coke-oven workers, both those working at

Low-level arsenic exposure via drinking water consumption and female fecundity - A preliminary investigation.

PubMed

Susko, Michele L; Bloom, Michael S; Neamtiu, Iulia A; Appleton, Allison A; Surdu, Simona; Pop, Cristian; Fitzgerald, Edward F; Anastasiu, Doru; Gurzau, Eugen S

2017-04-01

High level arsenic exposure is associated with reproductive toxicity in experimental and observational studies; however, few data exist to assess risks at low levels. Even less data are available to evaluate the impact of low level arsenic exposure on human fecundity. Our aim in this pilot study was a preliminary evaluation of associations between low level drinking water arsenic contamination and female fecundity. This retrospective study was conducted among women previously recruited to a hospital-based case-control study of spontaneous pregnancy loss in Timiṣ County, Romania. Women (n=94) with planned pregnancies of 5-20 weeks gestation completed a comprehensive physician-administered study questionnaire and reported the number of menstrual cycles attempting to conceive as the time to pregnancy (TTP). Drinking water samples were collected from residential drinking water sources and we determined arsenic levels using hydride generation-atomic absorption spectrometry (HG-AAS). Multivariable Cox-proportional hazards regression with Efron approximation was employed to evaluate TTP as a function of drinking water arsenic concentrations among planned pregnancies, adjusted for covariates. There was no main effect for drinking water arsenic exposure, yet the conditional probability for pregnancy was modestly lower among arsenic exposed women with longer TTPs, relative to women with shorter TTPs, and relative to unexposed women. For example, 1µg/L average drinking water arsenic conferred 5%, 8%, and 10% lower likelihoods for pregnancy in the 6th, 9th, and 12th cycles, respectively (P=0.01). While preliminary, our results suggest that low level arsenic contamination in residential drinking water sources may further impair fecundity among women with longer waiting times; however, this hypothesis requires confirmation by a future, more definitive study. Copyright © 2016 Elsevier Inc. All rights reserved.

Low-level arsenic exposure via drinking water consumption and female fecundity - a preliminary investigation

PubMed Central

Susko, Michele L.; Bloom, Michael S.; Neamtiu, Iulia A.; Appleton, Allison A.; Surdu, Simona; Pop, Cristian; Fitzgerald, Edward F.; Anastasiu, Doru; Gurzau, Eugen S.

2017-01-01

High level arsenic exposure is associated with reproductive toxicity in experimental and observational studies; however, few data exist to assess risks at low levels. Even less data are available to evaluate the impact of low level arsenic exposure on human fecundity. Our aim in this pilot study was a preliminary evaluation of associations between low level drinking water arsenic contamination and female fecundity. This retrospective study was conducted among women previously recruited to a hospital-based case-control study of spontaneous pregnancy loss in Timiş County, Romania. Women (n = 94) with planned pregnancies of 5–20 weeks gestation completed a comprehensive physician-administered study questionnaire and reported the number of menstrual cycles attempting to conceive as the time to pregnancy (TTP). Drinking water samples were collected from residential drinking water sources and we determined arsenic levels using hydride generation-atomic absorption spectrometry (HG-AAS). Multivariable Cox-proportional hazards regression with Efron approximation was employed to evaluate TTP as a function of drinking water arsenic concentrations among planned pregnancies, adjusted for covariates. There was no main effect for drinking water arsenic exposure, yet the conditional probability for pregnancy was modestly lower among arsenic exposed women with longer TTPs, relative to women with shorter TTPs, and relative to unexposed women For example, 1 μg/L average drinking water arsenic conferred 5%, 8%, and 10% lower likelihoods for pregnancy in the 6th, 9th, and 12th cycles, respectively (P = 0.01). While preliminary, our results suggest that low level arsenic contamination in residential drinking water sources may further impair fecundity among women with longer waiting times; however, this hypothesis requires confirmation by a future, more definitive study. PMID:28061371

School-based exposure to hazardous air pollutants and grade point average: A multi-level study.

PubMed

Grineski, Sara E; Clark-Reyna, Stephanie E; Collins, Timothy W

2016-05-01

The problem of environmental health hazards around schools is serious but it has been neglected by researchers and analysts. This is concerning because children are highly susceptible to the effects of chemical hazards. Some ecological studies have demonstrated that higher school-level pollution is associated with lower aggregate school-level standardized test scores likely, related to increased respiratory illnesses and/or impaired cognitive development. However, an important question remains unexamined: How do school-level exposures impact individual children's academic performance? To address this, we obtained socio-demographic and grades data from the parents of 1888 fourth and fifth grade children in the El Paso (Texas, USA) Independent School District in 2012. El Paso is located on the US-side of the Mexican border and has a majority Mexican-origin population. School-based hazardous air pollution (HAP) exposure was calculated using census block-level US Environmental Protection Agency National Air Toxics Assessment risk estimates for respiratory and diesel particulate matter (PM). School-level demographics were obtained from the school district. Multi-level models adjusting for individual-level covariates (e.g., age, sex, race/ethnicity, English proficiency, and economic deprivation) and school-level covariates (e.g., percent of students economically disadvantaged and student-teacher ratio) showed that higher school-level HAPs were associated with lower individual-level grade point averages. An interquartile range increase in school-level HAP exposure was associated with an adjusted 0.11-0.40 point decrease in individual students' grade point averages (GPAs), depending on HAP type and emission source. Respiratory risk from HAPs had a larger effect on GPA than did diesel PM risk. Non-road mobile and total respiratory risk had the largest effects on children's GPA of all HAP variables studied and only mother's level of education had a larger effect than those

Prenatal androgen exposure and children's aggressive behavior and activity level.

PubMed

Spencer, Debra; Pasterski, Vickie; Neufeld, Sharon; Glover, Vivette; O'Connor, Thomas G; Hindmarsh, Peter C; Hughes, Ieuan A; Acerini, Carlo L; Hines, Melissa

2017-11-01

Some human behaviors, including aggression and activity level, differ on average for males and females. Here we report findings from two studies investigating possible relations between prenatal androgen and children's aggression and activity level. For study 1, aggression and activity level scores for 43 girls and 38 boys, aged 4 to 11years, with congenital adrenal hyperplasia (CAH, a genetic condition causing increased adrenal androgen production beginning prenatally) were compared to those of similarly-aged, unaffected relatives (41 girls, 31 boys). Girls with CAH scored higher on aggression than unaffected girls, d=0.69, and unaffected boys scored higher on activity level than unaffected girls, d=0.50. No other group differences were significant. For study 2, the relationship of amniotic fluid testosterone to aggression and activity level was investigated in typically-developing children (48 girls, 44 boys), aged 3 to 5years. Boys scored higher than girls on aggression, d=0.41, and activity level, d=0.50. However, amniotic fluid testosterone was not a significant predictor of aggression or activity level for either sex. The results of the two studies provide some support for an influence of prenatal androgen exposure on children's aggressive behavior, but not activity level. The within-sex variation in amniotic fluid testosterone may not be sufficient to allow reliable assessment of relations to aggression or activity level. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of low-level sarin and cyclosarin exposure on hippocampal subfields in Gulf War Veterans.

PubMed

Chao, Linda L; Kriger, Stephen; Buckley, Shannon; Ng, Peter; Mueller, Susanne G

2014-09-01

More than 100,000 US troops were potentially exposed to chemical warfare agents sarin (GB) and cyclosarin (GF) when an ammunition dump at Khamisiyah, Iraq was destroyed during the 1991 Gulf War (GW). We previously reported reduced hippocampal volume in GW veterans with suspected GB/GF exposure relative to matched, unexposed GW veterans estimated from 1.5T magnetic resonance images (MRI). Here we investigate, in a different cohort of GW veterans, whether low-level GB/GF exposure is associated with structural alterations in specific hippocampal subfields, estimated from 4T MRI. The Automatic Segmentation of Hippocampal Subfields (ASHS) technique was used to quantify CA1, CA2, CA3 and dentate gyrus (DG), and subiculum (SUB) subfields volumes from high-resolution T2-weighted images acquired on a 4T MR scanner in 56 GW veterans with suspected GB/GF exposure and 56 "matched" unexposed GW veterans (mean age 49±7 years). GB/GF exposed veterans had smaller CA2 (p=0.003) and CA3/DG (p=0.01) subfield volumes compared to matched, unexposed GW veterans. There were no group difference in total hippocampal volume, quantified with FreeSurfer, and no dose-response relationship between estimated levels of GB/GF exposure and total hippocampal or subfield volume. These findings extend our previous report of structural alterations in the hippocampi of GW veterans with suspected GB/GF exposure to volume changes in the CA2, CA3, and DG hippocampal subfields in a different cohort of GW veterans with suspected GB/GF exposure. Published by Elsevier B.V.

Fibrin clot structure is affected by levels of particulate air pollution exposure in patients with venous thrombosis.

PubMed

Pan, Xiaoxi; Gong, Yun Yun; Martinelli, Ida; Angelici, Laura; Favero, Chiara; Bertazzi, Pier Alberto; Mannucci, Pier M; Ariëns, Robert A S; Routledge, Michael N

2016-01-01

Particulate air pollution is a risk factor for cardiovascular diseases and thrombosis. Long-term exposure to particulate matter with a diameter<10μm (PM10) has been associated with an increased risk of venous thrombosis. The aim of this study was to investigate whether or not particulate air pollution alters fibrin clot structure and thus modulates thrombosis risk. We investigated fibrin polymerization by turbidity (maximum absorbance mOD), clot structure by confocal microscopy (fibre number per μm) and fibrin pore size by permeability (Ks×10(-10)cm(2)) in 103 patients with deep vein thrombosis and 121 healthy controls, for whom levels of air pollution exposure had been recorded. Exposure groups were defined by mean PM10 concentrations over the 730days before the event. We found a higher average number of fibres per clot area in patients than controls, but no difference in Ks or fibre thickness. When the two groups were divided into high or low exposure to PM10, a significantly denser fibrin clot network structure with thicker fibres (higher maximum absorbance, p<0.05), decreased permeability (lower Ks value, p<0.05) and higher average fibre numbers per clot area (p<0.05) was observed in patients in the high exposure group compared to those with low exposure. There were no significant differences in fibrin clot structure between the two exposure levels in healthy subjects. PM10 levels are associated with altered fibrin clot structure in patients with deep vein thrombosis but not in controls, suggesting that air pollution may trigger differences in fibrin clot structure only in patients predisposed to thrombotic disease. Copyright © 2016 Elsevier Ltd. All rights reserved.

Low-level arsenic exposure via drinking water consumption and female fecundity - A preliminary investigation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Susko, Michele L.; Bloom, Michael S., E-mail: mbloom@albany.edu; Department of Environmental Health Sciences, University at Albany, State University of New York, Rensselaer, New York

High level arsenic exposure is associated with reproductive toxicity in experimental and observational studies; however, few data exist to assess risks at low levels. Even less data are available to evaluate the impact of low level arsenic exposure on human fecundity. Our aim in this pilot study was a preliminary evaluation of associations between low level drinking water arsenic contamination and female fecundity. This retrospective study was conducted among women previously recruited to a hospital-based case-control study of spontaneous pregnancy loss in Timiá¹£ County, Romania. Women (n=94) with planned pregnancies of 5–20 weeks gestation completed a comprehensive physician-administered study questionnairemore » and reported the number of menstrual cycles attempting to conceive as the time to pregnancy (TTP). Drinking water samples were collected from residential drinking water sources and we determined arsenic levels using hydride generation-atomic absorption spectrometry (HG-AAS). Multivariable Cox-proportional hazards regression with Efron approximation was employed to evaluate TTP as a function of drinking water arsenic concentrations among planned pregnancies, adjusted for covariates. There was no main effect for drinking water arsenic exposure, yet the conditional probability for pregnancy was modestly lower among arsenic exposed women with longer TTPs, relative to women with shorter TTPs, and relative to unexposed women. For example, 1 µg/L average drinking water arsenic conferred 5%, 8%, and 10% lower likelihoods for pregnancy in the 6th, 9th, and 12th cycles, respectively (P=0.01). While preliminary, our results suggest that low level arsenic contamination in residential drinking water sources may further impair fecundity among women with longer waiting times; however, this hypothesis requires confirmation by a future, more definitive study. - Highlights: • We assessed low level drinking water arsenic as a predictor of fecundability. �

Targeted and Non-Targeted Analysis of Serum Pools to Provide Chemical Exposure Data for Exposure Modeling and Chemical Prioritization

EPA Science Inventory

Biomonitoring data can help inform the development and calibration of high-throughput exposure modeling for use in prioritization and risk evaluation. A pilot project was conducted to evaluate the feasibility of using pooled banked blood samples to generate initial data on popul...

Metabonomics of Pig Blood Plasma Following Whole Body Exposure to Low Levels of Gb Vapor

DTIC Science & Technology

2005-10-01

METABONOMICS OF PIG BLOOD PLASMA FOLLOWING WHOLE BODY EXPOSURE TO LOW LEVELS OF GB VAPOR Vicky L. H. Bevilacqua▲, Terrence G...of chemometrics and NMR will yield metabonomics data useful for establishing biochemical markers for agent exposure. Ideally, such markers would...associated with environmental change, a field recently referred to as " metabonomics ." High field nuclear magnetic resonance (NMR) has emerged as a

Activation Levels, Handling, and Storage of Activated Components in the Target Hall at FRIB

NASA Astrophysics Data System (ADS)

Georgobiani, D.; Bennett, R.; Bollen, G.; Kostin, M.; Ronningen, R.

2018-06-01

The Facility for Rare Isotope Beams (FRIB) is a major new scientific user facility under construction in the United States for nuclear science research with beams of rare isotopes. 400 kW beam operations with heavy ions ranging from oxygen to uranium will create a high radiation environment for many components, particularly for the beam line components located in the target hall, where approximately 100 kW of beam power are dissipated in the target and another 300 kW are dissipated in the beam dump. Detailed studies of the component activation, their remote handling, storage, and transport, have been performed to ensure safe operation levels in this environment. Levels of activation are calculated for the beam line components within the FRIB target hall.

Association of dental enamel lead levels with risk factors for environmental exposure.

PubMed

Olympio, Kelly Polido Kaneshiro; Naozuka, Juliana; Oliveira, Pedro Vitoriano; Cardoso, Maria Regina Alves; Bechara, Etelvino José Henriques; Günther, Wanda Maria Risso

2010-10-01

To analyze household risk factors associated with high lead levels in surface dental enamel. A cross-sectional study was conducted with 160 Brazilian adolescents aged 1418 years living in poor neighborhoods in the city of Bauru, southeastern Brazil, from August to December 2008. Body lead concentrations were assessed in surface dental enamel acid-etch microbiopsies. Dental enamel lead levels were measured by graphite furnace atomic absorption spectrometry and phosphorus levels were measured by inductively coupled plasma optical emission spectrometry. The parents answered a questionnaire about their children's potential early (05 years old) exposure to well-known lead sources. Logistic regression was used to identify associations between dental enamel lead levels and each environmental risk factor studied. Social and familial covariables were included in the models. The results suggest that the adolescents studied were exposed to lead sources during their first years of life. Risk factors associated with high dental enamel lead levels were living in or close to a contaminated area (OR = 4.49; 95% CI: 1.69;11.97); and member of the household worked in the manufacturing of paints, paint pigments, ceramics or batteries (OR = 3.43; 95% CI: 1.31;9.00). Home-based use of lead-glazed ceramics, low-quality pirated toys, anticorrosive paint on gates and/or sale of used car batteries (OR = 1.31; 95% CI: 0.56;3.03) and smoking (OR = 1.66; 95% CI: 0.52;5.28) were not found to be associated with high dental enamel lead levels. Surface dental enamel can be used as a marker of past environmental exposure to lead and lead concentrations detected are associated to well-known sources of lead contamination.

Determination of carboxyhaemoglobin in humans following low-level exposures to carbon monoxide.

PubMed

Gosselin, Nathalie H; Brunet, Robert C; Carrier, Gaétan

2009-11-01

This study proposes to estimate carboxyhaemoglobin (COHb) levels in the blood of men and women of various ages exposed to common concentrations of carbon monoxide (CO) using a model with only one free parameter while integrating alveoli-blood and blood-tissue CO exchanges. The model retained is essentially that of Coburn et al. (1965) with two important additions: an alveoli compartment for the dynamics of CO exchanges between alveoli and blood, and a compartment for the significant amounts of CO bound to heme proteins in extravascular spaces. The model was validated by comparing its simulations with various published data sets for the COHb time profiles of volunteers exposed to known CO concentrations. Once the model was validated, it was used to simulate various situations of interest for their impact on public health. This approach yields reliable estimations of the time profiles of COHb levels resulting from different levels of CO exposure over various periods of time and under various conditions (resting, exercise, working, and smoking). The non-linear kinetics of CO, observed experimentally, were correctly reproduced by simulations with the model. Simulations were also carried out iteratively to determine the exposure times and CO concentrations in ambient air needed to reach the maximum levels of COHb recommended by Health Canada, the U.S. Environmental Protection Agency (EPA), and the World Health Organisation (WHO) for each age group of the general population. The lowest CO concentrations leading to maximum COHb levels of 1.5, 2, and 2.5% were determined.

NORMAL MAMMARY GLAND MORPHOLOGY IN PUBERTAL FEMALE MICE FOLLOWING IN UTERO AND LACTATIONAL EXPOSURE TO GENISTEIN AT LEVELS COMPARABLE TO HUMAN DIETARY EXPOSURE. (R827402)

EPA Science Inventory

The objective of the study was to determine the effect of in utero and lactational exposure to genistein (0, 0.1, 0.5, 2.5 and 10 mg/kg/day) on mammary gland morphology in female B6D2F1 mice at levels comparable to or greater than human exposures. The effect of diethylstilbest...

Evaluation of workplace exposure to respirable crystalline silica in Italy.

PubMed

Scarselli, Alberto; Corfiati, Marisa; Marzio, Davide Di; Iavicoli, Sergio

2014-10-01

Crystalline silica is a human carcinogen and its use is widespread among construction, mining, foundries, and other manufacturing industries. To evaluate occupational exposure to crystalline silica in Italy. Data were collected from exposure registries and descriptive statistics were calculated for exposure-related variables. The number of potentially exposed workers was estimated in a subset of industrial sectors. Linear mixed model analysis was performed to determine factors affecting the exposure level. We found 1387 cases of crystalline silica exposure between 1996 and 2012. Exposure was most common in construction work (AM = 0·057 mg/m(3), N = 505), and among miners and quarry workers (AM = 0·048 mg/m(3), N = 238). We estimated that 41 643 workers were at risk of exposure in the selected industrial sectors during the same period. This study identified high-risk sectors for occupational exposure to crystalline silica, which can help guide targeted dust control interventions and health promotion campaigns in the workplace.

Sensitivity of ecological soil-screening levels for metals to exposure model parameterization and toxicity reference values.

PubMed

Sample, Bradley E; Fairbrother, Anne; Kaiser, Ashley; Law, Sheryl; Adams, Bill

2014-10-01

Ecological soil-screening levels (Eco-SSLs) were developed by the United States Environmental Protection Agency (USEPA) for the purposes of setting conservative soil screening values that can be used to eliminate the need for further ecological assessment for specific analytes at a given site. Ecological soil-screening levels for wildlife represent a simplified dietary exposure model solved in terms of soil concentrations to produce exposure equal to a no-observed-adverse-effect toxicity reference value (TRV). Sensitivity analyses were performed for 6 avian and mammalian model species, and 16 metals/metalloids for which Eco-SSLs have been developed. The relative influence of model parameters was expressed as the absolute value of the range of variation observed in the resulting soil concentration when exposure is equal to the TRV. Rank analysis of variance was used to identify parameters with greatest influence on model output. For both birds and mammals, soil ingestion displayed the broadest overall range (variability), although TRVs consistently had the greatest influence on calculated soil concentrations; bioavailability in food was consistently the least influential parameter, although an important site-specific variable. Relative importance of parameters differed by trophic group. Soil ingestion ranked 2nd for carnivores and herbivores, but was 4th for invertivores. Different patterns were exhibited, depending on which parameter, trophic group, and analyte combination was considered. The approach for TRV selection was also examined in detail, with Cu as the representative analyte. The underlying assumption that generic body-weight-normalized TRVs can be used to derive protective levels for any species is not supported by the data. Whereas the use of site-, species-, and analyte-specific exposure parameters is recommended to reduce variation in exposure estimates (soil protection level), improvement of TRVs is more problematic. © 2014 The Authors

Sensitivity of ecological soil-screening levels for metals to exposure model parameterization and toxicity reference values

PubMed Central

Sample, Bradley E; Fairbrother, Anne; Kaiser, Ashley; Law, Sheryl; Adams, Bill

2014-01-01

Ecological soil-screening levels (Eco-SSLs) were developed by the United States Environmental Protection Agency (USEPA) for the purposes of setting conservative soil screening values that can be used to eliminate the need for further ecological assessment for specific analytes at a given site. Ecological soil-screening levels for wildlife represent a simplified dietary exposure model solved in terms of soil concentrations to produce exposure equal to a no-observed-adverse-effect toxicity reference value (TRV). Sensitivity analyses were performed for 6 avian and mammalian model species, and 16 metals/metalloids for which Eco-SSLs have been developed. The relative influence of model parameters was expressed as the absolute value of the range of variation observed in the resulting soil concentration when exposure is equal to the TRV. Rank analysis of variance was used to identify parameters with greatest influence on model output. For both birds and mammals, soil ingestion displayed the broadest overall range (variability), although TRVs consistently had the greatest influence on calculated soil concentrations; bioavailability in food was consistently the least influential parameter, although an important site-specific variable. Relative importance of parameters differed by trophic group. Soil ingestion ranked 2nd for carnivores and herbivores, but was 4th for invertivores. Different patterns were exhibited, depending on which parameter, trophic group, and analyte combination was considered. The approach for TRV selection was also examined in detail, with Cu as the representative analyte. The underlying assumption that generic body-weight–normalized TRVs can be used to derive protective levels for any species is not supported by the data. Whereas the use of site-, species-, and analyte-specific exposure parameters is recommended to reduce variation in exposure estimates (soil protection level), improvement of TRVs is more problematic. Environ Toxicol Chem 2014

Medium wave exposure characterisation using exposure quotients.

PubMed

Paniagua, Jesús M; Rufo, Montaña; Jiménez, Antonio; Antolín, Alicia; Pinar, Iván

2010-06-01

One of the aspects considered in the International Commission on Non-Ionizing Radiation Protection guidelines is that, in situations of simultaneous exposure to fields of different frequencies, exposure quotients for thermal and electrical stimulation effects should be examined. The aim of the present work was to analyse the electromagnetic radiation levels and exposure quotients for exposure to multiple-frequency sources in the vicinity of medium wave radio broadcasting antennas. The measurements were made with a spectrum analyser and a monopole antenna. Kriging interpolation was used to prepare contour maps and to estimate the levels in the towns and villages of the zone. The results showed that the exposure quotient criterion based on electrical stimulation effects to be more stringent than those based on thermal effects or power density levels. Improvement of dosimetry evaluations requires the spectral components of the radiation to be quantified, followed by application of the criteria for exposure to multiple-frequency sources.

Secondhand smoke exposure levels in outdoor hospitality venues: a qualitative and quantitative review of the research literature.

PubMed

Licht, Andrea S; Hyland, Andrew; Travers, Mark J; Chapman, Simon

2013-05-01

This paper considers the evidence on whether outdoor secondhand smoke (SHS) is present in hospitality venues at high levels enough to potentially pose health risks, particularly among employees. Searches in PubMed and Web of Science included combinations of environmental tobacco smoke, secondhand smoke, or passive smoke AND outdoor, yielding 217 and 5,199 results, respectively through June, 2012. Sixteen studies were selected that reported measuring any outdoor SHS exposures (particulate matter (PM) or other SHS indicators). The SHS measurement methods were assessed for inclusion of extraneous variables that may affect levels or the corroboration of measurements with known standards. The magnitude of SHS exposure (PM2.5) depends on the number of smokers present, measurement proximity, outdoor enclosures, and wind. Annual excess PM2.5 exposure of full-time waitstaff at outdoor smoking environments could average 4.0 to 12.2 μg/m3 under variable smoking conditions. Although highly transitory, outdoor SHS exposures could occasionally exceed annual ambient air quality exposure guidelines. Personal monitoring studies of waitstaff are warranted to corroborate these modeled estimates.

Respiratory symptoms associated with low level sulphur dioxide exposure in silicon carbide production workers.

PubMed Central

Osterman, J W; Greaves, I A; Smith, T J; Hammond, S K; Robins, J M; Thériault, G

1989-01-01

Relations between pulmonary symptoms and exposure to respirable dust and sulphur dioxide (SO2) were evaluated for 145 silicon carbide (SiC) production workers with an average of 13.9 (range 3-41) years of experience in this industry. Eight hour time weighted average exposures to SO2 were 1.5 ppm or less with momentary peaks up to 4 ppm. Cumulative SO2 exposure averaged 1.94 (range 0.02-19.5) ppm-years. Low level respirable dust exposures also occurred (0.63 +/- 0.26 mg/m3). After adjusting for age and current smoking status in multiple logistic regression models, highly significant, positive, dose dependent relations were found between cumulative and average exposure to SO2, and symptoms of usual and chronic phlegm, usual and chronic wheeze, and mild exertional dyspnoea. Mild and moderate dyspnoea were also associated with most recent exposure to SO2. Cough was not associated with SO2. No pulmonary symptoms were associated with exposure to respirable dust nor were any symptoms attributable to an interaction between dust and SO2. Cigarette smoking was strongly associated with cough, phlegm, and wheezing, but not dyspnoea. A greater than additive (synergistic) effect between smoking and exposure to SO2 was present for most symptoms. These findings suggest that long term, variable exposure to SO2 at 1.5 ppm or less was associated with significantly raised rates of phlegm, wheezing, and mild dyspnoea in SiC production workers, and that current threshold limits for SO2 may not adequately protect workers in this industry. PMID:2789966

Occupational exposure to acrylamide in closed system production plants: air levels and biomonitoring.

PubMed

Moorman, William J; Reutman, Susan S; Shaw, Peter B; Blade, Leo Michael; Marlow, David; Vesper, Hubert; Clark, John C; Schrader, Steven M

2012-01-01

The aim of this study was to evaluate biomarkers of acrylamide exposure, including hemoglobin adducts and urinary metabolites in acrylamide production workers. Biomarkers are integrated measures of the internal dose, and it is total acrylamide dose from all routes and sources that may present health risks. Workers from three companies were studied. Workers potentially exposed to acrylamide monomer wore personal breathing-zone air samplers. Air samples and surface-wipe samples were collected and analyzed for acrylamide. General-area air samples were collected in chemical processing units and control rooms. Hemoglobin adducts were isolated from ethylenediamine teraacetic acid (EDTA)-whole blood, and adducts of acrylamide and glycidamide, at the N-terminal valines of hemoglobin, were cleaved from the protein chain by use of a modified Edman reaction. Full work-shift, personal breathing zone, and general-area air samples were collected and analyzed for particulate and acrylamide monomer vapor. The highest general-area concentration of acrylamide vapor was 350 μg/cm(3) in monomer production. Personal breathing zone and general-area concentrations of acrylamide vapor were found to be highest in monomer production operations, and lower levels were in the polymer production operations. Adduct levels varied widely among workers, with the highest in workers in the monomer and polymer production areas. The acrylamide adduct range was 15-1884 pmol/g; glycidamide adducts ranged from 17.8 to 1376 p/mol/g. The highest acrylamide and glycidamide adduct levels were found among monomer production process operators. The primary urinary metabolite N-acetyl-S-(2-carbamoylethyl) cysteine (NACEC) ranged from the limit of detection to 15.4 μg/ml. Correlation of workplace exposure and sentinel health effects is needed to determine and control safe levels of exposure for regulatory standards.

Ubiquitin Carboxy-Terminal Hydrolase-L1 as a Serum Neurotrauma Biomarker for Exposure to Occupational Low-Level Blast

PubMed Central

Carr, Walter; Yarnell, Angela M.; Ong, Ricardo; Walilko, Timothy; Kamimori, Gary H.; da Silva, Uade; McCarron, Richard M.; LoPresti, Matthew L.

2015-01-01

Repeated exposure to low-level blast is a characteristic of a few select occupations and there is concern that such occupational exposures present risk for traumatic brain injury. These occupations include specialized military and law enforcement units that employ controlled detonation of explosive charges for the purpose of tactical entry into secured structures. The concern for negative effects from blast exposure is based on rates of operator self-reported headache, sleep disturbance, working memory impairment, and other concussion-like symptoms. A challenge in research on this topic has been the need for improved assessment tools to empirically evaluate the risk associated with repeated exposure to blast overpressure levels commonly considered to be too low in magnitude to cause acute injury. Evaluation of serum-based neurotrauma biomarkers provides an objective measure that is logistically feasible for use in field training environments. Among candidate biomarkers, ubiquitin carboxy-terminal hydrolase-L1 (UCH-L1) has some empirical support and was evaluated in this study. We used daily blood draws to examine acute change in UCH-L1 among 108 healthy military personnel who were exposed to repeated low-level blast across a 2-week period. These research volunteers also wore pressure sensors to record blast exposures, wrist actigraphs to monitor sleep patterns, and completed daily behavioral assessments of symptomology, postural stability, and neurocognitive function. UCH-L1 levels were elevated as a function of participating in the 2-week training with explosives, but the correlation of UCH-L1 elevation and blast magnitude was weak and inconsistent. Also, UCH-L1 elevations did not correlate with deficits in behavioral measures. These results provide some support for including UCH-L1 as a measure of central nervous system effects from exposure to low-level blast. However, the weak relation observed suggests that additional indicators of blast effect are needed

Should the Centers for Disease Control and Prevention's childhood lead poisoning intervention level be lowered?

PubMed

Bernard, Susan M

2003-08-01

The US Centers for Disease Control and Prevention (CDC) in 1991 chose 10 micro g/dL as an initial screening level for lead in children's blood. Current data on health risks and intervention options do not support generally lowering that level, but federal lead poisoning prevention efforts can be improved by revising the follow-up testing schedule for infants aged 1 year or less with blood lead levels of 5 micro g/dL or higher; universal education about lead exposure risks; universal administration of improved, locally validated risk-screening questionnaires; enhanced compliance with targeted screening recommendations and federal health program requirements; and development by regulatory agencies of primary prevention criteria that do not use the CDC's intervention level as a target "safe" lead exposure.

Effects of early adolescent methamphetamine exposure on anxiety-like behavior and corticosterone levels in mice.

PubMed

Rud, Micaela A; Do, Thao N; Siegel, Jessica A

2016-10-28

Methamphetamine (MA) is an addictive psychomotor stimulant that affects the central nervous system and alters behavior. The effects of MA are modulated by age, and while much research has examined the effects of MA use in adults, relatively little research has examined the effects in adolescents. As the brain is developing during adolescence, it is important that we understand the effects of MA exposure in adolescence. This research examined the effects of acute MA exposure on locomotor and anxiety-like behavior in the open field test and plasma corticosterone levels in adolescent male C57BL/6J mice. Baseline locomotor and anxiety-like behaviors were assessed in the open field test. Immediately following baseline measurements, mice were exposed to saline or 4mg/kg MA and locomotor and anxiety-like behavior were measured. Serum was collected immediately after testing and plasma corticosterone levels measured. There were no group differences in baseline behavioral measurements. MA-exposed adolescent mice showed increased locomotor activity and anxiety-like behavior in the open field compared with saline controls. There was no effect of MA on plasma corticosterone levels. These data suggest that acute MA exposure during adolescence increases locomotor activity and anxiety-like behavior, but does not alter plasma corticosterone levels. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Low level ozone exposure induces airways inflammation and modifies cell surface phenotypes in healthy humans

EPA Science Inventory

Background: The effects of low level ozone exposure (0.08 ppm) on pulmonary function in healthy young adults are well known, however much less is known about the inflammatory and immuno-modulatory effects oflow level ozone in the airways. Techniques such as induced sputum and flo...

Challenges in evaluating PM concentration levels, commuting exposure, and mask efficacy in reducing PM exposure in growing, urban communities in a developing country.

PubMed

Patel, Disa; Shibata, Tomoyuki; Wilson, James; Maidin, Alimin

2016-02-01

Particulate matter (PM) contributes to an increased risk of respiratory and cardiovascular illnesses, cancer, and preterm birth complications. This project assessed PM exposure in Eastern Indonesia's largest city, where air quality has not been comprehensively monitored. We examined the efficacy of wearing masks as an individual intervention effort to reduce in-transit PM exposures. Handheld particulate counters were used to investigate ambient air quality for spatial analysis, as well as the differences in exposure to PM2.5 and PM10 (μg/m(3)) by different transportation methods [e.g. motorcycle (n=97), pete-pete (n=53), and car (n=55); note: n=1 means 1m(3) of air sample]. Mask efficacy to reduce PM exposure was evaluated [e.g. surgical masks (n=39), bandanas (n=52), and motorcycle masks (n=39)]. A Monte Carlo simulation was used to provide a range of uncertainty in exposure assessment. Overall PM10 levels (91±124 μg/m(3)) were elevated compared to the World Health Organization (WHO)'s 24-hour air quality guideline (50 μg/m(3)). While average PM2.5 levels (9±14 μg/m(3)) were below the WHO's guideline (25 μg/m(3)), measurements up to 139 μg/m(3) were observed. Compared to cars, average motorcycle and pete-pete PM exposures were four and three times higher for PM2.5, and 13 and 10 times higher for PM10, respectively. Only surgical masks were consistent in lowering PM2.5 and PM10 (p<0.01). Young children (≤5) were the most vulnerable age group, and could not reach the safe dosage even when wearing surgical masks. Individual interventions can effectively reduce individual PM exposures; however, policy interventions will be needed to improve the overall air quality and create safer transportation. Copyright © 2015 Elsevier B.V. All rights reserved.

Adaptive bi-level programming for optimal gene knockouts for targeted overproduction under phenotypic constraints

PubMed Central

2013-01-01

Background Optimization procedures to identify gene knockouts for targeted biochemical overproduction have been widely in use in modern metabolic engineering. Flux balance analysis (FBA) framework has provided conceptual simplifications for genome-scale dynamic analysis at steady states. Based on FBA, many current optimization methods for targeted bio-productions have been developed under the maximum cell growth assumption. The optimization problem to derive gene knockout strategies recently has been formulated as a bi-level programming problem in OptKnock for maximum targeted bio-productions with maximum growth rates. However, it has been shown that knockout mutants in fact reach the steady states with the minimization of metabolic adjustment (MOMA) from the corresponding wild-type strains instead of having maximal growth rates after genetic or metabolic intervention. In this work, we propose a new bi-level computational framework--MOMAKnock--which can derive robust knockout strategies under the MOMA flux distribution approximation. Methods In this new bi-level optimization framework, we aim to maximize the production of targeted chemicals by identifying candidate knockout genes or reactions under phenotypic constraints approximated by the MOMA assumption. Hence, the targeted chemical production is the primary objective of MOMAKnock while the MOMA assumption is formulated as the inner problem of constraining the knockout metabolic flux to be as close as possible to the steady-state phenotypes of wide-type strains. As this new inner problem becomes a quadratic programming problem, a novel adaptive piecewise linearization algorithm is developed in this paper to obtain the exact optimal solution to this new bi-level integer quadratic programming problem for MOMAKnock. Results Our new MOMAKnock model and the adaptive piecewise linearization solution algorithm are tested with a small E. coli core metabolic network and a large-scale iAF1260 E. coli metabolic network

Adaptive bi-level programming for optimal gene knockouts for targeted overproduction under phenotypic constraints.

PubMed

Ren, Shaogang; Zeng, Bo; Qian, Xiaoning

2013-01-01

Optimization procedures to identify gene knockouts for targeted biochemical overproduction have been widely in use in modern metabolic engineering. Flux balance analysis (FBA) framework has provided conceptual simplifications for genome-scale dynamic analysis at steady states. Based on FBA, many current optimization methods for targeted bio-productions have been developed under the maximum cell growth assumption. The optimization problem to derive gene knockout strategies recently has been formulated as a bi-level programming problem in OptKnock for maximum targeted bio-productions with maximum growth rates. However, it has been shown that knockout mutants in fact reach the steady states with the minimization of metabolic adjustment (MOMA) from the corresponding wild-type strains instead of having maximal growth rates after genetic or metabolic intervention. In this work, we propose a new bi-level computational framework--MOMAKnock--which can derive robust knockout strategies under the MOMA flux distribution approximation. In this new bi-level optimization framework, we aim to maximize the production of targeted chemicals by identifying candidate knockout genes or reactions under phenotypic constraints approximated by the MOMA assumption. Hence, the targeted chemical production is the primary objective of MOMAKnock while the MOMA assumption is formulated as the inner problem of constraining the knockout metabolic flux to be as close as possible to the steady-state phenotypes of wide-type strains. As this new inner problem becomes a quadratic programming problem, a novel adaptive piecewise linearization algorithm is developed in this paper to obtain the exact optimal solution to this new bi-level integer quadratic programming problem for MOMAKnock. Our new MOMAKnock model and the adaptive piecewise linearization solution algorithm are tested with a small E. coli core metabolic network and a large-scale iAF1260 E. coli metabolic network. The derived knockout

Iron Metabolism Genes, Low-Level Lead Exposure, and QT Interval

PubMed Central

Park, Sung Kyun; Hu, Howard; Wright, Robert O.; Schwartz, Joel; Cheng, Yawen; Sparrow, David; Vokonas, Pantel S.; Weisskopf, Marc G.

2009-01-01

Background Cumulative exposure to lead has been shown to be associated with depression of electrocardiographic conduction, such as QT interval (time from start of the Q wave to end of the T wave). Because iron can enhance the oxidative effects of lead, we examined whether polymorphisms in iron metabolism genes [hemochromatosis (HFE), transferrin (TF) C2, and heme oxygenase-1 (HMOX-1)] increase susceptibility to the effects of lead on QT interval in 613 community-dwelling older men. Methods We used standard 12-lead electrocardiograms, K-shell X-ray fluorescence, and graphite furnace atomic absorption spectrometry to measure QT interval, bone lead, and blood lead levels, respectively. Results A one-interquartile-range increase in tibia lead level (13 μg/g) was associated with a 11.35-msec [95% confidence interval (CI), 4.05–18.65 msec] and a 6.81-msec (95% CI, 1.67–11.95 msec) increase in the heart-rate–corrected QT interval among persons carrying long HMOX-1 alleles and at least one copy of an HFE variant, respectively, but had no effect in persons with short and middle HMOX-1 alleles and the wild-type HFE genotype. The lengthening of the heart-rate–corrected QT interval with higher tibia lead and blood lead became more pronounced as the total number (0 vs. 1 vs. ≥2) of gene variants increased (tibia, p-trend = 0.01; blood, p-trend = 0.04). This synergy seems to be driven by a joint effect between HFE variant and HMOX-1 L alleles. Conclusion We found evidence that gene variants related to iron metabolism increase the impacts of low-level lead exposure on the prolonged QT interval. This is the first such report, so these results should be interpreted cautiously and need to be independently verified. PMID:19165391

Using the Instructional Level as a Criterion to Target Reading Interventions

ERIC Educational Resources Information Center

Parker, David C.; Burns, Matthew K.

2014-01-01

The instructional hierarchy offers a useful framework for targeting academic interventions. Within this framework, the accuracy with which a student reads might function as an indicator that the student should receive an intervention that focuses either on accuracy or on fluency. The current study examined whether the instructional level for…

Levels and Determinants of DDT and DDE Exposure in the VHEMBE Cohort.

PubMed

Gaspar, Fraser W; Chevrier, Jonathan; Quirós-Alcalá, Lesliam; Lipsitt, Jonah M; Barr, Dana Boyd; Holland, Nina; Bornman, Riana; Eskenazi, Brenda

2017-07-07

Although indoor residual spraying (IRS) is an effective tool for malaria control, its use contributes to high insecticide exposure in sprayed communities and raises concerns about possible unintended health effects. The Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) is a birth cohort study initiated in 2012 to characterize prenatal exposure to IRS insecticides and exposures' impacts on child health and development in rural South Africa. In this report, we describe the VHEMBE cohort and dichlorodiphenyltrichloroethane (DDT) and dichlorodiphenyldichloroethylene (DDE) serum concentrations measured in VHEMBE mothers when they presented for delivery. In addition, we applied a causal inference framework to estimate the potential reduction in population-level p , p' -DDT and p , p' -DDE serum concentrations under five hypothetical interventions. A total of 751 mothers were enrolled. Serum concentrations of p , p' isomers of DDT and DDE were above the limit of detection (LOD) in ≥98% of the samples, whereas the o , p' isomers were above the LOD in at least 80% of the samples. Median (interquartile range) p , p' -DDT and p , p' -DDE serum concentrations for VHEMBE cohort participants were 55.3 (19.0-259.3) and 242.2 (91.8-878.7) ng/g-lipid, respectively. Mothers reporting to have lived in a home sprayed with DDT for malaria control had ~5-7 times higher p , p' -DDT and p , p' -DDE serum concentrations than those who never lived in a home sprayed with DDT. Of the five potential interventions tested, we found increasing access to water significantly reduced p , p' -DDT exposure and increasing the frequency of household wet mopping significantly reduced p , p' -DDT and p , p' -DDE exposure. Our findings suggest that several intervention approaches may reduce DDT/DDE exposure in pregnant women living in IRS communities. https://doi.org/10.1289/EHP353.

Reduced exercise time in competitive simulations consequent to low level ozone exposure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schelegle, E.S.; Adams, W.C.

Ten highly trained endurance athletes were studied to determine the effects of exposure to low ozone (O/sub 3/) concentrations on simulated competitive endurance performance and associated physiological and subjective symptom responses. Each subject was randomly exposed to filtered air (FA), and to 0.12, 0.18, and 0.24 ppm O/sub 3/ while performing a 1 h competitive simulation protocol on a bicycle ergometer. Endurance performance was evaluated by the number of subjects unable to complete rides (last 30 min at an intense work load of approximately 86% VO/sub 2/max). All subjects completed the FA exposure, whereas one, five, and seven subjects didmore » not complete the 0.12, 0.18, and 0.24 ppm O/sub 3/ exposures, respectively. Statistical analysis indicated a significant (P less than 0.05) increase in the inability of subjects to complete the competitive simulations with increasing O/sub 3/ concentration, including a significant difference between the 0.24 ppm O/sub 3/ and FA exposure. Significant decreases (P less than 0.05) were also observed following the 0.18 and 0.24 ppm O/sub 3/ exposures, respectively, in forced vital capacity (-7.8 and -9.9%), and forced expiratory volume in 1 s (-5.8 and -10.5%). No significant O/sub 3/ effect was observed for exercise respiratory metabolism or ventilatory pattern responses. However, the number of reported subjective symptoms increased significantly following the 0.18 and 0.24 ppm O/sub 3/ protocols. These data demonstrate significant decrements in simulated competitive endurance performance and in pulmonary function, with accompanying enhanced subjective symptoms, following exposure to low O/sub 3/ levels commonly observed in numerous metropolitan environments during the summer months.« less

Using Geographic Information Systems for Exposure Assessment in Environmental Epidemiology Studies

PubMed Central

Nuckols, John R.; Ward, Mary H.; Jarup, Lars

2004-01-01

Geographic information systems (GIS) are being used with increasing frequency in environmental epidemiology studies. Reported applications include locating the study population by geocoding addresses (assigning mapping coordinates), using proximity analysis of contaminant source as a surrogate for exposure, and integrating environmental monitoring data into the analysis of the health outcomes. Although most of these studies have been ecologic in design, some have used GIS in estimating environmental levels of a contaminant at the individual level and to design exposure metrics for use in epidemiologic studies. In this article we discuss fundamentals of three scientific disciplines instrumental to using GIS in exposure assessment for epidemiologic studies: geospatial science, environmental science, and epidemiology. We also explore how a GIS can be used to accomplish several steps in the exposure assessment process. These steps include defining the study population, identifying source and potential routes of exposure, estimating environmental levels of target contaminants, and estimating personal exposures. We present and discuss examples for the first three steps. We discuss potential use of GIS and global positioning systems (GPS) in the last step. On the basis of our findings, we conclude that the use of GIS in exposure assessment for environmental epidemiology studies is not only feasible but can enhance the understanding of the association between contaminants in our environment and disease. PMID:15198921

Low-level lead exposure and the prevalence of gout: an observational study.

PubMed

Krishnan, Eswar; Lingala, Bharathi; Bhalla, Vivek

2012-08-21

Blood lead levels (BLLs) less than 1.21 µmol/L (<25 µg/dL) among adults are considered acceptable by current national standards. Lead toxicity can lead to gouty arthritis (gout), but whether the low lead exposure in the contemporary general population confers risk for gout is not known. To determine whether BLLs within the range currently considered acceptable are associated with gout. Population-based cross-sectional study. The National Health and Nutrition Examination Survey for 2005 through 2008. 6153 civilians aged 40 years or older with an estimated glomerular filtration rate greater than 10 mL/min per 1.73 m2. Outcome variables were self-reported physician diagnosis of gout and serum urate level. Blood lead level was the principal exposure variable. Additional data collected were anthropometric measures, blood pressure, dietary purine intake, medication use, medical history, and serum creatinine concentration. The prevalence of gout was 6.05% (95% CI, 4.49% to 7.62%) among patients in the highest BLL quartile (mean, 0.19 µmol/L [3.95 µg/dL]) compared with 1.76% (CI, 1.10% to 2.42%) among those in the lowest quartile (mean, 0.04 µmol/L [0.89 µg/dL]). Each doubling of BLL was associated with an unadjusted odds ratio of 1.74 (CI, 1.47 to 2.05) for gout and 1.25 (CI, 1.12 to 1.40) for hyperuricemia. After adjustment for renal function, diabetes, diuretic use, hypertension, race, body mass index, income, and education level, the highest BLL quartile was associated with a 3.6-fold higher risk for gout and a 1.9-fold higher risk for hyperuricemia compared with the lowest quartile. Blood lead level does not necessarily reflect the total body lead burden. Blood lead levels in the range currently considered acceptable are associated with increased prevalence of gout and hyperuricemia.

Effects of dietary lead exposure on vitamin levels in great tit nestlings - An experimental manipulation.

PubMed

Ruiz, Sandra; Espín, Silvia; Rainio, Miia; Ruuskanen, Suvi; Salminen, Juha-Pekka; Lilley, Thomas M; Eeva, Tapio

2016-06-01

Exposure to metal pollution negatively affects animal physiology, including nutrient metabolism, but in the wild an effect can seldom be attributed to a single metal. Moreover, little is known about how the metabolism of vitamins, essential micronutrients for developing juveniles, is affected by toxic metals. Therefore we experimentally investigated the effects of lead (Pb), a widespread toxic metal, on four fat-soluble vitamins A (total and retinol), D3, E (total and α-tocopherol) and K and carotenoids (lutein, zeaxanthin and unidentified) in great tit (Parus major) nestlings. In addition to a control group where no Pb was provided, two Pb-dosed groups were compared to a metal exposed group in the vicinity of a Ni-Cu smelter. We examined whether Pb treatment affects vitamin homeostasis and how the response of Pb-treated birds relates to that of a population under industrial exposure of Pb and other metals. For this purpose, vitamin and carotenoid levels were quantified with UPLC-MS from plasma of 7 days-old nestlings. All metal exposed groups showed increased vitamin A and retinol levels. However, vitamin levels were not directly associated with fecal Pb levels, with the exception of retinol, which was positively correlated with fecal Pb. Alpha-tocopherol, lutein and zeaxanthin levels were positively associated with body mass and wing growth rate. To conclude, Pb exposure increased plasma vitamin A and retinol levels while the levels of other vitamins and carotenoids rather reflected secondary pollution effects via differences in habitat and diet quality at the smelter site. Our findings suggest Pb exposed nestlings may allocate the vitamins needed for growth and development to fight the physiological stress thus compromising their fitness. Copyright © 2016 Elsevier Ltd. All rights reserved.

JP-8 jet fuel exposure rapidly induces high levels of IL-10 and PGE2 secretion and is correlated with loss of immune function.

PubMed

Harris, David T; Sakiestewa, Debbie; Titone, Dominic; Witten, Mark

2007-05-01

The US Air Force has implemented the widespread use of JP-8 jet fuel in its operations, although a thorough understanding of its potential effects upon exposed personnel is unclear. Previous work has demonstrated that JP-8 exposure is immunosuppressive. In the present study, the potential mechanisms for the effects of JP-8 exposure on the immune system were investigated. Exposure of mice to JP-8 for 1 h/day resulted in immediate secretion of two immunosuppressive agents; namely, interleukin-10 (IL-10) and prostaglandin E2 (PGE2). JP-8 exposure rapidly induced a persistently high level of serum IL-10 and PGE2 at an exposure concentration of 1000 mg/m3. IL-10 levels peaked at 2 h post-JP-8 exposure and then stabilized at significantly elevated serum levels, while PGE2 levels peaked after 2-3 days of exposure and then stabilized. Elevated IL-10 and PGE2 levels may at least partially explain the effects of JP-8 exposure on immune function. Elevated IL-10 and PGE2 levels, however, cannot explain all of the effects due to JP-8 exposure (e.g., decreased organ weights and decreased viable immune cells), as treatment with a PGE2 inhibitor did not completely reverse the immunosuppressive effects of jet fuel exposure. Thus, low concentration JP-8 jet fuel exposures have significant effects on the immune system, which can be partially explained by the secretion of immunosuppressive modulators, which are cumulative over time.

Multicenter field trial on possible health effects of toluene. II. Cross-sectional evaluation of acute low-level exposure.

PubMed

Neubert, D; Gericke, C; Hanke, B; Beckmann, G; Baltes, M M; Kühl, K P; Bochert, G; Hartmann, J

2001-11-15

Data on possible acute effects of today's relevant low-level exposure to toluene are contradictory, and information on possible effects of exposure under occupational conditions is largely lacking. In a controlled, multi-center, blinded field trial, effects possibly associated with acute toluene exposure were evaluated in workers of 12 German rotogravure factories. Medical examinations (inquiries on subjective symptoms, and standard tests of psycho-physiological and psycho-motor functions) were performed on almost 1500 volunteers, of whom 1290 were toluene-exposed (1178 men and 112 women), and about 200 participants served as references (157 men and 37 women), but the main aim of the trial was to reveal dose-response relationships. All volunteers were of the morning work-shift (6 h exposure). Both individual ambient air concentrations (time-weighted average) during the work-shift, as well as blood toluene concentrations after the work-shift were measured. Therefore, the medical data could for the first time be correlated with the actual individual body burden (blood toluene level) at the time of testing. In order to largely exclude confounding by chronic toluene exposure, kinetic measurements as well as the psycho-physiological and psycho-motoric tests were performed before and after the work-shift. Except for minor statistical deviations, neither convincing dose-dependent acute effects could be demonstrated with regression analyses in male volunteers at the exposure levels evaluated, nor were significant differences found when applying group statistics (highly toluene-exposed group versus volunteers with negligible exposure). Due to the rather large number of participants, the predictive power of the study is high, especially when compared with previous publications. In two psycho-physiological tests, a few more female volunteers with quite low toluene body burdens (<340 microg/l blood) showed relatively low scores when compared with participants of the reference

Global Projection of Coastal Exposure Associated with Sea-level Rise beyond Tipping Points

NASA Astrophysics Data System (ADS)

Tawatari, R.; Miyazaki, C.; Iseri, Y.; Kiguchi, M.; Kanae, S.

2015-12-01

Sea-level rise due to global warming becomes a great matter of concern for global coastal area. Additionally, it has reported in fifth report of IPCC (Intergovernmental Panel on Climate Change) that deglaciation of Greenland ice sheet and Antarctic ice sheet would occur rapidly and enhance sea-level rise if temperature passes certain "Tipping point". In terms of projecting damage induced by sea-level rise globally, some previous studies focused on duration until mainly 2100. Furthermore long-term estimations on centuries to millennial climatic response of the ice sheets which are supposed to be triggered within this or next century would be also important to think about future climate and lifestyle in coastal . In this study, I estimated the long term sea-level which take into account the tipping points of Greenland ice sheet (1.4℃) as sum of 4 factors (thermal expansion, glacier and ice cap, Greenland ice sheet, Antarctic ice sheet). The sea-level follows 4 representative concentration pathways up to 3000 obtained through literature reviewing since there were limited available sea-level projections up to 3000. I also estimated a number of affected population lives in coastal area up to 3000 with using the estimated sea-level. The cost for damage, adaptation and mitigation would be also discussed. These estimations would be useful when decision-makers propose policies for construction of dikes and proposing mitigation plans for sustainable future. The result indicates there would be large and relatively rapid increases in both sea-level rise and coastal exposure if global mean temperature passes the tipping point of Greenland ice sheet. However the tipping points, melting rate and timescale of response are highly uncertain and still discussed among experts. Thus more precise and credible information is required for further accurate estimation of long-term sea-level rise and population exposure in the future.

Coastal vertebrate exposure to predicted habitat changes due to sea level rise

USGS Publications Warehouse

Hunter, Elizabeth A.; Nibbelink, Nathan P.; Alexander, Clark R.; Barrett, Kyle; Mengak, Lara F.; Guy, Rachel; Moore, Clinton; Cooper, Robert J.

2015-01-01

Sea level rise (SLR) may degrade habitat for coastal vertebrates in the Southeastern United States, but it is unclear which groups or species will be most exposed to habitat changes. We assessed 28 coastal Georgia vertebrate species for their exposure to potential habitat changes due to SLR using output from the Sea Level Affecting Marshes Model and information on the species’ fundamental niches. We assessed forecasted habitat change up to the year 2100 using three structural habitat metrics: total area, patch size, and habitat permanence. Almost all of the species (n = 24) experienced negative habitat changes due to SLR as measured by at least one of the metrics. Salt marsh and ocean beach habitats experienced the most change (out of 16 categorical land cover types) across the three metrics and species that used salt marsh extensively (rails and marsh sparrows) were ranked highest for exposure to habitat changes. Species that nested on ocean beaches (Diamondback Terrapins, shorebirds, and terns) were also ranked highly, but their use of other foraging habitats reduced their overall exposure. Future studies on potential effects of SLR on vertebrates in southeastern coastal ecosystems should focus on the relative importance of different habitat types to these species’ foraging and nesting requirements. Our straightforward prioritization approach is applicable to other coastal systems and can provide insight to managers on which species to focus resources, what components of their habitats need to be protected, and which locations in the study area will provide habitat refuges in the face of SLR.

Coastal Vertebrate Exposure to Predicted Habitat Changes Due to Sea Level Rise.

PubMed

Hunter, Elizabeth A; Nibbelink, Nathan P; Alexander, Clark R; Barrett, Kyle; Mengak, Lara F; Guy, Rachel K; Moore, Clinton T; Cooper, Robert J

2015-12-01

Sea level rise (SLR) may degrade habitat for coastal vertebrates in the Southeastern United States, but it is unclear which groups or species will be most exposed to habitat changes. We assessed 28 coastal Georgia vertebrate species for their exposure to potential habitat changes due to SLR using output from the Sea Level Affecting Marshes Model and information on the species' fundamental niches. We assessed forecasted habitat change up to the year 2100 using three structural habitat metrics: total area, patch size, and habitat permanence. Almost all of the species (n = 24) experienced negative habitat changes due to SLR as measured by at least one of the metrics. Salt marsh and ocean beach habitats experienced the most change (out of 16 categorical land cover types) across the three metrics and species that used salt marsh extensively (rails and marsh sparrows) were ranked highest for exposure to habitat changes. Species that nested on ocean beaches (Diamondback Terrapins, shorebirds, and terns) were also ranked highly, but their use of other foraging habitats reduced their overall exposure. Future studies on potential effects of SLR on vertebrates in southeastern coastal ecosystems should focus on the relative importance of different habitat types to these species' foraging and nesting requirements. Our straightforward prioritization approach is applicable to other coastal systems and can provide insight to managers on which species to focus resources, what components of their habitats need to be protected, and which locations in the study area will provide habitat refuges in the face of SLR.

Coastal Vertebrate Exposure to Predicted Habitat Changes Due to Sea Level Rise

NASA Astrophysics Data System (ADS)

Hunter, Elizabeth A.; Nibbelink, Nathan P.; Alexander, Clark R.; Barrett, Kyle; Mengak, Lara F.; Guy, Rachel K.; Moore, Clinton T.; Cooper, Robert J.

2015-12-01

Sea level rise (SLR) may degrade habitat for coastal vertebrates in the Southeastern United States, but it is unclear which groups or species will be most exposed to habitat changes. We assessed 28 coastal Georgia vertebrate species for their exposure to potential habitat changes due to SLR using output from the Sea Level Affecting Marshes Model and information on the species' fundamental niches. We assessed forecasted habitat change up to the year 2100 using three structural habitat metrics: total area, patch size, and habitat permanence. Almost all of the species ( n = 24) experienced negative habitat changes due to SLR as measured by at least one of the metrics. Salt marsh and ocean beach habitats experienced the most change (out of 16 categorical land cover types) across the three metrics and species that used salt marsh extensively (rails and marsh sparrows) were ranked highest for exposure to habitat changes. Species that nested on ocean beaches (Diamondback Terrapins, shorebirds, and terns) were also ranked highly, but their use of other foraging habitats reduced their overall exposure. Future studies on potential effects of SLR on vertebrates in southeastern coastal ecosystems should focus on the relative importance of different habitat types to these species' foraging and nesting requirements. Our straightforward prioritization approach is applicable to other coastal systems and can provide insight to managers on which species to focus resources, what components of their habitats need to be protected, and which locations in the study area will provide habitat refuges in the face of SLR.

Meigo governs dendrite targeting specificity by modulating Ephrin level and N-glycosylation

PubMed Central

Sekine, Sayaka U; Haraguchi, Shuka; Chao, Kinhong; Kato, Tomoko; Luo, Liqun; Miura, Masayuki; Chihara, Takahiro

2016-01-01

Neural circuit assembly requires precise dendrite and axon targeting. We identified an evolutionarily conserved endoplasmic reticulum (ER) protein, Meigo, from a mosaic genetic screen in Drosophila melanogaster. Meigo was cell-autonomously required in olfactory receptor neurons and projection neurons to target their axons and dendrites to the lateral antennal lobe and to refine projection neuron dendrites into individual glomeruli. Loss of Meigo induced an unfolded protein response and reduced the amount of neuronal cell surface proteins, including Ephrin. Ephrin overexpression specifically suppressed the projection neuron dendrite refinement defect present in meigo mutant flies, and ephrin knockdown caused a similar projection neuron dendrite refinement defect. Meigo positively regulated the level of Ephrin N-glycosylation, which was required for its optimal function in vivo. Thus, Meigo, an ER-resident protein, governs neuronal targeting specificity by regulating ER folding capacity and protein N-glycosylation. Furthermore, Ephrin appears to be an important substrate that mediates Meigo’s function in refinement of glomerular targeting. PMID:23624514

Prenatal caffeine exposure induced a lower level of fetal blood leptin mainly via placental mechanism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Yi-meng; Luo, Han-wen; Kou, Hao

It's known that blood leptin level is reduced in intrauterine growth retardation (IUGR) fetus, and placental leptin is the major source of fetal blood leptin. This study aimed to investigate the decreased fetal blood leptin level by prenatal caffeine exposure (PCE) and its underlying placental mechanisms. Pregnant Wistar rats were intragastrically administered caffeine (30–120 mg/kg day) from gestational day 9 to 20. The level of fetal serum leptin and the expression of placental leptin-related genes were analyzed. Furthermore, we investigated the molecular mechanism of the reduced placental leptin's expression by treatment with caffeine (0.8–20 μM) in the BeWo cells. Inmore » vivo, PCE significantly decreased fetal serum leptin level in caffeine dose-dependent manner. Meanwhile, placental mRNA expression of adenosine A2a receptor (Adora2a), cAMP-response element binding protein (CREB), a short-type leptin receptor (Ob-Ra) and leptin was reduced in the PCE groups. In vitro, caffeine significantly decreased the mRNA expression of leptin, CREB and ADORA2A in concentration and time-dependent manners. The addition of ADORA2A agonist or adenylyl cyclase (AC) agonist reversed the inhibition of leptin expression induced by caffeine. PCE induced a lower level of fetal blood leptin, which the primary mechanism is that caffeine inhibited antagonized Adora2a and AC activities to decreased cAMP synthesis, thus inhibited the expression of the transcription factor CREB and target gene leptin in the placenta. Meantime, the reduced transportation of maternal leptin by placental Ob-Ra also contributed to the reduced fetal blood leptin. Together, PCE decreased fetal blood leptin mainly via reducing the expression and transportation of leptin in the placenta. - Highlights: • Caffeine reduced fetal blood leptin level. • Caffeine inhibited placental leptin production and transport. • Caffeine down-regulated placental leptin expression via antagonizing ADORA2. • Caffeine

The Relationship Between Population-Level Exposure to Alcohol Advertising on Television and Brand-Specific Consumption Among Underage Youth in the US

PubMed Central

Ross, Craig S.; Maple, Emily; Siegel, Michael; DeJong, William; Naimi, Timothy S.; Padon, Alisa A.; Borzekowski, Dina L.G.; Jernigan, David H.

2015-01-01

Aims: We investigated the population-level relationship between exposure to brand-specific advertising and brand-specific alcohol use among US youth. Methods: We conducted an internet survey of a national sample of 1031 youth, ages 13–20, who had consumed alcohol in the past 30 days. We ascertained all of the alcohol brands respondents consumed in the past 30 days, as well as which of 20 popular television shows they had viewed during that time period. Using a negative binomial regression model, we examined the relationship between aggregated brand-specific exposure to alcohol advertising on the 20 television shows [ad stock, measured in gross rating points (GRPs)] and youth brand-consumption prevalence, while controlling for the average price and overall market share of each brand. Results: Brands with advertising exposure on the 20 television shows had a consumption prevalence about four times higher than brands not advertising on those shows. Brand-level advertising elasticity of demand varied by exposure level, with higher elasticity in the lower exposure range. The estimated advertising elasticity of 0.63 in the lower exposure range indicates that for each 1% increase in advertising exposure, a brand's youth consumption prevalence increases by 0.63%. Conclusions: At the population level, underage youths' exposure to brand-specific advertising was a significant predictor of the consumption prevalence of that brand, independent of each brand's price and overall market share. The non-linearity of the observed relationship suggests that youth advertising exposure may need to be lowered substantially in order to decrease consumption of the most heavily advertised brands. PMID:25754127

Increased levels of oxidative DNA damage in pesticide sprayers in Thessaly Region (Greece). Implications of pesticide exposure.

PubMed

Koureas, Michalis; Tsezou, Aspasia; Tsakalof, Andreas; Orfanidou, Timoklia; Hadjichristodoulou, Christos

2014-10-15

The widespread use of pesticides substances nowadays largely guarantees the protection of crops and people from undesired pests. However, exposure to pesticides was related to a variety of human health effects. The present study was conducted in the region of Thessaly which is characterized by intensive agricultural activities and wide use of pesticides. The study aimed at estimating the oxidative damage to DNA in different subpopulations in Thessaly region (Greece) and investigating its correlation with exposure to pesticides and other potential risk factors. In total, the study involved 80 pesticide sprayers, 85 rural residents and 121 individuals, inhabitants of the city of Larissa. Demographic characteristics, habits, medical history and exposure history of the participants to pesticides were recorded by personal interviews. Blood and urine samples were collected from all participants. For the measurement of exposure to organophosphorus insecticides, dialkylphosphate (DAP) metabolites were quantified in urine, by gas chromatography-mass spectrometry. Genomic DNA was extracted from peripheral blood samples and the oxidation by-product 8-hydroxydeoxyguanosine (8-OHdG) was determined by Enzyme Immuno-Assay. Urinary metabolite concentrations were not associated with 8-OHdG levels but it was found that pesticide sprayers had significantly higher levels of 8-OHdG (p=0.007) in comparison to the control group. Last season's exposure to insecticides and fungicides, expressed as total area treated multiplied by the number of applications, showed a statistically significant association with the risk of having high 8-OHdG levels [RR: 2.19 (95%CI:1.09-4.38) and RR: 2.32 (95% CI:1.16-4.64) respectively]. Additionally, from the subgroups of pesticides examined, seasonal exposure to neonicotinoid insecticides [RR: 2.22 (95% CI:1.07-4.63)] and glufosinate ammonium [RR: 3.26 (95% CI:1.38-7.69)] was found to have the greater impact on 8-OHdG levels. This study produced findings

Low-level arsenic exposure: nutritional and dietary predictors in first-grade Uruguayan children

PubMed Central

Kordas, Katarzyna; Queirolo, Elena I; Mañay, Nelly; Peregalli, Fabiana; Hsiao, Pao Ying; Lu, Ying; Vahter, Marie

2016-01-01

Arsenic exposure in children is a public health concern but is understudied in relation to the predictors, and effects of low-level exposure. We examined the extent and dietary predictors of exposure to inorganic arsenic in 5–8 year old children from Montevideo, Uruguay. Children were recruited at school; 357 were enrolled, 328 collected morning urine samples, and 317 had two 24-hour dietary recalls. Urinary arsenic metabolites, i.e. inorganic arsenic (iAs), methylarsonic acid (MMA), and dimethylarsinic acid (DMA), were measured using high-performance liquid chromatography with hydride generation and inductively coupled plasma mass spectrometry (HPLC-HG-ICP-MS), and the sum concentration (U-As) used for exposure assessment. Proportions of arsenic metabolites (%iAs, %MMA and %DMA) in urine were modelled in OLS regressions as functions of food groups, dietary patterns, nutrient intake, and nutritional status. Exposure to arsenic was low (median U-As: 9.9 µg/L) and household water (water As: median 0.45 µg/L) was not a major contributor to exposure. Children with higher consumption of rice had higher U-As but lower %iAs, %MMA, and higher %DMA. Children with higher meat consumption had lower %iAs and higher %DMA. Higher scores on ”nutrient dense” dietary pattern were related to lower %iAs and %MMA, and higher %DMA. Higher intake of dietary folate was associated with lower %MMA and higher %DMA. Overweight children had lower %MMA and higher %DMA than normal-weight children. In summary, rice was an important predictor of exposure to inorganic arsenic and DMA. Higher meat and folate consumption, diet rich in green leafy and red-orange vegetables and eggs, and higher BMI contributed to higher arsenic methylation capacity. PMID:26828624

Low-level arsenic exposure: Nutritional and dietary predictors in first-grade Uruguayan children.

PubMed

Kordas, Katarzyna; Queirolo, Elena I; Mañay, Nelly; Peregalli, Fabiana; Hsiao, Pao Ying; Lu, Ying; Vahter, Marie

2016-05-01

Arsenic exposure in children is a public health concern but is understudied in relation to the predictors, and effects of low-level exposure. We examined the extent and dietary predictors of exposure to inorganic arsenic in 5-8 year old children from Montevideo, Uruguay. Children were recruited at school; 357 were enrolled, 328 collected morning urine samples, and 317 had two 24-h dietary recalls. Urinary arsenic metabolites, i.e. inorganic arsenic (iAs), methylarsonic acid (MMA), and dimethylarsinic acid (DMA), were measured using high-performance liquid chromatography with hydride generation and inductively coupled plasma mass spectrometry (HPLC-HG-ICP-MS), and the sum concentration (U-As) used for exposure assessment. Proportions of arsenic metabolites (%iAs, %MMA and %DMA) in urine were modelled in OLS regressions as functions of food groups, dietary patterns, nutrient intake, and nutritional status. Exposure to arsenic was low (median U-As: 9.9µg/L) and household water (water As: median 0.45µg/L) was not a major contributor to exposure. Children with higher consumption of rice had higher U-As but lower %iAs, %MMA, and higher %DMA. Children with higher meat consumption had lower %iAs and higher %DMA. Higher scores on "nutrient dense" dietary pattern were related to lower %iAs and %MMA, and higher %DMA. Higher intake of dietary folate was associated with lower %MMA and higher %DMA. Overweight children had lower %MMA and higher %DMA than normal-weight children. In summary, rice was an important predictor of exposure to inorganic arsenic and DMA. Higher meat and folate consumption, diet rich in green leafy and red-orange vegetables and eggs, and higher BMI contributed to higher arsenic methylation capacity. Copyright © 2016 Elsevier Inc. All rights reserved.

Evidence of underage targeting of alcohol advertising on television in the United States: Lessons from the Lockyer v. Reynolds decisions

PubMed Central

Ostroff, Joshua; Jernigan, David H.

2016-01-01

Underage alcohol use is a global public health problem and alcohol advertising has been associated with underage drinking. The alcohol industry regulates itself and is the primary control on alcohol advertising in many countries around the world, advising trade association members to advertise only in adult-oriented media. Despite high levels of compliance with these self-regulatory guidelines, in several countries youth exposure to alcohol advertising on television has grown faster than adult exposure. In the United States, we found that exposure for underage viewers ages 18–20 grew from 2005 through 2011 faster than any adult age group. Applying a method adopted from a court in the US to identify underage targeting of advertising, we found evidence of targeting of alcohol advertising to underage viewers ages 18–20. The court's rule appeared in Lockyer v. Reynolds (The People ex rel. Bill Lockyer v. R.J. Reynolds Tobacco Company, GIC764118, 2002). We demonstrated that alcohol companies were able to modify their advertising practices to maintain current levels of adult advertising exposure while reducing youth exposure. PMID:24424494

Evidence of underage targeting of alcohol advertising on television in the United States: lessons from the Lockyer v. Reynolds decisions.

PubMed

Ross, Craig S; Ostroff, Joshua; Jernigan, David H

2014-02-01

Underage alcohol use is a global public health problem and alcohol advertising has been associated with underage drinking. The alcohol industry regulates itself and is the primary control on alcohol advertising in many countries around the world, advising trade association members to advertise only in adult-oriented media. Despite high levels of compliance with these self-regulatory guidelines, in several countries youth exposure to alcohol advertising on television has grown faster than adult exposure. In the United States, we found that exposure for underage viewers ages 18-20 grew from 2005 through 2011 faster than any adult age group. Applying a method adopted from a court in the US to identify underage targeting of advertising, we found evidence of targeting of alcohol advertising to underage viewers ages 18-20. The court's rule appeared in Lockyer v. Reynolds (The People ex rel. Bill Lockyer v. R.J. Reynolds Tobacco Company, GIC764118, 2002). We demonstrated that alcohol companies were able to modify their advertising practices to maintain current levels of adult advertising exposure while reducing youth exposure.

Development of a Portable Tool for Screening Neuromotor Sequelae From Repetitive Low-Level Blast Exposure.

PubMed

Rhea, Christopher K; Kuznetsov, Nikita A; Ross, Scott E; Long, Benjamin; Jakiela, Jason T; Bailie, Jason M; Yanagi, Matthew A; Haran, F Jay; Wright, W Geoffrey; Robins, Rebecca K; Sargent, Paul D; Duckworth, Joshua L

2017-03-01

Blast exposure is a prevalent cause of mild traumatic brain injury (mTBI) in military personnel in combat. However, it is more common for a service member to be exposed to a low-level blast (LLB) that does not result in a clinically diagnosable mTBI. Recent research suggests that repetitive LLB exposure can result in symptomology similar to symptoms observed after mTBI. This manuscript reports on the use of an Android-based smartphone application (AccWalker app) to capture changes in neuromotor functioning after blast exposure. Active duty U.S. Navy personnel (N = 59) performed a stepping-in-place task before repetitive LLB exposure (heavy weapons training), and again immediately after, 24 hours after, and 72 to 96 hours after the completion of the training. The AccWalker app revealed that there are changes in neuromotor functioning after LLB exposure (slower self-selected movement pace and increased stride time variability) in participants who experienced neurocognitive decline. These data suggest that neurocognitive and neuromotor decline can occur after repeated LLB exposure. Reprint & Copyright © 2017 Association of Military Surgeons of the U.S.

Occurrence of 210Po and Biological Effects of Low-Level Exposure: The Need for Research

PubMed Central

Wiemels, Joseph L.

2012-01-01

Background: Polonium-210 (210Po) concentrations that exceed 1 Bq/L in drinking-water supplies have been reported from four widely separated U.S. states where exposure to it went unnoticed for decades. The radionuclide grandparents of 210Po are common in sediments, and segments of the public may be chronically exposed to low levels of 210Po in drinking water or in food products from animals raised in contaminated areas. Objectives: We summarized information on the environmental behavior, biokinetics, and toxicology of 210Po and identified the need for future research. Methods: Potential linkages between environmental exposure to 210Po and human health effects were identified in a literature review. Discussion: 210Po accumulates in the ovaries where it kills primary oocytes at low doses. Because of its radiosensitivity and tendency to concentrate 210Po, the ovary may be the critical organ in determining the lowest injurious dose for 210Po. 210Po also accumulates in the yolk sac of the embryo and in the fetal and placental tissues. Low-level exposure to 210Po may have subtle, long-term biological effects because of its tropism towards reproductive and embryonic and fetal tissues where exposure to a single alpha particle may kill or damage critical cells. 210Po is present in cigarettes and maternal smoking has several effects that appear consistent with the toxicology of 210Po. Conclusions: Much of the important biological and toxicological research on 210Po is more than four decades old. New research is needed to evaluate environmental exposure to 210Po and the biological effects of low-dose exposure to it so that public health officials can develop appropriate mitigation measures where necessary. PMID:22538346

Directional detection of dark matter with two-dimensional targets

NASA Astrophysics Data System (ADS)

Hochberg, Yonit; Kahn, Yonatan; Lisanti, Mariangela; Tully, Christopher G.; Zurek, Kathryn M.

2017-09-01

We propose two-dimensional materials as targets for direct detection of dark matter. Using graphene as an example, we focus on the case where dark matter scattering deposits sufficient energy on a valence-band electron to eject it from the target. We show that the sensitivity of graphene to dark matter of MeV to GeV mass can be comparable, for similar exposure and background levels, to that of semiconductor targets such as silicon and germanium. Moreover, a two-dimensional target is an excellent directional detector, as the ejected electron retains information about the angular dependence of the incident dark matter particle. This proposal can be implemented by the PTOLEMY experiment, presenting for the first time an opportunity for directional detection of sub-GeV dark matter.

Directional detection of dark matter with two-dimensional targets

DOE PAGES

Hochberg, Yonit; Kahn, Yonatan; Lisanti, Mariangela; ...

2017-09-01

We propose two-dimensional materials as targets for direct detection of dark matter. Using graphene as an example, we focus on the case where dark matter scattering deposits sufficient energy on a valence-band electron to eject it from the target. Here, we show that the sensitivity of graphene to dark matter of MeV to GeV mass can be comparable, for similar exposure and background levels, to that of semiconductor targets such as silicon and germanium. Moreover, a two-dimensional target is an excellent directional detector, as the ejected electron retains information about the angular dependence of the incident dark matter particle. Ourmore » proposal can be implemented by the PTOLEMY experiment, presenting for the first time an opportunity for directional detection of sub-GeV dark matter.« less

Directional detection of dark matter with two-dimensional targets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hochberg, Yonit; Kahn, Yonatan; Lisanti, Mariangela

We propose two-dimensional materials as targets for direct detection of dark matter. Using graphene as an example, we focus on the case where dark matter scattering deposits sufficient energy on a valence-band electron to eject it from the target. Here, we show that the sensitivity of graphene to dark matter of MeV to GeV mass can be comparable, for similar exposure and background levels, to that of semiconductor targets such as silicon and germanium. Moreover, a two-dimensional target is an excellent directional detector, as the ejected electron retains information about the angular dependence of the incident dark matter particle. Ourmore » proposal can be implemented by the PTOLEMY experiment, presenting for the first time an opportunity for directional detection of sub-GeV dark matter.« less

Kinetic Stability of MOF-5 in Humid Environments: Impact of Powder Densification, Humidity Level, and Exposure Time.

PubMed

Ming, Yang; Purewal, Justin; Yang, Jun; Xu, Chunchuan; Soltis, Rick; Warner, James; Veenstra, Mike; Gaab, Manuela; Müller, Ulrich; Siegel, Donald J

2015-05-05

Metal-organic frameworks (MOFs) are an emerging class of microporous, crystalline materials with potential applications in the capture, storage, and separation of gases. Of the many known MOFs, MOF-5 has attracted considerable attention because of its ability to store gaseous fuels at low pressure with high densities. Nevertheless, MOF-5 and several other MOFs exhibit limited stability upon exposure to reactive species such as water. The present study quantifies the impact of humid air exposure on the properties of MOF-5 as a function of exposure time, humidity level, and morphology (i.e., powders vs pellets). Properties examined include hydrogen storage capacity, surface area, and crystallinity. Water adsorption/desorption isotherms are measured using a gravimetric technique; the first uptake exhibits a type V isotherm with a sudden increase in uptake at ∼50% relative humidity. For humidity levels below this threshold only minor degradation is observed for exposure times up to several hours, suggesting that MOF-5 is more stable than generally assumed under moderately humid conditions. In contrast, irreversible degradation occurs in a matter of minutes for exposures above the 50% threshold. Fourier transform infrared spectroscopy indicates that molecular and/or dissociated water is inserted into the skeletal framework after long exposure times. Densification into pellets can slow the degradation of MOF-5 significantly, and may present a pathway to enhance the stability of some MOFs.

Nickel and associated metals in New Caledonia: Exposure levels and their determinants.

PubMed

St-Jean, Audray; Barguil, Yann; Dominique, Yannick; Le Bot, Barbara; Ayotte, Pierre; Cordier, Sylvaine

2018-06-01

The ultramafic massifs of the New Caledonian archipelago contain about 10% of the world's nickel reserves, which also contain significant but lower amounts of cobalt, chromium, and manganese. Natural erosion of these massifs and mining activities may contribute to the exposure of local populations to these metals through contamination of air, food, and water resources. We conducted a biomonitoring survey to evaluate exposure to these four metals and its main determinants by constructing a stratified sample of 732 adults and children (>3 years old) from visitors to 22 health centers across the archipelago. Urine was collected and analyzed by inductively-coupled plasma mass spectrometry to determine metal concentrations. A face-to-face interview was conducted to document sociodemographic characteristics, lifestyle and dietary habits, and residence-mine distance. Environmental samples (soil, house dust, water, and foodstuffs) were collected from two areas (one with and one without mining activity) to delineate determinants of exposure in more detail. Nickel and chromium were metals with the highest concentrations found in urine, especially in children, at levels exceeding reference values derived from representative national surveys elsewhere throughout the world (for children: 4.7 μg/g creatinine for nickel and 0.50 μg/g creatinine for chromium): 13% of children exceeded the reference value for nickel and 90% for chromium. Large variations were observed by region, age, and sex. In this geological setting, urinary and environmental nickel concentrations appear to be driven mainly by soil content. This is the first archipelago-wide survey of metal exposure in New Caledonia. The potential health consequences of this chronic high exposure need to be assessed. Copyright © 2018 Elsevier Ltd. All rights reserved.

Target fragmentation in radiobiology

NASA Technical Reports Server (NTRS)

Wilson, John W.; Cucinotta, Francis A.; Shinn, Judy L.; Townsend, Lawrence W.

1993-01-01

Nuclear reactions in biological systems produce low-energy fragments of the target nuclei seen as local high events of linear energy transfer (LET). A nuclear-reaction formalism is used to evaluate the nuclear-induced fields within biosystems and their effects within several biological models. On the basis of direct ionization interaction, one anticipates high-energy protons to have a quality factor and relative biological effectiveness (RBE) of unity. Target fragmentation contributions raise the effective quality factor of 10 GeV protons to 3.3 in reasonable agreement with RBE values for induced micronuclei in bean sprouts. Application of the Katz model indicates that the relative increase in RBE with decreasing exposure observed in cell survival experiments with 160 MeV protons is related solely to target fragmentation events. Target fragment contributions to lens opacity given an RBE of 1.4 for 2 GeV protons in agreement with the work of Lett and Cox. Predictions are made for the effective RBE for Harderian gland tumors induced by high-energy protons. An exposure model for lifetime cancer risk is derived from NCRP 98 risk tables, and protraction effects are examined for proton and helium ion exposures. The implications of dose rate enhancement effects on space radiation protection are considered.

Levels and source apportionment of children's lead exposure: could urinary lead be used to identify the levels and sources of children's lead pollution?

PubMed

Cao, Suzhen; Duan, Xiaoli; Zhao, Xiuge; Wang, Beibei; Ma, Jin; Fan, Delong; Sun, Chengye; He, Bin; Wei, Fusheng; Jiang, Guibin

2015-04-01

As a highly toxic heavy metal, the pollution and exposure risks of lead are of widespread concern for human health. However, the collection of blood samples for use as an indicator of lead pollution is not always feasible in most cohort or longitudinal studies, especially those involving children health. To evaluate the potential use of urinary lead as an indicator of exposure levels and source apportionment, accompanying with environmental media samples, lead concentrations and isotopic measurements (expressed as (207)Pb/(206)Pb, (208)Pb/(206)Pb and (204)Pb/(206)Pb) were investigated and compared between blood and urine from children living in the vicinities of a typical coking plant and lead-acid battery factory. The results showed urinary lead might not be a preferable proxy for estimating blood lead levels. Fortunately, urinary lead isotopic measurements could be used as an alternative for identifying the sources of children's lead exposure, which coincided well with the blood lead isotope ratio analysis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Family environmental and dietary implications for low-level prenatal lead exposure in Wujiang City, China.

PubMed

Yan, Jin; Gao, Zhenyan; Wang, Ju; Ma, Wenjuan; Ying, Xiaolan; Zhou, Cancan; Yan, Chonghuai

2018-05-01

To explore the potential environmental and dietary factors during pregnancy affecting low-level prenatal lead exposure, we conducted a longitudinal study in Wujiang City, China. A total of 1976 mother-infant pairs were included from 2009 to 2010. An interviewed questionnaire was conducted and cord blood samples were collected. The geometric means of cord blood lead level was 30.3 μg/L (95% CI, 29.8-30.8) with 99.24% below 100 μg/L. Maternal age, passive smoking, and living in the countryside were significantly associated with cord blood lead concentrations. Multiple logistic models showed that some family environmental factors including using firewood and electricity as kitchen fuel were positively correlated with increased cord blood lead levels. Among dietary sources recorded in this study, meat consumption (> 3 times/week), fish consumption (1-3 times/week), vegetables consumption (> 1 times/day), and fruit intake (> 1 times/day) had inverse relationship with cord blood lead levels. In general, our findings may have important implications for family environmental and dietary direction during pregnancy to decrease prenatal lead exposure.

Embryonic-only arsenic exposure in killifish (Fundulus heteroclitus) reduces growth and alters muscle IGF levels one year later.

PubMed

Szymkowicz, Dana B; Sims, Kaleigh C; Castro, Noemi M; Bridges, William C; Bain, Lisa J

2017-05-01

Arsenic is a contaminant of drinking water and crops in many parts of the world. Epidemiological studies have shown that arsenic exposure is linked to decreased birth weight, weight gain, and proper skeletal muscle function. The goal of this study was to use killifish (Fundulus heteroclitus) as a model to determine the long-term effects of embryonic-only arsenic exposure on muscle growth and the insulin-like growth factor (IGF) pathway. Killifish embryos were exposed to 0, 50, 200 or 800ppb As III from fertilization until hatching. Juvenile fish were reared in clean water and muscle samples were collected at 16, 28, 40 and 52 weeks of age. There were significant reductions in condition factors, ranging from 12 to 17%, in the fish exposed to arsenic at 16, 28 and 40 weeks of age. However, by 52 weeks, no significant changes in condition factors were seen. Alterations in IGF-1R and IGF-1 levels were assessed as a potential mechanism by which growth was reduced. While there no changes in hepatic IGF-1 transcripts, skeletal muscle cells can also produce their own IGF-1 and/or alter IGF-1 receptor levels to help enhance growth. After a 200 and 800ppb embryonic exposure, fish grown in clean water for 16 weeks had IGF-1R transcripts that were 2.8-fold and 2-fold greater, respectively, than unexposed fish. Through 40 weeks of age, IGF1-R remained elevated in the 200ppb and 800ppb embryonic exposure groups by 1.8-3.9-fold, while at 52 weeks of age, IGF-1R levels were still significantly increased in the 800ppb exposure group. Skeletal muscle IGF-1 transcripts were also significantly increased by 1.9-5.1 fold through the 52 weeks of grow-out in clean by water in the 800ppb embryonic exposure group. Based on these results, embryonic arsenic exposure has long-term effects in that it reduces growth and increases both IGF-1 and IGF-1R levels in skeletal muscle even 1year after the exposure has ended. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluating OSHA's ethylene oxide standard: exposure determinants in Massachusetts hospitals.

PubMed Central

LaMontagne, A D; Kelsey, K T

2001-01-01

OBJECTIVES: This study sought to identify determinants of workplace exposures to ethylene oxide to assess the effect of the Occupational Safety and Health Administration's (OSHA's) 1984 ethylene oxide standard. METHODS: An in-depth survey of all hospitals in Massachusetts that used ethylene oxide from 1990 through 1992 (96% participation, N = 90) was conducted. Three types of exposure events were modeled with logistic regression: exceeding the 8-hour action level, exceeding the 15-minute excursion limit, and worker exposures during unmeasured accidental releases. Covariates were drawn from data representing an ecologic framework including direct and indirect potential exposure determinants. RESULTS: After adjustment for frequencies of ethylene oxide use and exposure monitoring, a significant inverse relation was observed between exceeding the action level and the use of combined sterilizer-aerators, an engineering control technology developed after the passage of the OSHA standard. Conversely, the use of positive-pressure sterilizers that employ ethylene oxide gas mixtures was strongly related to both exceeding the excursion limit and the occurrence of accidental releases. CONCLUSIONS: These findings provide evidence of a positive effect of OSHA's ethylene oxide standard and specific targets for future prevention and control efforts. PMID:11236406

Evaluating OSHA's ethylene oxide standard: exposure determinants in Massachusetts hospitals.