Toxicological analysis of limonene reaction products using an in vitro exposure system

PubMed Central

Anderson, Stacey E.; Khurshid, Shahana S.; Meade, B. Jean; Lukomska, Ewa; Wells, J.R.

2015-01-01

Epidemiological investigations suggest a link between exposure to indoor air chemicals and adverse health effects. Consumer products contain reactive chemicals which can form secondary pollutants which may contribute to these effects. The reaction of limonene and ozone is a well characterized example of this type of indoor air chemistry. The studies described here characterize an in vitro model using an epithelial cell line (A549) or differentiated epithelial tissue (MucilAir™). The model is used to investigate adverse effects following exposure to combinations of limonene and ozone. In A549 cells, exposure to both the parent compounds and reaction products resulted in alterations in inflammatory cytokine production. A one hour exposure to limonene + ozone resulted in decreased proliferation when compared to cells exposed to limonene alone. Repeated dose exposures of limonene or limonene + ozone were conducted on MucilAir™ tissue. No change in proliferation was observed but increases in cytokine production were observed for both the parent compounds and reaction products. Factors such as exposure duration, chemical concentration, and sampling time point were identified to influence result outcome. These findings suggest that exposure to reaction products may produce more severe effects compared to the parent compound. PMID:23220291

The association between measurements of antimicrobial use and resistance in the faeces microbiota of finisher batches.

PubMed

Andersen, V D; DE Knegt, L V; Munk, P; Jensen, M S; Agersø, Y; Aarestrup, F M; Vigre, H

2017-10-01

The objectives were to present three approaches for calculating antimicrobial (AM) use in pigs that take into account the rearing period and rearing site, and to study the association between these measurements and phenotypical resistance and abundance of resistance genes in faeces samples from 10 finisher batches. The AM use was calculated relative to the rearing period of the batches as (i) 'Finisher Unit Exposure' at unit level, (ii) 'Lifetime Exposure' at batch level and (iii) 'Herd Exposure' at herd level. A significant effect on the occurrence of tetracycline resistance measured by cultivation was identified for Lifetime Exposure for the AM class: tetracycline. Furthermore, for Lifetime Exposure for the AM classes: macrolide, broad-spectrum penicillin, sulfonamide and tetracycline use as well as Herd Unit Exposure for the AM classes: aminoglycoside, lincosamide and tetracycline use, a significant effect was observed on the occurrence of genes coding for the AM resistance classes: aminoglycoside, lincosamide, macrolide, β-lactam, sulfonamide and tetracycline. No effect was observed for Finisher Unit Exposure. Overall, the study shows that Lifetime Exposure is an efficient measurement of AM use in finisher batches, and has a significant effect on the occurrence of resistance, measured either by cultivation or metagenomics.

Study on disinfestation of pulses using microwave technique.

PubMed

Singh, Ranjeet; Singh, K K; Kotwaliwale, N

2012-08-01

Mortality of the pulse beetle (Callosobruchus chinensis L.) exposed, continuously, to microwave radiation (2450 MHz) was evaluated as a function of exposure time and percent power level, at adult stages. The microwave exposure time to attain 100% insect mortality at 100 %, 80%, 60%, 40%, and 20% power levels for Chickpea, Pigeon Pea and Green Gram was optimized. Effect of optimized microwave exposure time on viability, germination, cooking and milling characteristics of Chickpea, Pigeon Pea and Green Gram was also evaluated. Adult stage study was characterized by a distinct dose-exposure curve. The mortality curve was following third degree polynomial equation. The seed viability and germination of Chickpea, Pigeon Pea and Green Gram was affected by microwave exposure time and power level. It was observed that as the power level is decreasing the germination and viability of all the pulses are increasing. The effect on cooking and milling characteristics are not affected by microwave exposure time and power level. The insects in the mobile state were observed to move towards the surface from inside the nutrient medium during microwave exposure. They also curled up and in some cases aggregation was observed.

EFFECT OF THE APOE ε4 ALLELE AND COMBAT EXPOSURE ON PTSD AMONG IRAQ/AFGHANISTAN-ERA VETERANS.

PubMed

Kimbrel, Nathan A; Hauser, Michael A; Garrett, Melanie; Ashley-Koch, Allison; Liu, Yutao; Dennis, Michelle F; Klein, Rebecca C; Beckham, Jean C

2015-05-01

The apolipoprotein E (APOE) ε4 allele has been implicated in a range of neuropsychiatric conditions. The present research examined if the ε4 allele of the APOE gene moderated the effect of combat exposure on posttraumatic stress disorder (PTSD) among Iraq/Afghanistan-era veterans. Participants included 765 non-Hispanic White (NHW) and 859 non-Hispanic Black (NHB) Iraq/Afghanistan-era veterans. A structured interview established psychiatric diagnoses. Combat exposure and PTSD symptom severity were assessed via self-report. The most common lifetime diagnoses were depression (39.2%), PTSD (38.4%), and alcohol dependence (24.38%). After correcting for multiple comparisons, no significant effects were observed on any of the outcomes among the NHW sample; however, within the NHB sample, significant gene × environment (G × E) interactions were observed for lifetime PTSD (P = .0029) and PTSD symptom severity (P = .0009). In each case, the APOE ε4 allele had no effect on the outcomes when combat exposure was low; however, when combat exposure was high, an additive effect was observed such that ε4 homozygotes exposed to high levels of combat reported the highest rates of PTSD (92%) and the worst symptom severity scores on the Davidson Trauma Scale (M = 79.5). Although preliminary, these findings suggest that the APOE ε4 allele, in conjunction with exposure to high levels of combat exposure, may increase veterans' risk for developing PTSD. © 2015 Wiley Periodicals, Inc.

Molecular, cellular, and tissue impact of depleted uranium on xenobiotic-metabolizing enzymes.

PubMed

Gueguen, Yann; Rouas, Caroline; Monin, Audrey; Manens, Line; Stefani, Johanna; Delissen, Olivia; Grison, Stéphane; Dublineau, Isabelle

2014-02-01

Enzymes that metabolize xenobiotics (XME) are well recognized in experimental models as representative indicators of organ detoxification functions and of exposure to toxicants. As several in vivo studies have shown, uranium can alter XME in the rat liver or kidneys after either acute or chronic exposure. To determine how length or level of exposure affects these changes in XME, we continued our investigation of chronic rat exposure to depleted uranium (DU, uranyl nitrate). The first study examined the effect of duration (1-18 months) of chronic exposure to DU, the second evaluated dose dependence, from a level close to that found in the environment near mining sites (0.2 mg/L) to a supra-environmental dose (120 mg/L, 10 times the highest level naturally found in the environment), and the third was an in vitro assessment of whether DU exposure directly affects XME and, in particular, CYP3A. The experimental in vivo models used here demonstrated that CYP3A is the enzyme modified to the greatest extent: high gene expression changed after 6 and 9 months. The most substantial effects were observed in the liver of rats after 9 months of exposure to 120 mg/L of DU: CYP3A gene and protein expression and enzyme activity all decreased by more than 40 %. Nonetheless, no direct effect of DU by itself was observed after in vitro exposure of rat microsomal preparations, HepG2 cells, or human primary hepatocytes. Overall, these results probably indicate the occurrence of regulatory or adaptive mechanisms that could explain the indirect effect observed in vivo after chronic exposure.

Synergistic effect of co-exposure to cadmium (II) and 4-n-nonylphenol on growth inhibition and oxidative stress of Chlorella sorokiniana.

PubMed

Wang, Lu; Kang, Yuan; Liang, Siyun; Chen, Danying; Zhang, Qiuyun; Zeng, Lixuan; Luo, Jiwen; Jiang, Feng

2018-06-15

Toxicological effect of freshwater algae co-exposure to Cd and 4-n-nonylphenol (4-n-NP) was seldom reported. In the present study, Chlorella sorokiniana was selected for testing the single and combined effect of Cd and 4-n-NP by detecting the growth inhibition and oxidative stress after exposure for 48 h, 72 h, and 96 h. The combined effects were evaluated by using toxic units (TU) method and concentration addition（CA）model. The synergistic effect of mixture on algal growth inhibition was both observed at 48 h and 72 h, and the additive effect was observed at 96 h. In addition, the significant alterations of superoxide, thiobarbituric acid reactive substances and antioxidant defenses (superoxide dismutase, catalase, glutathione) have been detected. It could be observed that the mixture predominantly lead to synergistic effects in superoxide induction, and the antagonistic effects in the GSH induction. A similar trend between the superoxide induction and growth inhibition were observed, which may indicate that the oxidative effects of Chlorella sorokiniana contributed to the growth inhibition after exposure to Cd and 4-n-NP. These findings may have important implications in the risk assessments of heavy metals and endocrine disruptors in the aquatic environment. Copyright © 2018 Elsevier Inc. All rights reserved.

High altitude memory impairment is due to neuronal apoptosis in hippocampus, cortex and striatum.

PubMed

Maiti, Panchanan; Singh, Shashi B; Mallick, Birendranath; Muthuraju, Sangu; Ilavazhagan, Govindasami

2008-12-01

Cognitive and neuropsychological functions have been impaired at high altitude and the effects depend on altitude and duration of stay. However, the neurobiological mechanism of this impairment is poorly understood especially exposure to different duration. Aim of the present study was to investigate the changes of behavior, biochemistry and morphology after exposure to different duration of hypobaric hypoxia. The rats were exposed continuously to a simulated high altitude of 6100m for 3, 7, 14 and 21 days in an animal decompression chamber. Spatial reference memory was tested by Morris water maze. The oxidative stress markers like free radicals, NO, lipid peroxidation, LDH activity and antioxidant systems like GSH, GSSG, GPx, GR, SOD were estimated from cortex, hippocampus and striatum. The morphological changes, neurodegeneration, DNA fragmentation and mode of cell death have also been studied. It was observed that the spatial reference memory was significantly affected after exposure to hypobaric hypoxia. Increased oxidative stress markers along with decreased effectiveness of antioxidant system were also observed in hypoxia-exposed animals. Further pyknotic, shrunken, tangle-like neurons were observed in all these regions after hypoxia and neurodegeneration, DNA fragmentation and apoptosis were also observed in all the three regions. But after 21 days of exposure, the spatial memory was improved along with improvement of antioxidant activities. Our result suggests that the apoptotic death may be involved in HA-induced memory impairment and after 7 days of exposure the effect was more pronounced but after 21 days of exposure recovery was observed.

Haloacetic acids in drinking water and risk for stillbirth

PubMed Central

King, W; Dodds, L; Allen, A; Armson, B; Fell, D; Nimrod, C

2005-01-01

Aims: To investigate the effects of haloacetic acid (HAA) compounds in drinking water on stillbirth risk. Methods: A population based case-control study was conducted in Nova Scotia and Eastern Ontario, Canada. Estimates of daily exposure to total and specific HAAs were based on household water samples and questionnaire information on water consumption at home and work. Results: The analysis included 112 stillbirth cases and 398 live birth controls. In analysis without adjustment for total THM exposure, a relative risk greater than 2 was observed for an intermediate exposure category for total HAA and dichloroacetic acid measures. After adjustment for total THM exposure, the risk estimates for intermediate exposure categories were diminished, the relative risk associated with the highest category was in the direction of a protective effect, and all confidence intervals included the null value. Conclusions: No association was observed between HAA exposures and stillbirth risk after controlling for THM exposures. PMID:15657195

Effect of sequential isoproturon pulse exposure on Scenedesmus vacuolatus.

PubMed

Vallotton, Nathalie; Eggen, Rik Ilda Lambertus; Chèvre, Nathalie

2009-04-01

Aquatic organisms are typically exposed to fluctuating concentrations of herbicides in streams. To assess the effects on algae of repeated peak exposure to the herbicide isoproturon, we subjected the alga Scenedesmus vacuolatus to two sequential pulse exposure scenarios. Effects on growth and on the inhibition of the effective quantum yield of photosystem II (PSII) were measured. In the first scenario, algae were exposed to short, 5-h pulses at high isoproturon concentrations (400 and 1000 microg/l), each followed by a recovery period of 18 h, while the second scenario consisted of 22.5-h pulses at lower concentrations (60 and 120 microg/l), alternating with short recovery periods (1.5 h). In addition, any changes in the sensitivity of the algae to isoproturon following sequential pulses were examined by determining the growth rate-EC(50) prior to and following exposure. In both exposure scenarios, we found that algal growth and its effective quantum yield were systematically inhibited during the exposures and that these effects were reversible. Sequential pulses to isoproturon could be considered a sequence of independent events. Nevertheless, a consequence of inhibited growth during the repeated exposures is the cumulative decrease in biomass production. Furthermore, in the second scenario, when the sequence of long pulses began to approach a scenario of continuous exposure, a slight increase in the tolerance of the algae to isoproturon was observed. These findings indicated that sequential pulses do affect algae during each pulse exposure, even if algae recover between the exposures. These observations could support an improved risk assessment of fluctuating exposures to reversibly acting herbicides.

Improvement, Verification, and Refinement of Spatially-Explicit Exposure Models in Risk Assessment - SEEM

DTIC Science & Technology

2015-06-01

hazard quotient HSI Habitat Suitability Index LOAEL lowest observed adverse effect level mg/kg milligrams per kilogram NOAEL no observed adverse... effect level NPL National Priorities List PRR Patuxent Research Refuge QA quality assurance QC quality control ACRONYMS AND...mean and maximum) for each individual for the exposure period; EHQs are then compiled to arrive at a modeled population— effects curve. Figure 1

Improvement, Verification, and Refinement of Spatially Explicit Exposure Models in Risk Assessment - SEEM Demonstration

DTIC Science & Technology

2015-06-01

hazard quotient HSI Habitat Suitability Index LOAEL lowest observed adverse effect level mg/kg milligrams per kilogram NOAEL no observed adverse... effect level NPL National Priorities List PRR Patuxent Research Refuge QA quality assurance QC quality control ACRONYMS AND...mean and maximum) for each individual for the exposure period; EHQs are then compiled to arrive at a modeled population— effects curve. Figure 1

Inhibitory action of halothane on rat masculine sexual behavior and sperm motility.

PubMed

Oropeza-Hernández, Luis F; Quintanilla-Vega, Betzabet; Albores, Arnulfo; Fernández-Guasti, Alonso

2002-07-01

Adult male rats were exposed to inhale halothane in the following regime: 15 ppm/4 h/5 days/week/9 weeks. Sexual behavior observations and sperm motility test were made before halothane exposure (0 days) and at 15, 30, 45 and 60 days of exposure. Fifteen days after halothane exposure, this anesthetic inhibited the proportion of animals displaying ejaculation. In those animals ejaculating, halothane produced an inhibition of masculine sexual behavior reflected as an increase in the intromission latency, number of mounts and postejaculatory interval. At 30 days after exposure, only an increase in the intromission latency was observed. At 45 and 60 days, the inhibitory effect of halothane on sexual behavior disappeared. Similarly, at 15 and 30 days, but not at 45 or 60 days of halothane exposure, a reduced sperm motility was observed. Such transient effects of halothane suggest the development of tolerance to the inhibitory actions of this anesthetic on sexual behavior and sperm motility. These halothane effects are in line with an inhibition of masculine sexual behavior after stimulation of the GABAergic system.

Human exposure to power frequency magnetic fields up to 7.6 mT: An integrated EEG/fMRI study.

PubMed

Modolo, Julien; Thomas, Alex W; Legros, Alexandre

2017-09-01

We assessed the effects of power-line frequency (60 Hz in North America) magnetic fields (MF) in humans using simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI). Twenty-five participants were enrolled in a pseudo-double-blind experiment involving "real" or "sham" exposure to sinusoidal 60 Hz MF exposures delivered using the gradient coil of an MRI scanner following two conditions: (i) 10 s exposures at 3 mT (10 repetitions); (ii) 2 s exposures at 7.6 mT (100 repetitions). Occipital EEG spectral power was computed in the alpha range (8-12 Hz, reportedly the most sensitive to MF exposure in the literature) with/without exposure. Brain functional activation was studied using fMRI blood oxygen level-dependent (BOLD, inversely correlated with EEG alpha power) maps. No significant effects were detected on occipital EEG alpha power during or post-exposure for any exposure condition. Consistent with EEG results, no effects were observed on fMRI BOLD maps in any brain region. Our results suggest that acute exposure (2-10 s) to 60 Hz MF from 3 to 7.6 mT (30,000 to 76,000 times higher than average public exposure levels for 60 Hz MF) does not induce detectable changes in EEG or BOLD signals. Combined with previous findings in which effects were observed on the BOLD signal after 1 h exposure to 3 mT, 60 Hz MF, this suggests that MF exposure in the low mT range (<10 mT) might require prolonged durations of exposure to induce detectable effects. Bioelectromagnetics. 38:425-435, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Effects of subchronic inhalation exposure of rats to emissions from a diesel engine burning soybean oil-derived biodiesel fuel.

PubMed

Finch, G L; Hobbs, C H; Blair, L F; Barr, E B; Hahn, F F; Jaramillo, R J; Kubatko, J E; March, T H; White, R K; Krone, J R; Ménache, M G; Nikula, K J; Mauderly, J L; Van Gerpen, J; Merceica, M D; Zielinska, B; Stankowski, L; Burling, K; Howell, S

2002-10-01

There is increasing interest in diesel fuels derived from plant oils or animal fats ("biodiesel"), but little information on the toxicity of biodiesel emissions other than bacterial mutagenicity. F344 rats were exposed by inhalation 6 h/day, 5 days/wk for 13 wk to 1 of 3 dilutions of emissions from a diesel engine burning 100% soybean oil-derived fuel, or to clean air as controls. Whole emissions were diluted to nominal NO(x) concentrations of 5, 25, or 50 ppm, corresponding to approximately 0.04, 0.2, and 0.5 mg particles/m(3), respectively. Biologically significant, exposure-related effects were limited to the lung, were greater in females than in males, and were observed primarily at the highest exposure level. There was a dose-related increase in the numbers of alveolar macrophages and the numbers of particles in the macrophages, as expected from repeated exposure, but no neutrophil response even at the highest exposure level. The macrophage response was reduced 28 days after cessation of the exposure. Among the high-level females, the group mean lung weight/body weight ratio was increased, and minimal, multifocal bronchiolar metaplasia of alveolar ducts was observed in 4 of 30 rats. Lung weights were not significantly increased, and metaplasia of the alveolar ducts was not observed in males. An increase in particle-laden macrophages was the only exposure-related finding in lungs at the intermediate and low levels, with fewer macrophages and fewer particles per macrophage at the low level. Alveolar histiocytosis was observed in a few rats in both exposed and control groups. There were statistically significant, but minor and not consistently exposure-related, differences in body weight, nonpulmonary organ weights, serum chemistry, and glial fibrillary acidic protein in the brain. There were no significant exposure-related effects on survival, clinical signs, feed consumption, ocular toxicity, hematology, neurohistology, micronuclei in bone marrow, sister chromatid exchanges in peripheral blood lymphocytes, fertility, reproductive toxicity, or teratology. This study demonstrated modest adverse effects at the highest exposure level, and none other than the expected physiological macrophage response to repeated particle exposure at the intermediate level.

Air ions and mood outcomes: a review and meta-analysis

PubMed Central

2013-01-01

Background Psychological effects of air ions have been reported for more than 80 years in the media and scientific literature. This study summarizes a qualitative literature review and quantitative meta-analysis, where applicable, that examines the potential effects of exposure to negative and positive air ions on psychological measures of mood and emotional state. Methods A structured literature review was conducted to identify human experimental studies published through August, 2012. Thirty-three studies (1957–2012) evaluating the effects of air ionization on depression, anxiety, mood states, and subjective feelings of mental well-being in humans were included. Five studies on negative ionization and depression (measured using a structured interview guide) were evaluated by level of exposure intensity (high vs. low) using meta-analysis. Results Consistent ionization effects were not observed for anxiety, mood, relaxation/sleep, and personal comfort. In contrast, meta-analysis results showed that negative ionization, overall, was significantly associated with lower depression ratings, with a stronger association observed at high levels of negative ion exposure (mean summary effect and 95% confidence interval (CI) following high- and low-density exposure: 14.28 (95% CI: 12.93-15.62) and 7.23 (95% CI: 2.62-11.83), respectively). The response to high-density ionization was observed in patients with seasonal or chronic depression, but an effect of low-density ionization was observed only in patients with seasonal depression. However, no relationship between the duration or frequency of ionization treatment on depression ratings was evident. Conclusions No consistent influence of positive or negative air ionization on anxiety, mood, relaxation, sleep, and personal comfort measures was observed. Negative air ionization was associated with lower depression scores particularly at the highest exposure level. Future research is needed to evaluate the biological plausibility of this association. PMID:23320516

Are environmental exposures to chlorophenoxy herbicides associated with adverse human health effects?

EPA Science Inventory

Background: Exposures to environmental pollutants are suspected of playing a role in the observed increases of many diseases. However, it is difficult to establish a firm link between exposure and disease, because environmental exposures are usually widespread, low-dose in natu...

Acute and chronic toxicity of nickel to rainbow trout (Oncorhynchus mykiss).

PubMed

Brix, Kevin V; Keithly, James; DeForest, David K; Laughlin, Jim

2004-09-01

Of the fish species tested in chronic Ni exposures, rainbow trout (Oncorhynchus mykiss) is the most sensitive. To develop additional Ni toxicity data and to investigate the toxic mode of action for Ni, we conducted acute (96-h) and chronic (85-d early life-stage) flow-through studies using rainbow trout. In addition to standard toxicological endpoints, we investigated the effects of Ni on ionoregulatory physiology (Na, Ca, and Mg). The acute median lethal concentration for Ni was 20.8 mg/L, and the 24-h gill median lethal accumulation was 666 nmol/g wet weight. No effects on plasma Ca, Mg, or Na were observed during acute exposure. In the chronic study, no significant effects on embryo survival, swim-up, hatching, or fingerling survival or growth were observed at dissolved Ni concentrations up to 466 microg/L, the highest concentration tested. This concentration is considerably higher than the only other reported chronic no-observed-effect concentration (<33 microg/L) for rainbow trout. Accumulation of Ni in trout eggs indicates the chorion is only a partial barrier with 36%, 63%, and 1% of total accumulated Ni associated with the chorion, yolk, and embryo, respectively. Whole-egg ion concentrations were reduced by Ni exposure. However, most of this reduction occurred in the chorion rather than in the embryos, and no effects on hatching success or larval survival were observed as a result. Plasma ion concentrations measured in swim-up fingerlings at the end of the chronic-exposure period were not significantly reduced by exposure to Ni. Nickel accumulated on the gill in an exponential manner but plateaued in trout plasma at waterborne Ni concentrations of 118 microg/L or greater. Consistent with previous studies, Ni did not appear to disrupt ionoregulation in acute exposures of rainbow trout. Our results also suggest that Ni is not an ionoregulatory toxicant in long-term exposures, but the lack of effects in the highest Ni treatment precludes a definitive conclusion.

Beneficial effects of low alcohol exposure, but adverse effects of high alcohol intake on glymphatic function.

PubMed

Lundgaard, Iben; Wang, Wei; Eberhardt, Allison; Vinitsky, Hanna Sophia; Reeves, Benjamin Cameron; Peng, Sisi; Lou, Nanhong; Hussain, Rashad; Nedergaard, Maiken

2018-02-02

Prolonged intake of excessive amounts of ethanol is known to have adverse effects on the central nervous system (CNS). Here we investigated the effects of acute and chronic ethanol exposure and withdrawal from chronic ethanol exposure on glymphatic function, which is a brain-wide metabolite clearance system connected to the peripheral lymphatic system. Acute and chronic exposure to 1.5 g/kg (binge level) ethanol dramatically suppressed glymphatic function in awake mice. Chronic exposure to 1.5 g/kg ethanol increased GFAP expression and induced mislocation of the astrocyte-specific water channel aquaporin 4 (AQP4), but decreased the levels of several cytokines. Surprisingly, glymphatic function increased in mice treated with 0.5 g/kg (low dose) ethanol following acute exposure, as well as after one month of chronic exposure. Low doses of chronic ethanol intake were associated with a significant decrease in GFAP expression, with little change in the cytokine profile compared with the saline group. These observations suggest that ethanol has a J-shaped effect on the glymphatic system whereby low doses of ethanol increase glymphatic function. Conversely, chronic 1.5 g/kg ethanol intake induced reactive gliosis and perturbed glymphatic function, which possibly may contribute to the higher risk of dementia observed in heavy drinkers.

Exposure to Interpersonal Violence and Socioemotional Adjustment in Economically Disadvantaged Preschoolers

PubMed Central

Bush, Hillary H.; Eisenhower, Abbey

2014-01-01

Focusing specifically on the experiences of economically disadvantaged preschoolers, the relations between interpersonal violence exposure, behavior problems, and social skills were examined in both the home and school settings. In this racially and ethnically diverse sample of preschoolers from poor, urban households (N = 64; 3-6 years old; 56% female), many children (33%) had been exposed to at least one type of interpersonal violence, and even more (70%) had been exposed to any type of potentially traumatic event (PTE). Although exposure to interpersonal violence was not directly associated with parent- or teacher-reported behavior problems or social skills, a significant interaction effect was observed between exposure to interpersonal violence and teacher-reported internalizing problems in predicting teacher-reported social skills; specifically, for children with the highest levels of internalizing problems, a positive relation between interpersonal violence exposure and social skills was observed. This indirect effect was observed only in the school setting, whereas children in this high-risk sample appeared to demonstrate resilience in the home setting. Given these high rates of exposure, additional, clinically-relevant research is needed to inform interventions for this vulnerable population. PMID:25175528

How effectively do horizontal and vertical response strategies of long-finned pilot whales reduce sound exposure from naval sonar?

PubMed

Wensveen, Paul J; von Benda-Beckmann, Alexander M; Ainslie, Michael A; Lam, Frans-Peter A; Kvadsheim, Petter H; Tyack, Peter L; Miller, Patrick J O

2015-05-01

The behaviour of a marine mammal near a noise source can modulate the sound exposure it receives. We demonstrate that two long-finned pilot whales both surfaced in synchrony with consecutive arrivals of multiple sonar pulses. We then assess the effect of surfacing and other behavioural response strategies on the received cumulative sound exposure levels and maximum sound pressure levels (SPLs) by modelling realistic spatiotemporal interactions of a pilot whale with an approaching source. Under the propagation conditions of our model, some response strategies observed in the wild were effective in reducing received levels (e.g. movement perpendicular to the source's line of approach), but others were not (e.g. switching from deep to shallow diving; synchronous surfacing after maximum SPLs). Our study exemplifies how simulations of source-whale interactions guided by detailed observational data can improve our understanding about motivations behind behaviour responses observed in the wild (e.g., reducing sound exposure, prey movement). Copyright © 2015 Elsevier Ltd. All rights reserved.

Prenatal exposure to polychlorinated biphenyls: a neuropsychologic analysis.

PubMed

Boucher, Olivier; Muckle, Gina; Bastien, Célyne H

2009-01-01

A large body of literature documents the effects of prenatal exposure to polychlorinated biphenyls (PCBs) on cognitive development of children. Despite this fact, no integrative synthesis has been published yet to identify the cognitive functions that are particularly affected. Our aim is to review this literature in an attempt to identify the cognitive profile associated with prenatal PCB exposure. Studies were identified by searching the PubMed database for articles published before June 2008. We reviewed data from nine prospective longitudinal birth cohorts for different aspects of cognition. Associations between indicators of prenatal PCB exposure and performance on cognitive tasks reported in the selected studies are summarized and classified as general cognitive abilities, verbal or visual-spatial skills, memory, attention, and executive functions. The most consistent effects observed across studies are impaired executive functioning related to increased prenatal PCB exposure. Negative effects on processing speed, verbal abilities, and visual recognition memory are also reported by most studies. Converging results from different cohort studies in which exposure arises from different sources make it unlikely that co-exposure with another associated contaminant is responsible for the observed effects. Prenatal PCB exposure appears to be related to a relatively specific cognitive profile of impairments. Failure to assess functions that are specifically impaired may explain the absence of effects found in some studies. Our findings have implications in the selection of cognitive assessment methods in future studies.

Derivation of an occupational exposure limit (OEL) for methylene chloride based on acute CNS effects and relative potency analysis.

PubMed

Storm, J E; Rozman, K K

1998-06-01

The Occupational Safety and Health Administration (OSHA) methylene chloride Permissible Exposure Level (PEL) or 25 ppm is quantitatively derived from mouse tumor results observed in a high-exposure National Toxicology Program bioassay. Because this approach depends on controversial interspecies and low-dose extrapolations, the PEL itself has stimulated heated debate. Here, an alternative safety assessment for methylene chloride is presented. It is based on an acute human lowest-observed-adverse-effect level (LOAEL) of 200 ppm for subtle central nervous system (CNS) depression. Steep, parallel exposure-response curves for anesthetic and subanesthetic CNS effects associated with compounds mechanistically and structurally related to methylene chloride are shown to support a safety factor of two to account for inter-individual variability in response. LOAEL/no-observed-adverse-effect ratios for subtle CNS effects associated with structurally related solvents are shown to support a safety factor range of two to four to account for uncertainty in identifying a subthreshold exposure level. Anesthetic relative potencies and anesthetic/subanesthetic effect level ratios are shown to be constant for the compounds evaluated, demonstrating that subanesthetic relative potencies are also constant. Relative potencies among similarly derived occupational exposure limits (OELs) for solvents structurally related to methylene chloride are therefore used to validate the derived methylene chloride OEL range of 25-50 ppm. Because this safety assessment is based on human (rather than rodent) data and empirical (rather than theoretical) exposure-response relationships and is supported by relative potency analysis, it is a defensible alternative to to the OSHA risk assessment and should positively contribute to the debate regarding the appropriate basis and value for a methylene chloride PEL.

Carcinogenic and Cocarcinogenic Effects of Radon and Radon Daughters in Rats.

PubMed Central

Monchaux, G; Morlier, JP; Morin, M; Chameaud, J; Lafuma, J; Masse, R

1994-01-01

It has been previously established that lung cancer could be induced in rats by exposure to radon and radon daughters. Although the oat-cell carcinomas that are common in humans were not found in rats, other histological types of lung carcinomas, especially squamous cell carcinomas and primitive lung adenocarcinomas, were similar to those observed in humans. A dose-effect relationship was established for cumulative doses varying from 25 to 3000 working-level-months (WLM), which was similar for medium and high cumulative doses to that observed in uranium miners. This experimental protocol was also used to study the potential cocarcinogenic effects of other environmental or industrial airborne pollutants such as tobacco smoke, mineral fibers, diesel exhausts, or minerals from metallic mine ores that may act synergistically with radon exposure. In rats exposed to radon and tobacco smoke combined, the incidence of lung cancers was higher by a factor of 2-4 according to the cumulative radon exposure and the duration of tobacco smoke exposure. When mineral fibers were injected intrapleurally, an increased incidence of malignant thoracic tumors was observed in rats exposed to radon and fibers combined, but synergistic effects resulted in additivity. With diesel exhausts or minerals from metallic ores, a slight, nonsignificant increase in the incidence of lung carcinomas was observed compared with rats exposed to radon alone. These results demonstrated that it is possible to establish the potential cocarcinogenic action, showing either multiplicative, additive, or no effect of various environmental or industrial airborne pollutants combined with radon exposure. This radon model is valid for investigating possible interactions between two occupational exposures. Images p64-a Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. PMID:9719670

Effects of sublethal exposure to metofluthrin on the fitness of Aedes aegypti in a domestic setting in Cairns, Queensland.

PubMed

Buhagiar, Tamara S; Devine, Gregor J; Ritchie, Scott A

2017-05-31

Metofluthrin is highly effective at reducing biting activity in Aedes aegypti. Its efficacy lies in the rapid onset of confusion, knockdown, and subsequent kill of a mosquito. In the field, there are a variety of scenarios that might result in sublethal exposure to metofluthrin, including mosquitoes that are active at the margins of the chemical's lethal range, brief exposure as mosquitoes fly in and out of treated spaces or decreasing efficacy of the emanators with time. Sublethal effects are key elements of insecticide exposure and selection. The metofluthrin dose for each treatment group of male and female Ae. aegypti was controlled using exposure time intervals to a 10% active ingredient (AI) metofluthrin emanator. Room size and distance from the emanator for all groups was maintained at 3 m. In bioassay cages, male Ae. aegypti were exposed at 0, 5, 10, 20, 30 and 40-min intervals. Females were exposed in bioassay cages at 0, 10, 20, 30, 40 and 60-min intervals. Mortality rates and fecundity were observed between the exposure time groups for both sexes. Female Ae. aegypti exposed for 60 min had a significantly higher mortality rate (50%), after a 24-h recovery period, than other exposure times, 10, 20, 30 and 40 min (P < 0.001). An overall difference in fecundity was not observed in females between treatments. A significant effect on male mortality was only observed at 40 min exposure times, three meters from the 10% AI emanator [Formula: see text]. Males that survived metofluthrin exposure were as likely to produce viable eggs with an unexposed female as males that had not been exposed (P > 0.05). Regardless of sex, if a mosquito survived exposure, it would be as biologically successful as its unexposed counterpart. Portability of the metofluthrin emanator and delayed knockdown effects create opportunities for sublethal exposure and potential pyrethroid resistance development in Ae. aegypti, and should be taken into consideration in recommendations for field application of this product, including minimum exposure periods and a prescribed number of emanators per room based on volume.

Evaluating Simulation Methodologies to Determine Best Strategies to Maximize Student Learning.

PubMed

Scherer, Yvonne K; Foltz-Ramos, Kelly; Fabry, Donna; Chao, Ying-Yu

2016-01-01

Limited evidence exists as to the most effective ways to provide simulation experiences to maximize student learning. This quasi-experimental study investigated 2 different strategies repeated versus 1 exposure and participation versus observation on student outcomes following exposure to a high-fidelity acute asthma exacerbation of asthma scenario. Immediate repeated exposure resulted in significantly higher scores on knowledge, student satisfaction and self-confidence, and clinical performance measures than a single exposure. Significant intergroup differences were found on participants' satisfaction and self-confidence as compared with observers. Implications for nurse educators include expanding the observer role when designing repeated exposure to simulations and integrating technical, cognitive, and behavioral outcomes as a way for faculty to evaluate students' clinical performance. Published by Elsevier Inc.

40 CFR 159.170 - Human epidemiological and exposure studies.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Human epidemiological and exposure... Information § 159.170 Human epidemiological and exposure studies. Information must be submitted which concerns... that a correlation may exist between exposure to a pesticide and observed adverse effects in humans...

40 CFR 159.170 - Human epidemiological and exposure studies.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Human epidemiological and exposure... Information § 159.170 Human epidemiological and exposure studies. Information must be submitted which concerns... that a correlation may exist between exposure to a pesticide and observed adverse effects in humans...

40 CFR 159.170 - Human epidemiological and exposure studies.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Human epidemiological and exposure... Information § 159.170 Human epidemiological and exposure studies. Information must be submitted which concerns... that a correlation may exist between exposure to a pesticide and observed adverse effects in humans...

40 CFR 159.170 - Human epidemiological and exposure studies.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Human epidemiological and exposure... Information § 159.170 Human epidemiological and exposure studies. Information must be submitted which concerns... that a correlation may exist between exposure to a pesticide and observed adverse effects in humans...

Ototoxic potential of JP-8 and a Fischer-Tropsch synthetic jet fuel following subacute inhalation exposure in rats.

PubMed

Fechter, Laurence D; Gearhart, Caroline A; Fulton, Sherry

2010-07-01

This study was undertaken to identify the ototoxic potential of two jet fuels presented alone and in combination with noise. Rats were exposed via a subacute inhalation paradigm to JP-8 jet fuel, a kerosene-based fuel refined from petroleum, and a synthetic fuel produced by the Fischer-Tropsch (FT) process. Although JP-8 contains small ( approximately 5%) concentrations of aromatic hydrocarbons some of which known to be ototoxic, the synthetic fuel does not. The objectives of this study were to identify a lowest observed adverse effect level and a no observed adverse effect level for each jet fuel and to provide some preliminary, but admittedly, indirect evidence concerning the possible role of the aromatic hydrocarbon component of petroleum-based jet fuel on hearing. Rats (n = 5-19) received inhalation exposure to JP-8 or to FT fuel for 4 h/day on five consecutive days at doses of 500, 1000, and 2000 mg/m(3). Additional groups were exposed to various fuel concentrations followed by 1 h of an octave band of noise, noise alone, or no exposure to fuel or noise. Significant dose-related impairment in the distortion product otoacoustic emissions (DPOAE) was seen in subjects exposed to combined JP-8 plus noise exposure when JP-8 levels of at least 1000 mg/m(3) were presented. No noticeable impairment was observed at JP-8 levels of 500 mg/m(3) + noise. In contrast to the effects of JP-8 on noise-induced hearing loss, FT exposure had no effect by itself or in combination with noise exposure even at the highest exposure level tested. Despite an observed loss in DPOAE amplitude seen only when JP-8 and noise were combined, there was no loss in auditory threshold or increase in hair cell loss in any exposure group.

Mutation signatures of carcinogen exposure: genome-wide detection and new opportunities for cancer prevention

PubMed Central

2014-01-01

Exposure to environmental mutagens is an important cause of human cancer, and measures to reduce mutagenic and carcinogenic exposures have been highly successful at controlling cancer. Until recently, it has been possible to connect the chemical characteristics of mutagens to actual mutations observed in human tumors only indirectly. Now, next-generation sequencing technology enables us to observe in detail the DNA-sequence-level effects of well-known mutagens, such as ultraviolet radiation and tobacco smoke, as well as endogenous mutagenic processes, such as those involving activated DNA cytidine deaminases (APOBECs). We can also observe the effects of less well-known but potent mutagens, including those recently found to be present in some herbal remedies. Crucially, we can now tease apart the superimposed effects of several mutational exposures and processes and determine which ones occurred during the development of individual tumors. Here, we review advances in detecting these mutation signatures and discuss the implications for surveillance and prevention of cancer. The number of sequenced tumors from diverse cancer types and multiple geographic regions is growing explosively, and the genomes of these tumors will bear the signatures of even more diverse mutagenic exposures. Thus, we envision development of wide-ranging compendia of mutation signatures from tumors and a concerted effort to experimentally elucidate the signatures of a large number of mutagens. This information will be used to link signatures observed in tumors to the exposures responsible for them, which will offer unprecedented opportunities for prevention. PMID:25031618

Noise exposure-response relationships established from repeated binary observations: Modeling approaches and applications.

PubMed

Schäffer, Beat; Pieren, Reto; Mendolia, Franco; Basner, Mathias; Brink, Mark

2017-05-01

Noise exposure-response relationships are used to estimate the effects of noise on individuals or a population. Such relationships may be derived from independent or repeated binary observations, and modeled by different statistical methods. Depending on the method by which they were established, their application in population risk assessment or estimation of individual responses may yield different results, i.e., predict "weaker" or "stronger" effects. As far as the present body of literature on noise effect studies is concerned, however, the underlying statistical methodology to establish exposure-response relationships has not always been paid sufficient attention. This paper gives an overview on two statistical approaches (subject-specific and population-averaged logistic regression analysis) to establish noise exposure-response relationships from repeated binary observations, and their appropriate applications. The considerations are illustrated with data from three noise effect studies, estimating also the magnitude of differences in results when applying exposure-response relationships derived from the two statistical approaches. Depending on the underlying data set and the probability range of the binary variable it covers, the two approaches yield similar to very different results. The adequate choice of a specific statistical approach and its application in subsequent studies, both depending on the research question, are therefore crucial.

When mere exposure leads to less liking: the incremental threat effect in intergroup contexts.

PubMed

Crisp, Richard J; Hutter, Russell R C; Young, Bryony

2009-02-01

In two experiments we tested the hypothesis that repeated exposure to out-group-relevant attitude objects would lead to less liking following a threat to identity. In Experiment 1 exposure to abstract artwork ostensibly created by a member of an out-group university led to more liking under baseline conditions, but not following a manipulation of threat. In Experiment 2 we observed a negative relationship between exposure and liking following threat: liking reversed the typical mere exposure effect. Reported emotion mediated the interactive effect of threat and exposure on liking. These findings illustrate how social identity threat can be experienced incrementally as a function of exposure. We discuss the findings in the context of an integration of research on exposure, identity, attitudes, and contact.

Reproductive toxicity parameters and biological monitoring in occupationally and environmentally boron-exposed persons in Bandirma, Turkey.

PubMed

Duydu, Yalçın; Başaran, Nurşen; Üstündağ, Aylin; Aydin, Sevtap; Ündeğer, Ülkü; Ataman, Osman Yavuz; Aydos, Kaan; Düker, Yalçın; Ickstadt, Katja; Waltrup, Britta Schulze; Golka, Klaus; Bolt, Hermann M

2011-06-01

Boric acid and sodium borates have been considered as being "toxic to reproduction and development", following results of animal studies with high doses. Experimentally, a NOAEL (no observed adverse effect level) of 17.5 mg B/kg-bw/day has been identified for the (male) reproductive effects of boron in a multigeneration study of rats, and a NOAEL for the developmental effects in rats was identified at 9.6 mg B/kg-bw/day. These values are being taken as the basis of current EU safety assessments. The present study was conducted to investigate the reproductive effects of boron exposure in workers employed in boric acid production plant in Bandirma, Turkey. In order to characterize the external and internal boron exposures, boron was determined in biological samples (blood, urine, semen), in workplace air, in food, and in water sources. Unfavorable effects of boron exposure on the reproductive toxicity indicators (concentration, motility, morphology of the sperm cells and blood levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and total testosterone) were not observed. The mean calculated daily boron exposure (DBE) of the highly exposed group was 14.45 ± 6.57 (3.32-35.62) mg/day. These human exposures represent worst-case exposure conditions to boric acid/borates in Turkey. These exposure levels are considerably lower than exposures, which have previously led to reproductive effects in experimental animals. In conclusion, this means that dose levels of boron associated with developmental and reproductive toxic effects in animals are by far not reachable for humans under conditions of normal handling and use.

40 CFR 799.9325 - TSCA 90-day dermal toxicity.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Health Effects Test Guidelines § 799.9325 TSCA 90-day dermal toxicity. (a) Scope. This section is...-observed-effects level (NOEL) and toxic effects associated with continuous or repeated exposure to a test... human exposure. (b) Source. The source material used in developing this TSCA test guideline is the...

40 CFR 799.9325 - TSCA 90-day dermal toxicity.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Health Effects Test Guidelines § 799.9325 TSCA 90-day dermal toxicity. (a) Scope. This section is...-observed-effects level (NOEL) and toxic effects associated with continuous or repeated exposure to a test... human exposure. (b) Source. The source material used in developing this TSCA test guideline is the...

40 CFR 799.9325 - TSCA 90-day dermal toxicity.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Health Effects Test Guidelines § 799.9325 TSCA 90-day dermal toxicity. (a) Scope. This section is...-observed-effects level (NOEL) and toxic effects associated with continuous or repeated exposure to a test... human exposure. (b) Source. The source material used in developing this TSCA test guideline is the...

40 CFR 799.9325 - TSCA 90-day dermal toxicity.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Health Effects Test Guidelines § 799.9325 TSCA 90-day dermal toxicity. (a) Scope. This section is...-observed-effects level (NOEL) and toxic effects associated with continuous or repeated exposure to a test... human exposure. (b) Source. The source material used in developing this TSCA test guideline is the...

40 CFR 799.9325 - TSCA 90-day dermal toxicity.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Health Effects Test Guidelines § 799.9325 TSCA 90-day dermal toxicity. (a) Scope. This section is...-observed-effects level (NOEL) and toxic effects associated with continuous or repeated exposure to a test... human exposure. (b) Source. The source material used in developing this TSCA test guideline is the...

Cumulative effects from repeated exposures to ultraviolet radiation

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

Kaidbey, K.H.; Kligman, A.M.

Repeated exposures to subliminal doses of UVR, given at 24-hr intervals, resulted in a lowering of the erythema threshold dose. At erythemogenically equivalent doses, UV-A was the most effective and UV-C the least. A similar and more pronounced effect was observed following repeated exposures to subthreshold doses of UV-A and topically applied 8-methoxypsoralen. These findings provide quantitative evidence for the cumulative nature of acute UVR damage in human skin.

Assessment of the effects of nickel on benthic macroinvertebrates in the field.

PubMed

Peters, Adam; Simpson, Peter; Merrington, Graham; Schlekat, Chris; Rogevich-Garman, Emily

2014-01-01

A field-based evaluation of the biological effects of potential nickel (Ni) exposures was conducted using monitoring data for benthic macroinvertebrates and water chemistry parameters for streams in England and Wales. Observed benthic community metrics were compared to expected community metrics under reference conditions using RIVPACS III+ software. In order to evaluate relationships between Ni concentrations and benthic community metrics, bioavailable Ni concentrations were also calculated for each site. A limiting effect from Ni on the 90th percentile of the maximum achievable ecological quality was derived at "bioavailable Ni" exposures of 10.3 μg l(-1). As snails have been identified as particularly sensitive to nickel exposure, snail abundance in the field in response to nickel exposure, relative to reference conditions, was also analysed. A "low effects" threshold for snail abundance based on an average of spring and autumn data was derived as 3.9 μg l(-1) bioavailable Ni. There was no apparent effect of Ni exposure on the abundance of Ephemeroptera (mayflies), Plecoptera (stoneflies) or Tricoptera (caddisflies) when expressed relative to a reference condition within the range of "bioavailable Ni" exposures observed within the dataset. Nickel exposure concentrations co-vary with the concentrations of other stressors in the dataset, and high concentrations of Ni are also associated with elevated concentrations of other contaminants.

Chronic exposure to trichloroethylene increases DNA methylation of the Ifng promoter in CD4+ T cells.

PubMed

Gilbert, Kathleen M; Blossom, Sarah J; Erickson, Stephen W; Broadfoot, Brannon; West, Kirk; Bai, Shasha; Li, Jingyun; Cooney, Craig A

2016-10-17

CD4 + T cells in female MRL+/+ mice exposed to solvent and water pollutant trichloroethylene (TCE) skew toward effector/memory CD4 + T cells, and demonstrate seemingly non-monotonic alterations in IFN-γ production. In the current study we examined the mechanism for this immunotoxicity using effector/memory and naïve CD4 + T cells isolated every 6 weeks during a 40 week exposure to TCE (0.5mg/ml in drinking water). A time-dependent effect of TCE exposure on both Ifng gene expression and IFN-γ protein production was observed in effector/memory CD4 + T cells, with an increase after 22 weeks of exposure and a decrease after 40 weeks of exposure. No such effect of TCE was observed in naïve CD4 + T cells. A cumulative increase in DNA methylation in the CpG sites of the promoter of the Ifng gene was observed in effector/memory, but not naïve, CD4 + T cells over time. Also unique to the Ifng promoter was an increase in methylation variance in effector/memory compared to naïve CD4 + T cells. Taken together, the CpG sites of the Ifng promoter in effector/memory CD4 + T cells were especially sensitive to the effects of TCE exposure, which may help explain the regulatory effect of the chemical on this gene. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Effects of chronic carbon monoxide exposure on fetal growth and development in mice

PubMed Central

2011-01-01

Background Carbon monoxide (CO) is produced endogenously, and can also be acquired from many exogenous sources: ie. cigarette smoking, automobile exhaust. Although toxic at high levels, low level production or exposure lends to normal physiologic functions: smooth muscle cell relaxation, control of vascular tone, platelet aggregation, anti- inflammatory and anti-apoptotic events. In pregnancy, it is unclear at what level maternal CO exposure becomes toxic to the fetus. In this study, we hypothesized that CO would be embryotoxic, and we sought to determine at what level of chronic CO exposure in pregnancy embryo/fetotoxic effects are observed. Methods Pregnant CD1 mice were exposed to continuous levels of CO (0 to 400 ppm) from conception to gestation day 17. The effect on fetal/placental growth and development, and fetal/maternal CO concentrations were determined. Results Maternal and fetal CO blood concentrations ranged from 1.12- 15.6 percent carboxyhemoglobin (%COHb) and 1.0- 28.6%COHb, respectively. No significant difference was observed in placental histological morphology or in placental mass with any CO exposure. At 400 ppm CO vs. control, decreased litter size and fetal mass (p < 0.05), increased fetal early/late gestational deaths (p < 0.05), and increased CO content in the placenta and the maternal spleen, heart, liver, kidney and lung (p < 0.05) were observed. Conclusions Exposure to levels at or below 300 ppm CO throughout pregnancy has little demonstrable effect on fetal growth and development in the mouse. PMID:22168775

Genomic investigation of year-long and multigenerational exposures of fathead minnow to the munitions compound RDX.

PubMed

Gust, Kurt A; Brasfield, Sandra M; Stanley, Jacob K; Wilbanks, Mitchell S; Chappell, Pornsawan; Perkins, Edward J; Lotufo, Guilherme R; Lance, Richard F

2011-08-01

We assessed the impacts of exposure to an environmentally representative concentration (0.83 mg/L) of the explosive cyclotrimethylenetrinitramine (RDX) on fathead minnows (Pimephales promelas) in one-year and multigenerational bioassays. In the one-year bioassay, impacts were assessed by statistical comparisons of females from breeding groups reared in control or RDX-exposure conditions. The RDX had no significant effect on gonadosomatic index or condition factor assayed at 1 d and at one, three, six, nine, and 12 months. The liver-somatic index was significantly increased versus controls only at the 12-month timepoint. RDX had no significant effect on live-prey capture rates, egg production, or fertilization. RDX caused minimal differential-transcript expression with no consistent discernable effect on gene-functional categories for either brain or liver tissues in the one-year exposure. In the multigenerational assay, the effects of acute (96 h) exposure to RDX were compared in fish reared to the F(2) generation in either control or RDX-exposure conditions. Enrichment of gene functions including neuroexcitatory glutamate metabolism, sensory signaling, and neurological development were observed comparing control-reared and RDX-reared fish. Our results indicated that exposure to RDX at a concentration representing the highest levels observed in the environment (0.83 mg/L) had limited impacts on genomic, individual, and population-level endpoints in fathead minnows in a one-year exposure. However, multigenerational exposures altered transcript expression related to neural development and function. Environ. Copyright © 2011 SETAC.

Within-session effect of repeated stress exposure on extinction circuitry function in social anxiety disorder.

PubMed

Åhs, Fredrik; Gingnell, Malin; Furmark, Tomas; Fredrikson, Mats

2017-03-30

Anxiety reduction following repeated exposure to stressful experiences is generally held to depend on neural processes involved in extinction of conditioned fear. We predicted that repeated exposure to stressful experiences would change activity throughout the circuitry serving extinction, including ventromedial prefrontal cortex (vmPFC), the hippocampus and the amygdala. To test this prediction, 36 participants diagnosed with SAD performed two successive speeches in front of an observing audience while regional cerebral blood flow (rCBF) was recorded using positron emission tomography. To control for non-anxiolytic effects of repeated exposure, rCBF was also measured during repeated presentations of neutral and angry facial expressions. Results showed that anxiety ratings and heart rate decreased from the first to the second speech, indicating an anxiolytic effect of repeated exposure. Exposure attenuated rCBF in the amygdala whereas no change in rCBF was observed in the vmPFC or hippocampus. The rCBF-reductions in the amygdala were greater following repetition of the speech task than repetition of face exposure indicating that they were specific to anxiety attenuation and not due to a reduced novelty. Our findings suggest that amygdala-related attenuation processes are key to understanding the working mechanisms of exposure therapy. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Pulmonary function in relation to total dust exposure at a bauxite refinery and alumina-based chemical products plant.

PubMed

Townsend, M C; Enterline, P E; Sussman, N B; Bonney, T B; Rippey, L L

1985-12-01

A cross-sectional study of 1,142 male employees at the Arkansas Operations of a large aluminum production company examined the effect on pulmonary function of chronic exposure to total dust produced in the mining and refining of bauxite and the production of alumina chemicals. Never smokers, ex-smokers, and current smokers were analyzed separately. Among never smokers, a pattern of decreasing FEV1 was observed in relation to increasing duration and cumulative total dust exposure. Among never smokers with cumulative total dust exposures of greater than or equal to 100 mg/m3 yr and greater than or equal to 20 yr of exposure, there was a mean reduction from the predicted FEV1 of 0.29 to 0.39 L, in addition to a 3- to 4-fold excess of observed/expected numbers of subjects with FEV1 less than 80% of predicted. These results were observed relative to an external and an internal comparison group. Among current smokers, the deviations from predicted and the excess numbers of subjects with FEV1 less than 80% of predicted were larger in all exposure groups than for the never smokers. However, the quality of the smoking data was inadequate to allow separation of the effects of smoking and dust exposure.

A realistic in vitro exposure revealed seasonal differences in (pro-)inflammatory effects from ambient air in Fribourg, Switzerland.

PubMed

Bisig, Christoph; Petri-Fink, Alke; Rothen-Rutishauser, Barbara

2018-01-01

Ambient air pollutant levels vary widely in space and time, therefore thorough local evaluation of possible effects is needed. In vitro approaches using lung cell cultures grown at the air-liquid interface and directly exposed to ambient air can offer a reliable addition to animal experimentations and epidemiological studies. To evaluate the adverse effects of ambient air in summer and winter a multi-cellular lung model (16HBE14o-, macrophages, and dendritic cells) was exposed in a mobile cell exposure system. Cells were exposed on up to three consecutive days each 12 h to ambient air from Fribourg, Switzerland, during summer and winter seasons. Higher particle number, particulate matter mass, and nitrogen oxide levels were observed in winter ambient air compared to summer. Good cell viability was seen in cells exposed to summer air and short-term winter air, but cells exposed three days to winter air were compromised. Exposure of summer ambient air revealed no significant upregulation of oxidative stress or pro-inflammatory genes. On the opposite, the winter ambient air exposure led to an increased oxidative stress after two exposure days, and an increase in three assessed pro-inflammatory genes already after 12 h of exposure. We found that even with a short exposure time of 12 h adverse effects in vitro were observed only during exposure to winter but not summer ambient air. With this work we have demonstrated that our simple, fast, and cost-effective approach can be used to assess (adverse) effects of ambient air.

HISTOPATHOLOGICAL BIOMARKERS AS INTEGRATORS OF CHEMICAL CONTAMINANT EXPOSURE AND EFFECTS IN FISH

EPA Science Inventory

Histopathology can be an extremely useful tool for assessing effects of chemical exposure in fish at the level of the individual. Although somewhat qualitative, the histopathological approach is especially valuable because observed lesions represent an integration of cumulative e...

Low dose TBT exposure decreases amphipod immunocompetence and reproductive fitness.

PubMed

Jacobson, Therese; Sundelin, Brita; Yang, Gongda; Ford, Alex T

2011-01-17

The antifouling agent tributyltin (TBT) is a highly toxic pollutant present in many aquatic ecosystems. Despite of regulations on the usage of TBT, it remains in high concentrations in sediments both in harbors and in off-shore sites. The toxicity of TBT in mollusks is well documented. However, adverse effects in other aquatic organisms, such as crustaceans, are less well known. This study is an effort to assess the effects of environmentally realistic concentrations of TBT on an ecologically important species in Swedish fresh and brackish water ecosystems, the benthic amphipod Monoporeia affinis. Field collected animals were exposed during gonad maturation to TBT (70 and 170 ng/g sediment d wt) for five weeks in static microcosms with natural sediment. Exposure concentrations were chosen to reflect effects at concentrations found in Swedish coastal sediment, but below expected effects on survival. TBT exposure resulted in a statistically significant adverse effect on oocyte viability and a doubling of the prevalence of microsporidian parasites in females, from 17% in the control to 34% in the 170 ng TBT/g sediment d wt exposure. No effects on survival were observed. Borderline significant effects were observed on male sexual maturation in the 70 ng TBT/g d wt exposure and on ecdysteroid levels in the 170 ng/g sediment d wt exposure. Both reproduction and parasite infection effects are of ecological importance since they have the potential to affect population viability in the field. This study gives further evidence to the connection between low dose contaminant exposure and increases in microsporidian parasite infection. Copyright © 2010 Elsevier B.V. All rights reserved.

EFFECTS OF X RAYS ON THE PRODUCTION OF AGGLUTININ IN GUINEA PIGS (in Russian)

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

Kovtunovich, L.G.

1958-11-01

Experiments were made with 62 guinea pigs in order to determine the effects of single whole-body exposure to 100 or 500 r on the production of typhoid agglutinins. A considerable depression of agglutinin production was observed only after the first vaccination. After repeated vaccinations, an increase in agglutinin level was observed in all irradiated animals regardless of the dose or length of exposure. (R.V.J.)

The associations between birth outcomes and satellite-estimated maternal PM2.5 exposure in Shanghai, China

NASA Astrophysics Data System (ADS)

Xiao, Q.; Liu, Y.; Strickland, M. J.; Chang, H. H.; Kan, H.

2017-12-01

Background: Satellite remote sensing data have been employed for air pollution exposure assessment, with the intent of better characterizing exposure spatio-temproal variations. However, non-random missingness in satellite data may lead to exposure error. Objectives: We explored the differences in health effect estimates due to different exposure metrics, with and without satellite data, when analyzing the associations between maternal PM2.5 exposure and birth outcomes. Methods: We obtained birth registration records of 132,783 singleton live births during 2011-2014 in Shanghai. Trimester-specific and total pregnancy exposures were estimated from satellite PM2.5 predictions with missingness, gap-filled satellite PM2.5 predictions with complete coverage and regional average PM2.5 measurements from monitoring stations. Linear regressions estimated associations between birth weight and maternal PM2.5 exposure. Logistic regressions estimated associations between preterm birth and the first and second trimester exposure. Discrete-time models estimated third trimester and total pregnancy associations with preterm birth. Effect modifications by maternal age and parental education levels were investigated. Results: we observed statistically significant associations between maternal PM2.5 exposure during all exposure windows and adverse birth outcomes. A 10 µg/m3 increase in pregnancy PM2.5 exposure was associated with a 12.85 g (95% CI: 18.44, 7.27) decrease in birth weight for term births, and a 27% (95% CI: 20%, 36%) increase in the risk of preterm birth. Greater effects were observed between first and third trimester exposure and birth weight, as well as between first trimester exposure and preterm birth. Mothers older than 35 years and without college education tended to have higher associations with preterm birth. Conclusions: Gap-filled satellite data derived PM2.5 exposure estimates resulted in reduced exposure error and more precise health effect estimates.

In vitro neurotoxic hazard characterization of different tricresyl phosphate (TCP) isomers and mixtures.

PubMed

Duarte, Daniel J; Rutten, Joost M M; van den Berg, Martin; Westerink, Remco H S

2017-03-01

Exposure to tricresyl phosphates (TCPs), via for example contaminated cabin air, has been associated with health effects including the so-called aerotoxic syndrome. While TCP neurotoxicity is mainly attributed to ortho-isomers like tri-ortho-cresyl phosphate (ToCP), recent exposure and risk assessments indicate that ToCP levels in cabin air are very low. However, the neurotoxic potential of non-ortho TCP isomers and TCP mixtures is largely unknown. We therefore measured effects of exposure (up to 48h) to different TCP isomers, mixtures and the metabolite of ToCP (CBDP: cresyl saligenin phosphate) on cell viability and mitochondrial activity, spontaneous neuronal electrical activity, and neurite outgrowth in primary rat cortical neurons. The results demonstrate that exposure to TCPs (24-48h, up to 10μM) increases mitochondrial activity, without affecting cell viability. Effects of acute TCP exposure (30min) on neuronal electrical activity are limited. However, electrical activity is markedly decreased for the majority of TCPs (10μM) following 48h exposure. Additional preliminary data indicate that exposure to TCPs (48h, 10μM) did not affect the number of neurites per cell or average neurite length, except for TmCP and the analytical TCP mixture (Sigma) that induced a reduction of average neurite length. The combined neurotoxicity data demonstrate that the different TCPs, including ToCP, are roughly equipotent and a clear structure-activity relation is not apparent for the studied endpoints. The no-observed-effect-concentrations (1μM) are well above current exposure levels indicating limited neurotoxic health risk, although exposures may have been higher in the past. Moreover, prolonged and/or repeated exposure to TCPs may exacerbate the observed neurotoxic effects, which argues for additional research. Copyright © 2016 Elsevier B.V. All rights reserved.

Measurement of the exposure of workers to pesticides*

PubMed Central

Durham, William F.; Wolfe, Homer R.

1962-01-01

There is not a single pesticide for which the interrelationships between occupational exposure by different routes, the fate of the compound in the human body, and its clinical effects are all adequately known. Results of the direct measurement of exposure to pesticides may be used in evaluating the relative hazard of different routes of exposure, different operational procedures, and different protective devices. Results of the indirect measurement of exposure may be of use for the same purpose; in addition, these indirect measures may be used in relating exposures under observed conditions to clinical effects. This paper describes and evaluates detailed procedures for the use of air samples, pads, and washes in the direct measurement of the dermal and respiratory exposure of workers to pesticides. Good methods are not available for measuring oral exposure. Any measure of the absorption, storage, physiological effect, or excretion of a compound constitutes an indirect indication of exposure to it. ImagesFIG. 2 PMID:13888659

Re-evaluation of the WHO (2010) formaldehyde indoor air quality guideline for cancer risk assessment.

PubMed

Nielsen, Gunnar Damgård; Larsen, Søren Thor; Wolkoff, Peder

2017-01-01

In 2010, the World Health Organization (WHO) established an indoor air quality guideline for short- and long-term exposures to formaldehyde (FA) of 0.1 mg/m 3 (0.08 ppm) for all 30-min periods at lifelong exposure. This guideline was supported by studies from 2010 to 2013. Since 2013, new key studies have been published and key cancer cohorts have been updated, which we have evaluated and compared with the WHO guideline. FA is genotoxic, causing DNA adduct formation, and has a clastogenic effect; exposure-response relationships were nonlinear. Relevant genetic polymorphisms were not identified. Normal indoor air FA concentrations do not pass beyond the respiratory epithelium, and therefore FA's direct effects are limited to portal-of-entry effects. However, systemic effects have been observed in rats and mice, which may be due to secondary effects as airway inflammation and (sensory) irritation of eyes and the upper airways, which inter alia decreases respiratory ventilation. Both secondary effects are prevented at the guideline level. Nasopharyngeal cancer and leukaemia were observed inconsistently among studies; new updates of the US National Cancer Institute (NCI) cohort confirmed that the relative risk was not increased with mean FA exposures below 1 ppm and peak exposures below 4 ppm. Hodgkin's lymphoma, not observed in the other studies reviewed and not considered FA dependent, was increased in the NCI cohort at a mean concentration ≥0.6 mg/m 3 and at peak exposures ≥2.5 mg/m 3 ; both levels are above the WHO guideline. Overall, the credibility of the WHO guideline has not been challenged by new studies.

Ice-based altitude distribution of natural radiation annual exposure rate in the Antarctica zone over the latitude range 69 degrees S-77 degrees S using a pair-filter thermoluminescence method.

PubMed

Nakajima, T; Kamiyama, T; Fujii, Y; Motoyama, H; Esumi, S

1995-12-01

Both ice-based altitude distributions of natural ionizing radiation exposure and the quasi-effective energy of natural radiation over Antartica over the latitude range 69 degrees S - 77 degrees S during approx. 500 days were measured using thermoluminescent dosimeters. The results shows that dependence on altitude above sea level of the exposure rate increases by almost three-fold with each increase of 2000 m of altitude, thus deviating from the general rule stating that the exposure rate should double with each 2000 m. Although the exposure rate shows a dependence on altitude, altitude dependence of the quasi-effective energy of natural radiation over Antartica is not observed. In the present study it is observed that natural radiation occurring over the ice base of Antartica consists mainly of cosmic rays.

Exposure-related effects of Pseudomonas fluorescens, strain CL145A, on coldwater, coolwater, and warmwater fish

USGS Publications Warehouse

Luoma, James A.; Weber, Kerry L.; Denise A. Mayer,

2015-01-01

Further investigations to evaluate the SDP-exposure related effects on freshwater fish at the maximum approved open-water label concentration and exposure duration (100 mg/L for 8 hours) and using the expected lentic application technique (static application) are warranted. The variation in tolerance to P. fluorescens, strain CL145A, exposure observed in this study indicates that fish species community composition should be considered before SDP is applied in open-water environments.

Exposure to Externalizing Peers in Early Childhood: Homophily and Peer Contagion Processes.

ERIC Educational Resources Information Center

Hanish, Laura D.; Martin, Carol Lynn; Fabes, Richard A.; Leonard, Stacie; Herzog, Melissa

2005-01-01

Guided by a transactional model, we examined the predictors and effects of exposure to externalizing peers in a low-risk sample of preschoolers and kindergarteners. On the basis of daily observations of peer interactions, we calculated measures of total exposure to externalizing peers and measures of exposure to same- and other-sex externalizing…

Exposure to blue light during lunch break: effects on autonomic arousal and behavioral alertness.

PubMed

Yuda, Emi; Ogasawara, Hiroki; Yoshida, Yutaka; Hayano, Junichiro

2017-07-11

Exposures to melanopsin-stimulating (melanopic) component-rich blue light enhance arousal level. We examined their effects in office workers. Eight healthy university office workers were exposed to blue and orange lights for 30 min during lunch break on different days. We compared the effects of light color on autonomic arousal level assessed by heart rate variability (HRV) and behavioral alertness by psychomotor vigilance tests (PVT). Heart rate was higher and high-frequency (HF, 0.150.45 Hz) power of HRV was lower during exposure to the blue light than to orange light. No significant difference with light color was observed, however, in any HRV indices during PVT or in PVT performance after light exposure. Exposure to blue light during lunch break, compared with that to orange light, enhances autonomic arousal during exposure, but has no sustained effect on autonomic arousal or behavioral alertness after exposure.

Sensitivity analysis for mistakenly adjusting for mediators in estimating total effect in observational studies.

PubMed

Wang, Tingting; Li, Hongkai; Su, Ping; Yu, Yuanyuan; Sun, Xiaoru; Liu, Yi; Yuan, Zhongshang; Xue, Fuzhong

2017-11-20

In observational studies, epidemiologists often attempt to estimate the total effect of an exposure on an outcome of interest. However, when the underlying diagram is unknown and limited knowledge is available, dissecting bias performances is essential to estimating the total effect of an exposure on an outcome when mistakenly adjusting for mediators under logistic regression. Through simulation, we focused on six causal diagrams concerning different roles of mediators. Sensitivity analysis was conducted to assess the bias performances of varying across exposure-mediator effects and mediator-outcome effects when adjusting for the mediator. Based on the causal relationships in the real world, we compared the biases of varying across the effects of exposure-mediator with those of varying across the effects of mediator-outcome when adjusting for the mediator. The magnitude of the bias was defined by the difference between the estimated effect (using logistic regression) and the total effect of the exposure on the outcome. In four scenarios (a single mediator, two series mediators, two independent parallel mediators or two correlated parallel mediators), the biases of varying across the effects of exposure-mediator were greater than those of varying across the effects of mediator-outcome when adjusting for the mediator. In contrast, in two other scenarios (a single mediator or two independent parallel mediators in the presence of unobserved confounders), the biases of varying across the effects of exposure-mediator were less than those of varying across the effects of mediator-outcome when adjusting for the mediator. The biases were more sensitive to the variation of effects of exposure-mediator than the effects of mediator-outcome when adjusting for the mediator in the absence of unobserved confounders, while the biases were more sensitive to the variation of effects of mediator-outcome than those of exposure-mediator in the presence of an unobserved confounder. © 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.

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

Assessing the risk to green sturgeon from application of imidacloprid to control burrowing shrimp in Willapa Bay, Washington--Part II: controlled exposure studies.

PubMed

Frew, John A; Grue, Christian E

2015-11-01

The activities of 2 species of burrowing shrimp have a negative impact on the growth and survival of oysters reared on intertidal mudflats in Willapa Bay and Grays Harbor, Washington (USA). To maintain viable harvests, oyster growers proposed the application of the neonicotinoid insecticide imidacloprid onto harvested beds for the control of burrowing shrimp. In test applications, water column concentrations of imidacloprid were relatively low and dissipated rapidly. The foraging activities of the green sturgeon (listed in the US Endangered Species Act) could result in exposure to higher, more sustained imidacloprid concentrations within sediment porewater and from the consumption of contaminated shrimp. Controlled experiments were conducted using surrogate white sturgeon to determine acute and chronic effect concentrations, to examine overt effects at more environmentally realistic concentrations and durations of exposure, and to assess chemical depuration. The 96-h median lethal concentration was 124 mg L(-1) , and the predicted 35-d no-observed-adverse-effect concentration was 0.7 mg L(-1) . No overt effects were observed following environmentally relevant exposures. Imidacloprid half-life in plasma was greater than 32 h. Measured concentrations of imidacloprid in porewater were significantly lower than the derived acute and chronic effect concentrations for white sturgeon. Exposure risk quotients were calculated using the effect concentrations and estimated environmental exposure. The resulting values were considerably below the level of concern for direct effects from either acute or chronic exposure to an endangered species. © 2015 SETAC.

Haloacetic acids in drinking water and risk for stillbirth.

PubMed

King, W D; Dodds, L; Allen, A C; Armson, B A; Fell, D; Nimrod, C

2005-02-01

Trihalomethanes (THMs) occurring in public drinking water sources have been investigated in several epidemiological studies of fetal death and results support a modest association. Other classes of disinfection by-products found in drinking water have not been investigated. To investigate the effects of haloacetic acid (HAA) compounds in drinking water on stillbirth risk. A population based case-control study was conducted in Nova Scotia and Eastern Ontario, Canada. Estimates of daily exposure to total and specific HAAs were based on household water samples and questionnaire information on water consumption at home and work. The analysis included 112 stillbirth cases and 398 live birth controls. In analysis without adjustment for total THM exposure, a relative risk greater than 2 was observed for an intermediate exposure category for total HAA and dichloroacetic acid measures. After adjustment for total THM exposure, the risk estimates for intermediate exposure categories were diminished, the relative risk associated with the highest category was in the direction of a protective effect, and all confidence intervals included the null value. No association was observed between HAA exposures and stillbirth risk after controlling for THM exposures.

Quantifying the mediating effects of smoking and occupational exposures in the relation between education and lung cancer: the ICARE study.

PubMed

Menvielle, Gwenn; Franck, Jeanna-Eve; Radoï, Loredana; Sanchez, Marie; Févotte, Joëlle; Guizard, Anne-Valérie; Stücker, Isabelle; Luce, Danièle

2016-12-01

Smoking only partly explains the higher lung cancer incidence observed among socially deprived people. Occupational exposures may account for part of these inequalities, but this issue has been little investigated. We investigated the extent to which smoking and occupational exposures to asbestos, silica and diesel motor exhaust mediated the association between education and lung cancer incidence in men. We analyzed data from a large French population-based case-control study (1976 lung cancers, 2648 controls). Detailed information on lifelong tobacco consumption and occupational exposures to various carcinogens was collected. We conducted inverse probability-weighted marginal structural models. A strong association was observed between education and lung cancer. The indirect effect through smoking varied by educational level, with the strongest indirect effect observed for those with the lowest education (OR = 1.34 (1.14-1.57)). The indirect effect through occupational exposures was substantial among men with primary (OR = 1.22 (1.15-1.30) for asbestos and silica) or vocational secondary education (OR = 1.18 (1.12-1.25)). The contribution of smoking to educational differences in lung cancer incidence ranged from 22 % (10-34) for men with primary education to 31 % (-3 to 84) for men with a high school degree. The contribution of occupational exposures to asbestos and silica ranged from 15 % (10-20) for men with a high school degree to 20 % (13-28) for men with vocational secondary education. Our results highlight the urgent need for public health policies that aim at decreasing exposure to carcinogens at work, in addition to tobacco control policies, if we want to reduce socioeconomic inequalities in the cancer field.

Effects of a chronic reduction of short-wavelength light input on melatonin and sleep patterns in humans: evidence for adaptation.

PubMed

Giménez, Marina C; Beersma, Domien G M; Bollen, Pauline; van der Linden, Matthijs L; Gordijn, Marijke C M

2014-06-01

Light is an important environmental stimulus for the entrainment of the circadian clock and for increasing alertness. The intrinsically photosensitive ganglion cells in the retina play an important role in transferring this light information to the circadian system and they are elicited in particular by short-wavelength light. Exposure to short wavelengths is reduced, for instance, in elderly people due to yellowing of the ocular lenses. This reduction may be involved in the disrupted circadian rhythms observed in aged subjects. Here, we tested the effects of reduced blue light exposure in young healthy subjects (n = 15) by using soft orange contact lenses (SOCL). We showed (as expected) that a reduction in the melatonin suppressing effect of light is observed when subjects wear the SOCL. However, after chronic exposure to reduced (short wavelength) light for two consecutive weeks we observed an increase in sensitivity of the melatonin suppression response. The response normalized as if it took place under a polychromatic light pulse. No differences were found in the dim light melatonin onset or in the amplitude of the melatonin rhythms after chronic reduced blue light exposure. The effects on sleep parameters were limited. Our results demonstrate that the non-visual light system of healthy young subjects is capable of adapting to changes in the spectral composition of environmental light exposure. The present results emphasize the importance of considering not only the short-term effects of changes in environmental light characteristics.

Confined space ventilation by shipyard welders: observed use and effectiveness.

PubMed

Pouzou, Jane G; Warner, Chris; Neitzel, Richard L; Croteau, Gerry A; Yost, Michael G; Seixas, Noah S

2015-01-01

Shipbuilding involves intensive welding activities within enclosed and confined spaces, and although ventilation is commonly used in the industry, its use and effectiveness has not been adequately documented. Workers engaged in welding in enclosed or confined spaces in two shipyards were observed for their use of ventilation and monitored for their exposure to particulate matter. The type of ventilation in use, its placement and face velocity, the movement of air within the space, and other ventilation-related parameters were recorded, along with task characteristics such as the type of welding, the welder's position, and the configuration of the space. Mechanical ventilation was present in about two-thirds of the 65 welding scenarios observed, with exhaust ventilation used predominantly in one shipyard and supply blowers predominantly in the other. Welders were observed working in apparent dead-spaces within the room in 53% of the cases, even where ventilation was in use. Respiratory protection was common in the two shipyards, observed in use in 77 and 100% of the cases. Welding method, the proximity of the welder's head to the fume, and air mixing were found to be significantly associated with the welder's exposure, while other characteristics of dilution ventilation did not produce appreciable differences in exposure level. These parameters associated with exposure reduction can be assessed subjectively and are thus good candidates for training on effective ventilation use during hot work in confined spaces. Ventilation used in confined space welding is often inadequate for controlling exposure to welding fume. © The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Dissociating mere exposure and repetition priming as a function of word type.

PubMed

Butler, Laurie T; Berry, Dianne C; Helman, Shaun

2004-07-01

The mere exposure effect is defined as enhanced attitude toward a stimulus that has been repeatedly exposed. Repetition priming is defined as facilitated processing of a previously exposed stimulus. We conducted a direct comparison between the two phenomena to test the assumption that the mere exposure effect represents an example of repetition priming. In two experiments, having studied a set of words or nonwords, participants were given a repetition priming task (perceptual identification) or one of two mere exposure (affective liking or preference judgment) tasks. Repetition priming was obtained for both words and nonwords, but only nonwords produced a mere exposure effect. This demonstrates a key boundary for observing the mere exposure effect, one not readily accommodated by a perceptual representation systems (Tulving & Schacter, 1990) account, which assumes that both phenomena should show some sensitivity to nonwords and words.

Environmental Enrichment Duration Differentially Affects Behavior and Neuroplasticity in Adult Mice.

PubMed

Leger, Marianne; Paizanis, Eleni; Dzahini, Kwamivi; Quiedeville, Anne; Bouet, Valentine; Cassel, Jean-Christophe; Freret, Thomas; Schumann-Bard, Pascale; Boulouard, Michel

2015-11-01

Environmental enrichment is a powerful way to stimulate brain and behavioral plasticity. However the required exposure duration to reach such changes has not been substantially analyzed. We aimed to assess the time-course of appearance of the beneficial effects of enriched environment. Thus, different behavioral tests and neurobiological parameters (such as neurogenesis, brain monoamines levels, and stress-related hormones) were concomitantly realized after different durations of enriched environment (24 h, 1, 3, or 5 weeks). While short enrichment exposure (24 h) was sufficient to improve object recognition memory performances, a 3-week exposure was required to improve aversive stimulus-based memory performances and to reduce anxiety-like behavior; effects that were not observed with longer duration. The onset of behavioral changes after a 3-week exposure might be supported by higher serotonin levels in the frontal cortex, but seems independent of neurogenesis phenomenon. Additionally, the benefit of 3-week exposure on memory was not observed 3 weeks after cessation of enrichment. Thus, the 3-week exposure appears as an optimal duration in order to induce the most significant behavioral effects and to assess the underlying mechanisms. Altogether, these results suggest that the duration of exposure is a keystone of the beneficial behavioral and neurobiological effects of environmental enrichment. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Exposure to fluoride in drinking water and hip fracture risk: a meta-analysis of observational studies.

PubMed

Yin, Xin-Hai; Huang, Guang-Lei; Lin, Du-Ren; Wan, Cheng-Cheng; Wang, Ya-Dong; Song, Ju-Kun; Xu, Ping

2015-01-01

Many observational studies have shown that exposure to fluoride in drinking water is associated with hip fracture risk. However, the findings are varied or even contradictory. In this work, we performed a meta-analysis to assess the relationship between fluoride exposure and hip fracture risk. PubMed and EMBASE databases were searched to identify relevant observational studies from the time of inception until March 2014 without restrictions. Data from the included studies were extracted and analyzed by two authors. Summary relative risks (RRs) with corresponding 95% confidence intervals (CIs) were pooled using random- or fixed-effects models as appropriate. Sensitivity analyses and meta-regression were conducted to explore possible explanations for heterogeneity. Finally, publication bias was assessed. Fourteen observational studies involving thirteen cohort studies and one case-control study were included in the meta-analysis. Exposure to fluoride in drinking water does not significantly increase the incidence of hip fracture (RRs, 1.05; 95% CIs, 0.96-1.15). Sensitivity analyses based on adjustment for covariates, effect measure, country, sex, sample size, quality of Newcastle-Ottawa Scale scores, and follow-up period validated the strength of the results. Meta-regression showed that country, gender, quality of Newcastle-Ottawa Scale scores, adjustment for covariates and sample size were not sources of heterogeneity. Little evidence of publication bias was observed. The present meta-analysis suggests that chronic fluoride exposure from drinking water does not significantly increase the risk of hip fracture. Given the potential confounding factors and exposure misclassification, further large-scale, high-quality studies are needed to evaluate the association between exposure to fluoride in drinking water and hip fracture risk.

Exposure to Fluoride in Drinking Water and Hip Fracture Risk: A Meta-Analysis of Observational Studies

PubMed Central

Yin, Xin-Hai; Huang, Guang-Lei; Lin, Du-Ren; Wan, Cheng-Cheng; Wang, Ya-Dong; Song, Ju-Kun; Xu, Ping

2015-01-01

Background Many observational studies have shown that exposure to fluoride in drinking water is associated with hip fracture risk. However, the findings are varied or even contradictory. In this work, we performed a meta-analysis to assess the relationship between fluoride exposure and hip fracture risk. Methods PubMed and EMBASE databases were searched to identify relevant observational studies from the time of inception until March 2014 without restrictions. Data from the included studies were extracted and analyzed by two authors. Summary relative risks (RRs) with corresponding 95% confidence intervals (CIs) were pooled using random- or fixed-effects models as appropriate. Sensitivity analyses and meta-regression were conducted to explore possible explanations for heterogeneity. Finally, publication bias was assessed. Results Fourteen observational studies involving thirteen cohort studies and one case-control study were included in the meta-analysis. Exposure to fluoride in drinking water does not significantly increase the incidence of hip fracture (RRs, 1.05; 95% CIs, 0.96–1.15). Sensitivity analyses based on adjustment for covariates, effect measure, country, sex, sample size, quality of Newcastle–Ottawa Scale scores, and follow-up period validated the strength of the results. Meta-regression showed that country, gender, quality of Newcastle–Ottawa Scale scores, adjustment for covariates and sample size were not sources of heterogeneity. Little evidence of publication bias was observed. Conclusion The present meta-analysis suggests that chronic fluoride exposure from drinking water does not significantly increase the risk of hip fracture. Given the potential confounding factors and exposure misclassification, further large-scale, high-quality studies are needed to evaluate the association between exposure to fluoride in drinking water and hip fracture risk. PMID:26020536

Brominated flame retardants as possible endocrine disrupters.

PubMed

Darnerud, P O

2008-04-01

Brominated flame retardants (BFR) are endocrine disrupters in experimental systems, both in vitro and in vivo. Although BFR effects on thyroid hormones are well confirmed, studies of effects on oestrogen/androgen systems are fewer but today growing in numbers. The effects of BFR on other hormone systems are still unknown. Hormonal effect levels in animals start from ca 1 mg/kg b.w., but there are exceptions: effects on spermatogenesis, suggesting hormonal causes, have been observed at a low dose (60 microg/kg b.w.) of a polybrominated diphenyl ether (PBDE) congener, BDE-99. It could be concluded that hormonal effects are of importance in risk assessment, and in some cases where effects are seen at low levels safety margins may be insufficient. One additional uncertainty is the lack of reliable human data that could be used to support animal BFR observations. In spite of the recent regulation of PBDE production, levels of both PBDE and of other BFR groups are still present in environmental samples. Thus, we have to deal with the possible effects of human BFR exposure for times to come. In order to reduce BFR exposure, the routes of exposure should be carefully examined and ways to reduce levels in major exposure routes considered.

Correlation of acoustic emissions associated with effects from diagnostic and therapeutic ultrasound

NASA Astrophysics Data System (ADS)

Samuel, Stanley

2007-12-01

This research has investigated the correlation of acoustic emissions with associated contrast-mediated ultrasound bio-effects. The hypothesis that motivated this study was that during exposure with ultrasound, the cavitation occurring in tissue emits acoustical signals, which if correlated with specific bio-effects, could provide a way to monitor the potential bio-effects of exposure. A good bio-effects indicator would find immediate use in research on drug and gene delivery, and could have clinical application in avoiding bio-effects in diagnosis. Studies conducted to test the hypothesis involved investigation of (i) the influence of pulse repetition frequency (PRF) and number of exposures on cell damage, (ii) the effect of total exposure duration and pulse-to-pulse bubble distribution on acoustic emissions and corresponding cell damage, and (iii) the translation of in vitro effects to an in situ environment. Exposures were primarily conducted at a peak rarefactional pressure of 2 MPa, 2.25 MHz insonating frequency and pulse length of 46 cycles. PRFs of 1-, 10-, 100-, 500-, and 1000 Hz were compared. High speed photography (2000 fps) was employed for the investigation of pulse-to-pulse bubble distribution while intravital microscopy was used for in situ studies. A strong correlation was observed between acoustic emissions and bio-effects with the availability of bubbles of resonant size serving as a key link between the two. It was observed that total exposure duration may play an important role in cell damage. Damage increased with increasing total exposure duration from 0 ms to 100 ms with a plateau at above 100 ms. These results were consistent for all studies. There is, therefore, an implication that manipulating these parameters may allow for measurement and control of the extent of bioeffects. Moreover, the correlation of acoustic emission and extravasation observed in in situ studies reveals that cumulative function of the relative integrated power spectrum (CRIPS) of the emissions may find use as a monitoring method related to tissue damage due to contrast-mediated ultrasound in vivo.

Joint nonparametric correction estimator for excess relative risk regression in survival analysis with exposure measurement error

PubMed Central

Wang, Ching-Yun; Cullings, Harry; Song, Xiao; Kopecky, Kenneth J.

2017-01-01

SUMMARY Observational epidemiological studies often confront the problem of estimating exposure-disease relationships when the exposure is not measured exactly. In the paper, we investigate exposure measurement error in excess relative risk regression, which is a widely used model in radiation exposure effect research. In the study cohort, a surrogate variable is available for the true unobserved exposure variable. The surrogate variable satisfies a generalized version of the classical additive measurement error model, but it may or may not have repeated measurements. In addition, an instrumental variable is available for individuals in a subset of the whole cohort. We develop a nonparametric correction (NPC) estimator using data from the subcohort, and further propose a joint nonparametric correction (JNPC) estimator using all observed data to adjust for exposure measurement error. An optimal linear combination estimator of JNPC and NPC is further developed. The proposed estimators are nonparametric, which are consistent without imposing a covariate or error distribution, and are robust to heteroscedastic errors. Finite sample performance is examined via a simulation study. We apply the developed methods to data from the Radiation Effects Research Foundation, in which chromosome aberration is used to adjust for the effects of radiation dose measurement error on the estimation of radiation dose responses. PMID:29354018

Chemical Risk Assessment: Traditional vs Public Health Perspectives

PubMed Central

Axelrad, Daniel A.; Bahadori, Tina; Bussard, David; Cascio, Wayne E.; Deener, Kacee; Dix, David; Thomas, Russell S.; Kavlock, Robert J.; Burke, Thomas A.

2017-01-01

Preventing adverse health effects of environmental chemical exposure is fundamental to protecting individual and public health. When done efficiently and properly, chemical risk assessment enables risk management actions that minimize the incidence and effects of environmentally induced diseases related to chemical exposure. However, traditional chemical risk assessment is faced with multiple challenges with respect to predicting and preventing disease in human populations, and epidemiological studies increasingly report observations of adverse health effects at exposure levels predicted from animal studies to be safe for humans. This discordance reinforces concerns about the adequacy of contemporary risk assessment practices for protecting public health. It is becoming clear that to protect public health more effectively, future risk assessments will need to use the full range of available data, draw on innovative methods to integrate diverse data streams, and consider health endpoints that also reflect the range of subtle effects and morbidities observed in human populations. Considering these factors, there is a need to reframe chemical risk assessment to be more clearly aligned with the public health goal of minimizing environmental exposures associated with disease. PMID:28520487

Effect of brief exposure to mitomycin C on cultured human nasal mucosa fibroblasts.

PubMed

Hu, D; Sires, B S; Tong, D C; Royack, G A; Oda, D

2000-03-01

To observe the effect of mitomycin C (MMC) on cultured human nasal mucosa fibroblasts. Cultured human nasal mucosa fibroblasts were exposed to MMC (0.1-0.4 mg/ml) for 1 to 5 minutes. The viability of the fibroblasts was determined by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assay; DNA fragmentation (apoptosis) by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL); apoptotic percentage by flow cytometry; and morphology by light microscopy. A portion of the fibroblasts survived the mitomycin treatment and showed evidence of regrowth within 2 to 3 days. These cells reached confluence in 5 to 7 days. The inhibition rates by MTT assay of 0.4 mg/ml MMC for 5-minute exposures was 31.3%. Dose-response effect was noted with the lower concentrations and shorter exposure times where the inhibition rates were lower (but not significantly so). DNA fragmentation was observed in fibroblasts 24 hours after MMC exposure (0.4 mg/ml) for 5 minutes compared with normal control. The apoptotic rate of fibroblasts treated by 0.4 mg/ml MMC was significantly higher than the control (p < 0.05). Short MMC exposure times have a variable cytotoxic effect and inhibit proliferation of cultured nasal mucosa fibroblasts. MMC also can induce apoptosis with a 5-minute exposure time. Therefore, it is possible that MMC has a complex effect in dacryocystorhinostomy.

Exposure of bed bugs to metarhizium anisopliae, and the effect of defensive secretions on fungal growth in vitro

USDA-ARS?s Scientific Manuscript database

Bed bugs Cimex lectularius were treated with conidia of the entomopathogenic fungus Metarhizium anisopliae by topical, spray, and contact exposure. One week post-exposure, inconsistent mortalities were observed, averaging 30% across all treatment groups and replicates. Microscopic examination of top...

Influence of exposure differences on city-to-city heterogeneity in PM2.5-mortality associations in US cities

EPA Science Inventory

Multi-city population-based epidemiological studies have observed heterogeneity between city-specific fine particulate matter (PM2.5)-mortality effect estimates. These studies typically use ambient monitoring data as a surrogate for exposure leading to potential exposure misclass...

The Long-Range Impact of Television.

ERIC Educational Resources Information Center

Comstock, George

Long range effects may be of three varieties: those which are observable in the immediate period subsequent to exposure but are long range because of their continuing repetitive accumulation with each exposure; those which represent the cumulative or delayed impact on individuals of exposure to television; or those which represent the immediate…

Measurement of acute response to draught in the eye.

PubMed

Wyon, N M; Wyon, D P

1987-08-01

In order to assess the sensitivity to draught of 7 different tests, 41 volunteer subjects were exposed experimentally: 18 to 1.0 m/s and 9 to 0.5 m/s in a climate chamber: 14 to an average of 0.67 m/s in an air-conditioned car. All exposures were at 21-22 degrees C. Exposures were for 30 min indoors, 45 min in the car. Break-up Time (BUT) of the pre-corneal film after a blink was observed before and after exposure in the laboratory. There was a significant decrease after exposure to 1.0 m/s (P less than 0.01) but not to 0.5 m/s. The variance of the observed BUT increased after exposure to 0.5 m/s (P less than 0.05). The Norn Lacrimal Dilution test showed increased tear flow after the climate-chamber exposures (P less than 0.05). Self-reported BUT(S) was always several times longer than BUT. There was a significant correlation between these measures (P less than 0.05) before exposure, but not after. BUT(S), like BUT, decreased after exposure to 1.0 m/s (P less than 0.01), but not after 0.05 m/s. However, the variance of BUT(S) did not increase significantly after 0.5 m/s; it decreased significantly after 1.0 m/s (P less than 0.01). A significantly improved mucus ferning pattern was observed after draught exposure (P less than 0.005), presumably due in part to increased lacrimal flow. There was no significant effect of draught on the albumin content of tear samples taken before and after exposure. Lissamine Green staining performed before and after exposure revealed no effect on micro-damage to the conjunctival epithelium.

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.

Exposure to seismic air gun signals causes physiological harm and alters behavior in the scallop Pecten fumatus

PubMed Central

McCauley, Robert D.; Fitzgibbon, Quinn P.; Hartmann, Klaas; Semmens, Jayson M.

2017-01-01

Seismic surveys map the seabed using intense, low-frequency sound signals that penetrate kilometers into the Earth’s crust. Little is known regarding how invertebrates, including economically and ecologically important bivalves, are affected by exposure to seismic signals. In a series of field-based experiments, we investigate the impact of exposure to seismic surveys on scallops, using measurements of physiological and behavioral parameters to determine whether exposure may cause mass mortality or result in other sublethal effects. Exposure to seismic signals was found to significantly increase mortality, particularly over a chronic (months postexposure) time scale, though not beyond naturally occurring rates of mortality. Exposure did not elicit energetically expensive behaviors, but scallops showed significant changes in behavioral patterns during exposure, through a reduction in classic behaviors and demonstration of a nonclassic “flinch” response to air gun signals. Furthermore, scallops showed persistent alterations in recessing reflex behavior following exposure, with the rate of recessing increasing with repeated exposure. Hemolymph (blood analog) physiology showed a compromised capacity for homeostasis and potential immunodeficiency, as a range of hemolymph biochemistry parameters were altered and the density of circulating hemocytes (blood cell analog) was significantly reduced, with effects observed over acute (hours to days) and chronic (months) scales. The size of the air gun had no effect, but repeated exposure intensified responses. We postulate that the observed impacts resulted from high seabed ground accelerations driven by the air gun signal. Given the scope of physiological disruption, we conclude that seismic exposure can harm scallops. PMID:28923925

Effect of in utero wi-fi exposure on the pre- and postnatal development of rats.

PubMed

Poulletier de Gannes, Florence; Haro, Emmanuelle; Hurtier, Annabelle; Taxile, Murielle; Athane, Axel; Ait-Aissa, Saliha; Masuda, Hiroshi; Percherncier, Yann; Ruffié, Gilles; Billaudel, Bernard; Dufour, Philippe; Veyret, Bernard; Lagroye, Isabelle

2012-04-01

The increase in exposure to the Wireless Fidelity (Wi-Fi) wireless communication signal has raised public health concerns especially for young people. Animal studies looking at the effects of early life and prenatal exposure to this source of electromagnetic fields, in the radiofrequency (RF) range, on development and behavior have been considered as high priority research needs by the World Health Organization. For the first time, our study assessed the effects of in utero exposure to a 2450 MHz Wi-Fi signal (2 hr/day, 6 days/week for 18 days) on pregnant rats and their pups. Three levels in terms of whole-body specific absorption rate were used: 0.08, 0.4, and 4 W/kg. The prenatal study on fetuses delivered by caesarean (P20) concerned five females/group. The dams and their offspring were observed for 28 days after delivery (15 females/group). For all test conditions, no abnormalities were noted in the pregnant rats and no significant signs of toxicity were observed in the pre- and postnatal development of the pups, even at the highest level of 4 W/kg. In the present study, no teratogenic effect of repeated exposures to the Wi-Fi wireless communication signal was demonstrated even at the highest level of 4 W/kg. The results from this screening study aimed at investigating Wi-Fi effects, strengthen the previous conclusions that teratology and development studies have not detected any noxious effects of exposures to mobile telephony-related RF fields at exposure levels below standard limits. © 2012 Wiley Periodicals, Inc.

Induction of oxidative stress by bisphenol A and its pleiotropic effects

PubMed Central

Gassman, Natalie R.

2016-01-01

Bisphenol A (BPA) has become a target of intense public scrutiny since concerns about its association with human diseases such as obesity, diabetes, reproductive disorders, and cancer have emerged. BPA is a highly prevalent chemical in consumer products, and human exposure is thought to be ubiquitous. Numerous studies have demonstrated its endocrine disrupting properties and attributed exposure with cytotoxic, genotoxic, and carcinogenic effects; however, the results of these studies are still highly debated and a consensus about BPA's safety and its role in human disease has not been reached. One of the contributing factors is a lack of molecular mechanisms or modes of action that explain the diverse and pleiotropic effects observed after BPA exposure. The increase in BPA research seen over the last ten years has resulted in more studies that examine molecular mechanisms and revealed links between BPA-induced oxidative stress and human disease. Here, a review of the current literature examining BPA exposure and the induction of reactive oxygen species (ROS) or oxidative stress will be provided to examine the landscape of the current BPA literature and provide a framework for understanding how induction of oxidative stress by BPA may contribute to the pleiotropic effects observed after exposure. PMID:28181297

Influence of exposure differences on city-to-city variations in PM2.5-mortality effect estimates

EPA Science Inventory

Multi-city population-based epidemiological studies have observed heterogeneity between city specific PM2.5-mortality effect estimates. One possibility is city-specific differences in overall population exposure to PM2.5. In a previous analysis we explored this latter point by cl...

Environmental effects on composites for aircraft

NASA Technical Reports Server (NTRS)

Pride, R. A.

1978-01-01

A number of ongoing, long-term environmental effects programs for composite materials are evaluated. The flight service experience was evaluated for 142 composite aircraft components after more than 5 years and 1 million successful component flight hours. Ground-based outdoor exposures of composite material coupons after 3 years of exposure at 5 sites have reached equilibrium levels of moisture pickup which are predictable. Solar ultraviolet-induced material loss is discussed for these same exposures. No significant degradation was observed in residual strength for either stressed or unstressed specimens, or for exposures to aviation fuels and fluids.

Effects of single intratracheal exposure to chlorhexidine gluconate on the rat lung.

PubMed

Orito, Kensuke; Hashida, Masaru; Hirata, Kiyotaka; Kurokawa, Akira; Shirai, Mitsuyuki; Akahori, Fumiaki

2006-01-01

Chlorhexidine gluconate (CHX) is an antiseptic that has been widely used for disinfection of cutaneous wound and gingivae. Recently, a patient who inhaled CHX solution died from acute respiratory distress syndrome (ARDS). Although it is highly possible that direct pulmonary damage might be the cause of ARDS, there is no preclinical information about the pulmonary toxicity of CHX. In the current study, the acute direct action of CHX to the lung was evaluated in rats. We successfully exposed the left but not the right lung either to CHX at concentrations of 1%, 0.1%, and 0.01% or to saline using a curved-tip administration tube. At the higher concentrations of CHX (0.1% and 1%), severe congestion to the alveoli and capillaries and perivascular and intra-alveolar hemorrhages were observed 1 day after exposure. Aniline blue-stained collagen fibers with an infiltration of inflammatory cells were present 7 days after exposure. The fibrotic changes and intra-alveolar inflammatory cells had decreased but were still observed sporadically 28 and 84 days after exposure. These detrimental effects were more severe at 1% than at 0.1% CHX. No remarkable effect was observed after exposures to 0.01% CHX and saline. We were able to evaluate the time-course changes in the pulmonary toxicity of CHX by exposures limited to the left lung. It is highly possible that CHX at a concentration of more than 0.1% might directly induce ARDS when aspirated and reaching to the alveoli.

Mortality from all cancers of asbestos factory workers in east London 1933-80

PubMed Central

Berry, G; Newhouse, M; Wagner, J

2000-01-01

OBJECTIVE—To give the observed and expected deaths due to cancer at all separate sites in asbestos workers in east London, and to analyse these for overall effect and exposure-response trend.
METHODS—The mortality experience of a cohort of over 5000 men and women followed up for over 30 years since first exposure to asbestos has been extracted.
RESULTS—There was a large excess of deaths due to cancer (537 observed, 222 expected). Most of these were due to cancer of the lung (232 observed, 77 expected) and pleural (52) and peritoneal (48) mesothelioma. The exposure-response trend for all these three causes was highly significant. There was also an excess of cancer of the colon (27 observed, 15 expected) which was significantly related to exposure. There were significant excesses of cancer of the ovary, of the liver, and of the oesophagus but with no consistent relation to exposure.
CONCLUSIONS—The excess risk of cancer after exposure to asbestos was mainly due to cancer of the lung and mesothelioma. An exposure related excess of cancer of the colon was also detected but the possibility that some of these deaths may have been peritoneal mesotheliomas could not be excluded. There was no consistent evidence of exposure related excesses at any other site.


Keywords: asbestos; cancer; exposure-response PMID:11024203

Health effects of subchronic exposure to diesel-water-methanol emulsion emission.

PubMed

Reed, M D; Blair, L F; Burling, K; Daly, I; Gigliotti, A P; Gudi, R; Mercieca, M D; McDonald, J D; O'Callaghan, J P; Seilkop, S K; Ronskoh, N L; Wagner, V O; Kraska, R C

2006-03-01

The U.S. Environmental Protection Agency's National Ambient Air Quality Standards for ozone and particulate matter (PM) require urban non-attainment areas to implement pollution-reduction strategies for anthropogenic source emissions. The type of fuel shown to decrease combustion emissions components versus traditional diesel fuel, is the diesel emulsion. The Lubrizol Corporation, in conjunction with Lovelace Respiratory Research Institute and several subcontracting laboratories, recently conducted a health assessment of the combustion emissions of PuriNOx diesel fuel emulsion (diesel-water-methanol) in rodents. Combustion emissions from either of two, 2002 model Cummins 5.9L ISB engines, were diluted with charcoal-filtered air to exposure concentrations of 125, 250 and 500 microg total PM/m3. The engines were operated on a continuous, repeating, heavy-duty certification cycle (U.S. Code of Federal Regulations, Title 40, Chapter I) using Rotella-T 15W-40 engine oil. Nitrogen oxide (NO) and PM were reduced when engines were operated on PuriNOx versus California Air Resources Board diesel fuel under these conditions. Male and female F344 rats were housed in Hazleton H2000 exposure chambers and exposed to exhaust atmospheres 6 h/day, five days/week for the first 11 weeks and seven days/week thereafter. Exposures ranged from 61 to 73 days depending on the treatment group. Indicators of general toxicity (body weight, organ weight, clinical pathology and histopathology), neurotoxicity (glial fibrillary acidic protein assay), genotoxicity (Ames assay, micronucleus, sister chromatid exchange), and reproduction and development were measured. Overall, effects observed were mild. Emulsion combustion emissions were not associated with neurotoxicity, reproductive/developmental toxicity, or in vivo genotoxicity. Small decreases in serum cholesterol in the 500-microg/m3 exposure group were observed. PM accumulation within alveolar macrophages was evident in all exposure groups. The latter findings are consistent with normal physiological responses to particle inhalation. Other statistically significant effects were present in some measured parameters of other exposed groups, but were not clearly attributed to emissions exposure. Positive mutagenic responses in several strains of Salmonella typhimurium were observed subsequent to treatment with emulsion emissions subfractions. Based on the cholesterol results, it can be concluded that the 250-microg/m3 exposure level was the no observed effect level. In general, biological findings in exposed rats and bacteria were consistent with exposure to petroleum diesel exhaust in the F344 rat and Ames assays.

Modification of neurobehavioral effects of mercury by genetic polymorphisms of metallothionein in children.

PubMed

Woods, James S; Heyer, Nicholas J; Russo, Joan E; Martin, Michael D; Pillai, Pradeep B; Farin, Federico M

2013-01-01

Mercury (Hg) is neurotoxic, and children may be particularly susceptible to this effect. A current major challenge is the identification of children who may be uniquely susceptible to Hg toxicity because of genetic disposition. We examined the hypothesis that genetic variants of metallothionein (MT) that are reported to affect Hg toxicokinetics in adults would modify the neurotoxic effects of Hg in children. Five hundred seven children, 8-12 years of age at baseline, participated in a clinical trial to evaluate the neurobehavioral effects of Hg from dental amalgam tooth fillings. Subjects were evaluated at baseline and at 7 subsequent annual intervals for neurobehavioral performance and urinary Hg levels. Following the completion of the clinical trial, we performed genotyping assays for variants of MT isoforms MT1M (rs2270837) and MT2A (rs10636) on biological samples provided by 330 of the trial participants. Regression modeling strategies were employed to evaluate associations between allelic status, Hg exposure, and neurobehavioral test outcomes. Among girls, few significant interactions or independent main effects for Hg exposure and either of the MT gene variants were observed. In contrast, among boys, numerous significant interaction effects between variants of MT1M and MT2A, alone and combined, with Hg exposure were observed spanning multiple domains of neurobehavioral function. All dose-response associations between Hg exposure and test performance were restricted to boys and were in the direction of impaired performance. These findings suggest increased susceptibility to the adverse neurobehavioral effects of Hg among children with relatively common genetic variants of MT, and may have important public health implications for future strategies aimed at protecting children and adolescents from the potential health risks associated with Hg exposure. We note that because urinary Hg reflects a composite exposure index that cannot be attributed to a specific source, these findings do not support an association between Hg in dental amalgams specifically and the adverse neurobehavioral outcomes observed. © 2013.

Screen Media Exposure and Obesity in Children and Adolescents

PubMed Central

Robinson, Thomas N.; Banda, Jorge A.; Hale, Lauren; Lu, Amy Shirong; Fleming-Milici, Frances; Calvert, Sandra L.; Wartella, Ellen

2018-01-01

Obesity is one of the best-documented outcomes of screen media exposure. Many observational studies find relationships between screen media exposure and increased risks of obesity. Randomized controlled trials of reducing screen time in community settings have reduced weight gain in children, demonstrating a cause and effect relationship. Current evidence suggests that screen media exposure leads to obesity in children and adolescents through increased eating while viewing; exposure to high-calorie, low-nutrient food and beverage marketing that influences children’s preferences, purchase requests, consumption habits; and reduced sleep duration. Some evidence also suggests promise for using interactive media to improve eating and physical activity behaviors to prevent or reduce obesity. Future interdisciplinary research is needed to examine the effects of newer mobile and other digital media exposures on obesity; to examine the effectiveness of additional interventions to mitigate the adverse effects of media exposures on obesity and possible moderators and mediators of intervention effects; to effectively use digital media interventions to prevent and reduce obesity; and to uncover the mechanisms underlying the causal relationships and interactions between obesity-related outcomes and media content, characteristics, and context. PMID:29093041

Results of the examination of LDEF polyurethane thermal control coatings

NASA Technical Reports Server (NTRS)

Golden, Johnny L.

1994-01-01

This report summarizes the condition of polyurethane thermal control coatings subjected to 69 months of low earth orbit (LEO) exposure on the Long Duration Exposure Facility (LDEF) mission. Specimens representing all environmental aspects obtainable by LDEF were analyzed. Widely varying changes in the thermo-optical and mechanical properties of these materials were observed, depending on atomic oxygen and ultraviolet radiation fluences. High atomic oxygen fluences, regardless of ultraviolet radiation exposure levels, resulted in near original optical properties for these coatings but with a degradation in their mechanical condition. A trend in solar absorptance increase with ultraviolet radiation fluence was observed. Contamination, though observed, exhibited minimal effects.

Potential teratogenicity of methimazole: exposure of zebrafish embryos to methimazole causes similar developmental anomalies to human methimazole embryopathy.

PubMed

Komoike, Yuta; Matsuoka, Masato; Kosaki, Kenjiro

2013-06-01

While methimazole (MMI) is widely used in the therapy for hyperthyroidism, several groups have reported that maternal exposure to MMI results in a variety of congenital anomalies, including choanal and esophageal atresia, iridic and retinal coloboma, and delayed neurodevelopment. Thus, adverse effects of maternal exposure to MMI on fetal development have long been suggested; however, direct evidence for the teratogenicity of MMI has not been presented. Therefore, we studied the effects of MMI on early development by using zebrafish as a model organism. The fertilized eggs of zebrafish were collected immediately after spawning and grown in egg culture water containing MMI at various concentrations. External observation of the embryos revealed that exposure to high concentrations of MMI resulted in loss of pigmentation, hypoplastic hindbrain, turbid tissue in the forebrain, swelling of the notochord, and curly trunk. Furthermore, these effects occurred in a dose-dependent manner. Precise observation of the serial cross-sections of MMI-exposed embryos elucidated delayed development and hypoplasia of the whole brain and spinal cord, narrowing of the pharynx and esophagus, severe disruption of the retina, and aberrant structure of the notochord. These neuronal, pharyngeal, esophageal, and retinal anomalous morphologies have a direct analogy to the congenital anomalies observed in children exposed to MMI in utero. Here, we show the teratogenic effects of MMI on the development of zebrafish and provide the first experimental evidence for the connection between exposure to MMI and human MMI embryopathy. © 2013 Wiley Periodicals, Inc.

Effect of electromagnetic pulse exposure on permeability of blood-testicle barrier in mice.

PubMed

Wang, Xiao-Wu; Ding, Gui-Rong; Shi, Chang-Hong; Zhao, Tao; Zhang, Jie; Zeng, Li-Hua; Guo, Guo-Zhen

2008-06-01

To study the effect of electromagnetic pulse (EMP) exposure on the permeability of blood-testicle barrier (BTB) in mice. Adult male BALB/c mice were exposed to EMP at 200 kV/m for 200 pulses with 2 seconds interval. The mice were injected with 2% Evans Blue solution through caudal vein at different time points after exposure, and the permeability of BTB was monitored using a fluorescence microscope. The testis sample for the transmission electron microscopy was prepared at 2 h after EMP exposure. The permeability of BTB in mice was observed by using Evans Blue tracer and lanthanum nitrate tracer. After exposure, cloudy Evans Blue was found in the testicle convoluted seminiferous tubule of mice. Lanthanum nitrate was observed not only between testicle spermatogonia near seminiferous tubule wall and sertoli cells, but also between sertoli cells and primary spermatocyte or secondary spermatocyte. In contrast, lanthanum nitrate in control group was only found in the testicle sertoli cells between seminiferous tubule and near seminiferous tubule wall. EMP exposure could increase the permeability of BTB in the mice.

Joint Toxicity of Arsenic, Copper and Glyphosate on Behavior, Reproduction and Heat Shock Protein Response in Caenorhabditis elegans.

PubMed

Wang, Yunbiao; Ezemaduka, Anastasia N; Li, Zhuheng; Chen, Zhanyan; Song, Chuantao

2017-04-01

The soil nematode Caenorhabditis elegans was used in 24-h acute exposures to arsenic (As), copper (Cu) and glyphosate (GPS) and to mixtures of As/Cu and As/GPS to investigate the effects of mixture exposures in the worms. A synergistic type of interaction was observed for acute toxicity with the As/Cu and As/GPS mixtures. Sublethal 24-h exposures of 1/1000, 1/100 and 1/10 of the LC50 concentrations for As, Cu and GPS individually and for As/Cu and As/GPS mixtures were conducted to observe responses in locomotory behavior (head thrashing), reproduction, and heat shock protein expression. Head thrash frequency and reproduction exhibited concentration dependent decreases in both individual and combined exposures to the tested chemical stressors, and showed synergistic interactions even at micromolar concentrations. Furthermore, the HSP70 protein level was significantly increased following exposure to individual and combined chemical stressors in wild-type C. elegans. Our findings establish for the first time the effects of exposure to As/GPS and As/Cu mixtures in C. elegans.

Rat fertility and embryo fetal development: influence of exposure to the Wi-Fi signal.

PubMed

Poulletier de Gannes, Florence; Billaudel, Bernard; Haro, Emmanuelle; Taxile, Murielle; Le Montagner, Laureline; Hurtier, Annabelle; Ait Aissa, Saliha; Masuda, Hiroshi; Percherancier, Yann; Ruffié, Gilles; Dufour, Philippe; Veyret, Bernard; Lagroye, Isabelle

2013-04-01

In recent decades, concern has been growing about decreasing fecundity and fertility in the human population. Exposure to non-ionizing electromagnetic fields (EMF), especially radiofrequency (RF) fields used in wireless communications has been suggested as a potential risk factor. For the first time, we evaluated the effects of exposure to the 2450MHz Wi-Fi signal (1h/day, 6days/week) on the reproductive system of male and female Wistar rats, pre-exposed to Wi-Fi during sexual maturation. Exposure lasted 3 weeks (males) or 2 weeks (females), then animals were mated and couples exposed for 3 more weeks. On the day before delivery, the fetuses were observed for lethality, abnormalities, and clinical signs. In our experiment, no deleterious effects of Wi-Fi exposure on rat male and female reproductive organs and fertility were observed for 1h per days. No macroscopic abnormalities in fetuses were noted, even at the critical level of 4W/kg. Copyright © 2012 Elsevier Inc. All rights reserved.

Attention bias and anxiety in young children exposed to family violence.

PubMed

Briggs-Gowan, Margaret J; Pollak, Seth D; Grasso, Damión; Voss, Joel; Mian, Nicholas D; Zobel, Elvira; McCarthy, Kimberly J; Wakschlag, Lauren S; Pine, Daniel S

2015-11-01

Attention bias toward threat is associated with anxiety in older youth and adults and has been linked with violence exposure. Attention bias may moderate the relationship between violence exposure and anxiety in young children. Capitalizing on measurement advances, this study examines these relationships at a younger age than previously possible. Young children (mean age 4.7, ±0.8) from a cross-sectional sample oversampled for violence exposure (N = 218) completed the dot-probe task to assess their attention biases. Observed fear/anxiety was characterized with a novel observational paradigm, the Anxiety Dimensional Observation Scale. Mother-reported symptoms were assessed with the Preschool Age Psychiatric Assessment and Trauma Symptom Checklist for Young Children. Violence exposure was characterized with dimensional scores reflecting probability of membership in two classes derived via latent class analysis from the Conflict Tactics Scales: Abuse and Harsh Parenting. Family violence predicted greater child anxiety and trauma symptoms. Attention bias moderated the relationship between violence and anxiety. Attention bias toward threat may strengthen the effects of family violence on the development of anxiety, with potentially cascading effects across childhood. Such associations maybe most readily detected when using observational measures of childhood anxiety.

Attention bias and anxiety in young children exposed to family violence

PubMed Central

Briggs-Gowan, Margaret J.; Pollak, Seth D.; Grasso, Damion; Voss, Joel; Mian, Nicholas D.; Zobel, Elvira; McCarthy, Kimberly J.; Wakschlag, Lauren S.; Pine, Daniel S.

2015-01-01

Background Attention bias towards threat is associated with anxiety in older youth and adults and has been linked with violence exposure. Attention bias may moderate the relationship between violence exposure and anxiety in young children. Capitalizing on measurement advances, the current study examines these relationships at a younger age than previously possible. Methods Young children (mean age 4.7, ±0.8) from a cross-sectional sample oversampled for violence exposure (N = 218) completed the dot-probe task to assess their attention biases. Observed fear/anxiety was characterized with a novel observational paradigm, the Anxiety Diagnostic Observation Schedule. Mother-reported symptoms were assessed with the Preschool-Age Psychiatric Assessment and Trauma Symptom Checklist for Young Children. Violence exposure was characterized with dimensional scores reflecting probability of membership in two classes derived via latent class analysis from the Conflict Tactics Scales: Abuse and Harsh Parenting. Results Family violence predicted greater child anxiety and trauma symptoms. Attention bias moderated the relationship between violence and anxiety. Conclusions Attention bias towards threat may strengthen the effects of family violence on the development of anxiety, with potentially cascading effects across childhood. Such associations may be most readily detected when using observational measures of childhood anxiety. PMID:26716142

Short daily exposure to hand-arm vibrations in Swedish car mechanics.

PubMed

Barregård, Lars

2003-01-01

The aim of the study was to examine the daily exposure times to hand-arm vibrations in Swedish car mechanics, to test a method for estimating the exposure time without observing the workers for whole days, and to use the results for predicting the prevalence of vibration-induced white fingers (VWF) by the ISO 5349-model. Six garages were surveyed. In each garage, 5-10 car mechanics were observed in random order every 30 seconds throughout working days. The daily exposure time for each mechanic was estimated from the fraction of the observations that the mechanic was exposed. A total of 51 mechanics were observed, most of them on two different working days, yielding estimates for 95 days. The median effective exposure time was 10 minutes per day (95% confidence interval 5-15 minutes, arithmetic mean 14 minutes, maximum 80 minutes), and most of the exposure time was attributable to fastening and loosening nuts. The within-worker and between-worker variability was high (total sigma2 0.99, geometric standard deviation of 2.7). Using the observed exposure time and data on vibration levels of the main tools in Swedish car mechanics (average weighted acceleration level of 3.5 m/s2), the model in ISO-standard 5349 would predict that only three percent of the car mechanics will suffer from VWF after 20 years of exposure. In contrast, a recent survey of VWF showed the prevalence to be 25 percent. The precision of the observation method was estimated and was found to be good for the group daily mean. On the individual level the precision was only acceptable if the daily exposure time was > or = 40 minutes. In conclusion, the daily exposure time was short and the vibration level was limited. Nevertheless, hand-arm vibrations cause VWF in a significant number of car mechanics. The method of observing workers intermittently seemed to work well.

Potentiation of glucocorticoid release does not modify the long-term effects of a single exposure to immobilization stress.

PubMed

Dal-Zotto, Silvina; Martí, Octavi; Delgado, Raúl; Armario, Antonio

2004-12-01

Previous work has shown that a single exposure of rats to a severe stressor (immobilization, IMO) results, days to weeks later, in a reduced response (desensitization) of the hypothalamic-pituitary-adrenal (HPA) axis to a second exposure to the same stressor. In the present work, we studied the influence of both length of exposure to IMO and circulating levels of corticosterone on the first day on the degree of desensitization of two sets of physiological variables: HPA hormones and food intake. Rats were given SC saline or ACTH administration and then exposed to IMO for 0, 1 or 20 min. Seven days later, all rats were exposed to 20 min IMO. HPA response was followed on both experimental days by repeated blood sampling and food intake was measured on a 24-h basis. Both ACTH administration and IMO activates the HPA axis and IMO reduced food intake for several days. A single previous experience with IMO enhanced the post-IMO return of HPA hormones to basal levels on day 8 and reduced the degree of anorexia. The protective effect of previous IMO on food intake was independent of, whereas that on HPA activation was positively related to, the length of exposure on day 1. Concomitant ACTH administration on day 1 did not modify the observed effects. Long-term protective effects of a single exposure to IMO are observed even with a brief exposure, but they are not potentiated by increasing corticosterone levels during the first exposure.

Combined exposure to protons and 56Fe leads to overexpression of Il13 and reactivation of repetitive elements in the mouse lung

NASA Astrophysics Data System (ADS)

Nzabarushimana, Etienne; Prior, Sara; Miousse, Isabelle R.; Pathak, Rupak; Allen, Antiño R.; Latendresse, John; Olsen, Reid H. J.; Raber, Jacob; Hauer-Jensen, Martin; Nelson, Gregory A.; Koturbash, Igor

2015-11-01

Interest in deep space exploration underlines the needs to investigate the effects of exposure to combined sources of space radiation. The lung is a target organ for radiation, and exposure to protons and heavy ions as radiation sources may lead to the development of degenerative disease and cancer. In this study, we evaluated the pro-fibrotic and epigenetic effects of exposure to protons (150 MeV/nucleon, 0.1 Gy) and heavy iron ions (56Fe, 600 MeV/nucleon, 0.5 Gy) alone or in combination (protons on Day 1 and 56Fe on Day 2) in C57BL/6 male mice 4 weeks after irradiation. Exposure to 56Fe, proton or in combination, did not result in histopathological changes in the murine lung. At the same time, combined exposure to protons and 56Fe resulted in pronounced molecular alterations in comparison with either source of radiation alone. Specifically, we observed a substantial increase in the expression of cytokine Il13, loss of expression of DNA methyltransferase Dnmt1, and reactivation of LINE-1, SINE B1 retrotransposons, and major and minor satellites. Given the deleterious potential of the observed effects that may lead to development of chronic lung injury, pulmonary fibrosis, and cancer, future studies devoted to the investigation of the long-term effects of combined exposures to proton and heavy ions are clearly needed.

Effect of Low Dose of Fumonisins on Pig Health: Immune Status, Intestinal Microbiota and Sensitivity to Salmonella

PubMed Central

Burel, Christine; Tanguy, Mael; Guerre, Philippe; Boilletot, Eric; Cariolet, Roland; Queguiner, Marilyne; Postollec, Gilbert; Pinton, Philippe; Salvat, Gilles; Oswald, Isabelle P.; Fravalo, Philippe

2013-01-01

The objective of this study was to measure the effects of chronic exposure to fumonisins via the ingestion of feed containing naturally contaminated corn in growing pigs infected or not with Salmonella spp. This exposure to a moderate dietary concentration of fumonisins (11.8 ppm) was sufficient to induce a biological effect in pigs (Sa/So ratio), but no mortality or pathology was observed over 63 days of exposure. No mortality or related clinical signs, even in cases of inoculation with Salmonella (5 × 104 CFU), were observed either. Fumonisins, at these concentrations, did not affect the ability of lymphocytes to proliferate in the presence of mitogens, but after seven days post-inoculation they led to inhibition of the ability of specific Salmonella lymphocytes to proliferate following exposure to a specific Salmonella antigen. However, the ingestion of fumonisins had no impact on Salmonella translocation or seroconversion in inoculated pigs. The inoculation of Salmonella did not affect faecal microbiota profiles, but exposure to moderate concentrations of fumonisins transiently affected the digestive microbiota balance. In cases of co-infection with fumonisins and Salmonella, the microbiota profiles were rapidly and clearly modified as early as 48 h post-Salmonella inoculation. Therefore under these experimental conditions, exposure to an average concentration of fumonisins in naturally contaminated feed had no effect on pig health but did affect the digestive microbiota balance, with Salmonella exposure amplifying this phenomenon. PMID:23612754

Combined exposure to protons and 56Fe leads to overexpression of Il13 and reactivation of repetitive elements in the mouse lung

PubMed Central

Nzabarushimana, Etienne; Prior, Sara; Miousse, Isabelle R.; Pathak, Rupak; Allen, Antino R.; Latendresse, John; Olsen, Reid H.J.; Raber, Jacob; Hauer-Jensen, Martin; Nelson, Gregory A.; Koturbash, Igor

2015-01-01

Interest in deep space exploration underlines the needs to investigate the effects of exposure to combined sources of space radiation. The lung is a target organ for radiation, and exposure to protons and heavy ions as radiation sources may lead to the development of degenerative disease and cancer. In this study, we evaluated the pro-fibrotic and epigenetic effects of exposure to protons (150 MeV/nucleon, 0.1 Gy) and heavy iron ions (56Fe, 600 MeV/nucleon, 0.5 Gy) alone or in combination (protons on Day 1 and 56Fe on Day 2) in C57BL/6 male mice 4 weeks after irradiation). Exposure to 56Fe, proton or in combination, did not result in histopathological changes in the murine lung. At the same time, combined exposure to protons and 56Fe resulted in pronounced molecular alterations in comparison with either source of radiation alone. Specifically, we observed a substantial increase in the expression of cytokine Il13, loss of expression of DNA methyltransferase Dnmt1, and reactivation of LINE-1, SINE B1 retrotransposons, and major and minor satellites. Given the deleterious potential of the observed effects that may lead to development of chronic lung injury, pulmonary fibrosis, and cancer, future studies devoted to the investigation of the long-term effects of combined exposures to proton and heavy ions are clearly needed. PMID:26553631

Measurement systems and indices of miners' exposure to radon daughter products in the air of mines.

PubMed

Domański, T

1990-01-01

This paper presents the classification of measurement systems that may be used for the assessment of miners' exposure to radiation in mines. The following systems were described and characterized as the Air Sampling System (ASS), the Environmental Control System (ECS), the Individual Dosimetry System (IDS), the Stream Monitoring System (SMS) and the Exhaust Monitoring System (EMS). The indices for evaluation of miners' working environments, or for assessment of individual or collective miners' exposure, were selected and determined. These are: average expected concentration (CAE), average observed concentration (CAO), average expected rate of exposure cumulation rate (EEXP), average observed exposure cumulation rate (EOBS), average effective exposure cumulation rate (EEFF). Mathematical formulae for determining all these indicators, according to the type of measurement system used in particular mines, are presented. The reliability of assessment of miners' exposure in particular measurement systems, as well as the role of the possible reference system, are discussed.

Linking Meteorology, Air Quality Models and Observations to Characterize Human Exposures in Support of the Environmental Health Studies

EPA Science Inventory

Epidemiologic studies are critical in establishing the association between exposure to air pollutants and adverse health effects. Results of epidemiologic studies are used by U.S. EPA in developing air quality standards to protect the public from the health effects of air polluta...

Effect of Same-day Sequential Exposure to Nitrogen Dioxide and Ozone on Cardiac and Ventilatory Function in Mice

EPA Science Inventory

This study examines the cardiac and ventilatory effects of sequential exposure to nitrogen dioxide and then ozone. The data show that mice exposed to both gases have increased arrhythmia and breathing changes not observed in the other groups. Although the mechanisms underlying ai...

Neurobehavioral effects of exposure to traffic-related air pollution and transportation noise in primary schoolchildren.

PubMed

van Kempen, Elise; Fischer, Paul; Janssen, Nicole; Houthuijs, Danny; van Kamp, Irene; Stansfeld, Stephen; Cassee, Flemming

2012-05-01

Children living close to roads are exposed to both traffic noise and traffic-related air pollution. There are indications that both exposures affect cognitive functioning. So far, the effects of both exposures have only been investigated separately. To investigate the relationship between air pollution and transportation noise on the cognitive performance of primary schoolchildren in both the home and school setting. Data acquired within RANCH from 553 children (aged 9-11 years) from 24 primary schools were analysed using multilevel modelling with adjustment for a range of socio-economic and life-style factors. Exposure to NO(2) (which is in urban areas an indicator for traffic-related air pollution) at school was statistically significantly associated with a decrease in the memory span length measured during DMST (χ(2)=6.8, df=1, p=0.01). This remained after additional adjustment for transportation noise. Statistically significant associations were observed between road and air traffic noise exposure at school and the number of errors made during the 'arrow' (χ(2)=7.5, df=1, p=0.006) and 'switch' (χ(2)=4.8, df=1, p=0.028) conditions of the SAT. This remained after adjustment for NO(2). No effects of air pollution exposure or transportation noise exposure at home were observed. Combined exposure of air pollution and road traffic noise had a significant effect on the reaction times measured during the SRTT and the 'block' and the 'arrow' conditions of the SAT. Our results provide some support that prolonged exposure to traffic-related air pollution as well as to noise adversely affects cognitive functioning. Copyright © 2012 Elsevier Inc. All rights reserved.

Antagonistic effects of gestational dietary exposure to low-dose vinclozolin and genistein on rat fetal germ cell development.

PubMed

Lehraiki, Abdelali; Messiaen, Sébastien; Berges, Raymond; Canivenc-Lavier, Marie-Chantal; Auger, Jacques; Habert, René; Levacher, Christine

2011-05-01

Continuous, low-dose exposure to a phytoestrogen (1 mg/kg/day genistein) and/or to an antiandrogenic food contaminant (1 mg/kg/day vinclozolin) has been recently reported to affect male reproductive tract and fertility [1] in adults. We investigated whether alterations of the testis are already present at the end of in utero exposure using the same rat model and doses following exposure from conception to delivery. After vinclozolin exposure, we observed in the neonate a slight but significant alteration of steroidogenesis and gametogenesis with a reduction of testosterone secretion and of the number of gonocytes. In contrast, genistein exposure had no effect. While the vinclozolin-genistein mixture acts in a synergistic manner to induce the most significant alterations in the adult, interestingly, genistein antagonized the deleterious effect of vinclozolin on germ cells in the neonate. This difference emphasizes the importance of studying the effects of endocrine disruptors during various developmental stages to understand their effects. Copyright © 2011 Elsevier Inc. All rights reserved.

A Physiological and Biochemical Study of the Effects of Extremely Low Frequency Electromagnetic Fields

DTIC Science & Technology

1979-07-01

microplasmodial cultures continuously subjected to the particular field conditions being studied. The stages in ’ ,oitotic cycle ,re determined by observing...of the decrease in rate varies with exposure conditions . Mean values of the decreases computed from the raw data are given on the righthand side of...exposures we were concerned about was the effect of long-term, chronic exposure. Figure 2 presents data for field conditions that are the same as

Field Measurements of Inadvertent Ingestion Exposure to Metals.

PubMed

Gorman Ng, Melanie; MacCalman, Laura; Semple, Sean; van Tongeren, Martie

2017-11-10

The determinants of inadvertent occupational ingestion exposure are poorly understood, largely due to a lack of available exposure measurement data. In this study, perioral exposure wipes were used as a surrogate for inadvertent ingestion exposure to measure exposure to eight metals (chromium, nickel, aluminium, cobalt, lead, arsenic, manganese, and tin) among 38 workers at 5 work sites in the UK. This work was done alongside a previously reported observational study of hand/object-to-mouth contact frequency. Systematic wipes of the perioral area, and of both hands were taken with proprietary cellulose wipes pre-moistened with deionized water. Measurements were taken at the beginning, middle and end of the shift. Mixed-effect models of exposure measurements were built with area of skin sampled, time during shift, and job group entered as fixed effects and worker identification as a random effect. Linear regression modelling was used to study the effect of hand/object-to-mouth contact frequency on perioral exposure, adjusting for the measured exposure on the hand and observed respirator use. Hand and perioral exposure measurements were correlated with one another (r = 0.79) but mass per unit area exposure was significantly higher on the perioral area than on the hands for seven of the metals (at P < 0.05). There were no significant differences between measurements taken at the middle or the end of the shift for five of the metals suggesting that dermal loading may remain relatively constant for much of the workday. This applies to both hand and perioral measurements. In linear regression modelling there was no relationship between hand/object-to-mouth contact frequency and perioral exposure, but hand exposure was significantly positively related to perioral exposure and workers who used respirators had significantly higher perioral exposure than those who did not. The results suggest the levels of exposure on the hand and respirator use are important determinants of potential inadvertent ingestion exposure. The results did not demonstrate a relationship between perioral exposure and hand-to-mouth contact frequency. Perioral wipe sampling may be a useful surrogate measure for exposure by the inadvertent ingestion route, but further research is required to confirm the link between perioral levels and actual exposure, measured using biological monitoring. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Is dietary nitrate/nitrite exposure a risk factor for development of thyroid abnormality? A systematic review and meta-analysis.

PubMed

Bahadoran, Zahra; Mirmiran, Parvin; Ghasemi, Asghar; Kabir, Ali; Azizi, Fereidoun; Hadaegh, Farzad

2015-05-01

The potential effects of inorganic nitrate/nitrite on global health are a much debated issue. In addition to possible methemoglobinemia and carcinogenic properties, anti-thyroid effects of nitrate/nitrite have been suggested. Considering the growing significance of nitrate/nitrite and since there is no comprehensive review in data available, clarifying the effect of nitrate/nitrite on thyroid disorder outcomes is essential. Therefore, we conducted this systematic review of experimental and clinical studies, and a meta-analysis of relevant cohort and cross-sectional studies investigating the association of nitrate/nitrite exposure and thyroid function. Most animal studies show that high exposure (~10-600 times of acceptable daily intake) to nitrate/nitrite induces anti-thyroid effects, including decreased serum level of thyroid hormones and histomorphological changes in thyroid gland; however no similar observations have been documented in humans. Based on our meta-analysis, no significant association was observed between nitrate exposure and the risk of thyroid cancer, hyper- and hypothyroidism; findings from three cohort studies however showed a significant association between higher exposure to nitrite and the risk of thyroid cancer (risk = 1.48, 95% confidence interval = 1.09-2.02, P = 0.012). Additional research is needed to clarify the association between nitrate/nitrite exposures and both thyroid function and cancer. Copyright © 2015 Elsevier Inc. All rights reserved.

Inhalation Exposure Method for Illegal Drugs.

PubMed

Inomata, Akiko; Ogata, Akio; Tada, Yukie; Nagasawa, Akemichi; Yuzawa, Katsuhiro; Ando, Hiroshi; Kubo, Yoshikazu; Takahashi, Hiroshi; Kaihoko, Fujifumi; Tanaka, Kazuyoshi; Nakajima, Jun'ichi; Suzuki, Atsuko; Uemura, Nozomi; Moriyasu, Takako; Watanabe, Daisuke; Ishihara, Kei; Usami, Takashi; Kamei, Satoru; Kohno, Yasuaki

2017-01-01

We developed a new inhalation exposure method to evaluate effects of synthetic cannabimimetics that are being distributed as new, unregulated drugs in the Tokyo area. We selected the commercial product "SOUTOU" containing AB-CHMINACA and 5F-AMB as the test drug and dried marshmallow (Althaea officinalis) leaves as the negative control. A half cigarette packed with dried marshmallow leaves or SOUTOU was ignited, then mainstream smoke from each was delivered to five mice in an exposure box. After the cigarettes were fully consumed, neurobehavioral observations and a catalepsy test were performed at 15, 30 and 60 min after exposure. The effluent air from the exposure box was poured into impingers containing acetonitrile (first impinger) and dimethyl sulfoxide (second impinger). The resulting solutions were analyzed to assess decomposition of the synthetic cannabimimetics. Mice exposed to SOUTOU smoke showed many excitement behaviors and some suppressive behaviors at 15, 30 and 60 min. These clearly included cannabimimetic specific pharmacological actions. Negative control mice also showed some suppressive behaviors at 15 min but these were attenuated at later times, nearly disappearing at 60 min. In addition, the behavioral effects observed in controls were less pronounced than those in SOUTOU exposed mice. The inhalation exposure method developed in our study would be effective for determining cannabinoid specific pharmacological effects of illegal drugs, as well as for assessing the presence of active compound(s) by comparing the test substance with a negative control.

Developmental and neurobehavioral effects of perinatal exposure to polychlorinated biphenyls in mice.

PubMed

Sugawara, Norio; Nakai, Kunihiko; Nakamura, Tomoyuki; Ohba, Takashi; Suzuki, Keita; Kameo, Satomi; Satoh, Chieko; Satoh, Hiroshi

2006-05-01

Because behavioral deficits associated with gestational exposure to polychlorinated biphenyls (PCBs) have been a concern, we studied the developmental and neurobehavioral effects of perinatal exposure to Aroclor 1254 (A1254), a commercial mixture of PCBs, in mice. The PCB mixture (A1254; 0, 6, 18, and 54 mg/kg body weight) was administered to pregnant mice (C57BL/6Cr) every 3 days by gavage from gestational day (GD) 6 to postnatal day (PND) 20. Compared with the control, treatment with A1254 did not alter the maternal body weight during the gestation and lactation periods. The body weight of the offspring did not differ among treatments. To assess the effects on offspring following such exposure, physical and neurobehavioral development (i.e., pinna detachment, hair growth, eye opening, incisor eruption, grasp reflex, righting reflex, walking, negative geotaxis, and cliff avoidance) was observed before weaning. At PND 7, poor adult-like responses in negative geotaxis were observed in all exposed groups. When the offspring were at 8-week old, the PCB-treated (18 mg/kg body weight) mice showed a decreased walking speed in the open-field test, and a prolonged time to reach the platform in the water maze test. Spontaneous locomotion activity was not affected by PCB exposure at 9 weeks . These results showed that perinatal exposure to PCBs produces several behavioral alterations in mice. Although dose-dependent changes were not observed, the neurobehavioral effects such as a decreased walking speed in the open-field test and a prolonged time to reach the platform in the water maze test remained in adulthood after the seeming recovery from the transient delay in development before weaning.

Adolescent alcohol exposure: Are there separable vulnerable periods within adolescence?

PubMed

Spear, Linda Patia

2015-09-01

There are two key alcohol use patterns among human adolescents that confer increased vulnerability for later alcohol abuse/dependence, along with neurocognitive alterations: (a) early initiation of use during adolescence, and (b) high rates of binge drinking that are particularly prevalent late in adolescence. The central thesis of this review is that lasting neurobehavioral outcomes of these two adolescent exposure patterns may differ. Although it is difficult to disentangle consequences of early use from later binge drinking in human studies given the substantial overlap between groups, these two types of problematic adolescent use are differentially heritable and hence separable to some extent. Although few studies using animal models have manipulated alcohol exposure age, those studies that have have typically observed timing-specific exposure effects, with more marked (or at least different patterns of) lasting consequences evident after exposures during early-mid adolescence than late-adolescence/emerging adulthood, and effects often restricted to male rats in those few instances where sex differences have been explored. As one example, adult male rats exposed to ethanol during early-mid adolescence (postnatal days [P] 25-45) were found to be socially anxious and to retain adolescent-typical ethanol-induced social facilitation into adulthood, effects that were not evident after exposure during late-adolescence/emerging adulthood (P45-65); exposure at the later interval, however, induced lasting tolerance to ethanol's social inhibitory effects that was not evident after exposure early in adolescence. Females, in contrast, were little influenced by ethanol exposure at either interval. Exposure timing effects have likewise been reported following social isolation as well as after repeated exposure to other drugs such as nicotine (and cannabinoids), with effects often, although not always, more pronounced in males where studied. Consistent with these timing-specific exposure effects, notable maturational changes in brain have been observed from early to late adolescence that could provide differential neural substrates for exposure timing-related consequences, with for instance exposure during early adolescence perhaps more likely to impact later self-administration and social/affective behaviors, whereas exposures later in adolescence may be more likely to influence cognitive tasks whose neural substrates (such as the prefrontal cortex [PFC]) are still undergoing maturation at that time. More work is needed, however to characterize timing-specific effects of adolescent ethanol exposures and their sex dependency, determine their neural substrates, and assess their comparability to and interactions with adolescent exposure to other drugs and stressors. Such information could prove critical for informing intervention/prevention strategies regarding the potential efficacy of efforts directed toward delaying onset of alcohol use versus toward reducing high levels of use and risks associated with that use later in adolescence. Copyright © 2015 Elsevier Inc. All rights reserved.

ADOLESCENT ALCOHOL EXPOSURE: ARE THERE SEPARABLE VULNERABLE PERIODS WITHIN ADOLESCENCE?

PubMed Central

Spear, Linda Patia

2015-01-01

There are two key alcohol use patterns among human adolescents that confer increased vulnerability for later alcohol abuse/dependence, along with neurocognitive alterations: (a) early initiation of use during adolescence, and (b) high rates of binge drinking that are particularly prevalent late in adolescence. The central thesis of this review is that lasting neurobehavioral outcomes of these two adolescent exposure patterns may differ. Although it is difficult to disentangle consequences of early use from later binge drinking in human studies given the substantial overlap between groups, these two types of problematic adolescent use are differentially heritable and hence separable to some extent. Although few studies using animal models have manipulated alcohol exposure age, those studies that have have typically observed timing-specific exposure effects, with more marked (or at least different patterns of) lasting consequences evident after exposures during early-mid adolescence than late-adolescence/emerging adulthood, and effects often restricted to male rats in those few instances where sex differences have been explored. As one example, adult male rats exposed to ethanol during early-mid adolescence (postnatal days [P] 25-45) were found to be socially anxious and to retain adolescent-typical ethanol-induced social facilitation into adulthood, effects that were not evident after exposure during late-adolescence/emerging adulthood (P45-65); exposure at the later interval, however, induced lasting tolerance to ethanol's social inhibitory effects that was not evident after exposure early in adolescence. Females, in contrast, were little influenced by ethanol exposure at either interval. Exposure timing effects have likewise been reported following social isolation as well as after repeated exposure to other drugs such as nicotine (and cannabinoids), with effects often, although not always, more pronounced in males where studied. Consistent with these timing-specific exposure effects, notable maturational changes in brain have been observed from early to late adolescence that could provide differential neural substrates for exposure timing-related consequences, with for instance exposure during early adolescence perhaps more likely to impact later self-administration and social/affective behaviors, whereas exposures later in adolescence may be more likely to influence cognitive tasks whose neural substrates (such as the prefrontal cortex [PFC]) are still undergoing maturation at that time. Substantial more work is needed, however to characterize timing-specific effects of adolescent ethanol exposures and their sex dependency, determine their neural substrates, and assess their comparability to and interactions with adolescent exposure to other drugs and stressors. Such information could prove critical for informing intervention/prevention strategies regarding the potential efficacy of efforts directed toward delaying onset of alcohol use versus toward reducing high levels of use and risks associated with that use later in adolescence. PMID:25624108

[Low risk of reproductive disorders among female greenhouse workers--safe work conditions or health selection for the light work?].

PubMed

Jurewicz, Joanna; Hanke, Wojciech; Makowiec-Dabrowska, Teresa

2008-01-01

There are two major potential hazards typical of work in greenhouses: hard physical work or exposure to pesticides. The aim of the study was to investigate whether the work in greenhouse during pregnancy have an adverse effect on its outcome (preterm delivery, spontaneous abortion and birth defects). The study was performed in a group of 460 women employed in 14 greenhouses involved in growing vegetables and flowers. The rate of spontaneous abortions was much elbeit insignificantly higher in the women working in greenhouses during pregnancy than in those employed out of them; that applied mostly to the women performing light jobs in greenhouses. An increased risk of preterm delivery and spontaneous abortion was also observed in women performing greenhouse light jobs. No significantly increased risk of birth defects was observed in children born to women working in greenhouses. Neither was there any relationship between exposure to RD or ED pesticides exposure--and the occurrence of preterm delivery, spontaneous abortion and birth defects. No higher risk of pathological pregnancy that could be associated with hard physical work and pesticide exposure was observed. This may result from the fact that women themselves select an appropriate kind of job during pregnancy and a possible removal of women with pathological pregnancy from jobs involving pesticide exposure, as well as from the promotion of biological protection. The greenhouse workers should be aware of the two typical hazards found in greenhouses (hard work and exposure to pesticides) and their potential negative effects on the reproduction. The results of this study warrant the need for further study of the effect of pesticide exposure and work load on the pregnancy outcome.

Long-term effects of a single exposure to stress in adult rats on behavior and hypothalamic-pituitary-adrenal responsiveness: comparison of two outbred rat strains.

PubMed

Belda, Xavier; Márquez, Cristina; Armario, Antonio

2004-10-05

We have previously observed that a single exposure to immobilization (IMO), a severe stressor, caused long-term (days to weeks) desensitization of the response of the hypothalamic-pituitary-adrenal (HPA) axis to the homotypic stressor, with no changes in behavioral reactivity to novel environments. In contrast, other laboratories have reported that a single exposure to footshock induced a long-term sensitization of both HPA and behavioral responses to novel environments. To test whether these apparent discrepancies can be explained by the use of different stressors or different strains of rats, we studied in the present work the long-term effects of a single exposure to two different stressors (footshock or IMO) in two different strains of rats (Sprague-Dawley from Iffa-Credo and Wistar rats from Harlan). We found that both strains showed desensitization of the HPA response to the same (homotypic) stressor after a previous exposure to either shock or IMO. The long-term effects were higher after IMO than shock. No major changes in behavior in two novel environments (circular corridor, CC and elevated plus-maze, EPM) were observed after a single exposure to shock or IMO in neither strain, despite the fact that shocked rats showed a conditioned freezing response to the shock boxes. The present results demonstrate that long-term stress-induced desensitization of the HPA axis is a reliable phenomenon that can be observed with different stressors and strains. However, only behavioral changes related to shock-induced conditioned fear were found, which suggests that so far poorly characterized factors are determining the long-term behavioral consequences of a single exposure to stress.

Bisphenol A Alters Autonomic Tone and Extracellular Matrix Structure and Induces Sex-Specific Effects on Cardiovascular Function in Male and Female CD-1 Mice

PubMed Central

Gear, Robin B.; Kendig, Eric L.

2015-01-01

The aim of this study was to determine whether bisphenol A (BPA) has adverse effects on cardiovascular functions in CD-1 mice and define sex-specific modes of BPA action in the heart. Dams and analyzed progeny were maintained on a defined diet containing BPA (0.03, 0.3, 3, 30, or 300 ppm) that resulted in BPA exposures from 4–5 to approximately 5000 μg/kg · d or a diet containing 17α-ethinyl estradiol (EE; ∼0.02, 0.2, and 0.15 μg/kg · d) as an oral bioavailable estrogen control. Assessment of electrocardiogram parameters using noninvasive methods found that ventricular functions in both male and female mice were not altered by either BPA or EE. However, exposure-related changes in the rates of ventricular contraction, suggestive of a shift in sympathovagal balance of heart rate control toward increased parasympathetic activity, were detected in males. Decreased systolic blood pressure was observed in males exposed to BPA above 5 μg/kg · d and in females from the highest BPA exposure group. Morphometric histological measures revealed sexually dimorphic changes in the composition of the cardiac collagen extracellular matrix, increases in fibrosis, and evidence of modest exposure-related remodeling. Experiments using the α-selective adrenergic agonist phenylephrine found that BPA enhanced reflex bradycardia in females, but not males, revealed that BPA and EE exposure sex specifically altered the sympathetic regulation of the baroreflex circuits. Increased sensitivity to the cardiotoxic effects of the β-adrenergic agonist isoproterenol was observed in BPA- and EE-exposed females. This effect was not observed in males, in which BPA or EE exposures were protective of isoproterenol-induced ischemic damage and hypertrophy. The results of RNA sequence analysis identified significant sex-specific changes in gene expression in response to BPA that were consistent with the observed exposure-related phenotypic changes in the collagenous and noncollagenous extracellular matrix, cardiac remodeling, altered autonomic responses, changes in ion channel and transporter functions, and altered glycolytic and lipid metabolism. PMID:25594700

Effects of Didecyldimethylammonium Chloride on Sprague-Dawley Rats after Two Weeks of Inhalation Exposure

PubMed Central

Chung, Yong-Hyun

2014-01-01

Didecyldimethylammonium chloride (DDAC) is used for various purposes, such as a fungicide for coolants, an antiseptic for wood, and disinfectant for cleaning. Despite the increasing likelihood of DDAC inhalation, available data on its toxicity from inhalation are scarce. Therefore, this study was aimed at confirming the toxicity of DDAC after inhalation exposure for 2 wk. Male Sprague-Dawley rats were exposed to approximately 0.15 mg/m3, 0.6 mg/m3, and 3.6 mg/m3 DDAC aerosols in whole-body exposure chambers. After DDAC exposure for 2 wk, effects of DDAC on body weight, blood, bronchoalveolar lavage (BAL), and the lungs were verified. The mass median aerodynamic diameter of DDAC aerosols was 1.86 μm and the geometric standard deviation was 2.75. The concentrations of DDAC aerosols for the low, medium, and high groups were 0.15 ± 0.15 mg/m3, 0.58 ± 0.40 mg/m3, and 3.63 ± 1.56 mg/m3, respectively. Body weight gain was significantly influenced by DDAC exposure. In the high group, a body weight decrease of 2.6 g was observed, whereas a 25.8 g increase was observed in the normal control group after the first 3 days. The low and medium groups showed 23.3 g and 20.4 g increases, respectively, after the first 3 days. Decreases in body weight were recovered during the next 4 days. In contrast, no changes were noted in hematological and blood biochemistry parameters after DDAC exposure. Furthermore, only mild effects were observed on bronchoalveolar cell differentiation counts and cell damage parameters in the BAL fluids of the medium and high groups. Although inflammatory cell infiltration and interstitial pneumonia were partially observed, fibrosis was not found in the lungs of the medium and high groups. In conclusion, body weight gain and the lungs were mainly affected by DDAC exposure. The noobserved-adverse-effect level (NOAEL) for DDAC was determined as 0.15 mg/m3. PMID:25343015

Effects of Nd:YAG and CO2 lasers on cerebral microvasculature. Study in normal rabbit brain.

PubMed

Kuroiwa, T; Tsuyumu, M; Takei, H; Inaba, Y

1986-01-01

The effect of Nd:YAG and CO2 laser beams on cerebral microvasculature was examined in experimental animals. Soft x-ray microangiography and histological examination of the brain after Nd:YAG laser exposure revealed broad avascular or oligovascular zones in the irradiated and the surrounding edematous tissue, in which the surviving vessels were narrowed and tapered without significant leakage of blood. After CO2 laser exposure, a wedge-shaped tissue defect surrounded by layers of charring, coagulation, and edema was observed. The main finding in the surrounding coagulation and edematous layers was dilatation of the vessels. Hemorrhage was sometimes observed, mainly in the edematous layer. These findings seem to explain the effective hemostatic capability of the Nd:YAG laser and the occasional hemorrhage following CO2 laser exposure, especially at high energy output.

The Effects of Child Abuse and Exposure to Domestic Violence on Adolescent Internalizing and Externalizing Behavior Problems.

PubMed

Moylan, Carrie A; Herrenkohl, Todd I; Sousa, Cindy; Tajima, Emiko A; Herrenkohl, Roy C; Russo, M Jean

2010-01-01

This study examines the effects of child abuse and domestic violence exposure in childhood on adolescent internalizing and externalizing behaviors. Data for this analysis are from the Lehigh Longitudinal Study, a prospective study of 457 youth addressing outcomes of family violence and resilience in individuals and families. Results show that child abuse, domestic violence, and both in combination (i.e., dual exposure) increase a child's risk for internalizing and externalizing outcomes in adolescence. When accounting for risk factors associated with additional stressors in the family and surrounding environment, only those children with dual exposure had an elevated risk of the tested outcomes compared to non-exposed youth. However, while there were some observable differences in the prediction of outcomes for children with dual exposure compared to those with single exposure (i.e., abuse only or exposure to domestic violence only), these difference were not statistically significant. Analyses showed that the effects of exposure for boys and girls are statistically comparable.

Effects of tobacco smoke exposure on asthma prevalence and medical care use in North Carolina middle school children.

PubMed

Sturm, Jesse J; Yeatts, Karin; Loomis, Dana

2004-02-01

We sought to determine the effects of exposure to environmental tobacco smoke (ETS) and childhood cigarette smoking on asthma symptoms among middle school children in North Carolina. During 1999-2000, information was collected from a survey completed by the children. Outcomes of asthma symptom reporting were regressed on tobacco smoke exposures. Children who currently smoked or reported any exposure to ETS were at increased risk of reporting active asthma symptoms. Exposure to ETS and childhood cigarette smoking was responsible for 15% of the asthma cases observed in the study population and $1.34 million in excess medical expenditures. Even at low levels of exposure, childhood cigarette smoking and ETS are independently associated with asthmatic symptoms.

Response of single bacterial cells to stress gives rise to complex history dependence at the population level

PubMed Central

Mathis, Roland; Ackermann, Martin

2016-01-01

Most bacteria live in ever-changing environments where periods of stress are common. One fundamental question is whether individual bacterial cells have an increased tolerance to stress if they recently have been exposed to lower levels of the same stressor. To address this question, we worked with the bacterium Caulobacter crescentus and asked whether exposure to a moderate concentration of sodium chloride would affect survival during later exposure to a higher concentration. We found that the effects measured at the population level depended in a surprising and complex way on the time interval between the two exposure events: The effect of the first exposure on survival of the second exposure was positive for some time intervals but negative for others. We hypothesized that the complex pattern of history dependence at the population level was a consequence of the responses of individual cells to sodium chloride that we observed: (i) exposure to moderate concentrations of sodium chloride caused delays in cell division and led to cell-cycle synchronization, and (ii) whether a bacterium would survive subsequent exposure to higher concentrations was dependent on the cell-cycle state. Using computational modeling, we demonstrated that indeed the combination of these two effects could explain the complex patterns of history dependence observed at the population level. Our insight into how the behavior of single cells scales up to processes at the population level provides a perspective on how organisms operate in dynamic environments with fluctuating stress exposure. PMID:26960998

Effects of air ions on the neonatal growth of laboratory rats

NASA Astrophysics Data System (ADS)

Hinsull, S. M.; Bellamy, D.; Head, E. L.

1981-12-01

The effect of continuous positive and negative ionization on the growth of rats during the pre and post natal period, up to 10 weeks of age was investigated. It was found that continuous exposure to 1.0×104 pos. ions/ml had no detrimental effect on the animals at any stage of their development. In contrast, exposure to 1.0×104 neg. ions/ml, during gestation and the early post natal period, resulted in some adverse effects on growth and development. However, when exposure to this level of negative ions began at the time of weaning, no adverse effects were observed.

Operational Prototype Development of a Global Aircraft Radiation Exposure Nowcast

NASA Astrophysics Data System (ADS)

Mertens, Christopher; Kress, Brian; Wiltberger, Michael; Tobiska, W. Kent; Bouwer, Dave

Galactic cosmic rays (GCR) and solar energetic particles (SEP) are the primary sources of human exposure to high linear energy transfer (LET) radiation in the atmosphere. High-LET radiation is effective at directly breaking DNA strands in biological tissue, or producing chemically active radicals in tissue that alter the cell function, both of which can lead to cancer or other adverse health effects. A prototype operational nowcast model of air-crew radiation exposure is currently under development and funded by NASA. The model predicts air-crew radiation exposure levels from both GCR and SEP that may accompany solar storms. The new air-crew radiation exposure model is called the Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) model. NAIRAS will provide global, data-driven, real-time exposure predictions of biologically harmful radiation at aviation altitudes. Observations are utilized from the ground (neutron monitors), from the atmosphere (the NCEP Global Forecast System), and from space (NASA/ACE and NOAA/GOES). Atmospheric observations characterize the overhead mass shielding and the ground-and space-based observations provide boundary conditions on the incident GCR and SEP particle flux distributions for transport and dosimetry calculations. Radiation exposure rates are calculated using the NASA physics-based HZETRN (High Charge (Z) and Energy TRaNsport) code. An overview of the NAIRAS model is given: the concept, design, prototype implementation status, data access, and example results. Issues encountered thus far and known and/or anticipated hurdles to research to operations transition are also discussed.

The cultural transmission of cooperative norms

PubMed Central

Zhou, Xinyue; Liu, Yan; Ho, Benjamin

2015-01-01

Cooperative behavior depends on cultural environment, so what happens when people move from to a new culture governed by a new norm? The dynamics of culture-induced cooperation has not been well understood. We expose lab participants to a sequence of different subject pools while playing a constrained Trust Game. We find prior exposure to different subject pools does in fact influence cooperative behavior; first impressions matter—the primacy effect plays a stronger role than the recency effect; and selfish first impressions matter more than cooperative first impressions—observing selfish behavior by others had a longer-lasting and greater influence on behaviors than observing cooperative behavior by others. Moreover, three consecutive exposures to cooperative environments were needed to neutralize one exposure to a selfish environment. PMID:26578993

Measures of fish behavior as indicators of sublethal toxicosis during standard toxicity tests

USGS Publications Warehouse

Little, E.E.; DeLonay, A.J.

1996-01-01

Behavioral functions essential for growth and survival can be dramatically altered by sublethal exposure to toxicants. Measures of these behavioral responses are effective in detecting adverse effects of sublethal contaminant exposure. Behavioral responses of fishes can be qualitatively and quantitatively evaluated during routine toxicity tests. At selected intervals of exposure, qualitative evaluations are accomplished through direct observations, whereas video recordings are used for quantitative evaluations. Standardized procedures for behavioral evaluation are readily applicable to different fish species and provide rapid, sensitive, and ecologically relevant assessments of sublethal exposure. The methods are readily applied to standardized test protocols.

Differential behavioral effects of nicotine in adult male and female rats with a history of prenatal methamphetamine exposure.

PubMed

Rorabaugh, Boyd; Seeley, Sarah; Evans, Mary; Marengo, Christina; D'Souza, Manoranjan

2017-06-09

The goal of the current study was to assess the effects of prenatal methamphetamine (MA)/saline exposure on nicotine-induced stimulant and aversive effects in both male and female adult rats. The aversive effects of nicotine were assessed using the nicotine-induced conditioned taste aversion model (0.4mg/kg, base), while the stimulant effects of nicotine were measured by assessing changes in spontaneous locomotor activity after subcutaneous administration of different doses of nicotine (0, 0.1 & 0.4mg/kg, base). The aversive effects of nicotine were significantly decreased in male, but not in female rats with a history of prenatal MA exposure compared to respective saline controls. No influence of prenatal MA exposure was observed on nicotine-induced increase in locomotor activity in either male or female rats. In conclusion, males with a history of prenatal MA exposure may be more vulnerable to nicotine addiction due to a decrease in nicotine-induced aversive effects. Copyright © 2017 Elsevier B.V. All rights reserved.

Arsenic exposure and its impact on health in Chile.

PubMed

Ferreccio, Catterina; Sancha, Ana María

2006-06-01

The problem of arsenic in Chile was reviewed. In Chile, the population is exposed to arsenic naturally via drinking-water and by air pollution resulted from mining activities. The sources of arsenic were identified to estimate the exposure of population to arsenic through air, water, and food. Health effects, particularly early effects, observed in children and adults, such as vascular diseases (premature cardiac infarct), respiratory illnesses (bronchiectasis), and skin lesions have been described. Chronic effects, such as lung and bladder cancers, were reported 20 years after peak exposure and persisted 27 years after mitigation measures for removing arsenic from drinking surface water were initiated. Although the effects of arsenic are similar in different ethnic and cultural groups (e.g. Japanese, Chinese, Indian, Bangladeshi, American, and Taiwanese), variations could be explained by age at exposure, the dose received, smoking, and nutrition. Since health effects were observed at arsenic levels of 50 microg/L in drinking-water, it is advised that Chile follows the World Health Organization's recommendation of 10 microg/L. The Chilean experience in removal of arsenic suggests that it is feasible to reach this level using the conventional coagulation process.

Human exposures to tilmicosin reported to poison centres, Texas, 1998-2003.

PubMed

Forrester, Mathias B

2005-05-01

Tilmicosin, or 20-deoxo-20-(3,5-dimethylpiperidin-1-yl)-desmycosin, is a macrolide antibiotic primarily utilized in livestock. This study examined 46 human exposure calls involving tilmicosin received by Texas poison centres during 1998-2003. The majority (91%) of the calls were received from northern and central Texas. All of the cases were unintentional exposures. The most frequent route of exposure was parenteral (48%). The majority of the patients were males (80%) and adults (84%). Only 46% of the patients were managed outside of health care facilities. Some sort of adverse medical outcome was reported in 93% of parenteral exposures and 54% of other-route exposures. However, only 21% of parenteral exposures and 15% of other-route exposures involved medical outcomes that were judged to be moderate or worse. No deaths were reported. The most frequently reported clinical effects among parenteral cases were dermal (79%), while only 9% of other-route exposures had dermal effects. Cardiovascular clinical effects were observed in a single case of parenteral exposure and a single case of other-route exposure. Although the majority of cases were managed with the assistance of health care facilities, the medical outcomes were usually not serious. Outcome depended on the route of exposure.

Assessing Spatial and Temporal Variability of VOCs and PM-Components in Outdoor Air during the Detroit Exposure and Aerosol Research Study (DEARS)

EPA Science Inventory

Exposure models for air pollutants often adjust for effects of the physical environment (e.g., season, urban vs. rural populations) in order to improve exposure and risk predictions. Yet attempts are seldom made to attribute variability in observed outdoor air measurements to spe...

Foetal Antiepileptic Drug Exposure and Verbal versus Non-Verbal Abilities at Three Years of Age

ERIC Educational Resources Information Center

Meador, Kimford J.; Baker, Gus A.; Browning, Nancy; Cohen, Morris J.; Clayton-Smith, Jill; Kalayjian, Laura A.; Kanner, Andres; Liporace, Joyce D.; Pennell, Page B.; Privitera, Michael; Loring, David W.

2011-01-01

We previously reported that foetal valproate exposure impairs intelligence quotient. In this follow-up investigation, we examined dose-related effects of foetal antiepileptic drug exposure on verbal and non-verbal cognitive measures. This investigation is an ongoing prospective observational multi-centre study in the USA and UK, which has enrolled…

Insensitivity of cardiovascular function to low power cm-/mm-microwaves.

PubMed

Kantz, J; Müller, J; Hadeler, K P; Landstorfer, F M; Lang, F

2005-06-01

A previous study failed to disclose an effect of short (15 min) exposure to low level energy microwaves (3 microW/cm2) emitted by a commercially available automobile radar system (77 GHz) for adaptive cruise control (ACC) on cardiovascular function. The present study explored whether a 15 min exposure to higher level energy microwaves of frequencies varying from 5.8 to 110 GHz influences cardiovascular function. To this end heart rate, skin temperature (thermocouple), skin conductance (Ag/AgCl electrodes), systolic and diastolic blood pressure (automatic cuff) were recorded in 50 test persons before, during and after a 15 min exposure to a sequential pattern of microwaves varying from 5.8 to 110 GHz (59.7 microW/cm2). After an equilibration period of 30 min the first group of test persons and after additional 30 min the second group of test persons were exposed. The study has been performed in a strict double blind design. While significant effects on the measured parameters were observed depending on time ("calming" effect), no significant difference was observed between exposure and sham exposure to microwaves. In view of the small scatter of the data the present study rules out physiologically relevant effects of moderate energy (59.7 microW/cm2) microwaves varying from 5.8 to 110 GHz on cardiovascular function.

[Exposure to liquid detergent capsules: a study of the cases reported to the Paris Poison Center, 2011-2012].

PubMed

Villa, A; Médernach, C; Arropetian, N; Lagrange, F; Langrand, J; Garnier, R

2014-06-01

To evaluate the toxicity of liquid detergent capsules for children. Analysis of 684 consecutive cases from the Paris Poison Center (2011-2012). Most enquiries (97 %) concerned children 5 years of age or younger. The main circumstances of exposure were ingestion alone (72.4 %) or together with eye or skin contact (7.5 % and 7.3 %, respectively). The effects observed were generally due to the irritating properties of concentrated detergents: minor digestive disturbances (particularly vomiting in nearly 50 % of cases) after ingestion and conjunctivitis and/or keratitis after eye contact. The main complications were 24 cases of keratitis and one case of pulmonary toxicity after ingestion. A rash was observed in nine patients; it was delayed in two. The effects observed with liquid detergent capsules were very similar to those resulting from exposure to other detergents. However, exposure to these agents are very frequent and often results in eye contact, which may be responsible for keratitis, and after ingestion detergent inhalation is a possible complication. All cases with eye symptoms or cough after liquid detergent capsule exposure deserve prompt medical examination and assistance. Greater awareness of both health professionals and consumers on the dangers and risks of these laundry detergent pods is required for better treatment of exposure accidents and for their prevention. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Chemical Risk Assessment: Traditional vs Public Health ...

EPA Pesticide Factsheets

Preventing adverse health impacts from exposures to environmental chemicals is fundamental to protecting individual and public health. When done efficiently and properly, chemical risk assessment enables risk management actions that minimize the incidence and impacts of environmentally-induced diseases related to chemical exposure. However, traditional chemical risk assessment is faced with multiple challenges with respect to predicting and preventing disease in human populations, and epidemiological studies increasingly report observations of adverse health effects at exposure levels predicted from animal studies to be safe for humans. This discordance reinforces concerns about the adequacy of contemporary risk assessment practices (Birnbaum, Burke, & Jones, 2016) for protecting public health. It is becoming clear that to protect public health more effectively, future risk assessments will need to use the full range of available data, draw on innovative methods to integrate diverse data streams, and consider health endpoints that also reflect the range of subtle effects and morbidities observed in human populations. Given these factors, there is a need to reframe chemical risk assessment to be more clearly aligned with the public health goal of minimizing environmental exposures associated with disease. Preventing adverse health impacts from exposures to environmental chemicals is fundamental to protecting individual and public health. Chemical risk assessments

Effects of binge-like ethanol exposure during adolescence on the hyperalgesia observed during sickness syndrome in rats.

PubMed

de Oliveira, Bruna M T; Telles, Tatiane M B B; Lomba, Luiz A; Correia, Diego; Zampronio, Aleksander R

2017-09-01

Acute and chronic ethanol exposure increases the risk of infection by altering the innate host's defense system. Adolescence is a critical period for brain development. Insults during this period may have long-lasting consequences. The present study investigated the effects of binge-like ethanol exposure in adolescent rats on mechanical hyperalgesia during sickness syndrome that was induced by a systemic injection of lipopolysaccharide (LPS) or an intracerebroventricular (i.c.v.) injection of interleukin-1β (IL-1β) after the cessation of ethanol exposure. Male Wistar rats were exposed to ethanol from postnatal day (PND) 25 to PND 38 in a binge-like pattern. Hyperalgesia was assessed on the right hindpaw after an intraperitoneal injection of LPS (5 and 50μg/kg, intraperitoneally) on PND 51 and PND 63 or an i.c.v. or intraplantar (i.pl.) injection of IL-β (3 and 1ng, respectively) on PND 51. Ethanol exposure during adolescence did not alter mechanical thresholds which increased normally with age. The systemic injection of LPS (0.5-50μg/kg) in adult rats induced dose-related mechanical hyperalgesia. Binge-like ethanol exposure significantly increased mechanical hyperalgesia that was induced by 50μg/kg LPS on PND 51 and 63, which lasted until 24h after the injection. This change was not observed at a lower dose of LPS (5μg/kg). Acute oral treatment with ethanol 24h prior to LPS administration did not alter mechanical hyperalgesia. The i.c.v. injection of IL-1β (1-10ng) also induced dose-related mechanical hyperalgesia in the right hindpaw in non-exposed animals. In animals that were exposed to binge-like ethanol, the i.c.v. or i.pl. injection of IL-1β also increased hyperalgesia on PND 51. These results suggest that binge-like ethanol exposure during adolescence causes alterations in the central nervous system that can increase mechanical hyperalgesia that is observed during sickness syndrome, and this effect can be observed until adulthood after the cessation of ethanol exposure. Copyright © 2017 Elsevier Inc. All rights reserved.

Cardio-autonomic control and wellbeing due to oscillating color light exposure.

PubMed

Grote, Vincent; Kelz, Christina; Goswami, Nandu; Stossier, Harald; Tafeit, Erwin; Moser, Maximilian

2013-04-10

We investigated the cardio-autonomic and psychological effects of colored light cycling with the wavelength of ultradian rhythms. In two consecutive experiments, an explorative, longitudinal test followed by a randomized crossover design, 20 healthy subjects each were exposed to oscillating red, green and blue light. Heart rate, heart rate variability (HRV) and subjective wellbeing were measured. Significant effects of the oscillating color light exposure were observed for heart rate and cardio-autonomic control rhythms, derived from HRV (p≤.001). These effects on HRV were replicated in the second experiment in comparison to a similar white light exposure protocol (p≤.05). Vigilance showed improvement over the two weeks (p≤.001) in the longitudinal study. External color light cycling at the wavelength of blood pressure oscillations appears to amplify the endogenous autonomic oscillations. This leads to an optimization of cardio-autonomic control; an effect that was reflected shortly after the onset of the light exposure sessions by the increase of heart rate variability. From the results, we conclude that it takes repeated light exposure session to foster the positive effects on the psychological aspects, as we observed an increase of subjectively perceived mood only in the longitudinal study, not for the crossover design study. The results of our study imply some possible health effects of a color light exposure that is adjusted to 10 s and 1 min oscillations of humans' ultradian rhythms. These novel results show possible applications of oscillating visual inputs to the activation of processes connected to physiological regulation. Copyright © 2013 Elsevier Inc. All rights reserved.

Multifactorial analysis of human blood cell responses to clinical total body irradiation

NASA Technical Reports Server (NTRS)

Yuhas, J. M.; Stokes, T. R.; Lushbaugh, C. C.

1972-01-01

Multiple regression analysis techniques are used to study the effects of therapeutic radiation exposure, number of fractions, and time on such quantal responses as tumor control and skin injury. The potential of these methods for the analysis of human blood cell responses is demonstrated and estimates are given of the effects of total amount of exposure and time of protraction in determining the minimum white blood cell concentration observed after exposure of patients from four disease groups.

Comparison of self-reported and observed water contact in an S. mansoni endemic village in Brazil.

PubMed

Friedman, J F; Kurtis, J D; McGarvey, S T; Fraga, A L; Silveira, A; Pizziolo, V; Gazzinelli, G; LoVerde, P; Corrêa-Oliveira, R

2001-03-30

Estimates of exposure are critical for immuno-epidemiologic and intervention studies in human schistosomiasis. Direct observation of human water contact patterns is both costly and time consuming. To address these issues, we determined whether individuals residing in a Schistosoma mansoni endemic village in Brazil could accurately self-report their water contact patterns. We compared the results of a water contact questionnaire to the present gold standard, direct observation of water contact in 86 volunteers, aged 8--29. We administered a survey to estimate volunteers' frequency and type of water contact and directly measured each volunteers' water contact patterns during 5 weeks of detailed water contact observations. We found a poor correlation between self reported frequency of contact and directly observed exposure (rho=0.119, P=NS). The questionnaire data was supplemented by information about average body surface area of exposure and duration of contact for specific activities derived from observations of this cohort. This 'supplemented questionnaire' data was significantly correlated with their exposure index (rho=0.227, P=0.05). It provides a starting point from which questionnaires may develop to provide a more cost-effective and less labor intensive method of assessing water contact exposure at the level of the individual.

Prenatal exposure to radiofrequencies: effects of WiFi signals on thymocyte development and peripheral T cell compartment in an animal model.

PubMed

Laudisi, Federica; Sambucci, Manolo; Nasta, Francesca; Pinto, Rosanna; Lodato, Rossella; Altavista, Pierluigi; Lovisolo, Giorgio Alfonso; Marino, Carmela; Pioli, Claudio

2012-12-01

Wireless local area networks are an increasing alternative to wired data networks in workplaces, homes, and public areas. Concerns about possible health effects of this type of signal, especially when exposure occurs early in life, have been raised. We examined the effects of prenatal (in utero) exposure to wireless fidelity (WiFi) signal-associated electromagnetic fields (2450 MHz center-frequency band) on T cell development and function. Pregnant mice were exposed whole body to a specific absorption rate of 4 W/kg, 2 h per day, starting 5 days after mating and ending 1 day before the expected delivery. Sham-exposed and cage control groups were used as controls. No effects on cell count, phenotype, and proliferation of thymocytes were observed. Also, spleen cell count, CD4/CD8 cell frequencies, T cell proliferation, and cytokine production were not affected by the exposure. These findings were consistently observed in the male and female offspring at early (5 weeks of age) and late (26 weeks of age) time points. Nevertheless, the expected differences associated with aging and/or gender were confirmed. In conclusion, our results do not support the hypothesis that the exposure to WiFi signals during prenatal life results in detrimental effects on the immune T cell compartment. Copyright © 2012 Wiley Periodicals, Inc.

Screen Media Exposure and Obesity in Children and Adolescents.

PubMed

Robinson, Thomas N; Banda, Jorge A; Hale, Lauren; Lu, Amy Shirong; Fleming-Milici, Frances; Calvert, Sandra L; Wartella, Ellen

2017-11-01

Obesity is one of the best-documented outcomes of screen media exposure. Many observational studies find relationships between screen media exposure and increased risks of obesity. Randomized controlled trials of reducing screen time in community settings have reduced weight gain in children, demonstrating a cause and effect relationship. Current evidence suggests that screen media exposure leads to obesity in children and adolescents through increased eating while viewing; exposure to high-calorie, low-nutrient food and beverage marketing that influences children's preferences, purchase requests, consumption habits; and reduced sleep duration. Some evidence also suggests promise for using interactive media to improve eating and physical activity behaviors to prevent or reduce obesity. Future interdisciplinary research is needed to examine the effects of newer mobile and other digital media exposures on obesity; to examine the effectiveness of additional interventions to mitigate the adverse effects of media exposures on obesity and possible moderators and mediators of intervention effects; to effectively use digital media interventions to prevent and reduce obesity; and to uncover the mechanisms underlying the causal relationships and interactions between obesity-related outcomes and media content, characteristics, and context. Copyright © 2017 by the American Academy of Pediatrics.

The after-effects of hypoxia exposure on the clam Ruditapes philippinarum in Omaehama beach, Japan

NASA Astrophysics Data System (ADS)

Kozuki, Yasunori; Yamanaka, Ryoichi; Matsushige, Maya; Saitoh, Azusa; Otani, Sosuke; Ishida, Tatsunori

2013-01-01

A number of reports describe the impact of hypoxic conditions on the manila clam Ruditapes philippinarum, but few deal with the after-effects of hypoxia on this clam species. Exposure experiments were carried out on the manila clam under conditions of low dissolved oxygen (DO, 0.5 mg/L). In the first exposure experiment (i.e., 3 days of hypoxia), a substantial change in mortality rate, glycogen content, and clearance rate was not observed in the period following the hypoxia. However, in the second exposure experiment (i.e., an additional 3 days of hypoxia following recovery from the first exposure), the mortality rate was significantly increased relative to that of the first exposure experiment, and glycogen content underwent a long-term decline. At the end of the experimental period, subsequent to the 2 exposures to hypoxia, the clearance rate had decreased until it was 77% of that of the normal manila clams unexposed to hypoxia. Moreover, the clearance rate was unable to recover following the second exposure. Thus, when the manila clams were repeatedly exposed to hypoxic conditions, the surviving individuals showed a residual disability, as reflected in the increased mortality and unrecovered clearance capacity. Afterward, the after-effects of hypoxia exposure on the clearance function of the manila clams in Omaehama beach, Japan, were assessed using the experimental results and the observed data. An examination of the effects of the residual disability showed a more extensive decrease in filtering capacity when a formula accounting for residual disability was used rather than a standard one. The clearance volume using our new formula was 75% of that of a standard formula. The formula equations that have been used up until now have only evaluated whether the manila clams die. However, the surviving individuals have a residual disability, and our formula indicates this effect would cause a further decline in the purification function of the beach.

Effects of waterborne exposure to 4-nonylphenol and nonylphenol ethoxylate on secondary sex characteristics and gonads of fathead minnows (Pimephales promelas)

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

Miles-Richardson, S.R.; Pierens, S.L.; Nichols, K.M.

1999-02-01

Fathead minnows were exposed to 4-nonylphenol (NP) or nonylphenol ethoxylate (NPEO) to determine the effects of these weak estrogen agonists on secondary sex characteristics and gonads of sexually mature males and females during 42-day continuous-flow exposures. Neither NP nor NPEO caused statistically significant effects on tubercles or fatpad size at the concentrations tested. Exposure to 1.1 or 3.4 {micro}g NP.L caused changes in the number and size of Sertoli cells and germ cell syncytia. Necrotic aggregates of various stages of germ cells in the spermatogenic sequence were observed in the testes of males exposed to NP. Electron microscopy of themore » testes of NP-exposed males revealed the presence of phagocytic cells in the lumina of seminiferous tubules. The cytoplasm of some Sertoli cells was distended with myelin figures and necrotic spermatozoa. No significant effects on the stages of follicular development were observed in females exposed to NP. There were no differences in the gonads or secondary sex characteristics of males or females exposed to 5.5 {micro}g NPEO/L, the greatest concentration studied. The histologic responses observed are sensitive indicators of waterborne exposure to NP at environmentally relevant concentrations, but not as sensitive as induction of plasma vitellogenin.« less

The mere exposure effect is differentially sensitive to different judgment tasks.

PubMed

Seamon, J G; McKenna, P A; Binder, N

1998-03-01

The mere exposure effect is the increase in positive affect that results from the repeated exposure to previously novel stimuli. We sought to determine if judgments other than affective preference could reliably produce a mere exposure effect for two-dimensional random shapes. In two experiments, we found that brighter and darker judgments did not differentiate target from distracter shapes, liking judgments led to target selection greater than chance, and disliking judgments led to distracter selection greater than chance. These results for brighter, darker, and liking judgments were obtained regardless of whether shape recognition was greater (Experiment 1) or not greater (Experiment 2) than chance. Effects of prior exposure to novel shapes were reliably observed only for affective judgment tasks. These results are inconsistent with general predictions made by the nonspecific activation hypothesis, but not the affective primacy or perceptual fluency hypotheses which were discussed in terms of cognitive neuroscience research. Copyright 1998 Academic Press.

Effect of short-term stainless steel welding fume inhalation exposure on lung inflammation, injury, and defense responses in rats.

PubMed

Antonini, James M; Stone, Sam; Roberts, Jenny R; Chen, Bean; Schwegler-Berry, Diane; Afshari, Aliakbar A; Frazer, David G

2007-09-15

Many welders have experienced bronchitis, metal fume fever, lung function changes, and an increase in the incidence of lung infection. Questions remain regarding the possible mechanisms associated with the potential pulmonary effects of welding fume exposure. The objective was to assess the early effects of stainless steel (SS) welding fume inhalation on lung injury, inflammation, and defense responses. Male Sprague-Dawley rats were exposed to gas metal arc-SS welding fume at a concentration of 15 or 40 mg/m(3) x 3 h/day for 1, 3, or 10 days. The control group was exposed to filtered air. To assess lung defense responses, some animals were intratracheally inoculated with 5x10(4) Listeria monocytogenes 1 day after the last exposure. Welding particles were collected during exposure, and elemental composition and particle size were determined. At 1, 4, 6, 11, 14, and 30 days after the final exposure, parameters of lung injury (lactate dehydrogenase and albumin) and inflammation (PMN influx) were measured in the bronchoalveolar lavage fluid. In addition, particle-induced effects on pulmonary clearance of bacteria and macrophage function were assessed. SS particles were composed of Fe, Cr, Mn, and Ni. Particle size distribution analysis indicated the mass median aerodynamic diameter of the generated fume to be 0.255 microm. Parameters of lung injury were significantly elevated at all time points post-exposure compared to controls except for 30 days. Interestingly, no significant difference in lung PMNs was observed between the SS and control groups at 1, 4, and 6 days post-exposure. After 6 days post-exposure, a dramatic increase in lung PMNs was observed in the SS group compared to air controls. Lung bacteria clearance and macrophage function were reduced and immune and inflammatory cytokines were altered in the SS group. In summary, short-term exposure of rats to SS welding fume caused significant lung damage and suppressed lung defense responses to bacterial infection, but had a delayed effect on pulmonary inflammation. Additional chronic inhalation studies are needed to further examine the lung effects associated with SS welding fume exposure.

Effect of short-term stainless steel welding fume inhalation exposure on lung inflammation, injury, and defense responses in rats

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

Antonini, James M.; Stone, Sam; Roberts, Jenny R.

Many welders have experienced bronchitis, metal fume fever, lung function changes, and an increase in the incidence of lung infection. Questions remain regarding the possible mechanisms associated with the potential pulmonary effects of welding fume exposure. The objective was to assess the early effects of stainless steel (SS) welding fume inhalation on lung injury, inflammation, and defense responses. Male Sprague-Dawley rats were exposed to gas metal arc-SS welding fume at a concentration of 15 or 40 mg/m{sup 3} x 3 h/day for 1, 3, or 10 days. The control group was exposed to filtered air. To assess lung defense responses,more » some animals were intratracheally inoculated with 5 x 10{sup 4}Listeria monocytogenes 1 day after the last exposure. Welding particles were collected during exposure, and elemental composition and particle size were determined. At 1, 4, 6, 11, 14, and 30 days after the final exposure, parameters of lung injury (lactate dehydrogenase and albumin) and inflammation (PMN influx) were measured in the bronchoalveolar lavage fluid. In addition, particle-induced effects on pulmonary clearance of bacteria and macrophage function were assessed. SS particles were composed of Fe, Cr, Mn, and Ni. Particle size distribution analysis indicated the mass median aerodynamic diameter of the generated fume to be 0.255 {mu}m. Parameters of lung injury were significantly elevated at all time points post-exposure compared to controls except for 30 days. Interestingly, no significant difference in lung PMNs was observed between the SS and control groups at 1, 4, and 6 days post-exposure. After 6 days post-exposure, a dramatic increase in lung PMNs was observed in the SS group compared to air controls. Lung bacteria clearance and macrophage function were reduced and immune and inflammatory cytokines were altered in the SS group. In summary, short-term exposure of rats to SS welding fume caused significant lung damage and suppressed lung defense responses to bacterial infection, but had a delayed effect on pulmonary inflammation. Additional chronic inhalation studies are needed to further examine the lung effects associated with SS welding fume exposure.« less

Effects of methyl mercury exposure on the growth of juvenile common loons

USGS Publications Warehouse

Kenow, K.P.; Gutreuter, S.; Hines, R.K.; Meyer, M.W.; Fournier, F.; Karasov, W.H.

2003-01-01

We conducted a dose-response laboratory study to quantify the level of mercury exposure associated with negative effects on the development of common loon chicks reared in captivity from hatch to 105 days. A dose regimen was implemented that provided exposure levels that bracketed relevant exposure levels of methyl mercury found in loon chicks across North America. We observed no overt signs of mercury toxicosis and detected no significant effect of dietary mercury exposure on growth or food consumption. However, asymptotic mass was lower in chicks that hatched from eggs collected from nests on low pH lakes relative to eggs from neutral pH lakes. Rapid excretion of methyl mercury during feather growth likely provides loon chicks protection from methyl mercury toxicity and may explain the lack of convincing toxicological findings in this study. Lake-source effects suggest that in ovo exposure to methyl mercury or other factors related to lake pH have consequences on chick development.

Vulnerability of the neural circuitry underlying sexual behavior to chronic adult exposure to oral bisphenol a in male mice.

PubMed

Picot, Marie; Naulé, Lydie; Marie-Luce, Clarisse; Martini, Mariangela; Raskin, Kalina; Grange-Messent, Valérie; Franceschini, Isabelle; Keller, Matthieu; Mhaouty-Kodja, Sakina

2014-02-01

There are human reproduction concerns associated with extensive use of bisphenol A (BPA)-containing plastic and, in particular, the leaching of BPA into food and beverages. In this context, it remains unclear whether and how exposure to BPA interferes with the developmental organization and adult activation of male sexual behavior by testosterone. We evaluated the developmental and adult exposure to oral BPA at doses equivalent to the no-observed-adverse-effect-level (5 mg/kg body weight per day) and tolerable daily intake (TDI) (50 μg/kg body weight per day) on mouse sexual behavior and the potential mechanisms underlying BPA effects. Adult exposure to BPA reduced sexual motivation and performance at TDI dose only. Exposed males took longer to initiate mating and reach ejaculation despite normal olfactory chemoinvestigation. This deficiency was not restored by sexual experience and was associated with unchanged circulating levels of testosterone. By contrast, developmental exposure to BPA at TDI or no-observed-adverse-effect-level dose did not reduce sexual behavior or alter the neuroanatomical organization of the preoptic area. Disrupting the neural androgen receptor resulted in behavioral and neuroanatomical effects similar to those induced by adult exposure to TDI dose. Moreover, adult exposure of mutant males to BPA at TDI dose did not trigger additional alteration of sexual behavior, suggesting that BPA and neural androgen receptor mutation share a common mechanism of action. This shows, for the first time, that the neural circuitry underlying male sexual behavior is vulnerable to chronic adult exposure to low dose of BPA and suggests that BPA could act in vivo as an antiandrogenic compound.

Phthalate esters and childhood asthma: A systematic review and congener-specific meta-analysis.

PubMed

Li, Ming-Chieh; Chen, Chi-Hsien; Guo, Yue Leon

2017-10-01

Exposure to phthalate esters (PAEs) has been associated with childhood asthma, but the congener-specific effects of PAEs on childhood asthma were unclear. We aimed to systematically review and meta-analyze observational studies on the associations between specific effects of PAEs and the risk of childhood asthma. Relevant studies were identified by searching three databases up to October 20, 2016. The reference lists of the retrieved articles were also reviewed. We included observational studies that reported risk estimates with 95% confidence intervals (CIs) for the associations between phthalate exposure and the risk of childhood asthma. Fixed-effects models were generally applied to calculate pooled risk estimates. When heterogeneity was present, random-effects models were applied. A total of nine studies featuring 43 data points were included in our final meta-analyses. Results indicated that the benzyl butyl phthalate (BBzP) exposure had a significant association with the risk of childhood asthma. The Odd Ratios (ORs) were from 1.39 to 1.41 for different combination strategies. Subgroup analyses by different exposure period or samples used showed that prenatal exposure to BBzP had a stronger association with the risk of childhood asthma (OR = 1.38, 95% CI = 1.09-1.75), compared to those with postnatal exposure. Besides, the association was evident when the phthalate exposure was measured from dust samples. The OR for the associations between di-2-ethylhexyl phthalate (DEHP) in dust and childhood asthma was 2.71 (95% CI = 1.39-5.28), and 2.08 (95% CI = 1.10-3.92) for BBzP. Our study suggested a positive association between DEHP and BBzP exposure and childhood asthma. Future studies are warranted to identify the underlying mechanisms of the association. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mendelian randomization analysis of a time-varying exposure for binary disease outcomes using functional data analysis methods.

PubMed

Cao, Ying; Rajan, Suja S; Wei, Peng

2016-12-01

A Mendelian randomization (MR) analysis is performed to analyze the causal effect of an exposure variable on a disease outcome in observational studies, by using genetic variants that affect the disease outcome only through the exposure variable. This method has recently gained popularity among epidemiologists given the success of genetic association studies. Many exposure variables of interest in epidemiological studies are time varying, for example, body mass index (BMI). Although longitudinal data have been collected in many cohort studies, current MR studies only use one measurement of a time-varying exposure variable, which cannot adequately capture the long-term time-varying information. We propose using the functional principal component analysis method to recover the underlying individual trajectory of the time-varying exposure from the sparsely and irregularly observed longitudinal data, and then conduct MR analysis using the recovered curves. We further propose two MR analysis methods. The first assumes a cumulative effect of the time-varying exposure variable on the disease risk, while the second assumes a time-varying genetic effect and employs functional regression models. We focus on statistical testing for a causal effect. Our simulation studies mimicking the real data show that the proposed functional data analysis based methods incorporating longitudinal data have substantial power gains compared to standard MR analysis using only one measurement. We used the Framingham Heart Study data to demonstrate the promising performance of the new methods as well as inconsistent results produced by the standard MR analysis that relies on a single measurement of the exposure at some arbitrary time point. © 2016 WILEY PERIODICALS, INC.

Younger rats are more susceptible to the lethal effects of sarin than adult rats: 24 h LC50 for whole-body (10 and 60 min) exposures.

PubMed

Wright, Linnzi K M; Lumley, Lucille A; Lee, Robyn B; Taylor, James T; Miller, Dennis B; Muse, William T; Emm, Edward J; Whalley, Christopher E

2017-04-01

Chemical warfare nerve agents (CWNA) inhibit acetylcholinesterase and are among the most lethal chemicals known to man. Children are predicted to be vulnerable to CWNA exposure because of their smaller body masses, higher ventilation rates and immature central nervous systems. While a handful of studies on the effects of CWNA in younger animals have been published, exposure routes relevant to battlefield or terrorist situations (i.e. inhalation for sarin) were not used. Thus, we estimated the 24 h LC 50 for whole-body (10 and 60 min) exposure to sarin using a stagewise, adaptive dose design. Specifically, male and female Sprague-Dawley rats were exposed to a range of sarin concentrations (6.2-44.0 or 1.6-12.5 mg/m³) for either 10 or 60 min, respectively, at six different times during their development (postnatal day [PND] 7, 14, 21, 28, 42 and 70). For male and female rats, the lowest LC 50 values were observed for PND 14 and the highest LC 50 values for PND 28. Sex differences were observed only for PND 42 for the 10 min exposures and PND 21 and 70 for the 60 min exposures. Thus, younger rats (PND 14) were more susceptible than older rats (PND 70) to the lethal effects of whole-body exposure to sarin, while adolescent (PND 28) rats were the least susceptible and sex differences were minimal. These results underscore the importance of controlling for the age of the animal in research on the toxic effects associated with CWNA exposure.

Drosophila melanogaster (fruit fly) locomotion during a sounding rocket flight

NASA Astrophysics Data System (ADS)

Miller, Mark S.; Keller, Tony S.

2008-05-01

The locomotor activity of young Drosophila melanogaster (fruit fly) was studied during a Nike-Orion sounding rocket flight, which included a short-duration microgravity exposure. An infrared monitoring system was used to determine the activity level, instantaneous velocity, and continuous velocity of 240 (120 male, 120 female) fruit flies. Individual flies were placed in chambers that limit their motion to walking. Chambers were oriented both vertically and horizontally with respect to the rocket's longitudinal axis. Significant changes in Drosophila locomotion patterns were observed throughout the sounding rocket flight, including launch, microgravity exposure, payload re-entry, and after ocean impact. During the microgravity portion of the flight (3.8 min), large increases in all locomotion measurements for both sexes were observed, with some measurements doubling compared to pad (1 G) data. Initial effects of microgravity were probably delayed due to large accelerations from the payload despining immediately before entering microgravity. The results indicate that short-duration microgravity exposure has a large effect on locomotor activity for both males and females, at least for a short period of time. The locomotion increases may explain the increased male aging observed during long-duration exposure to microgravity. Studies focusing on long-duration microgravity exposure are needed to confirm these findings, and the relationship of increased aging and locomotion.

Effect of high-flux H/He plasma exposure on tungsten damage due to transient heat loads

NASA Astrophysics Data System (ADS)

De Temmerman, G.; Morgan, T. W.; van Eden, G. G.; de Kruif, T.; Wirtz, M.; Matejicek, J.; Chraska, T.; Pitts, R. A.; Wright, G. M.

2015-08-01

The thermal shock behaviour of tungsten exposed to high-flux plasma is studied using a high-power laser. The cases of laser-only, sequential laser and hydrogen (H) plasma and simultaneous laser plus H plasma exposure are studied. H plasma exposure leads to an embrittlement of the material and the appearance of a crack network originating from the centre of the laser spot. Under simultaneous loading, significant surface melting is observed. In general, H plasma exposure lowers the heat flux parameter (FHF) for the onset of surface melting by ∼25%. In the case of He-modified (fuzzy) surfaces, strong surface deformations are observed already after 1000 laser pulses at moderate FHF = 19 MJ m-2 s-1/2, and a dense network of fine cracks is observed. These results indicate that high-fluence ITER-like plasma exposure influences the thermal shock properties of tungsten, lowering the permissible transient energy density beyond which macroscopic surface modifications begin to occur.

Combined exposure to protons and (56)Fe leads to overexpression of Il13 and reactivation of repetitive elements in the mouse lung.

PubMed

Nzabarushimana, Etienne; Prior, Sara; Miousse, Isabelle R; Pathak, Rupak; Allen, Antiño R; Latendresse, John; Olsen, Reid H J; Raber, Jacob; Hauer-Jensen, Martin; Nelson, Gregory A; Koturbash, Igor

2015-11-01

Interest in deep space exploration underlines the needs to investigate the effects of exposure to combined sources of space radiation. The lung is a target organ for radiation, and exposure to protons and heavy ions as radiation sources may lead to the development of degenerative disease and cancer. In this study, we evaluated the pro-fibrotic and epigenetic effects of exposure to protons (150 MeV/nucleon, 0.1 Gy) and heavy iron ions ((56)Fe, 600 MeV/nucleon, 0.5 Gy) alone or in combination (protons on Day 1 and (56)Fe on Day 2) in C57BL/6 male mice 4 weeks after irradiation. Exposure to (56)Fe, proton or in combination, did not result in histopathological changes in the murine lung. At the same time, combined exposure to protons and (56)Fe resulted in pronounced molecular alterations in comparison with either source of radiation alone. Specifically, we observed a substantial increase in the expression of cytokine Il13, loss of expression of DNA methyltransferase Dnmt1, and reactivation of LINE-1, SINE B1 retrotransposons, and major and minor satellites. Given the deleterious potential of the observed effects that may lead to development of chronic lung injury, pulmonary fibrosis, and cancer, future studies devoted to the investigation of the long-term effects of combined exposures to proton and heavy ions are clearly needed. Copyright © 2015 The Committee on Space Research (COSPAR). Published by Elsevier Ltd. All rights reserved.

Subacute effects of inhaled Jet Fuel-A (Jet A) on airway and immune function in female rats.

PubMed

Sweeney, Lisa M; Prues, Susan L; Reboulet, James E

2013-04-01

Two studies were conducted to assess the potential airway and immune effects following subacute (14 d) exposure of female rats to 500, 1000 or 2000 mg/m³ of Jet-A for 4 h/d. The first study used Sprague-Dawley rats; the second study included both Fischer 344 (F344) and Sprague-Dawley rats. In the first study, exposure to 2000 mg/m³ jet fuel may have caused significant upper airway inflammation on day 7 post-exposure, as indicated by elevated protein and lactate dehydrogenase in nasal lavage fluid, but any inflammation resolved by day 14 post-exposure. No significant impact on immune cell populations in the spleens was observed. The histological examination showed no evidence of infectious or toxic effect. In the second study, body weights of the F344 rats in the 2000 mg/m³ group were depressed, as compared to the controls, at the end of the exposure. Some lung lavage fluid markers were increased at 24 h after the final exposure, however, no test article-induced histological changes were observed in the lungs, nasal cavities, or any other tissue of any of the jet fuel exposed animals. Overall, these studies demonstrated limited evidence of effects of 14 d of exposure to Jet A on the airways, immune system, or any other organ or system of female Sprague-Dawley and F344 rats, with no remarkable differences between strains. The lack of identified significant airway or immune effects was in contrast to previous examinations of jet fuel for pulmonary toxicity in mice and rats and for immunotoxicity in mice.

Cellular alterations and enhanced induction of cleft palate after coadministration of retinoic acid and TCDD

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

Abbott, B.D.; Birnbaum, L.S.

1989-06-15

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and retinoic acid (RA) are both teratogenic in mice. TCDD is a highly toxic, stable environmental contaminant, while RA is a naturally occurring form of vitamin A. Exposure to TCDD induces hydronephrosis and cleft palate, and exposure to RA induces limb defects and cleft palate. Teratology studies previously have shown that the incidence of clefting is higher after exposure to RA + TCDD than would be observed for the same doses of either compound given alone. This study examines the cellular effects which result in cleft palate, after po administration on gestation Day (GD) 10 or 12 ofmore » RA + TCDD in corn oil (10 ml/kg total volume). Exposure on GD 10 to 6 micrograms TCDD + 40 mg RA/kg inhibited early growth of the shelves and clefting was due to a failure of shelves to meet and fuse. This effect on mesenchyme was observed in previous studies to occur after exposure on GD 10 to 40 mg/kg RA alone, but not after TCDD alone. After exposure on GD 12 to 6 micrograms TCDD + 80 mg RA/kg, clefting was due to a failure of shelves to fuse after making contact, because the medial cells differentiated into an oral-like epithelium. This response was observed in previous studies to occur after exposure to TCDD alone, but RA alone on GD 12 resulted in differentiation toward nasal-like cells. The interaction between TCDD and RA results in RA-like clefting after exposure on GD 10 and TCDD-like clefting after exposure on GD 12, and this clefting occurs at higher incidences than would occur after the same levels of either agent alone. After exposure on either GD 10 or 12 to RA + TCDD, the programmed cell death of the medial cells does not occur, and these cells continue to express EGF receptors and to bind 125I-EGF. The effects of RA and TCDD may involve modulation of the cells responses to embryonic growth and differentiation factors.« 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 association was observed between melatonin and serotonin levels as well. The study showed the EMF ability to influence plasma melatonin and serotonin concentration in radar workers, significantly in 12.5-18 GHz range with service period greater than 10 years.

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.

The role of clinical experience, diagnosis, and theoretical orientation in the treatment of posttraumatic and dissociative disorders: A vignette and survey investigation.

PubMed

Dorahy, Martin J; Lewis-Fernández, Roberto; Krüger, Christa; Brand, Bethany L; Şar, Vedat; Ewing, Jan; Martínez-Taboas, Alfonso; Stavropoulos, Pam; Middleton, Warwick

2017-01-01

Controversy exists regarding the merits of exposure-based treatments for posttraumatic stress disorder (PTSD) versus a phased approach when prominent dissociative symptoms are present. The first aim of this study was to examine the degree to which diagnosing dissociation in two traumatized patients' vignettes influenced clinicians' preference for phase-oriented treatment and whether clinicians' treatment experience contributed to their treatment preference. The second aim was to assess the extent to which participants had observed traumatized patients worsen when treated with exposure therapy or phase-oriented therapy and whether the theoretical orientation and treatment experience of the clinician were related to the observed deterioration. In the tradition of expert and practitioner surveys, 263 clinicians completed a survey of their diagnoses and treatment preferences for two vignettes and their treatment experience, theoretical orientation, and observations of patients' deterioration. When a marked degree of dissociation was noted in the PTSD vignette, respondents favored phased approaches regardless of the diagnosis given. Reports of having observed patient deterioration during both exposure and phased therapy were predicted by years of experience. Psychodynamic therapists reported more observations of worsening during exposure therapy than cognitive behavior therapy therapists. Clinical experience treating PTSD may heighten awareness of negative therapeutic effects, potentially because experienced clinicians have a lower threshold for detecting such effects and because they are referred more challenging cases.

Acute and chronic toxic effects of chloramphenicol on Scenedesmus obliquus and Chlorella pyrenoidosa.

PubMed

Zhang, Wei; Sun, Wenfang; An, Shuai; Xiong, Bang; Lin, Kuangfei; Cui, Xinhong; Guo, Meijin

2013-08-01

The acute and chronic toxicological effects of Chloramphenicol (CAP) on Scenedesmus obliquus and Chlorella pyrenoidosa are not well understood. The indoor experiments were carried to observe and analyze the CAP induced changes. Results of the observations have showed that CAP exposure could significantly inhibit the growth of Scenedesmus obliquus in almost all the treated groups, while Chlorella pyrenoidosa exhibited less sensitivity. Chlorophyll-a syntheses of Scenedesmus obliquus were all inhibited by CAP exposure, while Chlorella pyrenoidosa displayed obvious stimulation effect. Catalase (CAT) and Superoxide dismutase (SOD) activities of both algae were promoted in all the treatments. The experimental results indicated that the growth and Chlorophyll-a syntheses of Scenedesmus obliquus were more sensitive in response to CAP exposure than that of Chlorella pyrenoidosa. While for CAT and SOD activities, Chlorella pyrenoidosa showed more susceptible. This research provides a basic understanding of CAP toxicity to aquatic organisms.

Inhalation exposure of rats to metal aerosol. II. Study of mutagenic effect on alveolar macrophages.

PubMed

Chorvatovicová, D; Kováciková, Z

1992-02-01

The effects of inhalation exposure to metal aerosol derived from nickel refinery waste were studied on the frequency of chromosome aberrations in alveolar macrophages in Wistar rats. A 4-month exposure period resulted in significant (P less than 0.01) increases in chromosome aberrations. Relatively high variability without statistical significance was observed after a 4-week exposure period. Increase in damaged alveolar macrophages with the length of exposure seems to point to the role of pulmonary metal deposits. Comparison of the results with those found after 6 months of exposure in bone marrow cells confirmed that metal particles in nickel refinery waste are genotoxic. Thus, this study indicates that alveolar macrophages are suitable for monitoring the genotoxic potential of hazardous chemicals administered by inhalation.

Regular sun exposure benefits health.

PubMed

van der Rhee, H J; de Vries, E; Coebergh, J W

2016-12-01

Since it was discovered that UV radiation was the main environmental cause of skin cancer, primary prevention programs have been started. These programs advise to avoid exposure to sunlight. However, the question arises whether sun-shunning behaviour might have an effect on general health. During the last decades new favourable associations between sunlight and disease have been discovered. There is growing observational and experimental evidence that regular exposure to sunlight contributes to the prevention of colon-, breast-, prostate cancer, non-Hodgkin lymphoma, multiple sclerosis, hypertension and diabetes. Initially, these beneficial effects were ascribed to vitamin D. Recently it became evident that immunomodulation, the formation of nitric oxide, melatonin, serotonin, and the effect of (sun)light on circadian clocks, are involved as well. In Europe (above 50 degrees north latitude), the risk of skin cancer (particularly melanoma) is mainly caused by an intermittent pattern of exposure, while regular exposure confers a relatively low risk. The available data on the negative and positive effects of sun exposure are discussed. Considering these data we hypothesize that regular sun exposure benefits health. Copyright © 2016 Elsevier Ltd. All rights reserved.

A review of bio-aerosol exposures and associated health effects in veterinary practice.

PubMed

Samadi, Sadegh; Wouters, Inge M; Heederik, Dick J J

2013-01-01

Occupational exposure to bio-aerosols has been linked to various health effects. This review presents an overview of bio-aerosol exposure levels in veterinary practices, and investigates the possibility of health effects associated with bio-aerosol exposure. A systematic literature search was carried out in PubMed. Publications were included if they provided information on bio-aerosol exposure and related health effects through veterinary practice and other professions with similar exposures, occupationally exposed to animals. Few studies in veterinary settings showed that substantial bio-aerosol exposure levels (e.g. endotoxin and β(1→3)-glucan) were likely occur when handling farm animals and horses. Exposure levels are comparable to those levels observed in farming which have been associated with respiratory health effects. Animal specific allergen exposures have hardly been studied, but showed to be measurable in companion animal clinics and dairy barns. The Findings of the few studies available among veterinary populations, particularly those working with farm animals and horses, are indicative of an elevated risk for developing respiratory symptoms. Studies among pig farmers, exposed to similar environments as veterinarians, strongly confirm that veterinary populations are at an increased risk of developing respiratory diseases in relation to bio-aerosol exposure, in particular endotoxin. Exposure to animal allergens during veterinary practice may cause allergic inflammation, characterized by IgE-mediated reactions to animal allergens. Nonetheless, the occurrence of sensitization or allergy against animal allergens is poorly described, apart from laboratory animal allergy, especially known from exposure to rats and mice. Veterinary populations are likely exposed to elevated levels of bio-aerosols such as endotoxins, β(1→3)-glucans, and some specific animal allergens. Exposures to these agents in animal farmers are associated with allergic and non-allergic respiratory effects, proposing similar health effects in veterinary populations.

An examination of the association between 5-HTTLPR, combat exposure, and PTSD diagnosis among U.S. veterans.

PubMed

Liu, Yutao; Garrett, Melanie E; Dennis, Michelle F; Green, Kimberly T; Ashley-Koch, Allison E; Hauser, Michael A; Beckham, Jean C; Kimbrel, Nathan A

2015-01-01

To examine the association between the 5-HTTLPR polymorphism of the serotonin transporter (SLC6A4) gene, combat exposure, and posttraumatic stress disorder (PTSD) diagnosis and among two samples of combat-exposed veterans. The first sample included 550 non-Hispanic Black (NHB) combat-exposed veterans. The second sample included 555 non-Hispanic White (NHW) combat-exposed veterans. Participants were genotyped for the 5-HTTLPR/rs25531 variants of the SLC6A4 gene. A structured clinical interview was used to diagnose PTSD. Combat and civilian trauma exposure were assessed with validated self-report instruments. Logistic regression was used to test for main effects of 5-HTTLPR on PTSD diagnosis as well as gene x environment (GxE) interactions after adjusting for sex, ancestry proportion scores, civilian trauma exposure, and combat exposure. Within the NHB sample, a significant additive effect was observed for 5-HTTLPR (OR = 1.502, p = .0025), such that the odds of having a current diagnosis of PTSD increased by 1.502 for each additional S' allele. No evidence for an association between 5-HTTLPR and PTSD was observed in the NHW sample. In addition, no evidence for combat x 5-HTTLPR effects were observed in either sample. The present study suggests that there may be an association between 5-HTTLPR genotype and PTSD diagnosis among NHB veterans; however, no evidence for the hypothesized 5-HTTLPR x combat interaction was found.

Physiological responses and toxin production of Microcystis aeruginosa in short-term exposure to solar UV radiation.

PubMed

Hernando, Marcelo; Minaglia, Melina Celeste Crettaz; Malanga, Gabriela; Houghton, Christian; Andrinolo, Darío; Sedan, Daniela; Rosso, Lorena; Giannuzzi, Leda

2018-01-17

The aim of this study was to evaluate the effects of short-term (hours) exposure to solar UV radiation (UVR, 280-400 nm) on the physiology of Microcystis aeruginosa. Three solar radiation treatments were implemented: (i) PAR (PAR, 400-700 nm), (ii) TUVA (PAR + UVAR, 315-700 nm) and (iii) TUVR (PAR + UVAR + UVBR, 280-700 nm). Differential responses of antioxidant enzymes and the reactive oxygen species (ROS) production to UVR were observed. Antioxidant enzymes were more active at high UVR doses. However, different responses were observed depending on the exposure to UVAR or UVBR and the dose level. No effects were observed on the biomass, ROS production or increased activity of superoxide dismutase (SOD) and catalase (CAT) compared to the control when UVR + PAR doses were lower than 9875 kJ m -2 . For intermediate doses, UVR + PAR doses between 9875 and 10 275 kJ m -2 , oxidative stress increased while resistance was imparted through SOD and CAT in the cells exposed to UVAR. Despite the increased antioxidant activity, biomass decrease and photosynthesis inhibition were observed, but no effects were observed with added exposure to UVBR. At the highest doses (UVR + PAR higher than 10 275 kJ m -2 ), the solar UVR caused decreased photosynthesis and biomass with only activation of CAT by UVBR and SOD and CAT by UVAR. In addition, for such doses, a significant decrease of microcystins (MCs, measured as MC-LR equivalents) was observed as a consequence of UVAR. This study facilitates our understanding of the SOD and CAT protection according to UVAR and UVBR doses and cellular damage and reinforces the importance of UVR as an environmental stressor. In addition, our results support the hypothesized antioxidant function of MCs.

Reducing Sex-Typed Perceptions of Children: The Role of Environmental Exposure.

ERIC Educational Resources Information Center

Murphy, Kimberlee C.; Huston, Aletha C.

This study examined the effect of the amount and diversity of information about a child on adults' perceptions of the child's personality traits and sex-typed interests. A sample of 197 college students (ranging in age from 18 to 28 years) were randomly assigned one of three exposure conditions: (1) maximum exposure (subjects observed six boys,…

78 FR 65561 - D-Glucopyranose, oligomeric, decyl octyl glycosides; Exemption from the Requirement of a Tolerance

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-01

... exposure through drinking water and in residential settings, but does not include occupational exposure... ingredient through food, drinking water, and through other exposures that occur as a result of pesticide use... observed at the dose levels of 1,500 and 3,000 mg/kg/day, these effects are likely attributable to stress...

Photochemical mechanisms of ocular photic injury (Abstract Only)

NASA Astrophysics Data System (ADS)

Stuck, Bruce E.; Lund, David J.; Zuclich, Joseph A.

2000-03-01

Mechanisms of photic injury to the eye can be categorized as photochemical, photothermal or photodistruptive. Exposure wavelength, exposure duration, ocular tissue characteristics and response criteria are key factors in the delineation of the ocular injury mechanisms. Depending on the exposure condition, one or all of the laser-tissue interaction mechanisms can be involved. Although photic injury to the eye was initially assumed to involve thermal mechanisms, more recent research has demonstrated that ocular effects can be produced by light exposure without a significant retinal temperature rise. Photochemical mechanisms are also implicated in UV photic injury to the cornea and lens. Exposure of the retina to short visible wavelengths for prolonged durations results in photochemical retinal damage with negligible localized retinal temperature elevation. For exposure conditions where photochemical mechanisms are dominate, the reciprocity of irradiance and exposure duration is apparent. The latency until observation of a photochemical lesion is often 24-48 hours whereas a thermal lesion is observed immediately or within a few hours after the exposure. Action spectra for photochemical injury to the eye are discussed in the context of ocular injury thresholds and current permissible exposure limits.

Pathological effects of in utero methylmercury exposure on the cerebellum of the golden hamster: residual effects on the adult cerebellum-part 2

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

Reuhl, K.R.; Chang, L.W.; Townsend, J.W.

1981-12-01

The long-term effects of prenatal methylmercury exposure were studied in the golden hamster (Mesocricetus auratus). Pregnant animals were either 10 mg/kg methylmercury on gestational day 10 or 2 mg/kg on gestational days 10-15. Animals from treated and control litters were sacrificed as adults and cerebella examined by light and electron microscopy. Focal areas of astrogliosis were observed in the molecular layer of treated animals. Sequellae of previous injury, characterized primarily by abundant residual bodies, were observed in the perikarya and dendrites of granule and Purkinje neurons. Degenerative change of myelinated axons was observed. Possible hypotheses for continued neuronal degeneration inmore » prenatally exposed animals are discussed.« less

Evaluation of submarine atmospheres: effects of carbon monoxide, carbon dioxide and oxygen on general toxicology, neurobehavioral performance, reproduction and development in rats. I. Subacute exposures.

PubMed

Hardt, Daniel J; James, R Arden; Gut, Chester P; McInturf, Shawn M; Sweeney, Lisa M; Erickson, Richard P; Gargas, Michael L

2015-02-01

The inhalation toxicity of submarine contaminants is of concern to ensure the health of men and women aboard submarines during operational deployments. Due to a lack of adequate prior studies, potential general, neurobehavioral, reproductive and developmental toxicity was evaluated in male and female rats exposed to mixtures of three critical submarine atmospheric components: carbon monoxide (CO) and carbon dioxide (CO2; levels elevated above ambient), and oxygen (O2; levels decreased below ambient). In a 14-day, 23 h/day, whole-body inhalation study of exposure to clean air (0.4 ppm CO, 0.1% CO2 and 20.6% O2), low-dose, mid-dose and high-dose gas mixtures (high dose of 88.4 ppm CO, 2.5% CO2 and 15.0% O2), no adverse effects on survival, body weight or histopathology were observed. Reproductive, developmental and neurobehavioral performance were evaluated after a 28-day exposure in similar atmospheres. No adverse effects on estrus phase, mating, gestation or parturition were observed. No developmental or functional deficits were observed in either exposed parents or offspring related to motor activity, exploratory behavior or higher-level cognitive functions (learning and memory). Only minimal effects were discovered in parent-offspring emotionality tests. While statistically significant increases in hematological parameters were observed in the offspring of exposed parents compared to controls, these parameters remained within normal clinical ranges for blood cells and components and were not considered adverse. In summary, subacute exposures to elevated concentrations of the submarine atmosphere gases did not affect the ability of rats to reproduce and did not appear to have any significant adverse health effects.

Effects of dietary exposure to brominated flame retardant BDE-47 on thyroid condition, gonadal development and growth of zebrafish.

PubMed

Torres, Leticia; Orazio, Carl E; Peterman, Paul H; Patiño, Reynaldo

2013-10-01

Little is known about the effects of brominated flame retardants in teleosts and some of the information currently available is inconsistent. This study examined effects of dietary exposure to 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) on thyroid condition, body mass and size, and gonadal development of zebrafish. Pubertal, 49-day-old (posthatch) fish were fed diets without BDE-47 (control) or with 1, 5 or 25 μg/g BDE-47/diet. Treatments were conducted in triplicate 30-L tanks each containing 50 zebrafish, and 15 fish per treatment (5 per tank) were sampled at days 40, 80 and 120 of exposure. Measurements were taken of body mass, standard length, head depth and head length. Sex (at 40-120 days of exposure), germ cell stage (at 40 days) and thyroid condition (at 120 days; follicular cell height, colloid depletion, angiogenesis) were histologically determined. Whole-body BDE-47 levels at study completion were within the high end of levels reported in environmentally exposed (wild) fishes. Analysis of variance was used to determine differences among treatments at each sampling time. No effects were observed on thyroid condition or germ cell stage in either sex. Reduced head length was observed in females exposed to BDE-47 at 80 days but not at 40 or 120 days. In males, no apparent effects of BDE-47 were observed at 40 and 80 days, but fish exposed to 25 μg/g had lower body mass at 120 days compared to control fish. These observations suggest that BDE-47 at environmentally relevant whole-body concentrations does not affect thyroid condition or pubertal development of zebrafish but does affect growth during the juvenile-to-adult transition, especially in males.

Assessing the Effectiveness of Ramp-Up During Sonar Operations Using Exposure Models.

PubMed

von Benda-Beckmann, Alexander M; Wensveen, Paul J; Kvadsheim, Petter H; Lam, Frans-Peter A; Miller, Patrick J O; Tyack, Peter L; Ainslie, Michael A

2016-01-01

Ramp-up procedures are used to mitigate the impact of sound on marine mammals. Sound exposure models combined with observations of marine mammals responding to sound can be used to assess the effectiveness of ramp-up procedures. We found that ramp-up procedures before full-level sonar operations can reduce the risk of hearing threshold shifts with marine mammals, but their effectiveness depends strongly on the responsiveness of the animals. In this paper, we investigated the effect of sonar parameters (source level, pulse-repetition time, ship speed) on sound exposure by using a simple analytical model and highlight the mechanisms that limit the effectiveness of ramp-up procedures.

Evaluation of a Community-Based Intervention to Promote Rear Seating for Children

PubMed Central

Greenberg-Seth, Jennifer; Hemenway, David; Gallagher, Susan S.; Ross, Julie B.; Lissy, Karen S.

2004-01-01

Objectives. We evaluated the short-term effect of a community-based effort to promote child rear seating in a low-income Hispanic community. Methods. Child seating patterns were observed pre- and postintervention at intersections in 1 intervention and 2 control cities. Brief interviews assessed exposure to program messages. Results. Child rear seating increased from 33% to 49% in the intervention city (P < .0001), which represented a greater increase than that in the control cities (P < .0001). The greatest improvement was observed in relatively higher-income areas. Rear seating was significantly correlated with reported program exposure. Incentives and exposure to the program across multiple channels seemed to have the greatest effect. Conclusions. Independent of legislation, community-based programs incorporating incentives can increase child rear seating. PMID:15249307

Arsenic exposures alter clinical indicators of anemia in a male population of smokers and non-smokers in Bangladesh.

PubMed

Parvez, Faruque; Medina, Sebastian; Santella, Regina M; Islam, Tariqul; Lauer, Fredine T; Alam, Nur; Eunus, Mahbubul; Rahman, Mizanour; Factor-Litvak, Pam; Ahsan, Habib; Graziano, Joseph H; Liu, Ke Jian; Burchiel, Scott W

2017-09-15

Drinking water arsenic (WAs) exposure has been linked to a number of detrimental health outcomes including anemia, primarily among pregnant women. Little is known about the effects of arsenic (As) on hematological disorders among men. We have examined the role of As exposure on hematological indicators of anemia in a group of men exposed to a wide range of As in their drinking water. We conducted a cross-sectional investigation among 119 healthy men in the Health Effects of As Longitudinal Study (HEALS) cohort, in rural Bangladesh. The participants are part of an ongoing study focused on evaluating the influence of As and smoking on immune function. Samples were collected at recruitment and analyzed for water As, urinary As (UAs) and UAs metabolites to assess As exposure. Blood samples were also collected at recruitment and assayed immediately for hematological parameters. We found that increased WAs levels were associated with decreased red blood cell counts [β=-0.13, p<0.0001] as well as hematocrit packed cell volumes [β=-0.68, p=0.008] following adjustment for age, smoking, body mass index and polycyclic aromatic hydrocarbon-DNA adducts. Other measures of As exposure (UAs and its metabolites) demonstrated similar associations. Slightly stronger effects were observed among smokers. We also observed an effect of As on hemoglobin among smokers in relation to UAs [β=-0.54, p<0.05]. Our analysis revealed effects of As exposure on hematological indicators of anemia in a group of healthy male smokers and non-smokers. Copyright © 2017 Elsevier Inc. All rights reserved.

Prenatal methyl mercury exposure in relation to neurodevelopment and behavior at 19 years of age in the Seychelles Child Development Study.

PubMed

van Wijngaarden, E; Thurston, S W; Myers, G J; Strain, J J; Weiss, B; Zarcone, T; Watson, G E; Zareba, G; McSorley, E M; Mulhern, M S; Yeates, A J; Henderson, J; Gedeon, J; Shamlaye, C F; Davidson, P W

2013-01-01

Fish are important sources of protein and contain a variety of nutrients, such as n-3 long-chain polyunsaturated fatty acids (PUFA), essential for normal brain development. Nevertheless, all fish also contain methyl mercury (MeHg), a known neurotoxicant in adequate dosage. Our studies of the Seychelles Child Development Study (SCDS) Main Cohort enrolled in 1989-1990 (n=779) have found no consistent pattern of adverse MeHg effects at exposures achieved by daily fish consumption. Rather, we have observed evidence of improved performance on some cognitive endpoints as prenatal MeHg exposure increases in the range studied. These observations cannot be related to MeHg and may reflect the role of unmeasured covariates such as essential nutrients present in fish. To determine if these associations persist into young adulthood, we examined the relationship between prenatal MeHg exposure, recent PUFA exposure and subjects' neurodevelopment and behavior at 19 years of age. We examined 533 participants using the following test battery: the Profile of Mood States-Bipolar (POMS-Bi); Finger Tapping; Kaufman Brief Intelligence Test (K-BIT); measures of Fine Motor Control and Complex Perceptual Motor Control; and Visual Spatial Contrast Sensitivity. We collected the following covariates: maternal IQ, family life course stressors, socioeconomic status, and subjects' recent postnatal MeHg, sex, and computer use. Primary analyses (based on N=392-475) examined covariate-adjusted associations in multiple linear regression models with prenatal MeHg as the primary exposure measure. Secondary analyses additionally adjusted for total n-6 and fish-related n-3 PUFA measured in the subjects' serum at the 19-year examination. Study participants had a mean prenatal MeHg exposure of 6.9 ppm, and a mean recent postnatal exposure of 10.3 ppm. There were no adverse associations between prenatal MeHg and any of the measured endpoints. For recent postnatal MeHg exposure, however, adverse associations were observed for Finger Tapping (non-dominant hand) among women and for the K-BIT Matrices for both sexes, with or without adjustment for PUFA. Our findings continue to provide no evidence for an adverse effect of prenatal MeHg exposure on development in a cohort that consumes fish daily. Observations for postnatal MeHg exposure will need to be confirmed using more comprehensive exposure measures. Copyright © 2013 Elsevier Inc. All rights reserved.

Prenatal methyl mercury exposure in relation to neurodevelopment and behavior at 19 years of age in the Seychelles Child Development Study

PubMed Central

van Wijngaarden, E; Thurston, SW; Myers, GJ; Strain, JJ; Weiss, B; Zarcone, T; Watson, GE; Zareba, G; McSorley, EM; Mulhern, MS; Yeates, AJ; Henderson, J; Gedeon, J; Shamlaye, CF; Davidson, PW

2013-01-01

Background Fish are important sources of protein and contain a variety of nutrients, such as n-3 longchain polyunsaturated fatty acids (PUFA), essential for normal brain development. Nevertheless, all fish also contain methyl mercury (MeHg), a known neurotoxicant in adequate dosage. Our studies of the Seychelles Child Development Study (SCDS) Main Cohort enrolled in 1989–1990 (n=779) have found no consistent pattern of adverse MeHg effects at exposures achieved by daily fish consumption. Rather, we have observed evidence of improved performance on some cognitive endpoints as prenatal MeHg exposure increases in the range studied. These observations cannot be related to MeHg and may reflect the role of unmeasured covariates such as essential nutrients present in fish. To determine if these associations persist into young adulthood, we examined the relationship between prenatal MeHg exposure, recent PUFA exposure and subjects’ neurodevelopment and behavior at 19 years of age. Methods We examined 533 participants using the following test battery: the Profile of Mood States- Bipolar (POMS-Bi); Finger Tapping; Kaufman Brief Intelligence Test (K-BIT); measures of Fine Motor Control and Complex Perceptual Motor Control; and Visual Spatial Contrast Sensitivity. We collected the following covariates: maternal IQ, family life course stressors, socioeconomic status, and subjects’ recent postnatal MeHg, sex, and computer use. Primary analyses (based on N=392–475) examined covariate-adjusted associations in multiple linear regression models with prenatal MeHg as the primary exposure measure. Secondary analyses additionally adjusted for total n-6 and fish-related n-3 PUFA measured in the subjects serum at the 19-year examination. Results Study participants had a mean prenatal MeHg exposure of 6.9 ppm, and a mean recent postnatal exposure of 10.3 ppm. There were no adverse associations between prenatal MeHg and any of the measured endpoints. For recent postnatal MeHg exposure, however, adverse associations were observed for Finger Tapping (non-dominant hand) among women and for the K-BIT matrices for both sexes, with or without adjustment for PUFA. Conclusion Our findings continue to provide no evidence for an adverse effect of prenatal MeHg exposure on development in a cohort that consumes fish daily. Observations for postnatal MeHg exposure will need to be confirmed using more comprehensive exposure measures. PMID:23770126

Effects of prenatal exposure to diesel exhaust particles on postnatal development, behavior, genotoxicity and inflammation in mice

PubMed Central

Hougaard, Karin S; Jensen, Keld A; Nordly, Pernille; Taxvig, Camilla; Vogel, Ulla; Saber, Anne T; Wallin, Håkan

2008-01-01

Background Results from epidemiological studies indicate that particulate air pollution constitutes a hazard for human health. Recent studies suggest that diesel exhaust possesses endocrine activity and therefore may affect reproductive outcome. This study in mice aimed to investigate whether exposure to diesel exhaust particles (DEP; NIST 2975) would affect gestation, postnatal development, activity, learning and memory, and biomarkers of transplacental toxicity. Pregnant mice (C57BL/6; BomTac) were exposed to 19 mg/m3 DEP (~1·106 particles/cm3; mass median diameter ≅ 240 nm) on gestational days 9–19, for 1 h/day. Results Gestational parameters were similar in control and diesel groups. Shortly after birth, body weights of DEP offspring were slightly lower than in controls. This difference increased during lactation, so by weaning the DEP exposed offspring weighed significantly less than the control progeny. Only slight effects of exposure were observed on cognitive function in female DEP offspring and on biomarkers of exposure to particles or genotoxic substances. Conclusion In utero exposure to DEP decreased weight gain during lactation. Cognitive function and levels of biomarkers of exposure to particles or to genotoxic substances were generally similar in exposed and control offspring. The particle size and chemical composition of the DEP and differences in exposure methods (fresh, whole exhaust versus aged, resuspended DEP) may play a significant role on the biological effects observed in this compared to other studies. PMID:18331653

Heart rate variability affected by radiofrequency electromagnetic field in adolescent students.

PubMed

Misek, Jakub; Belyaev, Igor; Jakusova, Viera; Tonhajzerova, Ingrid; Barabas, Jan; Jakus, Jan

2018-05-01

This study examines the possible effect of radiofrequency (RF) electromagnetic fields (EMF) on the autonomic nervous system (ANS). The effect of RF EMF on ANS activity was studied by measuring heart rate variability (HRV) during ortho-clinostatic test (i.e., transition from lying to standing and back) in 46 healthy grammar school students. A 1788 MHz pulsed wave with intensity of 54 ± 1.6 V/m was applied intermittently for 18 min in each trial. Maximum specific absorption rate (SAR 10 ) value was determined to 0.405 W/kg. We also measured the respiration rate and estimated a subjective perception of EMF exposure. RF exposure decreased heart rate of subjects in a lying position, while no such change was seen in standing students. After exposure while lying, a rise in high frequency band of HRV and root Mean Square of the Successive Differences was observed, which indicated an increase in parasympathetic nerve activity. Tympanic temperature and skin temperature were measured showing no heating under RF exposure. No RF effect on respiration rate was observed. None of the tested subjects were able to distinguish real exposure from sham exposure when queried at the end of the trial. In conclusion, short-term RF EMF exposure of students in a lying position during the ortho-clinostatic test affected ANS with significant increase in parasympathetic nerve activity compared to sham exposed group. Bioelectromagnetics. 39:277-288, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

Investigating the effects of in utero benzene exposure on epigenetic modifications in maternal and fetal CD-1 mice.

PubMed

Philbrook, Nicola A; Winn, Louise M

2015-11-15

Exposure to the ubiquitous environmental pollutant benzene is positively correlated with leukemia in adults and may be associated with childhood leukemia following in utero exposure. While numerous studies implicate oxidative stress and DNA damage as playing a role in benzene-mediated carcinogenicity, emerging evidence suggests that alterations in epigenetic regulations may be involved. The present study aimed to determine whether DNA methylation and/or various histone modifications were altered following in utero benzene exposure in CD-1 mice. Global DNA methylation and promoter-specific methylation of the tumor suppressor gene, p15, were assessed. Additionally, levels of acetylated histones H3, H4, and H3K56, as well as methylated histones H3K9 and H3K27 were assessed by Western blotting. A significant decrease in global DNA methylation of maternal bone marrow was observed following benzene exposure; however no effect on global DNA methylation was detected in fetal livers. Additionally, no effect of benzene exposure was observed on p15 promoter methylation or any measured histone modifications in both maternal bone marrow and fetal livers. These results suggest that the methodology used in the present study did not reveal alterations in DNA methylation and histone modifications following in utero exposure to benzene; however further experimentation investigating these modifications at the whole genome/epigenome level, as well as at later stages of benzene-induced carcinogenesis, are warranted. Copyright © 2015 Elsevier Inc. All rights reserved.

Workshop on perinatal exposure to dioxin-like compounds. I. Summary.

PubMed Central

Lindström, G; Hooper, K; Petreas, M; Stephens, R; Gilman, A

1995-01-01

An international workshop reviewed 20 ongoing or recently completed studies of the effects of perinatal exposures to dioxins, dibenzofurans, and PCBs on the reproductive, endocrine, neurodevelopmental, and immune systems. Many of the observed effects are consistent with these compounds acting as "environmental hormones" or endocrine disrupters. This report summarizes the conclusions and future directions described at the workshop. PMID:7614935

Effects Of Combinations of Ozone and Diesel Exhaust Exposures On Blood, Cardiac, And Lung Endpoints

EPA Science Inventory

Human subjects were exposed to combinations of 300 ppb ozone (03) and 300 ug/m3 diesel exhaust (DE) to examine if synergistic effects were observed. Subjects received either filtered air (FA), 03, DE, or DE+03 on Day 1, followed by only 03 exposures on Day 2, and a follow-up on D...

Effect of exposure cycle on hot salt stress corrosion of a titanium alloy

NASA Technical Reports Server (NTRS)

Gray, H. R.; Johnston, J. R.

1974-01-01

The influence of exposure cycle on the hot-salt stress-corrosion cracking resistance of the Ti-8Al-1Mo-1V alloy was determined. Both temperature and stress were cycled simultaneously to simulate turbine-powered aircraft service cycles. Temperature and stress were also cycled independently to determine their individual effects. Substantial increases in crack threshold stresses were observed for cycles in which both temperature and stress or temperature alone were applied for 1 hour and removed for 3 hours. The crack threshold stresses for these cyclic exposures were twice those determined for continuous exposure for the same total time of 96 hours.

Airborne Particulate Matter Induces Nonallergic Eosinophilic Sinonasal Inflammation in Mice.

PubMed

Ramanathan, Murugappan; London, Nyall R; Tharakan, Anuj; Surya, Nitya; Sussan, Thomas E; Rao, Xiaoquan; Lin, Sandra Y; Toskala, Elina; Rajagopalan, Sanjay; Biswal, Shyam

2017-07-01

Exposure to airborne particulate matter (PM) has been linked to aggravation of respiratory symptoms, increased risk of cardiovascular disease, and all-cause mortality. Although the health effects of PM on the lower pulmonary airway have been extensively studied, little is known regarding the impact of chronic PM exposure on the upper sinonasal airway. We sought to test the impact of chronic airborne PM exposure on the upper respiratory system in vivo. Mice were subjected, by inhalation, to concentrated fine (2.5 μm) PM 6 h/d, 5 d/wk, for 16 weeks. Mean airborne fine PM concentration was 60.92 μm/m 3 , a concentration of fine PM lower than that reported in some major global cities. Mice were then killed and analyzed for evidence of inflammation and barrier breakdown compared with control mice. Evidence of the destructive effects of chronic airborne PM on sinonasal health in vivo, including proinflammatory cytokine release, and macrophage and neutrophil inflammatory cell accumulation was observed. A significant increase in epithelial barrier dysfunction was observed, as assessed by serum albumin accumulation in nasal airway lavage fluid, as well as decreased expression of adhesion molecules, including claudin-1 and epithelial cadherin. A significant increase in eosinophilic inflammation, including increased IL-13, eotaxin-1, and eosinophil accumulation, was also observed. Collectively, although largely observational, these studies demonstrate the destructive effects of chronic airborne PM exposure on the sinonasal airway barrier disruption and nonallergic eosinophilic inflammation in mice.

Children's cognitive ability from 4 to 9 years old as a function of prenatal cocaine exposure, environmental risk, and maternal verbal intelligence.

PubMed

Bennett, David S; Bendersky, Margaret; Lewis, Michael

2008-07-01

This study examined the effects of prenatal cocaine exposure, environmental risk, and maternal verbal intelligence on children's cognitive ability. Gender and age were examined as moderators of potential cocaine exposure effects. The Stanford-Binet IV intelligence test was administered to 231 children (91 cocaine exposed, 140 unexposed) at ages 4, 6, and 9 years. Neonatal medical risk and other prenatal exposures (alcohol, cigarettes, and marijuana) were also examined for their unique effects on child IQ. Mixed models analysis indicated that prenatal cocaine exposure interacted with gender, as cocaine-exposed boys had lower composite IQ scores. Age at assessment did not moderate this relation, indicating that cocaine-exposed boys had lower IQs across this age period. A stimulating home environment and high maternal verbal IQ also predicted higher composite IQ scores. Cocaine-exposed boys had lower scores on the Abstract/Visual Reasoning subscale, with trends for lower scores on the Short-Term Memory and Verbal Reasoning subscales, as exposure effects were observed across domains. The findings indicate that cocaine exposure continues to place children at risk for mild cognitive deficits into preadolescence. Possible mechanisms for the Exposure x Gender interaction are discussed.

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 exposure of cells at the air-liquid interface represents a valid and sensitive method to assess the toxicity of several poorly soluble nanomaterials. We underlined the importance of the cellular model used and offer the possibility to deal with low deposition doses by using more sensitive and physiologic cellular models. This brings perspectives towards the use of relevant in vitro methods of exposure to assess nanomaterial toxicity.

Risk for Neurobehavioral Disinhibition in Prenatal Methamphetamine-Exposed Young Children with Positive Hair Toxicology Results

PubMed Central

Himes, Sarah K.; LaGasse, Linda L.; Derauf, Chris; Newman, Elana; Smith, Lynne M.; Arria, Amelia M.; Grotta, Sheri A. Della; Dansereau, Lynne M.; Abar, Beau; Neal, Charles R.; Lester, Barry M.; Huestis, Marilyn A.

2014-01-01

Background The objective was to evaluate effects of prenatal methamphetamine exposure (PME) and postnatal drug exposures identified by child hair analysis on neurobehavioral disinhibition at 6.5 years of age. Methods Mother-infant pairs were enrolled in the Infant Development, Environment, and Lifestyle (IDEAL) Study in Los Angeles, Honolulu, Tulsa and Des Moines. PME was determined by maternal self-report and/or positive meconium results. At the 6.5-year follow-up visit, hair was collected and analyzed for methamphetamine, tobacco, cocaine, and cannabinoid markers. Child behavioral and executive function test scores were aggregated to evaluate child neurobehavioral disinhibition. Hierarchical linear regression models assessed the impact of PME, postnatal substances, and combined PME with postnatal drug exposures on the child’s neurobehavioral disinhibition aggregate score. Past year caregiver substance use was compared to child hair results. Results A total of 264 children were evaluated. Significantly more PME children (n=133) had hair positive for methamphetamine/amphetamine (27.1% versus 8.4%) and nicotine/cotinine (38.3% versus 25.2%) than children without PME (n=131). Overall, no significant differences in analyte hair concentrations were noted between groups. Significant differences in behavioral and executive function were observed between children with and without PME. No independent effects of postnatal methamphetamine or tobacco exposure, identified by positive hair test, were noted and no additional neurobehavioral disinhibition was observed in PME children with postnatal drug exposures, as compared to PME children without postnatal exposure. Conclusions Child hair testing offered a non-invasive means to evaluate postnatal environmental drug exposure, although no effects from postnatal drug exposure alone were seen. PME, alone and in combination with postnatal drug exposures, was associated with behavioral and executive function deficits at 6.5 years. PMID:24518561

Risk of neurobehavioral disinhibition in prenatal methamphetamine-exposed young children with positive hair toxicology results.

PubMed

Himes, Sarah K; LaGasse, Linda L; Derauf, Chris; Newman, Elana; Smith, Lynne M; Arria, Amelia M; Della Grotta, Sheri A; Dansereau, Lynne M; Abar, Beau; Neal, Charles R; Lester, Barry M; Huestis, Marilyn A

2014-08-01

The objective was to evaluate the effects of prenatal methamphetamine exposure (PME) and postnatal drug exposures identified by child hair analysis on neurobehavioral disinhibition at 6.5 years of age. Mother-infant pairs were enrolled in the Infant Development, Environment, and Lifestyle (IDEAL) Study in Los Angeles, Honolulu, Tulsa, and Des Moines. PME was determined by maternal self-report and/or positive meconium results. At the 6.5-year follow-up visit, hair was collected and analyzed for methamphetamine, tobacco, cocaine, and cannabinoid markers. Child behavioral and executive function test scores were aggregated to evaluate child neurobehavioral disinhibition. Hierarchical linear regression models assessed the impact of PME, postnatal substances, and combined PME with postnatal drug exposures on the child's neurobehavioral disinhibition aggregate score. Past year caregiver substance use was compared with child hair results. A total of 264 children were evaluated. Significantly more PME children (n = 133) had hair positive for methamphetamine/amphetamine (27.1% versus 8.4%) and nicotine/cotinine (38.3% versus 25.2%) than children without PME (n = 131). Overall, no significant differences in analyte hair concentrations were noted between groups. Significant differences in behavioral and executive function were observed between children with and without PME. No independent effects of postnatal methamphetamine or tobacco exposure, identified by positive hair test, were noted and no additional neurobehavioral disinhibition was observed in PME children with postnatal drug exposures, as compared with PME children without postnatal exposure. Child hair testing offered a noninvasive means to evaluate postnatal environmental drug exposure, although no effects from postnatal drug exposure alone were seen. PME, alone and in combination with postnatal drug exposures, was associated with behavioral and executive function deficits at 6.5 years.

The potential for disease initiation by inhaled beta-emitting nuclear particles.

PubMed

Aamodt, Norman O

2018-07-01

There were many anecdotal reports of injuries to humans, animals and plants following the Three Mile Island, Chernobyl and Fukushima accidents that were indicative of radiation exposures that delivered a dose of at least 0.5 Sieverts, but studies that attempted to relate observed increases of cancer rates and other injuries with exposure to the radioactive releases from these accidents have failed to find an association. To resolve this dissonance, it was assumed that an analysis of knowledge about accident releases and health effects gathered from one of these accidents could lead to the identification of an unrecognized exposure that could be inferred to have caused a specific observed injury that required a dose of at least 0.5 Sieverts. Because there is considerably more useful knowledge of reactor releases of radionuclides and observed health effects related to the Three Mile Island accident, that knowledge is analyzed. A relationship is inferred to exist between exposure to particulates in plumes released from the station vent stack and severe prolonged immunosuppression, a known effect of an exposure that delivers a dose of at least 0.5 Sieverts. More than ninety percent of the particulates were comprised of Strontium 89 nuclides, essentially pure beta emitters. Because Strontium is a metal, the nuclides in the particulates were configured as stable crystals which, when coming to rest in body tissue, functioned as intense point sources of chronic beta irradiation. The inference led to the hypothesis "particulates comprised of Strontium 89 nuclides provided the exposure that caused the health effects that were observed following the Three Mile Island accident". The hypothesis was tested for validity against two requirements; that only the humans beneath the plumes, who would have inhaled the particulates, expressed the abrupt and persistent rise in the health parameter Deaths from all Causes that would result from the severe prolonged immunosuppression that follows a 0.5 Sievert dose, and that they expressed the excess cancers that would be expected following organ doses of 0.5 or more Sieverts. These effects were found. The Hypothesis is therefore valid and leads to knowledge of the heretofore unknown mechanisms and effects of low LET beta irradiation by a particulate. Copyright © 2018. Published by Elsevier Ltd.

Prenatal and postnatal mothering by diesel exhaust PM2.5-exposed dams differentially program mouse energy metabolism.

PubMed

Chen, Minjie; Liang, Shuai; Zhou, Huifen; Xu, Yanyi; Qin, Xiaobo; Hu, Ziying; Wang, Xiaoke; Qiu, Lianglin; Wang, Wanjun; Zhang, Yuhao; Ying, Zhekang

2017-01-18

Obesity is one of the leading threats to global public health. It is consequent to abnormal energy metabolism. Currently, it has been well established that maternal exposure to environmental stressors that cause inappropriate fetal development may have long-term adverse effects on offspring energy metabolism in an exposure timing-dependent manner, known as developmental programming of health and diseases paradigm. Rapidly increasing evidence has indicated that maternal exposure to ambient fine particles (PM 2.5 ) correlates to abnormal fetal development. In the present study, we therefore assessed whether maternal exposure to diesel exhaust PM 2.5 (DEP), the major component of ambient PM 2.5 in urban areas, programs offspring energy metabolism, and further examined how the timing of exposure impacts this programming. The growth trajectory of offspring shows that although prenatal maternal exposure to DEP did not impact the birth weight of offspring, it significantly decreased offspring body weight from postnatal week 2 until the end of observation. This weight loss effect of prenatal maternal exposure to DEP coincided with decreased food intake but not alteration in brown adipose tissue (BAT) morphology. The hypophagic effect of prenatal maternal exposure to DEP was in concord with decreased hypothalamic expression of an orexigenic peptide NPY, suggesting that the prenatal maternal exposure to DEP impacts offspring energy balance primarily through programming of food intake. Paradoxically, the reduced body weight resulted from prenatal maternal exposure to DEP was accompanied by increased mass of epididymal adipose tissue, which was due to hyperplasia as morphological analysis did not observe any hypertrophy. In direct contrast, the postnatal mothering by DEP-exposed dams increased offspring body weight during lactation and adulthood, paralleled by markedly increased fat accumulation and decreased UCP1 expression in BAT but not alteration in food intake. The weight gain induced by postnatal mothering by DEP-exposed dams was also expressed as an increased adiposity. But it concurred with a marked hypertrophy of adipocytes. Prenatal and postnatal mothering by DEP-exposed dams differentially program offspring energy metabolism, underscoring consideration of the exposure timing when examining the adverse effects of maternal exposure to ambient PM 2.5 .

Hydrocarbon exposure may cause glomerulonephritis and worsen renal function: evidence based on Hill's criteria for causality.

PubMed

Ravnskov, U

2000-08-01

Many observational and experimental studies point to hydrocarbon exposure as an important pathogenic factor in glomerulonephritis. The findings have made little impact on current concepts and patient care, possibly because the hypothesis of a direct causal effect of the exposure and the hypothesis that the exposure worsens renal function have not been considered separately. This review examines these two hypotheses using Hill's criteria for causality. The results from 14 cross-sectional, 18 case-control studies, two cohort studies, 15 experiments on laboratory animals and two on human beings together with many case reports satisfy all but one of Hill's criteria for both hypotheses. Of particular importance is the finding in the case-control and follow-up studies of an association between degree of exposure and stage of renal disease, and an inverse association between degree of exposure and renal function, indicating that the most important effect of hydrocarbon exposure is its effect on renal function. End-stage renal failure may be preventable in many patients with glomerulonephritis provided a possible exposure to toxic chemicals is discontinued.

Effects of short-term exposure to powerline-frequency electromagnetic field on the electrical activity of the heart.

PubMed

Elmas, Onur; Comlekci, Selcuk; Koylu, Halis

2012-01-01

ABSTRACT The heart is a contractile organ that can generate its own rhythm. The contraction, or the rhythm, of the heart may be influenced by electromagnetic field (EMF) exposure, because of the heart's excitability characteristic. In previous studies, different methods have been used to study the possible effects of an extremely low frequency electromagnetic field (ELF-EMF) on the heart. But the studies' designs were not similar, and the results were also different. Recent studies have shown some evidence that short-term EMF exposure can influence the heart more than long-term exposure. This study investigated how the heart is affected in the first EMF exposure. In a simulation of the daily exposure of humans to a power frequency, Wistar albino rats were used. By utilizing the Helmholtz-coil set, we obtained a 50-Hz, 1-μT EMF and examined rat heart activity during short-term EMF exposure. No effect was observed under this exposure condition. The results obtained do not confirm a possible mechanism in the electrical activity of the rat heart model.

Acute, 2-week, and 13-week inhalation toxicity studies on dimethylethoxysilane vapor in Fischer 344 rats

NASA Technical Reports Server (NTRS)

Dodd, D. E.; Stuart, B. O.; Rothenberg, S. J.; Kershaw, M.; Mann, P. C.; James, J. T.; Lam, C. W.

1994-01-01

Dimethylethoxysilane (DMES), a volatile liquid, is used by NASA to waterproof the heat-protective silica tiles and blankets on the Space Shuttle. Acute, 2-wk, and 13-wk inhalation exposures to DMES vapor were conducted in male and female Fischer 344 rats. In the acute study, rats were exposed to 4000, 2000, 1000, 500, or 0 (control) ppm DMES for 4 h and observed for 14 days. There were no deaths. Narcosis and ataxia were observed in rats of the two highest concentrations only. These signs disappeared within 1 h following exposure. There were no DMES-related gross or microscopic tissue lesions in rats of all exposure groups. In the 2-wk study, rats were exposed for 6 h/day, 5 days/wk to 3000, 1000, 300, 100, or 0 ppm DMES. During exposure, narcosis was observed in rats of the 3000 and 1000 ppm groups. There was a mild decrease in body weight gain in rats of the 3000 ppm group. A decrease in platelet count, an increase in bile acids, and reduced weights of the thymus, testis, and liver were observed in rats of the 3000 ppm group. Microscopically, hypospermatogenesis and spermatid giant cells were observed in the seminiferous tubules of the testes of rats exposed to 3000 ppm DMES. In the 13-wk study, rats were exposed 6 h/day, 5 days/wk to 2000, 600, 160, 40, or 0 ppm DMES. During exposure, rats of the 2000 ppm group exhibited mild narcosis and loss of startle reflex. Recovery from these central nervous system signs was rapid. Body weights were mildly decreased for rats of the 2000 ppm group. There were no exposure-related effects in hematology, serum chemistry, or urinalysis. Female rats of the 2000 ppm group had delayed estrous cycles (6 days compared to 5 days in control rats). Noteworthy organ weight changes in rats of the 2000 ppm group included decreases in thymus, liver, and testicular weights; however, pathologic lesions were observed in the testes only. Sperm motility, epididymal sperm count, and testicular spermatid count were dramatically reduced. Microscopic lesions included degeneration of the seminiferous tubular cells, pyknosis or absence of germ cells, and hypospermia in the epididymis. Rats of the 600 ppm group had a slight decrease in thymic weight and a transient decrease in body weight. Results of the acute, 2-wk, and 13-wk inhalation studies indicate DMES concentrations of 1000 ppm and higher produce narcosis that rapidly disappears following exposure. Repeated exposure of rats to DMES at either 3000 ppm for 2 wk or 2000 ppm for 13 wk caused testicular atrophy and hypospermia in male rats. Female rats exposed to 2000 ppm for 13 wk had delayed estrous cycles. Toxicological effects in rats of the 600 ppm group were minimal and equivocal. The 160 ppm concentration was a no-observable-effect level (NOEL) for 13 wk of exposure to DMES.

Impact of Low Dose Oral Exposure to Bisphenol A (BPA) on the Neonatal Rat Hypothalamic and Hippocampal Transcriptome: A CLARITY-BPA Consortium Study

PubMed Central

Arambula, Sheryl E.; Belcher, Scott M.; Planchart, Antonio; Turner, Stephen D.

2016-01-01

Bisphenol A (BPA) is an endocrine disrupting, high volume production chemical found in a variety of products. Evidence of prenatal exposure has raised concerns that developmental BPA may disrupt sex-specific brain organization and, consequently, induce lasting changes on neurophysiology and behavior. We and others have shown that exposure to BPA at doses below the no-observed-adverse-effect level can disrupt the sex-specific expression of estrogen-responsive genes in the neonatal rat brain including estrogen receptors (ERs). The present studies, conducted as part of the Consortium Linking Academic and Regulatory Insights of BPA Toxicity program, expanded this work by examining the hippocampal and hypothalamic transcriptome on postnatal day 1 with the hypothesis that genes sensitive to estrogen and/or sexually dimorphic in expression would be altered by prenatal BPA exposure. NCTR Sprague-Dawley dams were gavaged from gestational day 6 until parturition with BPA (0-, 2.5-, 25-, 250-, 2500-, or 25 000-μg/kg body weight [bw]/d). Ethinyl estradiol was used as a reference estrogen (0.05- or 0.5-μg/kg bw/d). Postnatal day 1 brains were microdissected and gene expression was assessed with RNA-sequencing (0-, 2.5-, and 2500-μg/kg bw BPA groups only) and/or quantitative real-time PCR (all exposure groups). BPA-related transcriptional changes were mainly confined to the hypothalamus. Consistent with prior observations, BPA induced sex-specific effects on hypothalamic ERα and ERβ (Esr1 and Esr2) expression and hippocampal and hypothalamic oxytocin (Oxt) expression. These data demonstrate prenatal BPA exposure, even at doses below the current no-observed-adverse-effect level, can alter gene expression in the developing brain. PMID:27571134

Impact of Low Dose Oral Exposure to Bisphenol A (BPA) on the Neonatal Rat Hypothalamic and Hippocampal Transcriptome: A CLARITY-BPA Consortium Study.

PubMed

Arambula, Sheryl E; Belcher, Scott M; Planchart, Antonio; Turner, Stephen D; Patisaul, Heather B

2016-10-01

Bisphenol A (BPA) is an endocrine disrupting, high volume production chemical found in a variety of products. Evidence of prenatal exposure has raised concerns that developmental BPA may disrupt sex-specific brain organization and, consequently, induce lasting changes on neurophysiology and behavior. We and others have shown that exposure to BPA at doses below the no-observed-adverse-effect level can disrupt the sex-specific expression of estrogen-responsive genes in the neonatal rat brain including estrogen receptors (ERs). The present studies, conducted as part of the Consortium Linking Academic and Regulatory Insights of BPA Toxicity program, expanded this work by examining the hippocampal and hypothalamic transcriptome on postnatal day 1 with the hypothesis that genes sensitive to estrogen and/or sexually dimorphic in expression would be altered by prenatal BPA exposure. NCTR Sprague-Dawley dams were gavaged from gestational day 6 until parturition with BPA (0-, 2.5-, 25-, 250-, 2500-, or 25 000-μg/kg body weight [bw]/d). Ethinyl estradiol was used as a reference estrogen (0.05- or 0.5-μg/kg bw/d). Postnatal day 1 brains were microdissected and gene expression was assessed with RNA-sequencing (0-, 2.5-, and 2500-μg/kg bw BPA groups only) and/or quantitative real-time PCR (all exposure groups). BPA-related transcriptional changes were mainly confined to the hypothalamus. Consistent with prior observations, BPA induced sex-specific effects on hypothalamic ERα and ERβ (Esr1 and Esr2) expression and hippocampal and hypothalamic oxytocin (Oxt) expression. These data demonstrate prenatal BPA exposure, even at doses below the current no-observed-adverse-effect level, can alter gene expression in the developing brain.

Investigation of a direct effect of nanosecond pulse electric fields on mitochondria

NASA Astrophysics Data System (ADS)

Estlack, Larry E.; Roth, Caleb C.; Cerna, Cesario Z.; Wilmink, Gerald J.; Ibey, Bennett L.

2014-03-01

The unique cellular response to nanosecond pulsed electric field (nsPEF) exposure, as compared to longer pulse exposure, has been theorized to be due to permeabilization of intracellular organelles including the mitochondria. In this investigation, we utilized a high-throughput oxygen and pH sensing system (Seahorse® XF24 extracellular flux analyzer) to assess the mitochondrial activity of Jurkat and U937 cells after nsPEF. The XF Analyzer uses a transient micro-chamber of only a few μL in specialized cell culture micro-plates to enable oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) to be monitored in real-time. We found that for nsPEF exposures of 10 pulses at 10-ns pulse width and at 50 kV/cm e-field, we were able to cause an increase in OCR in both U937 and Jurkat cells. We also found that high pulse numbers (>100) caused a significant decrease in OCR. Higher amplitude 150 kV/cm exposures had no effect on U937 cells and yet they had a deleterious effect on Jurkat cells, matching previously published 24 hour survival data. These results suggest that the exposures were modulating metabolic activity in cells possibly due to direct effects on the mitochondria themselves. To validate this hypothesis, we isolated mitochondria from U937 cells and exposed them similarly and found no significant change in metabolic activity for any pulse number. In a final experiment, we removed calcium from the buffer solution that the cells were exposed in and found that no significant enhancement in metabolic activity was observed. These results suggest that direct permeabilization of the mitochondria is unlikely a primary effect of nsPEF exposure and calcium-mediated intracellular pathway activation is likely responsible for observed pulse-induced mitochondrial effects.

Chemical Risk Assessment: Selected Federal Agencies’ Procedures, Assumptions, and Policies

DTIC Science & Technology

2001-08-01

adverse effects of exposures to hazardous substances or situations. It is a complex but valuable set of tools for federal regulatory agencies, helping...Act DES diethylstilbestrol DOT Department of Transportation ED effective dose EPA Environmental Protection Agency EPCRA Emergency Planning and...ISO International Organization for Standardization LED lowest effective dose LOAEL lowest observed adverse effect level LOEL lowest observed effect

Spacesuit Radiation Shield Design Methods

NASA Technical Reports Server (NTRS)

Wilson, John W.; Anderson, Brooke M.; Cucinotta, Francis A.; Ware, J.; Zeitlin, Cary J.

2006-01-01

Meeting radiation protection requirements during EVA is predominantly an operational issue with some potential considerations for temporary shelter. The issue of spacesuit shielding is mainly guided by the potential of accidental exposure when operational and temporary shelter considerations fail to maintain exposures within operational limits. In this case, very high exposure levels are possible which could result in observable health effects and even be life threatening. Under these assumptions, potential spacesuit radiation exposures have been studied using known historical solar particle events to gain insight on the usefulness of modification of spacesuit design in which the control of skin exposure is a critical design issue and reduction of blood forming organ exposure is desirable. Transition to a new spacesuit design including soft upper-torso and reconfigured life support hardware gives an opportunity to optimize the next generation spacesuit for reduced potential health effects during an accidental exposure.

Shared and unshared exposure measurement error in occupational cohort studies and their effects on statistical inference in proportional hazards models.

PubMed

Hoffmann, Sabine; Laurier, Dominique; Rage, Estelle; Guihenneuc, Chantal; Ancelet, Sophie

2018-01-01

Exposure measurement error represents one of the most important sources of uncertainty in epidemiology. When exposure uncertainty is not or only poorly accounted for, it can lead to biased risk estimates and a distortion of the shape of the exposure-response relationship. In occupational cohort studies, the time-dependent nature of exposure and changes in the method of exposure assessment may create complex error structures. When a method of group-level exposure assessment is used, individual worker practices and the imprecision of the instrument used to measure the average exposure for a group of workers may give rise to errors that are shared between workers, within workers or both. In contrast to unshared measurement error, the effects of shared errors remain largely unknown. Moreover, exposure uncertainty and magnitude of exposure are typically highest for the earliest years of exposure. We conduct a simulation study based on exposure data of the French cohort of uranium miners to compare the effects of shared and unshared exposure uncertainty on risk estimation and on the shape of the exposure-response curve in proportional hazards models. Our results indicate that uncertainty components shared within workers cause more bias in risk estimation and a more severe attenuation of the exposure-response relationship than unshared exposure uncertainty or exposure uncertainty shared between individuals. These findings underline the importance of careful characterisation and modeling of exposure uncertainty in observational studies.

Shared and unshared exposure measurement error in occupational cohort studies and their effects on statistical inference in proportional hazards models

PubMed Central

Laurier, Dominique; Rage, Estelle

2018-01-01

Exposure measurement error represents one of the most important sources of uncertainty in epidemiology. When exposure uncertainty is not or only poorly accounted for, it can lead to biased risk estimates and a distortion of the shape of the exposure-response relationship. In occupational cohort studies, the time-dependent nature of exposure and changes in the method of exposure assessment may create complex error structures. When a method of group-level exposure assessment is used, individual worker practices and the imprecision of the instrument used to measure the average exposure for a group of workers may give rise to errors that are shared between workers, within workers or both. In contrast to unshared measurement error, the effects of shared errors remain largely unknown. Moreover, exposure uncertainty and magnitude of exposure are typically highest for the earliest years of exposure. We conduct a simulation study based on exposure data of the French cohort of uranium miners to compare the effects of shared and unshared exposure uncertainty on risk estimation and on the shape of the exposure-response curve in proportional hazards models. Our results indicate that uncertainty components shared within workers cause more bias in risk estimation and a more severe attenuation of the exposure-response relationship than unshared exposure uncertainty or exposure uncertainty shared between individuals. These findings underline the importance of careful characterisation and modeling of exposure uncertainty in observational studies. PMID:29408862

Histopathology of repeated, intermittent exposure of chloramine-T to walleye (Sander vitreum) and (Ictalurus punctalus) channel catfish

USGS Publications Warehouse

Gaikowski, M.P.; Densmore, Christine L.; Blazer, V.S.

2009-01-01

Chloramine-T (Cl-T) has been used safely and effectively to control bacterial gill disease in salmonids at a maximum exposure regimen of up to four consecutive, once-daily exposures administered for 60??min at 20??mg/L. However, data to document safe treatment concentrations of Cl-T are lacking for freshwater-reared fish other than salmonids. We report the histopathology resultant from the administration of 12 consecutive, once-daily, 180-min static immersion baths of 0, 20, 50, or 80??mg Cl-T/L to walleye (20????C) and channel catfish (27????C). Twelve fish of each species were euthanized immediately before the first exposure (initial controls) and then after the twelfth exposure and 7 and 14??days after the twelfth exposure. Only initial controls and fish euthanized immediately after the twelfth exposure were processed for histological review because of the general lack of exposure-related lesions in exposed fish. The only exposure-related histological changes were in the spleen where significantly greater erythrocyte swelling and necrosis was observed in channel catfish exposed at 80??mg/L relative to exposure at 0??mg/L; similar histological changes were insignificant for walleye, though there appeared to be a shift in the general category of histological change with degenerative changes (necrosis, etc.) observed following exposure at 50 or 80??mg/L compared to the inflammatory and hemodynamic changes (congestion, leukocyte infiltrate, etc.) observed in walleye exposed at 0 or 20??mg/L. The only significant change in peripheral blood cytology was that walleye fingerlings exposed at 80??mg/L had significantly fewer mature red blood cells and significantly more immature red blood cells per oil-immersion field than controls. The histopathological changes observed following exposure to Cl-T under an exaggerated exposure regimen suggest that walleye or channel catfish therapeutically exposed to Cl-T will not have treatment-related histological changes.

Intraoperative observation of changes in cochlear nerve action potentials during exposure to electromagnetic fields generated by mobile phones.

PubMed

Colletti, Vittorio; Mandalà, Marco; Manganotti, Paolo; Ramat, Stefano; Sacchetto, Luca; Colletti, Liliana

2011-07-01

The rapid spread of devices generating electromagnetic fields (EMF) has raised concerns as to the possible effects of this technology on humans. The auditory system is the neural organ most frequently and directly exposed to electromagnetic activity owing to the daily use of mobile phones. In recent publications, a possible correlation between mobile phone usage and central nervous system tumours has been detected. Very recently a deterioration in otoacoustic emissions and in the auditory middle latency responses after intensive and long-term magnetic field exposure in humans has been demonstrated. To determine with objective observations if exposure to mobile phone EMF affects acoustically evoked cochlear nerve compound action potentials, seven patients suffering from Ménière's disease and undergoing retrosigmoid vestibular neurectomy were exposed to the effects of mobile phone placed over the craniotomy for 5 min. All patients showed a substantial decrease in amplitude and a significant increase in latency of cochlear nerve compound action potentials during the 5 min of exposure to EMF. These changes lasted for a period of around 5 min after exposure. The possibility that EMF can produce relatively long-lasting effects on cochlear nerve conduction is discussed and analysed in light of contrasting previous literature obtained under non-surgical conditions. Limitations of this novel approach, including the effects of the anaesthetics, craniotomy and surgical procedure, are presented in detail.

Gestational exposure to perfluorooctanoic acid (PFOA): alterations in motor related behaviors

PubMed Central

Goulding, David R.; White, Sally S.; McBride, Sandra J.; Fenton, Suzanne E.; Harry, G. Jean

2016-01-01

Perfluoroalkyl and polyfluoroalkyl substances are used in commercial applications and developmental exposure has been implicated in alterations in neurobehavioral functioning. While associations between developmental perfluorooctanoic acid (PFOA) exposure and human outcomes have been inconsistent, studies in experimental animals suggest alterations in motor related behaviors. To examine a dose-response pattern of neurobehavioral effects following gestational exposure to PFOA, pregnant CD-1 mice received PFOA (0, 0.1, 0.3, 1.0 mg/kg/day) via oral gavage from gestational day 1–17 and the male offspring examined. Motor activity assessments on postnatal day (PND)18, 19, and 20 indicated a shift in the developmental pattern with an elevated activity level observed in the 1.0 mg/kg/day dose group on PND18. In the adult, no alterations were observed in body weights, activity levels, diurnal pattern of running wheel activity, startle response, or pre-pulse startle inhibition. In response to a subcutaneous injection of saline or nicotine (80 µg/kg), all animals displayed a transient increase in activity likely associated with handling with no differences observed across dose groups. Inhibition of motor activity over 18 days of 400µg/kg nicotine injection was not significantly different across dose groups. Hyperactivity induced by 2mg/kg (+)-methamphetamine hydrochloride intraperitoneal injection was significantly lower in the 1.0 mg/kg/day PFOA dose group as compared to controls. Taken together, these data suggest that the effects on motor-related behaviors with gestational PFOA exposure do not mimic those reported for acute postnatal exposure. Changes were not observed at dose level under 1.0 mg/kg/day PFOA. Further examination of pathways associated with methamphetamine-induced activity is warranted. PMID:27888120

Personal medical electronic devices and walk-through metal detector security systems: assessing electromagnetic interference effects.

PubMed

Guag, Joshua; Addissie, Bisrat; Witters, Donald

2017-03-20

There have been concerns that Electromagnetic security systems such as walk-through metal detectors (WTMDs) can potentially cause electromagnetic interference (EMI) in certain active medical devices including implantable cardiac pacemakers and implantable neurostimulators. Incidents of EMI between WTMDs and active medical devices also known as personal medical electronic devices (PMED) continue to be reported. This paper reports on emission measurements of sample WTMDs and testing of 20 PMEDs in a WTMD simulation system. Magnetic fields from sample WTMD systems were characterized for emissions and exposure of certain PMEDs. A WTMD simulator system designed and evaluated by FDA in previous studies was used to mimic the PMED exposures to the waveform from sample WTMDs. The simulation system allows for controlled PMED exposure enabling careful study with adjustable magnetic field strengths and exposure duration, and provides flexibility for PMED exposure at elevated levels in order to study EMI effects on the PMED. The PMED samples consisted of six implantable cardiac pacemakers, six implantable cardioverter defibrillators (ICD), five implantable neurostimulators, and three insulin pumps. Each PMED was exposed in the simulator to the sample WTMD waveforms using methods based on appropriate consensus test standards for each of the device type. Testing the sample PMEDs using the WTMD simulator revealed EMI effects on two implantable pacemakers and one implantable neurostimulator for exposure field strength comparable to actual WTMD field strength. The observed effects were transient and the PMEDs returned to pre-exposure operation within a few seconds after removal from the simulated WTMD exposure fields. No EMI was observed for the sample ICDs or insulin pumps. The findings are consistent with earlier studies where certain sample PMEDs exhibited EMI effects. Clinical implications were not addressed in this study. Additional studies are needed to evaluate potential PMED EMI susceptibilities over a broader range of security systems.

Toxicological impact of cadmium-based quantum dots towards aquatic biota: Effect of natural sunlight exposure.

PubMed

Silva, B F; Andreani, T; Gavina, A; Vieira, M N; Pereira, C M; Rocha-Santos, T; Pereira, R

2016-07-01

Cadmium-based quantum dots (QDs) are increasingly applied in existent and emerging technologies, especially in biological applications due to their exceptional photophysical and functionalization properties. However, they are very toxic compounds due to the high reactive and toxic cadmium core. The present study aimed to determine the toxicity of three different QDs (CdS 380, CdS 480 and CdSeS/ZnS) before and after the exposure of suspensions to sunlight, in order to assess the effect of environmentally relevant irradiation levels in their toxicity, which will act after their release to the environment. Therefore, a battery of ecotoxicological tests was performed with organisms that cover different functional and trophic levels, such as Vibrio fischeri, Raphidocelis subcapitata, Chlorella vulgaris and Daphnia magna. The results showed that core-shell type QDs showed lower toxic effects to V. fischeri in comparison to core type QDs before sunlight exposure. However, after sunlight exposure, there was a decrease of CdS 380 and CdS 480 QD toxicity to bacterium. Also, after sunlight exposure, an effective decrease of CdSeS/ZnS and CdS 480 toxicity for D. magna and R. subcapitata, and an evident increase in CdS 380 QD toxicity, at least for D. magna, were observed. The results of this study suggest that sunlight exposure has an effect in the aggregation and precipitation reactions of larger QDs, causing the degradation of functional groups and formation of larger bulks which may be less prone to photo-oxidation due to their diminished surface area. The same aggregation behaviour after sunlight exposure was observed for bare QDs. These results further emphasize that the shell of QDs seems to make them less harmful to aquatic biota, both under standard environmental conditions and after the exposure to a relevant abiotic factor like sunlight. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of BPA and BPS exposure limited to early embryogenesis persist to impair non-associative learning in adults.

PubMed

Mersha, Mahlet D; Patel, Bansri M; Patel, Dipen; Richardson, Brittany N; Dhillon, Harbinder S

2015-09-17

Bisphenol-A (BPA) is a polymerizing agent used in plastic bottles and several routinely used consumer items. It is classified among endocrine disrupting chemicals suspected to cause adverse health effects in mammals ranging from infertility and cancer to behavioral disorders. Work with the invertebrate lab model Caenorhabditis elegans has shown that BPA affects germ cells by disrupting double-stranded DNA break repair mechanisms. The current study utilizes this model organism to provide insight into low-dose and long-term behavioral effects of BPA and bisphenol-S (BPS), a supposed safer replacement for BPA. Experiments presented in our report demonstrate that the effects of embryonic exposure to considerably low levels of BPA persist into adulthood, affecting neural functionality as assayed by measuring habituation to mechano-sensory stimuli in C. elegans. These results are noteworthy in that they are based on low-dose exposures, following the rationale that subtler effects that may not be morphologically apparent are likely to be discernible through behavioral changes. In addition, we report that embryonic exposure to BPS follows a pattern similar to BPA. Building upon previous observations using the C. elegans model, we have shown that exposure of embryos to BPA and BPS affects their behavior as adults. These long-term effects are in line with recommended alternate low-dose chemical safety testing approaches. Our observation that the effects of BPS are similar to BPA is not unexpected, considering their structural similarity. This, to our knowledge, is the first reported behavioral study on low-dose toxicity of any endocrine disrupting chemical in C. elegans.

Prenatal exposure to non-ionizing radiation: effects of WiFi signals on pregnancy outcome, peripheral B-cell compartment and antibody production.

PubMed

Sambucci, Manolo; Laudisi, Federica; Nasta, Francesca; Pinto, Rosanna; Lodato, Rossella; Altavista, Pierluigi; Lovisolo, Giorgio Alfonso; Marino, Carmela; Pioli, Claudio

2010-12-01

During embryogenesis, the development of tissues, organs and systems, including the immune system, is particularly susceptible to the effects of noxious agents. We examined the effects of prenatal (in utero) exposure to WiFi signals on pregnancy outcome and the immune B-cell compartment, including antibody production. Sixteen mated (plug-positive) female mice were assigned to each of the following groups: cage control, sham-exposed and microwave-exposed (WiFi signals at 2.45 GHz, whole body, SAR 4 W/kg, 2 h/day, 14 consecutive days starting 5 days after mating). No effects due to exposure to WiFi signals during pregnancy on mating success, number of newborns/mother and body weight at birth were found. Newborn mice were left to grow until 5 or 26 weeks of age, when immunological analyses were performed. No differences due to exposure were found in spleen cell number, B-cell frequency or antibody serum levels. When challenged in vitro with LPS, B cells from all groups produced comparable amounts of IgM and IgG, and proliferated at a similar level. All these findings were consistently observed in the female and male offspring at both juvenile (5 weeks) and adult (26 weeks) ages. Stress-associated effects as well as age- and/or sex-related differences were observed for several parameters. In conclusion, our results do not show any effect on pregnancy outcome or any early or late effects on B-cell differentiation and function due to prenatal exposure to WiFi signals.

Age as a risk factor for the disruption of cognitive performance by exposure to the types of radiation encounted on exploratory class missions to other planets

USDA-ARS?s Scientific Manuscript database

Exposure to the types of radiation encountered in space (particles of high energy and charge [HZE particles]) produces changes in neurocognitive performance similar to those observed in the aged organism. As such, it is possible that there would be an interaction between the effects of exposure to ...

Poisoning Young Minds.

ERIC Educational Resources Information Center

Schmidt, Charles W.

1999-01-01

Notes that neurobehavioral problems from exposure to lead and other toxins can be observed at doses far below those that cause more obvious signs of exposure. Calls for refining tests of cognitive and developmental skills in exposed children, identifying additional contaminants and mechanisms for behavioral effects, and improving dose- repose…

Observations of Interference between Portable Particle Counters and NOx Monitors

EPA Science Inventory

Studies in environmental exposure science have developed a preference for smaller devices that can be easily co-located without need for gas standards, such as those instruments utilized in the Near-road Exposures and Effects from Urban Air Pollutants Study (NEXUS). One operatio...

Hyperconnectivity of local neocortical microcircuitry induced by prenatal exposure to valproic acid.

PubMed

Rinaldi, Tania; Silberberg, Gilad; Markram, Henry

2008-04-01

Exposure to valproic acid (VPA) during embryogenesis can cause several teratogenic effects, including developmental delays and in particular autism in humans if exposure occurs during the third week of gestation. We examined the postnatal effects of embryonic exposure to VPA on microcircuit properties of juvenile rat neocortex using in vitro electrophysiology. We found that a single prenatal injection of VPA on embryonic day 11.5 causes a significant enhancement of the local recurrent connectivity formed by neocortical pyramidal neurons. The study of the biophysical properties of these connections revealed weaker excitatory synaptic responses. A marked decrease of the intrinsic excitability of pyramidal neurons was also observed. Furthermore, we demonstrate a diminished number of putative synaptic contacts in connection between layer 5 pyramidal neurons. Local hyperconnectivity may render cortical modules more sensitive to stimulation and once activated, more autonomous, isolated, and more difficult to command. This could underlie some of the core symptoms observed in humans prenatally exposed to valproic acid.

Silent latency periods in methylmercury poisoning and in neurodegenerative disease.

PubMed

Weiss, Bernard; Clarkson, Thomas W; Simon, William

2002-10-01

This article discusses three examples of delay (latency) in the appearance of signs and symptoms of poisoning after exposure to methylmercury. First, a case is presented of a 150-day delay period before the clinical manifestations of brain damage after a single brief (<1 day) exposure to dimethylmercury. The second example is taken from the Iraq outbreak of methylmercury poisoning in which the victims consumed contaminated bread for several weeks without any ill effects. Indeed, signs of poisoning did not appear until weeks or months after exposure stopped. The last example is drawn from observations on nonhuman primates and from the sequelae of the Minamata, Japan, outbreak in which low chronic doses of methylmercury may not have produced observable behavioral effects for periods of time measured in years. The mechanisms of these latency periods are discussed for both acute and chronic exposures. Parallels are drawn with other diseases that affect the central nervous system, such as Parkinson disease and post-polio syndrome, that also reflect the delayed appearance of central nervous system damage.

Placental transport and in vitro effects of Bisphenol A.

PubMed

Mørck, Thit J; Sorda, Giuseppina; Bechi, Nicoletta; Rasmussen, Brian S; Nielsen, Jesper B; Ietta, Francesca; Rytting, Erik; Mathiesen, Line; Paulesu, Luana; Knudsen, Lisbeth E

2010-08-01

Bisphenol A (BPA), an estrogen-like chemical, leaches from consumer products potentially causing human exposure. To examine the effects of BPA exposure during pregnancy, we performed studies using the BeWo trophoblast cell line, placental explant cultures, placental perfusions and skin diffusion models, all of human origin. Results showed BPA cytotoxicity in BeWo cells with an apparent EC50 at 100-125 microM. BPA exposure significantly increased beta-hCG secretion and caspase-3 expression in placental explants at an environmentally relevant concentration of 1 nM. In the transport studies, a rapid transfer of BPA was observed across the term placentae and the BeWo cell monolayer. Further, transdermal transport of BPA was observed. These results indicate that fetal BPA exposure through placental exchange occurs with potential adverse implications for placental and fetal development. This battery of test systems within the realm of human implantation and fetal development represents important elements in risk assessment of reproductive toxicity. Copyright 2010 Elsevier Inc. All rights reserved.

Antiepileptic drugs and brain maturation: fetal exposure to lamotrigine generates cortical malformations in rats.

PubMed

Manent, Jean-Bernard; Jorquera, Isabel; Franco, Valentina; Ben-Ari, Yehezkel; Perucca, Emilio; Represa, Alfonso

2008-02-01

Intake of antiepileptic drugs (AEDs) during pregnancy can provoke severe and subtle fetal malformations associated with deleterious sequelae, reflecting the need for experimental investigations on the comparative teratogenic potential of these agents. We recently reported that prenatal exposure to vigabatrin and valproate, two AEDs which act through GABAergic mechanisms, induces hippocampal and cortical dysplasias in rodents. We have now investigated the effects of phenobarbital (PB, 30 mg/kg day) i.p.), a drug also endowed with GABAergic effects, and the new generation AEDs lamotrigine (LTG, 5-20mg/kg/day i.p.), topiramate (TPM, 10mg/kg/day i.p.), and levetiracetam (LEV, 50mg/kg/day i.p.) on brain development. Prenatal exposure to LTG induced hippocampal and cortical malformations in a dose-dependent manner, at maternal plasma concentrations within the clinically occurring range. These abnormalities were not observed after exposure to PB, TP and LEV. These observations raise concerns about potential clinical correlates and call for detailed comparative investigations on the consequences of AED use during pregnancy.

Effects of tributyltin (TBT) on Xenopus tropicalis embryos at environmentally relevant concentrations.

PubMed

Guo, Suzhen; Qian, Lijuan; Shi, Huahong; Barry, Terence; Cao, Qinzhen; Liu, Junqi

2010-04-01

Tributyltin (TBT) has been widely used as a biocide in antifouling paints and is a known endocrine disrupting chemical. In this paper, we exposed embryos of Xenopus tropicalis to 50-400ngL(-1) tributyltin chloride. TBT significantly decreased the survival rate, reduced the body length and retarded the development of embryos after 24, 36 and 48h of exposure. These effects of TBT were concentration- and time-dependent. Embryos treated with TBT showed multiple malformations. The most obvious alterations were abnormal eyes, enlarged proctodaeum, narrow fins, and skin hypopigmentation. Enlarged proctodaeum and narrow fins were mainly observed after 36 and 48h of exposure. The loss of eye pigmentation or the absence of external eyes occurred after 24 and 36h of exposure, while extended lenses or edemas of eyes were more commonly observed after 48h of exposure. Additional malformations included: small anterior region of heads, pericardial edemas, enlarged trunks, and bent tails. These results suggested that TBT is very toxic to X. tropicalis embryos at environmentally relevant concentrations.

Antibiotic exposure in neonates and early adverse outcomes: a systematic review and meta-analysis.

PubMed

Esaiassen, Eirin; Fjalstad, Jon Widding; Juvet, Lene Kristine; van den Anker, John N; Klingenberg, Claus

2017-07-01

To systematically review and meta-analyse the relationship between antibiotic exposure in neonates and the following early adverse outcomes: necrotizing enterocolitis (NEC), invasive fungal infections (IFIs) and/or death. Data sources were PubMed, Embase, Medline and the Cochrane Database (to December 2016), supplemented by manual searches of reference lists. Randomized controlled trials (RCTs) and observational studies were included if they provided data on different categories of antibiotic exposures (yes versus no, long versus short duration, and/or broad- versus narrow-spectrum regimens) and the risk of developing NEC, IFI and/or death in the neonatal period. Two reviewers extracted data and evaluated the risk of bias using the Cochrane Handbook, adapted to include observational studies. When appropriate, meta-analyses were conducted using the random-effect model. We identified 9 RCTs and 38 observational studies. The quality of the majority of studies was poor to moderate. There was a significant association between prolonged antibiotic exposure and an increased risk of NEC in five observational studies (5003 participants) and/or risk of death in five observational studies (13 534 participants). Eleven of 15 studies with data on broad- versus narrow-spectrum regimens reported an increased risk of IFI after broad-spectrum antibiotic exposure, in particular with third-generation cephalosporins and carbapenems. Meta-analysis was limited by few and old RCTs, insufficient sample sizes and diversity of antibiotic exposure and outcomes reported. Prolonged antibiotic exposure in uninfected preterm infants is associated with an increased risk of NEC and/or death, and broad-spectrum antibiotic exposure is associated with an increased risk of IFI. © The Author 2017. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Response terminated displays unload selective attention

PubMed Central

Roper, Zachary J. J.; Vecera, Shaun P.

2013-01-01

Perceptual load theory successfully replaced the early vs. late selection debate by appealing to adaptive control over the efficiency of selective attention. Early selection is observed unless perceptual load (p-Load) is sufficiently low to grant attentional “spill-over” to task-irrelevant stimuli. Many studies exploring load theory have used limited display durations that perhaps impose artificial limits on encoding processes. We extended the exposure duration in a classic p-Load task to alleviate temporal encoding demands that may otherwise tax mnemonic consolidation processes. If the load effect arises from perceptual demands alone, then freeing-up available mnemonic resources by extending the exposure duration should have little effect. The results of Experiment 1 falsify this prediction. We observed a reliable flanker effect under high p-Load, response-terminated displays. Next, we orthogonally manipulated exposure duration and task-relevance. Counter-intuitively, we found that the likelihood of observing the flanker effect under high p-Load resides with the duration of the task-relevant array, not the flanker itself. We propose that stimulus and encoding demands interact to produce the load effect. Our account clarifies how task parameters differentially impinge upon cognitive processes to produce attentional “spill-over” by appealing to visual short-term memory as an additional processing bottleneck when stimuli are briefly presented. PMID:24399983

Response terminated displays unload selective attention.

PubMed

Roper, Zachary J J; Vecera, Shaun P

2013-01-01

Perceptual load theory successfully replaced the early vs. late selection debate by appealing to adaptive control over the efficiency of selective attention. Early selection is observed unless perceptual load (p-Load) is sufficiently low to grant attentional "spill-over" to task-irrelevant stimuli. Many studies exploring load theory have used limited display durations that perhaps impose artificial limits on encoding processes. We extended the exposure duration in a classic p-Load task to alleviate temporal encoding demands that may otherwise tax mnemonic consolidation processes. If the load effect arises from perceptual demands alone, then freeing-up available mnemonic resources by extending the exposure duration should have little effect. The results of Experiment 1 falsify this prediction. We observed a reliable flanker effect under high p-Load, response-terminated displays. Next, we orthogonally manipulated exposure duration and task-relevance. Counter-intuitively, we found that the likelihood of observing the flanker effect under high p-Load resides with the duration of the task-relevant array, not the flanker itself. We propose that stimulus and encoding demands interact to produce the load effect. Our account clarifies how task parameters differentially impinge upon cognitive processes to produce attentional "spill-over" by appealing to visual short-term memory as an additional processing bottleneck when stimuli are briefly presented.

Exposure-response relationship and risk assessment for cognitive deficits in early welding-induced manganism.

PubMed

Park, Robert M; Bowler, Rosemarie M; Roels, Harry A

2009-10-01

The exposure-response relationship for manganese (Mn)-induced adverse nervous system effects is not well described. Symptoms and neuropsychological deficits associated with early manganism were previously reported for welders constructing bridge piers during 2003 to 2004. A reanalysis using improved exposure, work history information, and diverse exposure metrics is presented here. Ten neuropsychological performance measures were examined, including working memory index (WMI), verbal intelligence quotient, design fluency, Stroop color word test, Rey-Osterrieth Complex Figure, and Auditory Consonant Trigram tests. Mn blood levels and air sampling data in the form of both personal and area samples were available. The exposure metrics used were cumulative exposure to Mn, body burden assuming simple first-order kinetics for Mn elimination, and cumulative burden (effective dose). Benchmark doses were calculated. Burden with a half-life of about 150 days was the best predictor of blood Mn. WMI performance declined by 3.6 (normal = 100, SD = 15) for each 1.0 mg/m3 x mo exposure (P = 0.02, one tailed). At the group mean exposure metric (burden; half-life = 275 days), WMI performance was at the lowest 17th percentile of normal, and at the maximum observed metric, performance was at the lowest 2.5 percentiles. Four other outcomes also exhibited statistically significant associations (verbal intelligence quotient, verbal comprehension index, design fluency, Stroop color word test); no dose-rate effect was observed for three of the five outcomes. A risk assessment performed for the five stronger effects, choosing various percentiles of normal performance to represent impairment, identified benchmark doses for a 2-year exposure leading to 5% excess impairment prevalence in the range of 0.03 to 0.15 mg/m3, or 30 to 150 microg/m3, total Mn in air, levels that are far below those permitted by current occupational standards. More than one-third of workers would be impaired after working 2 years at 0.2 mg/m3 Mn (the current threshold limit value).

Tolerance and sensitization to inhaled 1,1,1-trichloroethane in mice: results from open-field behavior and a functional observational battery.

PubMed

Bowen, Scott E; Balster, Robert L

2006-05-01

1,1,1-Trichloroethane (TCE), a representative abused solvent, has well described acute behavioral effects in animals. Much less is known about repeated high-concentration exposures as would be encountered in inhalant abusers. Tolerance has been demonstrated in some, but not all, studies with TCE while sensitization has also been seen with other abused solvents. The present study was designed to further characterize changes in the effects of repeated exposure to TCE on a variety of mouse behaviors. Mice were tested using locomotor activity as well as a functional observational battery (FOB) both before and after a regimen of daily exposures to various concentrations of TCE. The initial locomotor effects of acute 30-min exposures to TCE were biphasic with concentration-dependent increases in activity at lower concentrations and decreases observed at higher concentrations. The profile of acute effects as measured by the FOB included changes in posture, decreased arousal, disturbances in gait, delayed righting reflexes, and decreased sensorimotor reactivity. Animals were then divided into five groups and exposed 30 min/day to either air or one of four concentrations of TCE (2,000, 6,000, 10,000, or 13,300 ppm) for 15 consecutive days. The TCE concentration used primarily affected the magnitude of change, not whether tolerance or sensitization occurred. Tolerance developed on the measures of forelimb grip strength, inverted screen, and number of rears. Conversely, sensitization developed to measures of locomotor activity. Depending on the behavioral measure, both tolerance and sensitization can occur in mice with repeated exposure to TCE. Both of these phenomena are characteristic of drugs of abuse.

Neurophysiological evidence that perceptions of fluency produce mere exposure effects.

PubMed

Leynes, P Andrew; Addante, Richard J

2016-08-01

Recent exposure to people or objects increases liking ratings, the "mere exposure effect" (Zajonc in American Psychologist, 35, 117-123, 1968), and an increase in processing fluency has been identified as a potential mechanism for producing this effect. This fluency hypothesis was directly tested by altering the trial-by-trial image clarity (i.e., fluency) while Event-Related Potentials (ERPs) were recorded. In Experiment 1, clarity was altered across two trial blocks that each had homogenous trial-by-trial clarity, whereas clarity varied randomly across trials in Experiment 2. Blocking or randomizing image clarity across trials was expected to produce different levels of relative fluency and alter mere exposure effects. The mere exposure effect (i.e., old products liked more than new products) was observed when stimulus clarity remained constant across trials, and clear image ERPs were more positive than blurry image ERPs. Importantly, these patterns were reversed when clarity varied randomly across test trials, such that participants liked clear images more than blurry (i.e., no mere exposure effect) and clear image ERPs were more negative than blurry image ERPs. The findings provide direct experimental support from both behavioral and electrophysiological measures that, in some contexts, mere exposure is the product of top-down interpretations of fluency.

MP-12 virus containing the clone 13 deletion in the NSs gene prevents lethal disease when administered after Rift Valley fever virus infection in hamsters.

PubMed

Gowen, Brian B; Westover, Jonna B; Sefing, Eric J; Bailey, Kevin W; Nishiyama, Shoko; Wandersee, Luci; Scharton, Dionna; Jung, Kie-Hoon; Ikegami, Tetsuro

2015-01-01

Rift Valley fever virus (RVFV; Bunyaviridae, Phlebovirus) causes a range of illnesses that include retinitis, fulminant hepatitis, neurologic disease, and hemorrhagic fever. In hospitalized individuals, case fatality rates can be as high as 10-20%. There are no vaccines or antivirals approved for human use to prevent or treat severe RVFV infections. We previously tested the efficacy of the MP-12 vaccine strain and related variants with NSs truncations as a post-exposure prophylaxis in mice infected with wild-type pathogenic RVFV strain ZH501. Post-exposure efficacy of the rMP12-C13type, a recombinant MP-12 vaccine virus which encodes an in-frame truncation removing 69% of the NSs protein, resulted in 30% survival when administering the virus within 30 min of subcutaneous ZH501 challenge in mice, while the parental MP-12 virus conferred no protection by post-exposure vaccination. Here, we demonstrate uniform protection of hamsters by post-exposure vaccination with rMP12-C13type administered 6 h post-ZH501 infection while no efficacy was observed with the parental MP-12 virus. Notably, both the MP-12 and rMP12-C13type viruses were highly effective (100% protection) when administered 21 days prior to challenge. In a subsequent study delaying vaccination until 8, 12, and 24 h post-RVFV exposure, we observed 80, 70, and 30% survival, respectively. Our findings indicate that the rapid protective innate immune response elicited by rMP12-C13type may be due to the truncated NSs protein, suggesting that the resulting functional inactivation of NSs plays an important role in the observed post-exposure efficacy. Taken together, the data demonstrate that post-exposure vaccination with rMP12-C13type is effective in limiting ZH501 replication and associated disease in standard pre-exposure vaccination and post-challenge treatment models of RVFV infection, and suggest an extended post-exposure prophylaxis window beyond that initially observed in mice.

Specific Features of the Hypothalamic Leptin Signaling Response to Cold Exposure Are Reflected in Peripheral Blood Mononuclear Cells in Rats and Ferrets

PubMed Central

Reynés, Bàrbara; Klein Hazebroek, Marlou; García-Ruiz, Estefanía; Keijer, Jaap; Oliver, Paula; Palou, Andreu

2017-01-01

Objectives: Cold exposure induces hyperphagia to counteract fat loss related to lipid mobilization and thermogenic activation. The aim of this study was investigate on the molecular mechanisms involved in cold-induced compensatory hyperphagia. Methods: We analyzed the effect of cold exposure on gene expression of orexigenic and anorexigenic peptides, and of leptin signaling-related genes in the hypothalamus of rats at different ages (1, 2, 4, and 6 months), as well as in ferrets. We also evaluated the potential of peripheral blood mononuclear cells to reflect hypothalamic molecular responses. Results: As expected, cold exposure induced hypoleptinemia in rats, which could be responsible for the increased ratio of orexigenic/anorexigenic peptides gene expression in the hypothalamus, mainly due to decreased anorexigenic gene expression, especially in young animals. In ferrets, which resemble humans more closely, cold exposure induced greater changes in hypothalamic mRNA levels of orexigenic genes. Despite the key role of leptin in food intake control, the effect of cold exposure on the expression of key hypothalamic leptin signaling cascade genes is not clear. In our study, cold exposure seemed to affect leptin signaling in 4-month-old rats (increased Socs3 and Lepr expression), likely associated with the smaller-increase in food intake and decreased body weight observed at this particular age. Similarly, cold exposed ferrets showed greater hypothalamic Socs3 and Stat3 gene expression. Interestingly, peripheral blood mononuclear cells (PBMC) mimicked the hypothalamic increase in Lepr and Socs3 observed in 4-month-old rats, and the increased Socs3 mRNA expression observed in ferrets in response to cold exposure. Conclusions: The most outstanding result of our study is that PBMC reflected the specific modulation of leptin signaling observed in both animal models, rats and ferrets, which points forwards PBMC as easily obtainable biological material to be considered as a potential surrogate tissue to perform further studies on the regulation of hypothalamic leptin signaling in response to cold exposure. PMID:28860997

In Utero Alcohol Exposure and the Alteration of Histone Marks in the Developing Fetus: An Epigenetic Phenomenon of Maternal Drinking

PubMed Central

Mandal, Chanchal; Halder, Debasish; Jung, Kyoung Hwa; Chai, Young Gyu

2017-01-01

Ethanol is well known for its teratogenic effects during fetal development. Maternal alcohol consumption allows the developing fetus to experience the detrimental effects of alcohol exposure. Alcohol-mediated teratogenic effects can vary based on the dosage and the length of exposure. The specific mechanism of action behind this teratogenic effect is still unknown. Previous reports demonstrated that alcohol participates in epigenetic alterations, especially histone modifications during fetal development. Additional research is necessary to understand the correlation between major epigenetic events and alcohol-mediated teratogenesis such as that observed in fetal alcohol spectrum disorder (FASD). Here, we attempted to collect all the available information concerning alcohol-mediated histone modifications during gestational fetal development. We hope that this review will aid researchers to further examine the issues associated with ethanol exposure. PMID:29104501

Modeling adverse environmental impacts on the reproductive system.

PubMed

Sussman, N B; Mazumdar, S; Mattison, D R

1999-03-01

When priority topics are being established for the study of women's health, it is generally agreed that one important area on which to focus research is reproduction. For example, increasing attention has been directed to environmental exposures that disrupt the endocrine system and alter reproduction. These concerns also suggest the need to give greater attention to the use of animal toxicologic testing to draw inferences about human reproductive risks. Successful reproduction requires multiple simultaneous and sequential processes in both the male and female, and the effect of toxicity on reproduction-related processes is time dependent. Currently, however, the risk assessment approach does not allow for the use of multiple processes or for considering the reproductive process response as a function of time. We discuss several issues in modeling exposure effects on reproductive function for risk assessment and present an overview of approaches for reproductive risk assessment. Recommendations are provided for an effective animal study design for determining reproductive risk that addresses optimization of the duration of dosing, observation of the effects of exposure on validated biomarkers, analysis of several biomarkers for complete characterization of the exposure on the underlying biologic processes, the need for longitudinally observed exposure effects, and a procedure for estimating human reproductive risk from the animal findings. An approach to characterizing reproductive toxicity to estimate the increased fertility risks in a dibromochloropropane (DBCP)-exposed human population is illustrated, using several reproductive biomarkers simultaneously from a longitudinal rabbit inhalation study of DBCP and an interspecies extrapolation method.

Developmental effects of magnetic field (50 Hz) in combination with ionizing radiation and chemical teratogens.

PubMed

Pafková, H; Jerábek, J; Tejnorová, I; Bednár, V

1996-11-01

The influence of a 50 Hz magnetic field (MF) on avian and mammalian embryogenesis, the MF level and vector, as well as the effect of exposure to MF (50 Hz, 10 mT) in combination with X-rays has been recently reported [2,3]. No significant alterations of chick or rat embryogenesis were found after repeated exposures to 50 Hz MF at 10 mT or 6 microT or with different vectors. However, X-ray chick embryotoxicity was significantly affected by repeated exposures of developing organisms to MF. A strong dependence of effect on the type of interaction was revealed. A decrease of X-ray induced teratogenicity was observed when MF preceded X-ray exposure (indirect interaction), while MF exposure applied immediately after X-ray radiation (direct interaction) non-significantly potentiated adverse developmental effects of ionizing radiation. This study deals with the effects of MF in combination with insulin or tetracycline. Exposure of chick embryos to MF influenced the sensitivity of embryonic morphogenetic systems to the subsequently administered chemical teratogens, insulin and/or tetracycline. A protective effect of MF was detected similarly as in the case of indirect interaction with ionizing radiation.

Wavelet-based functional linear mixed models: an application to measurement error-corrected distributed lag models.

PubMed

Malloy, Elizabeth J; Morris, Jeffrey S; Adar, Sara D; Suh, Helen; Gold, Diane R; Coull, Brent A

2010-07-01

Frequently, exposure data are measured over time on a grid of discrete values that collectively define a functional observation. In many applications, researchers are interested in using these measurements as covariates to predict a scalar response in a regression setting, with interest focusing on the most biologically relevant time window of exposure. One example is in panel studies of the health effects of particulate matter (PM), where particle levels are measured over time. In such studies, there are many more values of the functional data than observations in the data set so that regularization of the corresponding functional regression coefficient is necessary for estimation. Additional issues in this setting are the possibility of exposure measurement error and the need to incorporate additional potential confounders, such as meteorological or co-pollutant measures, that themselves may have effects that vary over time. To accommodate all these features, we develop wavelet-based linear mixed distributed lag models that incorporate repeated measures of functional data as covariates into a linear mixed model. A Bayesian approach to model fitting uses wavelet shrinkage to regularize functional coefficients. We show that, as long as the exposure error induces fine-scale variability in the functional exposure profile and the distributed lag function representing the exposure effect varies smoothly in time, the model corrects for the exposure measurement error without further adjustment. Both these conditions are likely to hold in the environmental applications we consider. We examine properties of the method using simulations and apply the method to data from a study examining the association between PM, measured as hourly averages for 1-7 days, and markers of acute systemic inflammation. We use the method to fully control for the effects of confounding by other time-varying predictors, such as temperature and co-pollutants.

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

PubMed

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

2010-12-01

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

Effects of Parental Deafness and Early Exposure to Manual Communication on the Cognitive Skills, English Language Skill, and Field Independence of Young Deaf Adults.

ERIC Educational Resources Information Center

Parasnis, Ila

1983-01-01

Differential effects of parental deafness and early exposure to manual communication were not observed in the cognitive and communication performance of the 38 experimental subjects. Furthermore, the Delayed sign language group performed significantly better than the early American Sign Language group on tests of speech perception and speech…

Prenatal exposure to vanilla or alcohol induces crawling after these odors in the neonate rat: The role of mu and kappa opioid receptor systems.

PubMed

Gaztañaga, Mirari; Aranda-Fernández, P Ezequiel; Chotro, M Gabriela

2015-09-01

Rat fetuses can perceive chemosensory stimuli derived from their mother's diet, and they may learn about those stimuli. In previous studies we have observed that prenatal exposure to alcohol during the last days of gestation increases the acceptance and liking of an alcohol flavor in infant and adolescent rats. While these results were not found after prenatal exposure to vanilla, cineole or anise, suggesting that the pharmacological properties of alcohol, mediated by the opioid system, underlie the effects observed with this drug. Considering that other studies report enhanced acceptance of non-alcohol flavors experienced prenatally when subjects were tested before infancy, we explore the possibility of observing similar results if testing 1-day old rats exposed prenatally to vanilla. Using an "odor-induced crawling" testing procedure, it was observed that neonates exposed prenatally to vanilla or alcohol crawl for a longer distance towards the experienced odor than to other odors or than control pups. Blocking mu, but not kappa opioid receptors, reduced the attraction of vanilla odor to neonates exposed to vanilla in utero, while the response to alcohol in pups exposed prenatally to this drug was affected by both antagonists. Results confirm that exposure to a non-alcohol odor enhances postnatal responses to it, observable soon after birth, while also suggesting that the mu opioid receptor system plays an important role in generating this effect. The results also imply that with alcohol exposure, the prenatal opioid system is wholly involved, which could explain the longer retention of the enhanced attraction to alcohol following prenatal experience with the drug. Copyright © 2014 Elsevier Inc. All rights reserved.

Time dependent effect of chronic embryonic exposure to ethanol on zebrafish: Morphology, biochemical and anxiety alterations.

PubMed

Ramlan, Nurul Farhana; Sata, Nurul Syafida Asma Mohd; Hassan, Siti Norhidayah; Bakar, Noraini Abu; Ahmad, Syahida; Zulkifli, Syaizwan Zahmir; Abdullah, Che Azurahanim Che; Ibrahim, Wan Norhamidah Wan

2017-08-14

Exposure to ethanol during critical period of development can cause severe impairments in the central nervous system (CNS). This study was conducted to assess the neurotoxic effects of chronic embryonic exposure to ethanol in the zebrafish, taking into consideration the time dependent effect. Two types of exposure regimen were applied in this study. Withdrawal exposure group received daily exposure starting from gastrulation until hatching, while continuous exposure group received daily exposure from gastrulation until behavioural assessment at 6dpf (days post fertilization). Chronic embryonic exposure to ethanol decreased spontaneous tail coiling at 24hpf (hour post fertilization), heart rate at 48hpf and increased mortality rate at 72hpf. The number of apoptotic cells in the embryos treated with ethanol was significantly increased as compared to the control. We also measured the morphological abnormalities and the most prominent effects can be observed in the treated embryos exposed to 1.50% and 2.00%. The treated embryos showed shorter body length, larger egg yolk, smaller eye diameter and heart edema as compared to the control. Larvae received 0.75% continuous ethanol exposure exhibited decreased swimming activity and increased anxiety related behavior, while withdrawal ethanol exposure showed increased swimming activity and decreased anxiety related behavior as compared to the respective control. Biochemical analysis exhibited that ethanol exposure for both exposure regimens altered proteins, lipids, carbohydrates and nucleic acids of the zebrafish larvae. Our results indicated that time dependent effect of ethanol exposure during development could target the biochemical processes thus leading to induction of apoptosis and neurobehavioral deficits in the zebrafish larvae. Thus it raised our concern about the safe limit of alcohol consumption for pregnant mother especially during critical periods of vulnerability for developing nervous system. Copyright © 2017 Elsevier B.V. All rights reserved.

UMTS base station-like exposure, well-being, and cognitive performance.

PubMed

Regel, Sabine J; Negovetic, Sonja; Röösli, Martin; Berdiñas, Veronica; Schuderer, Jürgen; Huss, Anke; Lott, Urs; Kuster, Niels; Achermann, Peter

2006-08-01

Radio-frequency electromagnetic fields (RF EMF) of mobile communication systems are widespread in the living environment, yet their effects on humans are uncertain despite a growing body of literature. We investigated the influence of a Universal Mobile Telecommunications System (UMTS) base station-like signal on well-being and cognitive performance in subjects with and without self-reported sensitivity to RF EMF. We performed a controlled exposure experiment (45 min at an electric field strength of 0, 1, or 10 V/m, incident with a polarization of 45 degrees from the left back side of the subject, weekly intervals) in a randomized, double-blind crossover design. A total of 117 healthy subjects (33 self-reported sensitive, 84 nonsensitive subjects) participated in the study. We assessed well-being, perceived field strength, and cognitive performance with questionnaires and cognitive tasks and conducted statistical analyses using linear mixed models. Organ-specific and brain tissue-specific dosimetry including uncertainty and variation analysis was performed. In both groups, well-being and perceived field strength were not associated with actual exposure levels. We observed no consistent condition-induced changes in cognitive performance except for two marginal effects. At 10 V/m we observed a slight effect on speed in one of six tasks in the sensitive subjects and an effect on accuracy in another task in nonsensitive subjects. Both effects disappeared after multiple end point adjustment. In contrast to a recent Dutch study, we could not confirm a short-term effect of UMTS base station-like exposure on well-being. The reported effects on brain functioning were marginal and may have occurred by chance. Peak spatial absorption in brain tissue was considerably smaller than during use of a mobile phone. No conclusions can be drawn regarding short-term effects of cell phone exposure or the effects of long-term base station-like exposure on human health.

UMTS Base Station-like Exposure, Well-Being, and Cognitive Performance

PubMed Central

Regel, Sabine J.; Negovetic, Sonja; Röösli, Martin; Berdiñas, Veronica; Schuderer, Jürgen; Huss, Anke; Lott, Urs; Kuster, Niels; Achermann, Peter

2006-01-01

Background Radio-frequency electromagnetic fields (RF EMF) of mobile communication systems are widespread in the living environment, yet their effects on humans are uncertain despite a growing body of literature. Objectives We investigated the influence of a Universal Mobile Telecommunications System (UMTS) base station-like signal on well-being and cognitive performance in subjects with and without self-reported sensitivity to RF EMF. Methods We performed a controlled exposure experiment (45 min at an electric field strength of 0, 1, or 10 V/m, incident with a polarization of 45° from the left back side of the subject, weekly intervals) in a randomized, double-blind crossover design. A total of 117 healthy subjects (33 self-reported sensitive, 84 nonsensitive subjects) participated in the study. We assessed well-being, perceived field strength, and cognitive performance with questionnaires and cognitive tasks and conducted statistical analyses using linear mixed models. Organ-specific and brain tissue–specific dosimetry including uncertainty and variation analysis was performed. Results In both groups, well-being and perceived field strength were not associated with actual exposure levels. We observed no consistent condition-induced changes in cognitive performance except for two marginal effects. At 10 V/m we observed a slight effect on speed in one of six tasks in the sensitive subjects and an effect on accuracy in another task in nonsensitive subjects. Both effects disappeared after multiple end point adjustment. Conclusions In contrast to a recent Dutch study, we could not confirm a short-term effect of UMTS base station-like exposure on well-being. The reported effects on brain functioning were marginal and may have occurred by chance. Peak spatial absorption in brain tissue was considerably smaller than during use of a mobile phone. No conclusions can be drawn regarding short-term effects of cell phone exposure or the effects of long-term base station-like exposure on human health. PMID:16882538

The effect of electromagnetic radiation emitted by display screens on cell oxygen metabolism - in vitro studies.

PubMed

Lewicka, Małgorzata; Henrykowska, Gabriela A; Pacholski, Krzysztof; Śmigielski, Janusz; Rutkowski, Maciej; Dziedziczak-Buczyńska, Maria; Buczyński, Andrzej

2015-12-10

Research studies carried out for decades have not solved the problem of the effect of electromagnetic radiation of various frequency and strength on the human organism. Due to this fact, we decided to investigate the changes taking place in human blood platelets under the effect of electromagnetic radiation (EMR) emitted by LCD monitors. The changes of selected parameters of oxygen metabolism were measured, i.e. reactive oxygen species concentration, enzymatic activity of antioxidant defence proteins - superoxide dismutase (SOD-1) and catalase (CAT) - and malondialdehyde concentration (MDA). A suspension of human blood platelets was exposed to electromagnetic radiation of 1 kHz frequency and 150 V/m and 220 V/m intensity for 30 and 60 min. The level of changes of the selected parameters of oxidative stress was determined after the exposure and compared to the control samples (not exposed). The measurements revealed an increase of the concentration of reactive oxygen species. The largest increase of ROS concentration vs. the control sample was observed after exposure to EMF of 220 V/m intensity for 60 min (from x = 54.64 to x = 72.92). The measurement of MDA concentration demonstrated a statistically significant increase after 30-min exposure to an EMF of 220 V/m intensity in relation to the initial values (from x = 3.18 to x = 4.41). The enzymatic activity of SOD-1 decreased after exposure (the most prominent change was observed after 60-min and 220 V/m intensity from x = 3556.41 to x = 1084.83). The most significant change in activity of catalase was observed after 60 min and 220 v/m exposure (from x = 6.28 to x = 4.15). The findings indicate that exposure to electromagnetic radiation of 1 kHz frequency and 150 V/m and 220 V/m intensity may cause adverse effects within blood platelets' oxygen metabolism and thus may lead to physiological dysfunction of the organism.

Effect of different alcohols, gelatinizing times, calcination and microwave on characteristics of TiO2 nanoparticles synthesized by sol-gel method

NASA Astrophysics Data System (ADS)

Bahar, Mahmoud; Mozaffari, Masoud; Esmaeili, Sahar

2017-03-01

In this work, nanoparticles of titanium dioxide (TiO2) were synthesized by means of TiCl4 as precursor. Effects of alcohol type, calcination, gelatinizing time and microwave exposure on the particle size, morphology, crystallinity and particle phase are studied using XRD patterns and SEM images. Results showed that alcohols such as ethanol increased the particle size; calcination increased the particle size and improved the crystallinity of particles. Microwave exposure of particles resulted in smaller particles; adding water increased the impact of microwave. Effect of microwave exposure in rutile phase formation is also observed during this study.

Environmentally relevant concentrations of polyethylene microplastics negatively impact the survival, growth and emergence of sediment-dwelling invertebrates.

PubMed

Ziajahromi, Shima; Kumar, Anupama; Neale, Peta A; Leusch, Frederic D L

2018-05-01

Microplastics are a widespread environmental pollutant in aquatic ecosystems and have the potential to eventually sink to the sediment, where they may pose a risk to sediment-dwelling organisms. While the impacts of exposure to microplastics have been widely reported for marine biota, the effects of microplastics on freshwater organisms at environmentally realistic concentrations are largely unknown, especially for benthic organisms. Here we examined the effects of a realistic concentration of polyethylene microplastics in sediment on the growth and emergence of a freshwater organism Chironomus tepperi. We also assessed the influence of microplastic size by exposing C. tepperi larvae to four different size ranges of polyethylene microplastics (1-4, 10-27, 43-54 and 100-126 μm). Exposure to an environmentally relevant concentration of microplastics, 500 particles/kg sediment , negatively affected the survival, growth (i.e. body length and head capsule) and emergence of C. tepperi. The observed effects were strongly dependent on microplastic size with exposure to particles in the size range of 10-27 μm inducing more pronounced effects. While growth and survival of C. tepperi were not affected by the larger microplastics (100-126 μm), a significant reduction in the number of emerged adults was observed after exposure to the largest microplastics, with the delayed emergence attributed to exposure to a stressor. While scanning electron microscopy showed a significant reduction in the size of the head capsule and antenna of C. tepperi exposed to microplastics in the 10-27 μm size range, no deformities to the external structure of the antenna and mouth parts in organisms exposed to the same size range of microplastics were observed. These results indicate that environmentally relevant concentrations of microplastics in sediment induce harmful effects on the development and emergence of C. tepperi, with effects greatly dependent on particle size. Copyright © 2018 Elsevier Ltd. All rights reserved.

Sub-lethal and lethal toxicities of elevated CO2 on embryonic, juvenile, and adult stages of marine medaka Oryzias melastigma.

PubMed

Lee, Changkeun; Kwon, Bong-Oh; Hong, Seongjin; Noh, Junsung; Lee, Junghyun; Ryu, Jongseong; Kang, Seong-Gil; Khim, Jong Seong

2018-06-06

The potential leakage from marine CO 2 storage sites is of increasing concern, but few studies have evaluated the probable adverse effects on marine organisms. Fish, one of the top predators in marine environments, should be an essential representative species used for water column toxicity testing in response to waterborne CO 2 exposure. In the present study, we conducted fish life cycle toxicity tests to fully elucidate CO 2 toxicity mechanism effects. We tested sub-lethal and lethal toxicities of elevated CO 2 concentrations on marine medaka (Oryzias melastigma) at different developmental stages. At each developmental stage, the test species was exposed to varying concentrations of gaseous CO 2 (control air, 5%, 10%, 20%, and 30%), with 96 h of exposure at 0-4 d (early stage), 4-8 d (middle stage), and 8-12 d (late stage). Sub-lethal and lethal effects, including early developmental delays, cardiac edema, tail abnormalities, abnormal pigmentation, and mortality were monitored daily during the 14 d exposure period. At the embryonic stage, significant sub-lethal and lethal effects were observed at pH < 6.30. Hypercapnia can cause long-term and/or delayed developmental embryonic problems, even after transfer back to clean seawater. At fish juvenile and adult stages, significant mortality was observed at pH < 5.70, indicating elevated CO 2 exposure might cause various adverse effects, even during short-term exposure periods. It should be noted the early embryonic stage was found more sensitive to CO 2 exposure than other developmental stages of the fish life cycle. Overall, the present study provided baseline information for potential adverse effects of high CO 2 concentration exposure on fish developmental processes at different life cycle stages in marine ecosystems. Copyright © 2018 Elsevier Ltd. All rights reserved.

Non-Renal Effects and the Risk Assessment of Environmental Cadmium Exposure

PubMed Central

Barregard, Lars; Bergdahl, Ingvar A.; Nordberg, Gunnar F.; Nordberg, Monica; Skerfving, Staffan

2014-01-01

Background: Exposure to cadmium (Cd) has long been recognized as a health hazard, both in industry and in general populations with high exposure. Under the currently prevailing health risk assessment, the relationship between urinary Cd (U-Cd) concentrations and tubular proteinuria is used. However, doubts have recently been raised regarding the justification of basing the risk assessment on this relationship at very low exposure. Objectives: Our objective was to review available information on health effects of Cd exposure with respect to human health risk assessment. Discussion: The associations between U-Cd and urinary proteins at very low exposure may not be due to Cd toxicity, and the clinical significance of slight proteinuria may also be limited. More importantly, other effects have been reported at very low Cd exposure. There is reason to challenge the basis of the existing health risk assessment for Cd. Our review of the literature found that exposure to low concentrations of Cd is associated with effects on bone, including increased risk of osteoporosis and fractures, and that this observation has implications for the health risk assessment of Cd. Other effects associated with Cd should also be considered, in particular cancer, although the information is still too limited for appropriate use in quantitative risk assessment. Conclusion: Non-renal effects should be considered critical effects in the health risk assessment of Cd. Citation: Åkesson A, Barregard L, Bergdahl IA, Nordberg GF, Nordberg M, Skerfving S. 2014. Non-renal effects and the risk assessment of environmental cadmium exposure. Environ Health Perspect 122:431–438; http://dx.doi.org/10.1289/ehp.1307110 PMID:24569905

Permeabilization of the nuclear envelope following nanosecond pulsed electric field exposure.

PubMed

Thompson, Gary L; Roth, Caleb C; Kuipers, Marjorie A; Tolstykh, Gleb P; Beier, Hope T; Ibey, Bennett L

2016-01-29

Permeabilization of cell membranes occurs upon exposure to a threshold absorbed dose (AD) of nanosecond pulsed electric fields (nsPEF). The ultimate, physiological bioeffect of this exposure depends on the type of cultured cell and environment, indicating that cell-specific pathways and structures are stimulated. Here we investigate 10 and 600 ns duration PEF effects on Chinese hamster ovary (CHO) cell nuclei, where our hypothesis is that pulse disruption of the nuclear envelope membrane leads to observed cell death and decreased viability 24 h post-exposure. To observe short-term responses to nsPEF exposure, CHO cells have been stably transfected with two fluorescently-labeled proteins known to be sequestered for cellular chromosomal function within the nucleus - histone-2b (H2B) and proliferating cell nuclear antigen (PCNA). H2B remains associated with chromatin after nsPEF exposure, whereas PCNA leaks out of nuclei permeabilized by a threshold AD of 10 and 600 ns PEF. A downturn in 24 h viability, measured by MTT assay, is observed at the number of pulses required to induce permeabilization of the nucleus. Copyright © 2015 Elsevier Inc. All rights reserved.

Neurotoxicity of low bisphenol A (BPA) exposure for young male mice: Implications for children exposed to environmental levels of BPA.

PubMed

Zhou, Yuanxiu; Wang, Zhouyu; Xia, Minghan; Zhuang, Siyi; Gong, Xiaobing; Pan, Jianwen; Li, Chuhua; Fan, Ruifang; Pang, Qihua; Lu, Shaoyou

2017-10-01

To investigate the neuron toxicities of low-dose exposure to bisphenol A (BPA) in children, mice were used as an animal model. We examined brain cell damage and the effects of learning and memory ability after BPA exposure in male mice (4 weeks of age) that were divided into four groups and chronically received different BPA treatments for 8 weeks. The comet assay and hippocampal neuron counting were used to detect the brain cell damage. The Y-maze test was applied to test alterations in learning and memory ability. Long term potentiation induction by BPA exposure was performed to study the potential mechanism of performance. The percentages of tail DNA, tail length and tail moment in brain cells increased with increasing BPA exposure concentrations. Significant differences in DNA damage were observed among the groups, including between the low-dose and control groups. In the Y-maze test, the other three groups qualified for the learned standard one day earlier than the high-exposed group. Furthermore, the ratio of qualified mice in the high-exposed group was always the lowest among the groups, indicating that high BPA treatment significantly altered the spatial memory performance of mice. Different BPA treatments exerted different effects on the neuron numbers of different regions in the hippocampus. In the CA1 region, the high-exposed group had a significant decrease in neuron numbers. A non-monotonic relationship was observed between the exposure concentrations and neuron quantity in the CA3 region. The hippocampal slices in the control and medium-exposed groups generated long-term potentiation after induction by theta burst stimulation, but the low-exposed group did not. A significant difference was observed between the control and low-exposed groups. In conclusion, chronic exposure to a low level of BPA had adverse effects on brain cells and altered the learning and memory ability of adolescent mice. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sensory and other neurogenic effects of exposures to airborne office dust

NASA Astrophysics Data System (ADS)

Mølhave, L.; Kjærgaard, S. K.; Attermann, J.

This Danish Office Dust Experiment investigated the response of 24 healthy non-sensitive adult subjects to exposure to normal office dust in the air (7 μg m -3 clean air, 136 and 390 μg m -3 TSP). The dust had no major identifiable specific reactive components. The exposure duration was 5 1/4 h and was arranged in a climate chamber in controlled atmospheric conditions. Measurements were made acutely at exposure onset, subacutely at exposure end and next day (late). As secondary aims the time course and threshold of any observed effect of the exposures, and the characteristics of any hyperresponding subgroup were investigated. In a questionnaire with 36 questions the dust exposures caused increased acute, subacute and late perceptions of reduced air quality, acute and subacute increased odor intensity, acute eye irritation, acute and late heavy head, subacute feeling of perspiration, and subacute general irritation. Cough increased subacutely during exposures. In addition, a performance test showed effects of dust exposures which also affected "Mood Scale" ratings. No effect was seen on an addition test for distraction, and objective measurements of skin humidity. The overall conclusion of the study is that healthy subjects without hypersensitivity reactions seem to respond to airborne house dust. The responses are both subjective sensory reactions and other neurogenic effects even at exposure levels within the range found in normal buildings. Some of the effects appeared acutely and decreased through adaptation while others increased during prolonged exposure and remained for more than 17 h after the exposure ended. The findings may indicate for this type of dust a threshold level for the dose-response relationships below 140 μg m -3.

Effect of acute heat stress on rat adrenal glands: a morphological and stereological study.

PubMed

Koko, Vesna; Djordjeviae, Jelena; Cvijiae, Gordana; Davidoviae, Vukosava

2004-11-01

The morphological and stereological structure of rat adrenal gland was analysed by light microscopy after an acute (60 min) exposure to high ambient temperature (38 degrees C). A significant increase in plasma corticotrophin (ACTH) and serum corticosterone (CORT) concentrations was observed, confirming that acute heat exposure has a strong stressful effect. Under these conditions the adrenal gland mass and volume were decreased, probably as the consequence of adrenal cortex reduction, especially that of the zona fasciculata (ZF). Histological examination revealed that many ZF cells were deprived of lipid droplets. Fibrosis was observed in all parts of the adrenal gland, both cortex and medulla, of heat stressed animals. Mitotic figures were absent in cortical cells after heat exposure, but there were no differences in ZF and zona reticularis (ZR) small blood vessels compared to nonstressed controls.

Effects of Bisphenol A on Incidence and Severity of Cardiac Lesions in the NCTR- Sprague-Dawley Rat: A CLARITY-BPA Study

PubMed Central

Gear, Robin; Kendziorski, Jessica A.; Belcher, Scott M.

2017-01-01

The goal of this study was to determine whether bisphenol A (BPA) had adverse effects indicative of cardiac toxicity. As part of the “Consortium Linking Academic and Regulatory Insights on BPA Toxicity” (CLARITY-BPA), study dams and offspring were exposed by daily gavage to five doses of BPA ranging from 2.5 to 25000 μg/kg/day, 0.05 or 0.5 μg/kg/day 17α-ethinyl-estradiol (EE) or 0.3% carboxymethylcellulose vehicle. Exposure-related effects were analyzed in isolated hearts by quantitative morphometry and histopathology. No dose-related changes in body weight were detected. Across all exposure groups including vehicle controls, body weight of continuously dosed males was reduced compared to males dosed only until PND21. Heart weight was increased only in females exposed to EE, and consistent alterations in LV wall thickness were not observed. Exposure-related changes in collagen accumulation were minor and limited to highest EE exposure groups with increased collagen accumulation in PND21 males. Decreased collagen was observed in hearts of BPA or EE exposed females at PND90 and PND180. In BPA or EE treated females cardiomyopathy incidence and severity was significantly increased compared to control females at PND21 with myocardial degeneration observed in both males and females at PND21 and PND90. PMID:28499613

Marked depression of time interval between fertilization period and hatching period following exposure to low-dose X-rays in zebrafish.

PubMed

Miyachi, Yukihisa; Kanao, Tomoko; Okamoto, Takehito

2003-10-01

In recent years there has been growing concern over the stimulating effects of very low-dose X-rays. Our laboratory had observed that zebrafish irradiated with low-dose X-rays tended to emerge earlier than sham controls. This observation led us to quantitatively examine the effects of low-dose X irradiation on a series of stages of development in the zebrafish. The embryos were fertilized simultaneously in vitro and incubated at an optimal temperature without crowding. Following exposure of the cleavage period (1.5 h after fertilization) to 0.025-Gy X-rays, the duration to hatching was slightly shorter than that of the sham controls. This tendency was increased when the X-ray exposure occurred during the blastula period (3.5 h). In these embryos, the duration to hatching decreased significantly by an average of 6 h sooner than for sham controls. No differences in duration to hatching were seen when irradiation was given during either the zygote period (45 min) or the segmentation period (12 h). On the contrary, upon exposure to 0.5-Gy X-rays during the blastula period, the duration to hatching increased significantly relative to that of sham controls. These results suggest that the radiation-induced early hatching effect is observed for low doses of X-rays.

The effects of fluoride on neuronal function occurs via cytoskeleton damage and decreased signal transmission.

PubMed

Chen, Lingli; Ning, Hongmei; Yin, Zhihong; Song, Xiaochao; Feng, Yongchao; Qin, Hao; Li, Yi; Wang, Jundong; Ge, Yaming; Wang, Wenkui

2017-10-01

It has been reported that fluoride exposure may cause serious public health problems, particularly neurotoxicity. However, the underlying mechanisms remain unclear. This study used Neuro-2A cells to investigate the effects of fluoride on the cytoskeleton. The Neuro-2A cells were exposed to 0, 1, 2, 4 and 6 mM sodium fluoride (NaF) for 24 h. Cell viability and lactate dehydrogenase (LDH) release were examined. It was observed that exposure to NaF reduced cell viability, disrupted cellular membrane integrity, and high levels of LDH were released. The observed changes occurred in a dose response manner. Morphologic observations showed that cell became rounded and were loosely adherent following exposure to NaF. Axon spines and normal features disappeared with high dose NaF treatment. The expression of MAP2 and synaptophysin decreased, particularly at 4 mM and 6 mM (P < 0.05) for MAP2. These results corroborate the morphologic observations. The content of glutamate and NMDAR (glutamate receptor) protein were assessed to help understand the relationship between synapses and neurotransmitter release using ELISA and Western-blot. Compared with the control, glutamate and NMDAR expression declined significantly at 4 mM and 6 mM (P < 0.05) group. Finally, the ultrastructural changes observed with increasing doses of NaF were: disappearance of synapses, mitochondrial agglutination, vacuole formation, and cellular edema. Taken together, NaF exposure disrupted cellular integrity and suppressed the release of neurotransmitters, thus effecting neuronal function. These findings provide deeper insights into roles of NaF in neuron damage, which could contribute to a better understanding of fluoride-induced neurotoxicity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Health effects of subchronic exposure to diesel-water emulsion emission.

PubMed

Reed, M D; Blair, L F; Burling, K; Daly, I; Gigliotti, A P; Gudi, R; Mercieca, M D; McDonald, J D; Naas, D J; O'callaghan, J P; Seilkop, S K; Ronsko, N L; Wagner, V O; Kraska, R C

2005-12-15

The U.S. Environmental Protection Agency (EPA) National Ambient Air Quality Standards for ozone and particulate matter are requiring urban nonattainment areas to implement pollution-reduction strategies for anthropogenic source emissions. A type of fuel shown to decrease combustion emissions components versus traditional diesel fuels is the diesel-water emulsion. The Lubrizol Corporation in conjunction with Lovelace Respiratory Research Institute and several subcontracting laboratories recently conducted a rodent health assessment of inhaled combustion emissions of PuriNO(x) diesel fuel emulsion. Combustion emissions from either of two 2001 model Cummins 5.9-L ISB engines were diluted with charcoal-filtered air to exposure concentrations of 100, 200, and 400 microg total particulate matter/m(3). The engines were operated on a continuously repeating, heavy-duty certification cycle (U.S. Code of Federal Regulations, Title 40, Chapter I) using Rotella-T 15W-40 engine oil. Nitrogen oxide and particulate matter were reduced when engines were operated on PuriNO(x) versus California Air Resources Board diesel fuel under these conditions. Male and female F344 rats were housed in Hazleton H2000 exposure chambers and exposed to exhaust atmospheres 6 h/day, 5 days/wk for the first 11 wk and 7 days/wk threafter. Exposures ranged from 58 to 70 days, depending on the treatment group. Indicators of general toxicity (body weight, organ weight, clinical pathology, and histopathology), neurotoxicity (glial fibrillary acidic protein assay), genotoxicity (Ames assay, micronucleus, sister chromatid exchange), and reproduction and development were measured. Overall, effects observed were mild. Emulsion combustion emissions were not associated with neurotoxicity, reproductive/developmental toxicity, or in vivo genotoxicity. Small decreases in serum cholesterol and small increases in platelet values in some groups of exposed animals were observed. Particulate matter accumulation within alveolar macrophages was evident in all exposure groups. These findings are consistent with normal physiological responses to particle inhalation. Other statistically significant effects were present in some measured parameters of other exposed groups but were not clearly attributed to emissions exposure. Positive mutagenic responses in several strains of Salmonella typhimurium were observed subsequent to treatment with emulsion emissions subfractions. Based on the cholesterol and platelet results, it can be concluded that the 100 microg/m(3) exposure level was the no-observed-effect level. In general, biological findings in diesel emulsion emission-exposed animals and bacteria were consistent with exposure to petroleum diesel exhaust in the F344 rat and Ames assays.

Prenatal Bisphenol A Exposure Alters Sex-Specific Estrogen Receptor Expression in the Neonatal Rat Hypothalamus and Amygdala

PubMed Central

Patisaul, Heather B.

2013-01-01

Bisphenol A (BPA) exposure is ubiquitous, and in laboratory animals, early-life BPA exposure has been shown to alter sex-specific neural organization, neuroendocrine physiology, and behavior. The specific mechanisms underlying these brain-related outcomes, however, remain largely unknown, constraining the capacity to ascertain the potential human relevance of neural effects observed in animal models. In the perinatal rat brain, estrogen is masculinizing, suggesting that BPA-induced perturbation of estrogen receptor (ESR) expression may underpin later in-life neuroendocrine effects. We hypothesized that prenatal BPA exposure alters sex-specific ESR1 (ERα) and ESR2 (ERβ) expression in postnatal limbic nuclei. Sprague Dawley rats were mated and gavaged on gestational days (GDs) 6–21 with vehicle, 2.5 or 25 μg/kg bw/day BPA, or 5 or 10 μg/kg bw/day ethinyl estradiol. An additional group was restrained but not gavaged (naïve control). Offspring were sacrificed the day after birth to quantify ESR gene expression throughout the hypothalamus and amygdala by in situ hybridization. Relative to the vehicle group, significant effects of BPA were observed on ESR1 and ESR2 expression throughout the mediobasal hypothalamus and amygdala in both sexes. Significant differences in ESR expression were also observed in the mediobasal hypothalamus and amygdala of the naïve control group compared with the vehicle group, highlighting the potential for gavage to influence gene expression in the developing brain. These results indicate that ESR expression in the neonatal brain of both sexes can be altered by low-dose prenatal BPA exposure. PMID:23457122

Toxicity assessment of a common laundry detergent using the freshwater flagellate Euglena gracilis.

PubMed

Azizullah, Azizullah; Richter, Peter; Häder, Donat-Peter

2011-09-01

Synthetic detergents are among the commonly used chemicals in everyday life. Detergents, reaching aquatic environments through domestic and municipal wastewater, can cause many different effects in aquatic organisms. The present study was aimed at the toxicity evaluation of a commonly used laundry detergent, Ariel, using the freshwater flagellate Euglena gracilis as a biotest organism. Different parameters of the flagellate like motility, swimming velocity, cell shape, gravitactic orientation, photosynthesis and concentration of light harvesting pigments were used as end points for the toxicity assessment. No Observed Effect Concentration (NOEC) and EC(50) values were calculated for the end point parameters at four different incubation times, i.e. 0, 6, 24 and 72 h. After 72 h incubation, swimming velocity of the cells was found to be the most sensitive parameter giving NOEC and EC(50) values of 10.8 and 34 mg L(-1), respectively. After 72 h exposure to the detergent, chlorophyll a and total carotenoids were significantly decreased in cultures treated with Ariel at concentrations of 50 mg L(-1) and above while chlorophyll b significantly decreased at concentrations above 750 mg L(-1). The maximum inhibitory effect on the quantum yield of photosystem II was observed after 24 h exposure and thereafter a recovery trend was observed. Motility, gravitaxis and cell shape were strongly impaired immediately upon exposure to the detergent, but with increasing exposure time these parameters showed acclimatization to the stress and thus the NOEC values obtained after 72 h were higher than those immediately after exposure. Copyright © 2011 Elsevier Ltd. All rights reserved.

Investigation of temporal vascular effects induced by focused ultrasound treatment with speckle-variance optical coherence tomography

PubMed Central

Tsai, Meng-Tsan; Chang, Feng-Yu; Lee, Cheng-Kuang; Gong, Cihun-Siyong Alex; Lin, Yu-Xiang; Lee, Jiann-Der; Yang, Chih-Hsun; Liu, Hao-Li

2014-01-01

Focused ultrasound (FUS) can be used to locally and temporally enhance vascular permeability, improving the efficiency of drug delivery from the blood vessels into the surrounding tissue. However, it is difficult to evaluate in real time the effect induced by FUS and to noninvasively observe the permeability enhancement. In this study, speckle-variance optical coherence tomography (SVOCT) was implemented for the investigation of temporal effects on vessels induced by FUS treatment. With OCT scanning, the dynamic change in vessels during FUS exposure can be observed and studied. Moreover, the vascular effects induced by FUS treatment with and without the presence of microbubbles were investigated and quantitatively compared. Additionally, 2D and 3D speckle-variance images were used for quantitative observation of blood leakage from vessels due to the permeability enhancement caused by FUS, which could be an indicator that can be used to determine the influence of FUS power exposure. In conclusion, SVOCT can be a useful tool for monitoring FUS treatment in real time, facilitating the dynamic observation of temporal effects and helping to determine the optimal FUS power. PMID:25071945

Olfactory function in chemical workers exposed to acrylate and methacrylate vapors.

PubMed Central

Schwartz, B S; Doty, R L; Monroe, C; Frye, R; Barker, S

1989-01-01

An investigation of the olfactory function of 731 workers at a chemical facility which manufacturers acrylates and methacrylates was undertaken using a standardized quantitative test. In a cross-sectional analysis of the data, no associations of chemical exposure with olfactory test scores were observed. A nested case-control study designed to evaluate the cumulative effects of exposure on olfactory function, however, revealed elevated crude exposure odds ratios (95% confidence interval) of 2.0 (1.1, 3.8) for all workers and 6.0 (1.7, 21.5) for workers who never smoked cigarettes. Logistic regression analysis, adjusting for multiple confounders, revealed exposure odds ratios of 2.8 (1.1, 7.0) and 13.5 (2.1, 87.6) in these same groups, respectively, and a dose-response relationship between olfactory dysfunction and cumulative exposure scores--semi-quantitative indices of lifetime exposure to the acrylates. The data also revealed decreasing exposure odds ratios with increasing duration since last exposure to these chemicals, suggesting that the effects may be reversible. PMID:2784947

Trends in exposure to respirable crystalline silica (1986-2014) in Australian mining.

PubMed

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

2017-08-01

Respirable crystalline silica (RCS) has been associated with severe health risks. Exposures in Western Australia (WA) have been typically high in hard-rock mining and have reduced substantially since the mid-1900s. We described trends in RCS exposure in WA miners over the past 30 years. A total of 79 445 reported personal RCS exposure measurements, covering the years 1986-2014, were examined. Mixed-effects models were applied to estimate RCS exposure levels, including spline terms to estimate a time trend. An overall downward trend of about -8% per year was observed for RCS exposures in WA mining. Highest RCS exposure levels were modeled for base metal mining and exploration settings. Drilling occupations were among the highest exposed jobs. RCS exposure levels have fallen considerably in the last three decades. However, there are still mining occupations that may need further attention to avoid adverse health effects in these workers. © 2017 Wiley Periodicals, Inc.

Threats to validity of nonrandomized studies of postdiagnosis exposures on cancer recurrence and survival.

PubMed

Chubak, Jessica; Boudreau, Denise M; Wirtz, Heidi S; McKnight, Barbara; Weiss, Noel S

2013-10-02

Studies of the effects of exposures after cancer diagnosis on cancer recurrence and survival can provide important information to the growing group of cancer survivors. Observational studies that address this issue generally fall into one of two categories: 1) those using health plan automated data that contain "continuous" information on exposures, such as studies that use pharmacy records; and 2) survey or interview studies that collect information directly from patients once or periodically postdiagnosis. Reverse causation, confounding, selection bias, and information bias are common in observational studies of cancer outcomes in relation to exposures after cancer diagnosis. We describe these biases, focusing on sources of bias specific to these types of studies, and we discuss approaches for reducing them. Attention to known challenges in epidemiologic research is critical for the validity of studies of postdiagnosis exposures and cancer outcomes.

Threats to Validity of Nonrandomized Studies of Postdiagnosis Exposures on Cancer Recurrence and Survival

PubMed Central

2013-01-01

Studies of the effects of exposures after cancer diagnosis on cancer recurrence and survival can provide important information to the growing group of cancer survivors. Observational studies that address this issue generally fall into one of two categories: 1) those using health plan automated data that contain “continuous” information on exposures, such as studies that use pharmacy records; and 2) survey or interview studies that collect information directly from patients once or periodically postdiagnosis. Reverse causation, confounding, selection bias, and information bias are common in observational studies of cancer outcomes in relation to exposures after cancer diagnosis. We describe these biases, focusing on sources of bias specific to these types of studies, and we discuss approaches for reducing them. Attention to known challenges in epidemiologic research is critical for the validity of studies of postdiagnosis exposures and cancer outcomes. PMID:23940288

Rapid-onset/offset, variably scheduled 60 Hz electric and magnetic field exposure reduces nocturnal serum melatonin concentration in nonhuman primates

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

Rogers, W.R.; Smith, H.D.; Reiter, R.J.

Experiments with rodents indicate that power-frequency electric field (EF) or magnetic field (MF) exposure can suppress the normal nocturnal increase in melatonin concentration in pineal gland and blood. In a separate set of three experiments conducted with nonhuman primates, the authors did not observe melatonin suppression as a result of 6 weeks of day-time exposure to combined 60 Hz electric and magnetic fields (E/MF) with regularly schedule ``slow`` E/MF onsets/offsets. The study described here used a different exposure paradigm in which two baboons were exposed to E/MF with ``rapid`` E/MF onsets/offsets accompanied by EF transients not found with slowly rampedmore » E/MF onset/offset; profound reductions in nocturnal serum melatonin concentration were observed in this experiment. If replicated in a more extensive experiment, the observation of melatonin suppression only in the presence of E/MF transients would suggest that very specific exposure parameters determine the effects of 60 Hz E/MF on melatonin.« less

Residential energy use emissions dominate health impacts from exposure to ambient particulate matter in India.

PubMed

Conibear, Luke; Butt, Edward W; Knote, Christoph; Arnold, Stephen R; Spracklen, Dominick V

2018-02-12

Exposure to ambient fine particulate matter (PM 2.5 ) is a leading contributor to diseases in India. Previous studies analysing emission source attributions were restricted by coarse model resolution and limited PM 2.5 observations. We use a regional model informed by new observations to make the first high-resolution study of the sector-specific disease burden from ambient PM 2.5 exposure in India. Observed annual mean PM 2.5 concentrations exceed 100 μg m -3 and are well simulated by the model. We calculate that the emissions from residential energy use dominate (52%) population-weighted annual mean PM 2.5 concentrations, and are attributed to 511,000 (95UI: 340,000-697,000) premature mortalities annually. However, removing residential energy use emissions would avert only 256,000 (95UI: 162,000-340,000), due to the non-linear exposure-response relationship causing health effects to saturate at high PM 2.5 concentrations. Consequently, large reductions in emissions will be required to reduce the health burden from ambient PM 2.5 exposure in India.

Sex-, tissue-, and exposure duration-dependent effects of imidacloprid modulated by piperonyl butoxide and menadione in rats. Part I: oxidative and neurotoxic potentials.

PubMed

Yardimci, Mustafa; Sevgiler, Yusuf; Rencuzogullari, Eyyup; Arslan, Mehmet; Buyukleyla, Mehmet; Yilmaz, Mehmet

2014-12-01

Earlier research has evidenced the oxidative and neurotoxic potential of imidacloprid, a neonicotinoid insecticide, in different animal species. The primary aim of this study was to determine how metabolic modulators piperonyl butoxide and menadione affect imidacloprid's adverse action in the liver and kidney of Sprague-Dawley rats of both sexes. The animals were exposed to imidacloprid alone (170 mg kg⁻¹) or in combination with piperonyl butoxide (100 mg kg⁻¹) or menadione (25 mg kg⁻¹) for 12 and 24 h. Their liver and kidney homogenates were analysed spectrophotometrically for glutathione peroxidase, glutathione S-transferase, catalase, total cholinesterase specific activities, total glutathione, total protein content, and lipid peroxidation levels. Imidacloprid displayed its prooxidative and neurotoxic effects predominantly in the kidney of male rats after 24 h of exposure. Our findings suggest that the observed differences in prooxidative and neurotoxic potential of imidacloprid could be related to differences in its metabolism between the sexes. Co-exposure (90-min pre-treatment) with piperonyl butoxide or menadione revealed tissue-specific effect of imidacloprid on total cholinesterase activity. Increased cholinesterase activity in the kidney could be an adaptive response to imidacloprid-induced oxidative stress. In the male rat liver, co-exposure with piperonyl butoxide or menadione exacerbated imidacloprid toxicity. In female rats, imidacloprid+menadione co-exposure caused prooxidative effects, while no such effects were observed with imidacloprid alone or menadione alone. In conclusion, sex-, tissue-, and duration-specific effects of imidacloprid are remarkable points in its toxicity.

Effects of mobile phone exposure (GSM 900 and WCDMA/UMTS) on polysomnography based sleep quality: An intra- and inter-individual perspective.

PubMed

Danker-Hopfe, Heidi; Dorn, Hans; Bolz, Thomas; Peter, Anita; Hansen, Marie-Luise; Eggert, Torsten; Sauter, Cornelia

2016-02-01

Studies on effects of radio frequency-electromagnetic fields (RF-EMF) on the macrostructure of sleep so far yielded inconsistent results. This study investigated whether possible effects of RF-EMF exposure differ between individuals. In a double-blind, randomized, sham-controlled cross-over study possible effects of electromagnetic fields emitted by pulsed Global System for Mobile Communications (GSM) 900 and Wideband Code-Division Multiple Access (WCDMA)/Universal Mobile Telecommunications System (WCDMA/UMTS) devices on sleep were analysed. Thirty healthy young men (range 18-30 years) were exposed three times per exposure condition while their sleep was recorded. Sleep was evaluated according to the American Academy of Sleep Medicine standard and eight basic sleep variables were considered. Data analyses at the individual level indicate that RF-EMF effects are observed in 90% of the individuals and that all sleep variables are affected in at least four subjects. While sleep of participants was affected in various numbers, combinations of sleep variables and in different directions, showing improvements but also deteriorations, the only consistent finding was an increase of stage R sleep under GSM 900MHz exposure (9 of 30 subjects) as well as under WCDMA/UMTS exposure (10 of 30 subjects). The results underline that sleep of individuals can be affected differently. The observations found here may indicate an underlying thermal mechanism of RF-EMF on human REM sleep. Nevertheless, the effect of an increase in stage R sleep in one third of the individuals does not necessarily indicate a disturbance of sleep. Copyright © 2015 Elsevier Inc. All rights reserved.

Late Dose-Response Effects of Prenatal Cocaine Exposure on Newborn Neurobehavioral Performance

PubMed Central

Tronick, Edward Z.; Frank, Deborah A.; Cabral, Howard; Mirochnick, Mark; Zuckerman, Barry

2008-01-01

Objective To determine in a representative sample of full-term urban newborns of English-speaking mothers whether an immediate or late dose-response effect could be demonstrated between prenatal cocaine exposure and newborn neurobehavioral performance, controlling for confounding factors. Methods The Neonatal Behavioral Assessment Scale (NBAS) was administered by masked examiners to a total sample of 251 clinically healthy, full-term infants at 2 days and/or 17 days. Three in utero cocaine exposure groups were defined: heavily exposed (n = 44, >75th percentile self-reported days of use during pregnancy and/or >75th percentile of meconium benzoylecognine concentration); lightly exposed (n = 79, less than both 75th percentiles); and unexposed (n = 101, no positive biological or self-report marker). At the 3-week examination there were 38 heavily exposed, 73 lightly exposed, and 94 unexposed infants. Controlling for infant birth weight, gestational age, infant age at the time of examination, mothers’ age, perinatal risk, obstetric medication, and alcohol, marijuana, and cigarette use, a regression analysis evaluated the effects of levels of cocaine exposure on NBAS performance. Results No neurobehavioral effects of exposure on the newborn NBAS cluster scores or on the qualifier scores were found when confounders were controlled for at 2 to 3 days of age. At 3 weeks, after controlling for covariates, a significant dose effect was observed, with heavily exposed infants showing poorer state regulation and greater excitability. Conclusions These findings demonstrate specific dose-related effects of cocaine on 3-week neurobehavioral performance, particularly for the regulation of arousal, which was not observed in the first few days of life. PMID:8668416

Seeing and liking cigarette advertisements: is there a 'mere exposure' effect?.

PubMed

Morgenstern, Matthis; Isensee, Barbara; Hanewinkel, Reiner

2013-01-01

We aimed to explain the association between exposure to a cigarette advertisement and favorable attitudes towards the advertisement. We used data from an observational cross-sectional study with a sample of 3,415 German schoolchildren aged 10-17 years. Cigarette advertising exposure was assessed with an image of a Marlboro ad, asking for contact frequency (number of times seen the ad) and brand name. Liking of the ad was measured with two items (alpha = 0.78). We found a positive linear association between exposure to the Marlboro ad and liking it. This association remained significant (standardized β = 0.09; p < 0.001) even after statistical control for smoking status, smoking of friends and parents, attitudes towards smoking in general, cigarette advertising receptivity (having a favorite cigarette ad), exposure to other advertisings, age, sex, socioeconomic status, rebelliousness and sensation seeking, self-reported school performance, and study region. The association between exposure to an advertisement and liking it was robust and could not be fully explained without referring to either unmeasured confounding or implicit advertising effects (e.g. mere exposure). Implicit effects have implications for prevention strategies as it may be very difficult to counteract unconscious advertising effects. Copyright © 2012 S. Karger AG, Basel.

Seven-day cumulative effects of air pollutants increase respiratory ER visits up to threefold.

PubMed

Schvartsman, Cláudio; Pereira, Luiz Alberto Amador; Braga, Alfésio Luiz Ferreira; Farhat, Sylvia Costa Lima

2017-02-01

Children are especially vulnerable to respiratory injury induced by exposure to air pollutants. In the present study, we investigate periods of up to 7 days, and evaluate the lagged effects of exposure to air pollutants on the daily number of children and adolescents visiting the emergency room (ER) for the treatment of lower respiratory obstructive diseases (LROD), in the city of São Paulo, Brazil. Daily records of LROD-related ER visits by children and adolescents under the age of 19, from January 2000 to December 2007 (2,922 days) were included in the study. Time-series regression models (generalized linear Poisson) were used to control for short- and long-term trends, as well as for temperature and relative humidity. Third-degree polynomial lag models were used to estimate both lag structures and the cumulative effects of air pollutants. Effects of air pollutants were expressed as the percentage increase in LROD-related ER visits. We observed an acute effect at the same day of exposure to air pollutants; however, the cumulative effects of air pollutants on the number of LROD-related ER visits was almost threefold greater than the one observed at the same day of exposure to PM 10 , SO 2 , and NO 2 mainly in children aged 5 years and under. The 7-day cumulative effect of SO 2 reached 11.0% (95% CI: 5.0-16.7) increase in visits. Conclusion and Relevance: This study highlights the effects of intermediate-term exposure to air pollutants on LROD in children. Pediatr Pulmonol. 2017;52:205-212. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Sexually immature male ERE-Luc reporter mice to assess low dose estrogen-like effects of CdCl2 versus dietary Cd

PubMed Central

Ramachandran, Balaji; Rizzi, Nicoletta; Maggi, Adriana

2014-01-01

CdCl2 salt is widely used in exposure oriented studies, while the biological exposure of Cadmium (Cd) occurs mostly through diet. Hence, we designed a in vivo imaging methodology with sexually immature male ERE-Luc reporter mice to test the estrogen-like (EL) effects of Cd as a natural component in wheat and flax bread based diets (containing 17.57 and 49.22 ug/kg Cd concentrations respectively) and CdCl2 per-oral dose of 1 ug/kg/bw/day. Total exposure of ingested and % bioaccumulation of Cd in selected organs were estimated as 547 ng (4.4%), 776 ng (0.3%) and 2131.8 ng (0.1%) corresponding to CdCl2, wheat and flax bread based diet treatments respectively. Cd from CdCl2 bioaccumulated more readily, despite the exposure of Cd is higher with bread based diets. Longitudinal in vivo imaging did not reveal significant changes in luciferase activity. White adipose tissue (WAT) and prostate were identified as novel target organs of Cd. Indeed, the rest of the observed EL effects, endogenous target gene expression and necropsy findings are not consistent to any particular organ or treatment. This implies that, the observed EL effects due to low doses of Cd (either from CdCl2 or dietary form) occur only as subtle changes at the molecular level, but inadequate to cause significant changes at the anatomo-pathological level during the 21 day exposure period. The study demonstrates the sensitivity of the methodology to assess EL effects of food embedded Cd and underlines the limitations of directly extrapolating the results of suspected chemicals in their pure form to dietary exposure scenarios. PMID:24795841

Inflammatory markers in relation to long-term air pollution.

PubMed

Mostafavi, Nahid; Vlaanderen, Jelle; Chadeau-Hyam, Marc; Beelen, Rob; Modig, Lars; Palli, Domenico; Bergdahl, Ingvar A; Vineis, Paolo; Hoek, Gerard; Kyrtopoulos, Soterios Α; Vermeulen, Roel

2015-08-01

Long-term exposure to ambient air pollution can lead to chronic health effects such as cancer, cardiovascular and respiratory disease. Systemic inflammation has been hypothesized as a putative biological mechanism contributing to these adverse health effects. We evaluated the effect of long-term exposure to air pollution on blood markers of systemic inflammation. We measured a panel of 28 inflammatory markers in peripheral blood samples from 587 individuals that were biobanked as part of a prospective study. Participants were from Varese and Turin (Italy) and Umea (Sweden). Long-term air pollution estimates of nitrogen oxides (NOx) were available from the European Study of Cohorts for Air Pollution Effects (ESCAPE). Linear mixed models adjusted for potential confounders were applied to assess the association between NOx and the markers of inflammation. Long-term exposure to NOx was associated with decreased levels of interleukin (IL)-2, IL-8, IL-10 and tumor necrosis factor-α in Italy, but not in Sweden. NOx exposure levels were considerably lower in Sweden than in Italy (Sweden: median (5th, 95th percentiles) 6.65 μg/m(3) (4.8, 19.7); Italy: median (5th, 95th percentiles) 94.2 μg/m(3) (7.8, 124.5)). Combining data from Italy and Sweden we only observed a significant association between long-term exposure to NOx and decreased levels of circulating IL-8. We observed some indication for perturbations in the inflammatory markers due to long-term exposure to NOx. Effects were stronger in Italy than in Sweden, potentially reflecting the difference in air pollution levels between the two cohorts. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effort-reward imbalance at work and 5-year changes in blood pressure: the mediating effect of changes in body mass index among 1400 white-collar workers.

PubMed

Trudel, Xavier; Brisson, Chantal; Milot, Alain; Masse, Benoit; Vézina, Michel

2016-11-01

A number of prospective studies have documented the effect of adverse psychosocial work factors (work stress) on high blood pressure (BP). Weight gain could be an important pathway by which work stress exerts its effect on BP. No previous prospective study has examined this mediating effect. The aim of the present study was to examine the mediating effect of body mass index (BMI) in the association between psychosocial work factors from Siegrist's effort-reward imbalance model (ERI) and ambulatory BP (ABP). A prospective study was conducted among 1436 white-collar workers. Data were collected three times during a 5-year period. ERI was measured using validated scales, at each time. BMI was measured by a trained assistant. ABP was measured every 15 min during a working day. ERI exposure onset over 3 years was indirectly associated with ABP changes (0.49 mmHg; 95 % CI 0.05, 1.22), through BMI changes, in women with baseline BMI ≥25 kg/m 2 . An effect of similar magnitude and of borderline significance was observed for ERI chronic exposure. No mediating effect was observed among men, and using ERI exposure over 5 years. The mediating effect of BMI was of small magnitude and observed in certain subgroups and time frame only. Subgroup-specific mediating pathways might be involved to explain the effect of work stress on cardiovascular diseases risk.

Variable Effects of Exposure to Formulated Microbicides on Antibiotic Susceptibility in Firmicutes and Proteobacteria

PubMed Central

Forbes, Sarah; Knight, Christopher G.; Cowley, Nicola L.; Amézquita, Alejandro; McClure, Peter; Humphreys, Gavin

2016-01-01

ABSTRACT Microbicides are broad-spectrum antimicrobial agents that generally interact with multiple pharmacological targets. While they are widely deployed in disinfectant, antiseptic, and preservative formulations, data relating to their potential to select for microbicide or antibiotic resistance have been generated mainly by testing the compounds in much simpler aqueous solutions. In the current investigation, antibiotic susceptibility was determined for bacteria that had previously exhibited decreased microbicide susceptibility following repeated exposure to microbicides either in formulation with sequestrants and surfactants or in simple aqueous solution. Statistically significant increases in antibiotic susceptibility occurred for 12% of bacteria after exposure to microbicides in formulation and 20% of bacteria after exposure to microbicides in aqueous solutions, while 22% became significantly less susceptible to the antibiotics, regardless of formulation. Of the combinations of a bacterium and an antibiotic for which British Society for Antimicrobial Chemotherapy breakpoints are available, none became resistant. Linear modeling taking into account phylogeny, microbicide, antibiotic, and formulation identified small but significant effects of formulation that varied depending on the bacterium and microbicide. Adaptation to formulated benzalkonium chloride in particular was more likely to increase antibiotic susceptibility than adaptation to the simple aqueous solution. In conclusion, bacterial adaptation through repeated microbicide exposure was associated with both increases and decreases in antibiotic susceptibility. Formulation of the microbicide to which the bacteria had previously adapted had an identifiable effect on antibiotic susceptibility, but it effect was typically small relative to the differences observed among microbicides. Susceptibility changes resulting in resistance were not observed. IMPORTANCE The safety of certain microbicide applications has been questioned due to the possibility that microbicide exposure could select for microbicide and antibiotic resistance. Evidence that this may happen is based mainly on in vitro experiments where bacteria have been exposed to microbicides in aqueous solution. Microbicides are, however, normally deployed in products formulated with surfactants, sequestrants, and other compounds. While this may influence the frequency and extent of susceptibility changes, few studies reported in the literature have assessed this. In the current investigation, therefore, we have investigated changes in antibiotic susceptibility in bacteria which exhibited decreased microbicide susceptibility following repeated exposure to microbicides in simple aqueous solutions and in formulation. We report that the microbicide formulation had an identifiable effect on antibiotic susceptibility, but it was typically small relative to the differences observed among microbicides. We did not observe susceptibility changes resulting in resistance. PMID:27060123

The effect of D-cycloserine on subliminal cue exposure in spider fearful individuals.

PubMed

Gutner, Cassidy A; Weinberger, Joel; Hofmann, Stefan G

2012-01-01

Research on D-cycloserine (DCS) has demonstrated a significant effect on symptom reduction in human studies that utilized conventional exposure-based approaches. Recent studies have offered promising results for targeting fears through subliminal paradigms. In this double-blind, randomized placebo-controlled study, 45 spider fearful individuals received DCS or placebo pills prior to completing a subliminal cue exposure task to images of spiders. Participants completed self-report questionnaires and a behavioral approach task to a live caged tarantula. After repeated exposure to subliminal spider cues, participants in the DCS group reported a greater reduction in disgust than individuals in the placebo group. No difference was observed in fear ratings. These findings suggest that DCS augments the reduction in disgust in spider fearful subjects after subliminal exposure to spider cues.

Unique Behavioral and Neurochemical Effects Induced by Repeated Adolescent Consumption of Caffeine-Mixed Alcohol in C57BL/6 Mice

PubMed Central

Robins, Meridith T.; Lu, Julie

2016-01-01

The number of highly caffeinated products has increased dramatically in the past few years. Among these products, highly caffeinated energy drinks are the most heavily advertised and purchased, which has resulted in increased incidences of co-consumption of energy drinks with alcohol. Despite the growing number of adolescents and young adults reporting caffeine-mixed alcohol use, knowledge of the potential consequences associated with co-consumption has been limited to survey-based results and in-laboratory human behavioral testing. Here, we investigate the effect of repeated adolescent (post-natal days P35-61) exposure to caffeine-mixed alcohol in C57BL/6 mice on common drug-related behaviors such as locomotor sensitivity, drug reward and cross-sensitivity, and natural reward. To determine changes in neurological activity resulting from adolescent exposure, we monitored changes in expression of the transcription factor ΔFosB in the dopaminergic reward pathway as a sign of long-term increases in neuronal activity. Repeated adolescent exposure to caffeine-mixed alcohol exposure induced significant locomotor sensitization, desensitized cocaine conditioned place preference, decreased cocaine locomotor cross-sensitivity, and increased natural reward consumption. We also observed increased accumulation of ΔFosB in the nucleus accumbens following repeated adolescent caffeine-mixed alcohol exposure compared to alcohol or caffeine alone. Using our exposure model, we found that repeated exposure to caffeine-mixed alcohol during adolescence causes unique behavioral and neurochemical effects not observed in mice exposed to caffeine or alcohol alone. Based on similar findings for different substances of abuse, it is possible that repeated exposure to caffeine-mixed alcohol during adolescence could potentially alter or escalate future substance abuse as means to compensate for these behavioral and neurochemical alterations. PMID:27380261

Transient Exposure to Ethanol during Zebrafish Embryogenesis Results in Defects in Neuronal Differentiation: An Alternative Model System to Study FASD

PubMed Central

Joya, Xavier; Garcia-Algar, Oscar; Vall, Oriol; Pujades, Cristina

2014-01-01

Background The exposure of the human embryo to ethanol results in a spectrum of disorders involving multiple organ systems, including the impairment of the development of the central nervous system (CNS). In spite of the importance for human health, the molecular basis of prenatal ethanol exposure remains poorly understood, mainly to the difficulty of sample collection. Zebrafish is now emerging as a powerful organism for the modeling and the study of human diseases. In this work, we have assessed the sensitivity of specific subsets of neurons to ethanol exposure during embryogenesis and we have visualized the sensitive embryonic developmental periods for specific neuronal groups by the use of different transgenic zebrafish lines. Methodology/Principal Findings In order to evaluate the teratogenic effects of acute ethanol exposure, we exposed zebrafish embryos to ethanol in a given time window and analyzed the effects in neurogenesis, neuronal differentiation and brain patterning. Zebrafish larvae exposed to ethanol displayed small eyes and/or a reduction of the body length, phenotypical features similar to the observed in children with prenatal exposure to ethanol. When neuronal populations were analyzed, we observed a clear reduction in the number of differentiated neurons in the spinal cord upon ethanol exposure. There was a decrease in the population of sensory neurons mainly due to a decrease in cell proliferation and subsequent apoptosis during neuronal differentiation, with no effect in motoneuron specification. Conclusion Our investigation highlights that transient exposure to ethanol during early embryonic development affects neuronal differentiation although does not result in defects in early neurogenesis. These results establish the use of zebrafish embryos as an alternative research model to elucidate the molecular mechanism(s) of ethanol-induced developmental toxicity at very early stages of embryonic development. PMID:25383948

Effect of postnatal low-dose exposure to environmental chemicals on the gut microbiome in a rodent model.

PubMed

Hu, Jianzhong; Raikhel, Vincent; Gopalakrishnan, Kalpana; Fernandez-Hernandez, Heriberto; Lambertini, Luca; Manservisi, Fabiana; Falcioni, Laura; Bua, Luciano; Belpoggi, Fiorella; L Teitelbaum, Susan; Chen, Jia

2016-06-14

This proof-of-principle study examines whether postnatal, low-dose exposure to environmental chemicals modifies the composition of gut microbiome. Three chemicals that are widely used in personal care products-diethyl phthalate (DEP), methylparaben (MPB), triclosan (TCS)-and their mixture (MIX) were administered at doses comparable to human exposure to Sprague-Dawley rats from birth through adulthood. Fecal samples were collected at two time points: postnatal day (PND) 62 (adolescence) and PND 181 (adulthood). The gut microbiome was profiled by 16S ribosomal RNA gene sequencing, taxonomically assigned and assessed for diversity. Metagenomic profiling revealed that the low-dose chemical exposure resulted in significant changes in the overall bacterial composition, but in adolescent rats only. Specifically, the individual taxon relative abundance for Bacteroidetes (Prevotella) was increased while the relative abundance of Firmicutes (Bacilli) was reduced in all treated rats compared to controls. Increased abundance was observed for Elusimicrobia in DEP and MPB groups, Betaproteobacteria in MPB and MIX groups, and Deltaproteobacteria in TCS group. Surprisingly, these differences diminished by adulthood (PND 181) despite continuous exposure, suggesting that exposure to the environmental chemicals produced a more profound effect on the gut microbiome in adolescents. We also observed a small but consistent reduction in the bodyweight of exposed rats in adolescence, especially with DEP and MPB treatment (p < 0.05), which is consistent with our findings of a reduced Firmicutes/Bacteroidetes ratio at PND 62 in exposed rats. This study provides initial evidence that postnatal exposure to commonly used environmental chemicals at doses comparable to human exposure is capable of modifying the gut microbiota in adolescent rats; whether these changes lead to downstream health effects requires further investigation.

Zebrafish as a model for acetylcholinesterase-inhibiting organophosphorus agent exposure and oxime reactivation

PubMed Central

Koenig, Jeffrey A.; Dao, Thuy L.; Kan, Robert K.; Shih, Tsung-Ming

2016-01-01

The current research progression efforts for investigating novel treatments for exposure to organophosphorus (OP) compounds that inhibit acetylcholinesterase (AChE), including pesticides and chemical warfare nerve agents (CWNAs), rely solely on in vitro cell assays and in vivo rodent models. The zebrafish (Danio rerio) is a popular, well-established vertebrate model in biomedical research that offers high-throughput capabilities and genetic manipulation not readily available with rodents. A number of research studies have investigated the effects of subacute developmental exposure to OP pesticides in zebrafish, observing detrimental effects on gross morphology, neuronal development, and behavior. Few studies, however, have utilized this model to evaluate treatments, such as oxime reactivators, anticholinergics, or anticonvulsants, following acute exposure. Preliminary work has investigated the effects of CWNA exposure. The results clearly demonstrated relative toxicity and oxime efficacy similar to that reported for the rodent model. This review surveys the current literature utilizing zebrafish as a model for OP exposure and highlights its potential use as a high-throughput system for evaluating AChE reactivator antidotal treatments to acute pesticide and CWNA exposure. PMID:27123828

Effects of chronic dietary exposure to environmentally relevant concentrations to 2,3,7,8-tetrachlorodibenzo-p-dioxin on survival, growth, reproduction and biochemical responses of female rainbow trout (Oncorhynchus mykiss)

USGS Publications Warehouse

Giesy, John P.; Jones, Paul D.; Kannan, Kurunthachalam; Newsted, John L.; Tillitt, Donald E.; Williams, Lisa L.

2002-01-01

Adult female rainbow trout were exposed to dietary 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) at concentrations of 1.8, 18 and 90 ng TCDD/kg (ww) food for up to 300 day. At the end of the exposure fish were spawned and the reproductive outcomes were assessed. TCDD was accumulated into tissues and eggs in a dose-dependent manner with steady state being achieved after 50–100 day of exposure. Biochemical and hematological parameters were monitored at 50, 100, 150, and 200 day after the beginning of exposure. The survival of adult female trout was reduced in a dose-dependent manner by exposure to TCDD in the diet. Fish fed 1.8 ng TCDD/kg, moist weight of diet, showed significantly reduced survival compared with those fed the control diet. TCDD also affected survival of fry from females fed 1.8 ng TCDD/kg. Observed adverse effects in adult fish were as sensitive as early life-stage endpoints. Liver EROD activity was only moderately increased in all exposure groups after 250+ day of exposure. Low rates of edema and deformities were observed in fry from all treatment groups including controls. This study has demonstrated adverse effects of TCDD to both adults and fry at concentrations comparable to current environmental concentrations. This suggests that direct adult toxicity as well as reproductive endpoints need to be incorporated in the current risk assessment paradigm for these compounds.

Use of a human skin in vitro model to investigate the influence of 'every-day' clothing and skin surface decontamination on the percutaneous penetration of organophosphates.

PubMed

Moore, C A; Wilkinson, S C; Blain, P G; Dunn, M; Aust, G A; Williams, F M

2014-08-17

Organophosphates (OPs) are widely used in agriculture. Many studies have investigated the capability of personal protective equipment (PPE) to reduce chemical exposure; however, investigations into the protective effect of 'every-day' clothing are rare. The purpose of this study was to investigate the protective effect of 'every-day' clothing against dermal exposure and to measure early decontamination of skin following exposure to chlorpyrifos and dichlorvos. Using human skin in vitro, absorption of (14)C-labelled chlorpyrifos (500 ng/cm(2)), was shown to be significantly reduced when applied to clothed skin (cotton shirt), regardless of application vehicle (isopropanol (IPA) or propylene glycol (PG)). The majority of applied dose was retained within the clothing after 4 h exposure. Significant reduction in absorption of chlorpyrifos (in PG) was seen through clothed skin when supplemented with skin decontamination at 4 h, compared with clothed skin decontaminated after 24 h, however, this was not observed with IPA. Absorption of dichlorvos (5 μg/cm(2)) was greater through unclothed skin than chlorpyrifos for all vehicles (IPA, isopropyl myristate (IPM) and PG). Significant reduction in absorption was observed when decontaminating clothed skin at 30 min, compared with decontamination at 24 h (post-exposure) for all vehicles. indicate that 'every-day' clothing is effective at reducing exposure to chemicals in contact with skin. Washing the skin surface immediately following removal of exposed clothing can further reduce exposure, depending on the properties of the chemical and vehicle applied. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Chronic Carcinogenicity Study of Gasoline Vapor Condensate (GVC) and GVC Containing Methyl Tertiary-Butyl Ether in F344 Rats

PubMed Central

Benson, Janet M.; Gigliotti, Andrew P.; March, Thomas H.; Barr, Edward B.; Tibbetts, Brad M.; Skipper, Betty J.; Clark, Charles R.; Twerdok, Lorraine

2011-01-01

Chronic inhalation studies were conducted to compare the toxicity and potential carcinogenicity of evaporative emissions from unleaded gasoline (GVC) and gasoline containing the oxygenate methyl tertiary-butyl ether (MTBE; GMVC). The test materials were manufactured to mimic vapors people would be exposed to during refueling at gas stations. Fifty F344 rats per gender per exposure level per test article were exposed 6 h/d, 5 d/wk for 104 wk in whole body chambers. Target total vapor concentrations were 0, 2, 10, or 20 g/m3 for the control, low-, mid-, and high-level exposures, respectively. Endpoints included survival, body weights, clinical observations, organs weights, and histopathology. GVC and GMVC exerted no marked effects on survival or clinical observations and few effects on organ weights. Terminal body weights were reduced in all mid- and high-level GVC groups and high-level GMVC groups. The major proliferative lesions attributable to gasoline exposure with or without MTBE were renal tubule adenomas and carcinomas in male rats. GMV exposure led to elevated testicular mesothelioma incidence and an increased trend for thyroid carcinomas in males. GVMC inhalation caused an increased trend for testicular tumors with exposure concentration. Mid- and high-level exposures of GVC and GMVC led to elevated incidences of nasal respiratory epithelial degeneration. Overall, in these chronic studies conducted under identical conditions, the health effects in F344 rats following 2 yr of GVC or GMVC exposure were comparable in the production of renal adenomas and carcinomas in male rats and similar in other endpoints. PMID:21432714

Chronic carcinogenicity study of gasoline vapor condensate (GVC) and GVC containing methyl tertiary-butyl ether in F344 rats.

PubMed

Benson, Janet M; Gigliotti, Andrew P; March, Thomas H; Barr, Edward B; Tibbetts, Brad M; Skipper, Betty J; Clark, Charles R; Twerdok, Lorraine

2011-01-01

Chronic inhalation studies were conducted to compare the toxicity and potential carcinogenicity of evaporative emissions from unleaded gasoline (GVC) and gasoline containing the oxygenate methyl tertiary-butyl ether (MTBE; GMVC). The test materials were manufactured to mimic vapors people would be exposed to during refueling at gas stations. Fifty F344 rats per gender per exposure level per test article were exposed 6 h/d, 5 d/wk for 104 wk in whole body chambers. Target total vapor concentrations were 0, 2, 10, or 20 g/m³ for the control, low-, mid-, and high-level exposures, respectively. Endpoints included survival, body weights, clinical observations, organs weights, and histopathology. GVC and GMVC exerted no marked effects on survival or clinical observations and few effects on organ weights. Terminal body weights were reduced in all mid- and high-level GVC groups and high-level GMVC groups. The major proliferative lesions attributable to gasoline exposure with or without MTBE were renal tubule adenomas and carcinomas in male rats. GMV exposure led to elevated testicular mesothelioma incidence and an increased trend for thyroid carcinomas in males. GVMC inhalation caused an increased trend for testicular tumors with exposure concentration. Mid- and high-level exposures of GVC and GMVC led to elevated incidences of nasal respiratory epithelial degeneration. Overall, in these chronic studies conducted under identical conditions, the health effects in F344 rats following 2 yr of GVC or GMVC exposure were comparable in the production of renal adenomas and carcinomas in male rats and similar in other endpoints.

Biological Applications and Effects of Optical Masers.

DTIC Science & Technology

1983-08-01

exposures began. By March 1983 after 316 daily exposures, there were large lesions in the superior and temporal macula and the exposure regime was stopped...epithelium (RPE) depigmentation in the superior macula . Now funduscopic examination of 11 the exposed eye disclosed a large lesion in the superior...paramacula where an edematous area had been observed previously and another large lesion in the temporal macula . There were numerous small depigmented

Female reproductive impacts of dietary methylmercury in yellow perch (Perca flavescens) and zebrafish (Danio rerio).

PubMed

DeBofsky, Abigail R; Klingler, Rebekah H; Mora-Zamorano, Francisco X; Walz, Marcus; Shepherd, Brian; Larson, Jeremy K; Anderson, David; Yang, Luobin; Goetz, Frederick; Basu, Niladri; Head, Jessica; Tonellato, Peter; Armstrong, Brandon M; Murphy, Cheryl; Carvan, Michael J

2018-03-01

The purpose of this study was to evaluate the effects of environmentally relevant dietary MeHg exposures on adult female yellow perch (Perca flavescens) and female zebrafish (Danio rerio) ovarian development and reproduction. Yellow perch were used in the study for their socioeconomic and ecological importance within the Great Lakes basin, and the use of zebrafish allowed for a detailed analysis of the molecular effects of MeHg following a whole life-cycle exposure. Chronic whole life dietary exposure of F 1 zebrafish to MeHg mimics realistic wildlife exposure scenarios, and the twenty-week adult yellow perch exposure (where whole life-cycle exposures are difficult) captures early seasonal ovarian development. For both species, target dietary accumulation values were achieved prior to analyses. In zebrafish, several genes involved in reproductive processes were shown to be dysregulated by RNA-sequencing and quantitative real-time polymerase chain reaction (QPCR), but no significant phenotypic changes were observed regarding ovarian staging, fecundity, or embryo mortality. Yellow perch were exposed to dietary MeHg for 12, 16, or 20 weeks. In this species, a set of eight genes were assessed by QPCR in the pituitary, liver, and ovary, and no exposure-related changes were observed. The lack of genomic resources in yellow perch hinders the characterization of subtle molecular impacts. The ovarian somatic index, circulating estradiol and testosterone, and ovarian staging were not significantly altered by MeHg exposure in yellow perch. These results suggest that environmentally relevant MeHg exposures do not drastically reduce the reproductively important endpoints in these fish, but to capture realistic exposure scenarios, whole life-cycle yellow perch exposures are needed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Estimated exposure to zearalenone, ochratoxin A and aflatoxin B1 through the consume of bakery products and pasta considering effects of food processing.

PubMed

Bol, Emilli Keller; Araujo, Letícia; Veras, Flávio Fonseca; Welke, Juliane Elisa

2016-03-01

The objective of this research was to estimate the processing effect on mycotoxins levels and the exposure to zearalenone (ZEA), ochratoxin (OTA) and aflatoxin B1 (AFB1) through the consumption of pasta and bakery products. The higher reduction percentage of mycotoxins was observed in cake production (95, 90 and 70% for ZEA, OTA and AFB1, respectively). Bread and biscuit showed similar reduction in mycotoxins levels (89 and 90% for ZEA; 80 and 85% for OTA; 36 and 40% for AFB1, respectively). The lower reduction in the levels of mycotoxins has been observed for pasta (75, 65 and 10% for ZEA, OTA and AFB1, respectively). The consumption of these products could represent 12.6% of the maximum tolerable daily intake of ZEA and 30.5% of the tolerable weekly intake of OTA. The margin of exposure value related to the exposure to AFB1 was 24.6. The exposure to ZEA and OTA through the consumption of bakery products and pasta would not represent risk for consumer health, (although conjugated forms were not determined). However, the exposure to AFB1 represents a risk (even without considering the AFB1-conjugated forms). Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of A 60 Hz Magnetic Field of Up to 50 milliTesla on Human Tremor and EEG: A Pilot Study.

PubMed

Davarpanah Jazi, Shirin; Modolo, Julien; Baker, Cadence; Villard, Sebastien; Legros, Alexandre

2017-11-24

Humans are surrounded by sources of daily exposure to power-frequency (60 Hz in North America) magnetic fields (MFs). Such time-varying MFs induce electric fields and currents in living structures which possibly lead to biological effects. The present pilot study examined possible extremely low frequency (ELF) MF effects on human neuromotor control in general, and physiological postural tremor and electroencephalography (EEG) in particular. Since the EEG cortical mu-rhythm (8-12 Hz) from the primary motor cortex and physiological tremor are related, it was hypothesized that a 60 Hz MF exposure focused on this cortical region could acutely modulate human physiological tremor. Ten healthy volunteers (age: 23.8 ± 4 SD) were fitted with a MRI-compatible EEG cap while exposed to 11 MF conditions (60 Hz, 0 to 50 mT rms , 5 mT rms increments). Simultaneously, physiological tremor (recorded from the contralateral index finger) and EEG (from associated motor and somatosensory brain regions) were measured. Results showed no significant main effect of MF exposure conditions on any of the analyzed physiological tremor characteristics. In terms of EEG, no significant effects of the MF were observed for C1, C3, C5 and CP1 electrodes. However, a significant main effect was found for CP3 and CP5 electrodes, both suggesting a decreased mu-rhythm spectral power with increasing MF flux density. This is however not confirmed by Bonferroni corrected pairwise comparisons. Considering both EEG and tremor findings, no effect of the MF exposure on human motor control was observed. However, MF exposure had a subtle effect on the mu-rhythm amplitude in the brain region involved in tactile perception. Current findings are to be considered with caution due to the small size of this pilot work, but they provide preliminary insights to international agencies establishing guidelines regarding electromagnetic field exposure with new experimental data acquired in humans exposed to high mT-range MFs.

Impacts of the phenylpyrazole insecticide fipronil on larval fish: time-series gene transcription responses in fathead minnow (Pimephales promelas) following short-term exposure.

PubMed

Beggel, Sebastian; Werner, Inge; Connon, Richard E; Geist, Juergen P

2012-06-01

The utilization of molecular endpoints in ecotoxicology can provide rapid and valuable information on immediate organismal responses to chemical stressors and is increasingly used for mechanistic interpretation of effects at higher levels of biological organization. This study contributes knowledge on the sublethal effects of a commonly used insecticide, the phenylpyrazole fipronil, on larval fathead minnow (Pimephales promelas), utilizing a quantitative transcriptomic approach. Immediately after 24h of exposure to fipronil concentrations of ≥31 μg.L(-1), highly significant changes in gene transcription were observed for aspartoacylase, metallothionein, glucocorticoid receptor, cytochrome P450 3A126 and vitellogenin. Different mechanisms of toxicity were apparent over the course of the experiment, with short-term responses indicating neurotoxic effects. After 6 days of recovery, endocrine effects were observed with vitellogenin being up-regulated 90-fold at 61 μg.L(-1) fipronil. Principal component analysis demonstrated a significant increase in gene transcription changes over time and during the recovery period. In conclusion, multiple mechanisms of action were observed in response to fipronil exposure, and unknown delayed effects would have been missed if transcriptomic responses had only been measured at a single time-point. These challenges can be overcome by the inclusion of multiple endpoints and delayed effects in experimental designs. Copyright © 2012 Elsevier B.V. All rights reserved.

Effects of exposure to oil spills on human health: Updated review.

PubMed

Laffon, Blanca; Pásaro, Eduardo; Valdiglesias, Vanessa

2016-01-01

Oil spills may involve health risks for people participating in the cleanup operations and coastal inhabitants, given the toxicological properties of the oil components. In spite of this, only after a few major oil spills (crude oil or fuel oil no. 6) have studies on effects of exposure to diverse aspects of human health been performed. Previously, Aguilera et al. (2010) examined all documents published to that date dealing with any type of human health outcome in populations exposed to oil spills. The aim of the present review was to compile all new information available and determine whether evidence reported supports the existence of an association between exposure and adverse human health risks. Studies were classified in three groups according to type of health outcome addressed: (i) effects on mental health, (ii) physical/physiological effects, and (iii) genotoxic, immunotoxic, and endocrine toxicity. New studies published on oil-spill-exposed populations-coastal residents in the vicinity of the spills or participants in cleanup operations-provide additional support to previous evidence on adverse health effects related to exposure regarding different parameters in all three categories considered. Some of the observed effects even indicated that several symptoms may persist for some years after exposure. Hence, (1) health protection in these individuals should be a matter of concern; and (2) health risk assessment needs to be carried out not only at the time of exposure but also for prolong periods following exposure, to enable early detection of any potential exposure-related harmful effects.

Mobile phone radiation alters proliferation of hepatocarcinoma cells.

PubMed

Ozgur, Elcin; Guler, Goknur; Kismali, Gorkem; Seyhan, Nesrin

2014-11-01

This study investigated the effects of intermittent exposure (15 min on, 15 min off for 1, 2, 3, or 4 h, at a specific absorption rate of 2 W/kg) to enhanced data rates for global system for mobile communication evolution-modulated radiofrequency radiation (RFR) at 900- and 1,800-MHz frequencies on the viability of the Hepatocarcinoma cells (Hep G2). Hep G2 cell proliferation was measured by a colorimetric assay based on the cleavage of the tetrazolium salt WST-1 by mitochondrial dehydrogenases in viable cells. Cell injury was evaluated by analyzing the levels of lactate dehydrogenase (LDH) and glucose released from lysed cells into the culture medium. Morphological observation of the nuclei was carried out by 4',6-diamidino-2-phenylindole (DAPI) staining using fluorescence microscopy. In addition, TUNEL assay was performed to confirm apoptotic cell death. It was observed that cell viability, correlated with the LDH and glucose levels, changed according to the frequency and duration of RFR exposure. Four-hour exposure produced more pronounced effects than the other exposure durations. 1,800-MHz RFR had a larger impact on cell viability and Hep G2 injury than the RFR at 900 MHz. Morphological observations also supported the biochemical results indicating that most of the cells showed irregular nuclei pattern determined by using the DAPI staining, as well as TUNEL assay which shows DNA damage especially in the cells after 4 h of exposure to 1,800-MHz RFR. Our results indicate that the applications of 900- and 1,800-MHz (2 W/kg) RFR cause to decrease in the proliferation of the Hep G2 cells after 4 h of exposure. Further studies will be conducted on other frequency bands of RFR and longer duration of exposure.

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

Aerosolized ZnO nanoparticles induce toxicity in alveolar type II epithelial cells at the air-liquid interface

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

Xie, Yumei; Williams, Nolann G.; Tolic, Ana

The majority of in vitro studies characterizing the impact of engineered nanoparticles (NPs) on cells that line the respiratory tract were conducted in cells exposed to NPs in suspension. This approach introduces processes that are unlikely to occur during inhaled NP exposures in vivo, such as the shedding of toxic doses of dissolved ions. ZnO NPs are used extensively and pose significant sources for human exposure. Exposures to airborne ZnO NPs can induce adverse effects, but the relevance of the dissolved Zn2+ to the observed effects in vivo is still unclear. Our goal was to mimic in vivo exposures tomore » airborne NPs and decipher the contribution of the intact NP from the contribution of the dissolved ions to airborne ZnO NP toxicity. We established the exposure of alveolar type II epithelial cells to aerosolized NPs at the air-liquid interface (ALI), and compared the impact of aerosolized ZnO NPs and NPs in suspension at the same cellular doses, measured as the number of particles per cell. By evaluating membrane integrity and cell viability 6 and 24 hours post exposure we found that aerosolized NPs induced toxicity at the ALI at doses that were in the same order of magnitude as doses required to induce toxicity in submersed cultures. In addition, distinct patterns of oxidative stress were observed in the two exposure systems. These observations unravel the ability of airborne ZnO NPs to induce toxicity without the contribution of dissolved Zn2+ and suggest distinct mechanisms at the ALI and in submersed cultures.« less

Motor and Cognitive Outcomes Through Three Years Of Age In Children Exposed To Prenatal Methamphetamine

PubMed Central

Smith, Lynne M.; LaGasse, Linda L.; Derauf, Chris; Newman, Elana; Shah, Rizwan; Haning, William; Arria, Amelia; Huestis, Marilyn; Strauss, Arthur; Grotta, Sheri Della; Dansereau, Lynne M.; Lin, Hai; Lester, Barry M.

2010-01-01

Background Methamphetamine (MA) use among pregnant women is an increasing problem in the United States. The impact of prenatal MA exposure on development in childhood is unknown. Objective To examine the effects of prenatal MA exposure on motor and cognitive development in children at 1, 2, and 3 years of age. Design/Methods IDEAL enrolled 412 mother-infant pairs at four sites (Tulsa OK, Des Moines IA, Los Angeles CA, and Honolulu HI). MA subjects (n=204) were identified by self-report or GC/MS confirmation of amphetamine and metabolites in infant meconium. Comparison subjects (n=208) were matched (race, birth weight, maternal education, type of insurance), denied amphetamine use, and had a negative meconium screen. Both groups included prenatal alcohol, tobacco and marijuana use, but excluded use of opiates, lysergic acid diethylamide, phencyclidine or cocaine only. The Peabody Developmental Motor Scales (PDMS-2) were administered to the infants at the 1 and 3 year visits. This analysis includes a subsample (n=350) of the IDEAL study with completed 1 and/or 3 year visits (n= 330 and 281, respectively). At each annual visit we also conducted the Bayley Scales of Infant Development (BSID-II) as a general evaluation of mental and motor development. The BSID-II analysis includes a subsample (n=356) of the IDEAL study with completed 1, 2, and/or 3 year visits (n= 331, 288, and 278 respectively). GLM analysis conducted on the PDMS-2 and BSID-II examined the effects of MA exposure and heavy MA exposure (≥3 days of use/week), with and without covariates. Longitudinal analyses were used to examine the effects of MA exposure on changes in motor and cognitive performance over time. Results Heavy MA exposure was associated with significantly lower grasping scores than some and no use at 1 year (P = 0.018). In longitudinal analysis, lower grasping scores associated with any MA exposure and heavy exposure persisted to 3 years. There were no effects of MA exposure, including heavy exposure, on the Bayley Mental Development Index (MDI) or Psychomotor Development Index (PDI) at any or across age. Conclusions There were no differences in cognition as assessed by the BSID-II between the groups. There was a subtle MA exposure effect on fine motor performance at 1 year with the poorest performance observed in the most heavily exposed children. By 3 years, no differences in fine motor performance were observed. These findings suggest MA exposure has modest motor effects at 1 year that are mostly resolved by 3 years. PMID:21256431

Motor and cognitive outcomes through three years of age in children exposed to prenatal methamphetamine.

PubMed

Smith, Lynne M; LaGasse, Linda L; Derauf, Chris; Newman, Elana; Shah, Rizwan; Haning, William; Arria, Amelia; Huestis, Marilyn; Strauss, Arthur; Della Grotta, Sheri; Dansereau, Lynne M; Lin, Hai; Lester, Barry M

2011-01-01

Methamphetamine (MA) use among pregnant women is an increasing problem in the United States. The impact of prenatal MA exposure on development in childhood is unknown. To examine the effects of prenatal MA exposure on motor and cognitive development in children at 1, 2, and 3 years of age. IDEAL enrolled 412 mother-infant pairs at four sites (Tulsa OK, Des Moines IA, Los Angeles CA, and Honolulu HI). MA subjects (n=204) were identified by self report or GC/MS confirmation of amphetamine and metabolites in infant meconium. Comparison subjects (n=208) were matched (race, birth weight, maternal education, and type of insurance), denied amphetamine use, and had a negative meconium screen. Both groups included prenatal alcohol, tobacco and marijuana use, but excluded use of opiates, lysergic acid diethylamide, phencyclidine or cocaine only. The Peabody Developmental Motor Scales (PDMS-2) were administered to the infants at the 1 and 3 year visits. This analysis includes a subsample (n=350) of the IDEAL study with completed 1 and/or 3 year visits (n=330 and 281, respectively). At each annual visit we also conducted the Bayley Scales of Infant Development (BSID-II) as a general evaluation of mental and motor development. The BSID-II analysis includes a subsample (n=356) of the IDEAL study with completed 1, 2, and/or 3 year visits (n=331, 288, and 278 respectively). GLM analysis conducted on the PDMS-2 and BSID-II examined the effects of MA exposure and heavy MA exposure (≥3 days of use/week), with and without covariates. Longitudinal analyses were used to examine the effects of MA exposure on changes in motor and cognitive performance over time. Heavy MA exposure was associated with significantly lower grasping scores than some and no use at 1 year (P=0.018). In longitudinal analysis, lower grasping scores associated with any MA exposure and heavy exposure persisted to 3 years. There were no effects of MA exposure, including heavy exposure, on the Bayley Mental Development Index (MDI) or Psychomotor Development Index (PDI) at any or across age. There were no differences in cognition as assessed by the BSID-II between the groups. There was a subtle MA exposure effect on fine motor performance at 1 year with the poorest performance observed in the most heavily exposed children. By 3 years, no differences in fine motor performance were observed. These findings suggest MA exposure has modest motor effects at 1 year that are mostly resolved by 3 years. Copyright © 2010 Elsevier Inc. All rights reserved.

Antidepressant use during pregnancy and risk of autism spectrum disorder and attention deficit hyperactivity disorder: systematic review of observational studies and methodological considerations.

PubMed

Morales, Daniel R; Slattery, Jim; Evans, Stephen; Kurz, Xavier

2018-01-15

Antidepressant exposure during pregnancy has been associated with an increased risk of autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) in several observational studies. We performed a systematic review of these studies to highlight the effect that important methodological limitations have on such analyses and to consider approaches to the conduct, reporting and interpretation of future studies. A review of MEDLINE and EMBASE identified case-control, cohort and sibling studies assessing the risk of ASD and ADHD with antidepressant use during pregnancy. Approaches to confounding adjustment were described. Crude and adjusted effect estimates for comparisons between antidepressant exposure during pregnancy vs. all unexposed women were first meta-analysed using a generic inverse variance method of analysis, followed by effect estimates for alternative pre-selected comparison groups. A total of 15 studies measuring ASD as an outcome (involving 3,585,686 children and 40,585 cases) and seven studies measuring ADHD as an outcome (involving 2,765,723 patients and 52,313 cases) were identified. Variation in confounding adjustment existed between studies. Updated effect estimates for the association between maternal antidepressant exposure during pregnancy vs. all unexposed women remained statistically significant for ASD (adjusted random-effects risk ratio [RaRR] 1.53, 95% confidence interval [CI] 1.31-1.78). Similar significant associations were observed using pre-pregnancy maternal antidepressant exposure (RaRR 1.48, 95% CI 1.29-1.71) and paternal antidepressant exposure during pregnancy (1.29, 95% CI 1.08-1.53), but analyses restricted to using women with a history of affective disorder (1.18, 95% CI 0.91-1.52) and sibling studies (0.96, 95% CI 0.65-1.42) were not statistically significant. Corresponding associations for risk of ADHD with exposure were: RaRR 1.38, 95% CI 1.13-1.69 (during pregnancy), RaRR 1.38, 95% CI 1.14-1.69 (during pre-pregnancy), RaRR 1.71, 95% CI 1.31-2.23 (paternal exposure), RaRR 0.98, 95% CI 0.77-1.24 (women with a history of affective disorder) and RaRR 0.88, 95% CI 0.70-1.11 (sibling studies). Existing observational studies measuring the risk of ASD and ADHD with antidepressant exposure are heterogeneous in their design. Classical comparisons between exposed and unexposed women during pregnancy are at high risk of residual confounding. Alternative comparisons and sibling designs may aid the interpretation of causality and their utility requires further evaluation, including understanding potential limitations of undertaking meta-analyses with such data.

A meta-analysis of the evidence on the impact of prenatal and early infancy exposures to mercury on autism and attention deficit/hyperactivity disorder in the childhood.

PubMed

Yoshimasu, Kouichi; Kiyohara, Chikako; Takemura, Shigeki; Nakai, Kunihiko

2014-09-01

Although a measurable number of epidemiological studies have been conducted to clarify the associations between mercury exposure during embryo or early infancy and later incidences of autism spectrum disorders (ASD) or attention-deficit hyperactivity disorder (ADHD), the conclusion still remains unclear. Meta-analysis was conducted for two major exposure sources; i.e., thimerosal vaccines that contain ethylmercury (clinical exposure), and environmental sources, using relevant literature published before April 2014. While thimerosal exposures did not show any material associations with an increased risk of ASD or ADHD (the summary odds ratio (OR) 0.99, 95% confidence interval (CI) 0.80-1.24 for ASD; OR 0.91, 95% CI 0.70-1.13 for ADHD/ADD), significant associations were observed for environmental exposures in both ASD (OR 1.66, 95% CI 1.14-2.17) and ADHD (OR 1.60, 95% CI 1.10-2.33). The summary ORs were similar after excluding studies not adjusted for confounders. Moderate adverse effects were observed only between environmental inorganic or organic mercury exposures and ASD/ADHD. However, these results should be interpreted with caution since the number of epidemiological studies on this issue was limited and still at an early stage. Further studies focused on subjects with genetic vulnerabilities of developmental disorders are warranted for better understanding of the effects of such environmental exposures. Copyright © 2014 Elsevier Inc. All rights reserved.

Predicting the effect of cytochrome P450 inhibitors on substrate drugs: analysis of physiologically based pharmacokinetic modeling submissions to the US Food and Drug Administration.

PubMed

Wagner, Christian; Pan, Yuzhuo; Hsu, Vicky; Grillo, Joseph A; Zhang, Lei; Reynolds, Kellie S; Sinha, Vikram; Zhao, Ping

2015-01-01

The US Food and Drug Administration (FDA) has seen a recent increase in the application of physiologically based pharmacokinetic (PBPK) modeling towards assessing the potential of drug-drug interactions (DDI) in clinically relevant scenarios. To continue our assessment of such approaches, we evaluated the predictive performance of PBPK modeling in predicting cytochrome P450 (CYP)-mediated DDI. This evaluation was based on 15 substrate PBPK models submitted by nine sponsors between 2009 and 2013. For these 15 models, a total of 26 DDI studies (cases) with various CYP inhibitors were available. Sponsors developed the PBPK models, reportedly without considering clinical DDI data. Inhibitor models were either developed by sponsors or provided by PBPK software developers and applied with minimal or no modification. The metric for assessing predictive performance of the sponsors' PBPK approach was the R predicted/observed value (R predicted/observed = [predicted mean exposure ratio]/[observed mean exposure ratio], with the exposure ratio defined as [C max (maximum plasma concentration) or AUC (area under the plasma concentration-time curve) in the presence of CYP inhibition]/[C max or AUC in the absence of CYP inhibition]). In 81 % (21/26) and 77 % (20/26) of cases, respectively, the R predicted/observed values for AUC and C max ratios were within a pre-defined threshold of 1.25-fold of the observed data. For all cases, the R predicted/observed values for AUC and C max were within a 2-fold range. These results suggest that, based on the submissions to the FDA to date, there is a high degree of concordance between PBPK-predicted and observed effects of CYP inhibition, especially CYP3A-based, on the exposure of drug substrates.

Long-term effect of noise exposure during military service in South Korea.

PubMed

Kim, SungHee; Lim, Eun Jung; Kim, Tae Hoon; Park, Jun Ho

2017-02-01

Most Korean men spend at least two years in the military service usually in their early twenties. The aim of this study was to identify the long-term effect of exposure to military noise during military service by comparing two regressions of age-related hearing loss between groups with and without exposure to military noise. Cross-sectional observational study. Finally, 4079 subjects were included, among 10,286 data of men's audiogram from January 2004 to April 2010. We excluded repeated testers and any subjects who had other known external causes or had an asymmetric audiogram. We grouped subjects with exposure to military noise (N = 3163) and those without as the control group (N = 916). There was a significant effect of exposure to military noise at 4 and 8 kHz after controlling for the effect of age. The annual threshold deterioration rates were faster in the military noise exposed group than in the control group at 1, 2 and 4 kHz (p < 0.05). The long-term effect of exposure to military noise on age-related hearing loss showed an adding effect at 8 kHz and an accelerating effect in the frequency region from 1 to 4 kHz.

Dihydroxyacetone induces G2/M arrest and apoptotic cell death in A375P melanoma cells.

PubMed

Smith, Kelly R; Granberry, Molley; Tan, Marcus C B; Daniel, Casey L; Gassman, Natalie R

2018-03-01

The active ingredient in sunless tanning products (STPs) is a simple sugar, dihydroxyacetone (DHA). Several studies have demonstrated that DHA is absorbed within the viable layers of skin and not fully contained within the stratum corneum. Additionally, spray tanning and other aerosolized application methods have increased the risk of internal exposure through mucous membranes and inhalation. Beyond its presence in STPs, DHA also occurs as an endogenous by-product of fructose metabolism, and an excess of DHA in cells can induce advanced glycation end (AGE) products and oxidative stress. Therefore, exogenous and endogenous exposures to DHA may be harmful to cells, and it has already been demonstrated that exogenous exposure to DHA is cytotoxic in immortalized keratinocytes. Still, little is known about the exogenous DHA exposure effects on other skin components. In this study, we explore the effects of exogenous DHA exposure in a human melanoma cell line, A375P. Melanoma cells were sensitive to DHA and displayed a transient burst of reactive oxygen species within an hour of exposure. Cell cycle arrest at G2/M was observed within 24 h of exposure, and apoptosis, monitored by the cleavage of PARP-1 and Caspase-3, was detected within 72 h of exposure to DHA. Together, these demonstrate that exogenous exposure to DHA has cytotoxic effects in our selected cell model and indicates the need to further investigate the exogenous exposure effects of DHA in other relevant exposure models. © 2017 Wiley Periodicals, Inc.

Lung cancer risk and occupational exposure to meat and live animals.

PubMed

Durusoy, Raika; Boffetta, Paolo; Mannetje, Andrea 't; Zaridze, David; Szeszenia-Dabrowska, Neonila; Rudnai, Peter; Lissowska, Jolanta; Fabiánová, Eleonóra; Cassidy, Adrian; Mates, Dana; Bencko, Vladimir; Salajka, Frantisek; Janout, Vladimir; Fevotte, Joelle; Fletcher, Tony; Brennan, Paul

2006-05-15

An increased risk of lung cancer has been reported for butchers and meat workers in several cohort studies, although confounding from tobacco smoking could not be ruled out in any of these studies. These exposures, as well as a potential risk associated with contact with live animals, are addressed here in a large case-control study with full adjustment for smoking. More than 5,900 subjects were included in a case-control study conducted in 7 European countries. For each job they employed local experts who assessed the exposure to a number of occupational agents, including (i) meat aerosols and (ii) live animals, on the basis of detailed occupational questionnaires. Information on tobacco consumption and other risk factors was also collected. A small increased risk of lung cancer was observed with exposure to meat aerosols, after adjusting for smoking, (odds ratio (OR)=1.27, 95% confidence interval (CI): 0.92, 1.75), which was most apparent for the upper tertile of cumulative exposure (OR=1.73, 95% CI: 1.03, 2.92). A similar overall effect was observed for exposure to live animals, with an increased risk observed for a high frequency of exposure, (OR=1.69, 95% CI: 1.21, 2.36) and a high intensity of exposure, (OR=1.85, 95% CI: 1.16, 2.94), with significant trends for increasing frequency (p=0.012), intensity (p=0.015) and cumulative exposure (p=0.024). In conclusion, this study provides evidence for an association between exposure to meat aerosols and lung cancer apparent in the highest tertile of exposure. The authors identified a more consistent association with exposure to live animals. Copyright (c) 2005 Wiley-Liss, Inc.

Pupil Response and the Subliminal Mere Exposure Effect

PubMed Central

Yoshimoto, Sanae; Imai, Hisato; Kashino, Makio; Takeuchi, Tatsuto

2014-01-01

The subliminal mere exposure effect (SMEE) is the phenomenon wherein people tend to prefer patterns they have repeatedly observed without consciously identifying them. One popular explanation for the SMEE is that perceptual fluency within exposed patterns is misattributed to a feeling of preference for those patterns. Assuming that perceptual fluency is negatively correlated with the amount of mental effort needed to analyze perceptual aspects of incoming stimuli, pupil diameter should associate with SMEE strength since the former is known to reflect mental effort. To examine this hypothesis, we measured participants’ pupil diameter during exposure to subthreshold stimuli. Following exposure, a preference test was administered. Average pupil diameter throughout exposure was smaller when the SMEE was induced than when the SMEE was not induced. This supports the hypothesis that increasing perceptual fluency during mere exposure modulates autonomic nervous responses, such as pupil diameter, and eventually leads to preference. PMID:24587408

Pupil response and the subliminal mere exposure effect.

PubMed

Yoshimoto, Sanae; Imai, Hisato; Kashino, Makio; Takeuchi, Tatsuto

2014-01-01

The subliminal mere exposure effect (SMEE) is the phenomenon wherein people tend to prefer patterns they have repeatedly observed without consciously identifying them. One popular explanation for the SMEE is that perceptual fluency within exposed patterns is misattributed to a feeling of preference for those patterns. Assuming that perceptual fluency is negatively correlated with the amount of mental effort needed to analyze perceptual aspects of incoming stimuli, pupil diameter should associate with SMEE strength since the former is known to reflect mental effort. To examine this hypothesis, we measured participants' pupil diameter during exposure to subthreshold stimuli. Following exposure, a preference test was administered. Average pupil diameter throughout exposure was smaller when the SMEE was induced than when the SMEE was not induced. This supports the hypothesis that increasing perceptual fluency during mere exposure modulates autonomic nervous responses, such as pupil diameter, and eventually leads to preference.

Long term effects of radiation exposure on telomere lengths of leukocytes and its associated biomarkers among atomic-bomb survivors.

PubMed

Lustig, Ana; Shterev, Ivo; Geyer, Susan; Shi, Alvin; Hu, Yiqun; Morishita, Yukari; Nagamura, Hiroko; Sasaki, Keiko; Maki, Mayumi; Hayashi, Ikue; Furukawa, Kyoji; Yoshida, Kengo; Kajimura, Junko; Kyoizumi, Seishi; Kusunoki, Yoichiro; Ohishi, Waka; Nakachi, Kei; Weng, Nan-Ping; Hayashi, Tomonori

2016-06-28

Ionizing radiation (IR) is a major source of cellular damage and the immediate cellular response to IR has been well characterized. But the long-term impact of IR on cell function and its relationship with aging are not known. Here, we examined the IR effects on telomere length and other biomarkers 50 to 68 years post-exposure (two time points per person) in survivors of the atomic bombing at Hiroshima during WWII. We found that telomere length of leukocytes was inversely correlated with the dose of IR (p=0.008), and this effect was primarily found in survivors who were exposed at younger ages; specifically those <12 years old (p=0.0004). Although a dose-related retardation of telomere shortening with age was observed in the cross-sectional data, longitudinal follow-up after 11 years did not show IR exposure-related alteration of the rate of telomere shortening with age. In addition, IR diminished the associations between telomere length and selected aging biomarkers that were observed in survivors with no dose. These included uric acid metabolism, cytokines, and blood T cell counts. These findings showed long-lasting detrimental effects of IR on telomere length of leukocytes in both dose- and age-at-exposure dependent manner, and on alterations of biomarkers with aging.

Inhalation of diethylamine--acute nasal effects and subjective response

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

Lundqvist, G.R.; Yamagiwa, M.; Pedersen, O.F.

1992-03-01

Adult volunteers were exposed to 25 ppm (75 mg/m3) diethylamine in a climate chamber for 15 min in order to study the acute nasal reactions to an exposure equivalent to the present threshold limit value-short-term exposure limit. Changes in nasal volume and nasal resistance were measured by acoustic rhinometry and by rhinomanometry. Acute change in nasal volume, usually seen as acute nasal mucosa response to thermal stimuli, was not observed, nor was an acute change in nasal airway resistance. In a subsequent experiment, the aim was to measure acute sensory effects. Exposure to a concentration increasing from 0 to 12more » ppm took place for 60 min, equal to an average concentration of 10 ppm (30 mg/m3). A moderate to strong olfactory response and distinct nasal and eye irritation were observed. In spite of considerable individual variation, the results were in agreement with sensory effect estimates obtained from animal studies.« less

Evolution of phenolic compounds and astringency during aging of red wine: effect of oxygen exposure before and after bottling.

PubMed

Gambuti, Angelita; Rinaldi, Alessandra; Ugliano, Maurizio; Moio, Luigi

2013-02-27

The aim of this study was to evaluate the effect of oxygen exposure of red wine, before (micro-oxygenation) and after (nano-oxygenation) bottling, on the phenolic composition and astringency of wine. The astringency was evaluated by sensory analysis and by a method based on the SDS-PAGE of salivary proteins after reaction of saliva with wine (SPI, saliva precipitation index). Micro-oxygenation caused a stabilization of color, but this effect disappeared after long aging. For the wine with the lower pH a decrease of wine astringency and SPI was observed 42 months after micro-oxygenation. Oxygen ingress through the closure postbottling was positively correlated with the decrease of SPI. Therefore, the astringency and reactivity of wines toward salivary proteins of a bottled red wine can be modulated by controlled oxygen exposure during aging. For both experiments the effect of oxygen exposure depended on wine composition.

Facilitation or disengagement? Attention bias in facial affect processing after short-term violent video game exposure

PubMed Central

Liu, Yanling; Lan, Haiying; Teng, Zhaojun; Guo, Cheng; Yao, Dezhong

2017-01-01

Previous research has been inconsistent on whether violent video games exert positive and/or negative effects on cognition. In particular, attentional bias in facial affect processing after violent video game exposure continues to be controversial. The aim of the present study was to investigate attentional bias in facial recognition after short term exposure to violent video games and to characterize the neural correlates of this effect. In order to accomplish this, participants were exposed to either neutral or violent video games for 25 min and then event-related potentials (ERPs) were recorded during two emotional search tasks. The first search task assessed attentional facilitation, in which participants were required to identify an emotional face from a crowd of neutral faces. In contrast, the second task measured disengagement, in which participants were required to identify a neutral face from a crowd of emotional faces. Our results found a significant presence of the ERP component, N2pc, during the facilitation task; however, no differences were observed between the two video game groups. This finding does not support a link between attentional facilitation and violent video game exposure. Comparatively, during the disengagement task, N2pc responses were not observed when participants viewed happy faces following violent video game exposure; however, a weak N2pc response was observed after neutral video game exposure. These results provided only inconsistent support for the disengagement hypothesis, suggesting that participants found it difficult to separate a neutral face from a crowd of emotional faces. PMID:28249033

Facilitation or disengagement? Attention bias in facial affect processing after short-term violent video game exposure.

PubMed

Liu, Yanling; Lan, Haiying; Teng, Zhaojun; Guo, Cheng; Yao, Dezhong

2017-01-01

Previous research has been inconsistent on whether violent video games exert positive and/or negative effects on cognition. In particular, attentional bias in facial affect processing after violent video game exposure continues to be controversial. The aim of the present study was to investigate attentional bias in facial recognition after short term exposure to violent video games and to characterize the neural correlates of this effect. In order to accomplish this, participants were exposed to either neutral or violent video games for 25 min and then event-related potentials (ERPs) were recorded during two emotional search tasks. The first search task assessed attentional facilitation, in which participants were required to identify an emotional face from a crowd of neutral faces. In contrast, the second task measured disengagement, in which participants were required to identify a neutral face from a crowd of emotional faces. Our results found a significant presence of the ERP component, N2pc, during the facilitation task; however, no differences were observed between the two video game groups. This finding does not support a link between attentional facilitation and violent video game exposure. Comparatively, during the disengagement task, N2pc responses were not observed when participants viewed happy faces following violent video game exposure; however, a weak N2pc response was observed after neutral video game exposure. These results provided only inconsistent support for the disengagement hypothesis, suggesting that participants found it difficult to separate a neutral face from a crowd of emotional faces.

Cumulative doses analysis in young trauma patients: a single-centre experience.

PubMed

Salerno, Sergio; Marrale, Maurizio; Geraci, Claudia; Caruso, Giuseppe; Lo Re, Giuseppe; Lo Casto, Antonio; Midiri, Massimo

2016-02-01

Multidetector computed tomography (MDCT) represents the main source of radiation exposure in trauma patients. The radiation exposure of young patients is a matter of considerable medical concern due to possible long-term effects. Multiple MDCT studies have been observed in the young trauma population with an increase in radiation exposure. We have identified 249 young adult patients (178 men and 71 women; age range 14-40 years) who had received more than one MDCT study between June 2010 and June 2014. According to the International Commission on Radiological Protection publication, we have calculated the cumulative organ dose tissue-weighting factors by using CT-EXPO software(®). We have observed a mean cumulative dose of about 27 mSv (range from 3 to 297 mSv). The distribution analysis is characterised by low effective dose, below 20 mSv, in the majority of the patients. However, in 29 patients, the effective dose was found to be higher than 20 mSv. Dose distribution for the various organs analysed (breasts, ovaries, testicles, heart and eye lenses) shows an intense peak for lower doses, but in some cases high doses were recorded. Even though cumulative doses may have long-term effects, which are still under debate, high doses are observed in this specific group of young patients.

Extreme Precipitation and Flooding: Exposure Characterization and the Association Between Exposure and Mortality in 108 United States Communities, 1987-2005

NASA Astrophysics Data System (ADS)

Severson, R. L.; Peng, R. D.; Anderson, G. B.

2017-12-01

There is substantial evidence that extreme precipitation and flooding are serious threats to public health and safety. These threats are predicted to increase with climate change. Epidemiological studies investigating the health effects of these events vary in the methods used to characterize exposure. Here, we compare two sources of precipitation data (National Oceanic and Atmospheric Administration (NOAA) station-based and North American Land Data Assimilation Systems (NLDAS-2) Reanalysis data-based) for estimating exposure to extreme precipitation and two sources of flooding data, based on United States Geological Survey (USGS) streamflow gages and the NOAA Storm Events database. We investigate associations between each of the four exposure metrics and short-term risk of four causes of mortality (accidental, respiratory-related, cardiovascular-related, and all-cause) in the United States from 1987 through 2005. Average daily precipitation values from the two precipitation data sources were moderately correlated (Spearman's rho = 0.74); however, values from the two data sources were less correlated when comparing binary metrics of exposure to extreme precipitation days (Jaccard index (J) = 0.35). Binary metrics of daily flood exposure were poorly correlated between the two flood data sources (Spearman's rho = 0.07; J = 0.05). There was little correlation between extreme precipitation exposure and flood exposure in study communities. We did not observe evidence of a positive association between any of the four exposure metrics and risk of any of the four mortality outcomes considered. Our results suggest, due to the observed lack of agreement between different extreme precipitation and flood metrics, that exposure to extreme precipitation may not serve as an effective surrogate for exposures related to flooding. Furthermore, It is possible that extreme precipitation and flood exposures may often be too localized to allow accurate exposure assessment at the community level for epidemiological studies.

Subtle Consequences of Exposure to Weak Microwave Fields: Are There Non-Thermal Effects?

DTIC Science & Technology

1983-01-01

8217" /\\ Lovely -3 When we speak of ’#subtle consequences of exposi ~res we’mean only that the effects were observed in the absence of cb nges in core temper...there is the possibility that any effects observed may be due to residual or proactive treatment effects on the dam which cause her to engage in ab

Characterization of selected LDEF polymer matrix resin composite materials

NASA Technical Reports Server (NTRS)

Young, Philip R.; Slemp, Wayne S.; Witte, William G., Jr.; Shen, James Y.

1991-01-01

The characterization of selected graphite fiber reinforced epoxy (934 and 5208) and polysulfone (P1700) matrix resin composite materials which received 5 years and 10 months of exposure to the LEO environment on the Long Duration Exposure Facility is reported. Resin loss and a decrease in mechanical performance as well as dramatic visual effects were observed. However, chemical characterization including infrared, thermal, and selected solution property measurements showed that the molecular structure of the polymeric matrix had not changed significantly in response to this exposure. The potential effect of a silicon-containing molecular contamination of these specimens is addressed.

Genotoxic effects and induction of phytochelatins in the presence of cadmium in Vicia faba roots.

PubMed

Béraud, Eric; Cotelle, Sylvie; Leroy, Pierre; Férard, Jean-François

2007-10-04

This study investigates different effects in roots of Vicia faba (broad bean) after exposure to cadmium. Genotoxic effects were assessed by use of the well-known Vicia root tip micronucleus assay. Cytotoxic effects were evaluated by determining the mitotic index in root tip cells. Finally, molecular induction mechanisms were evaluated by measuring phytochelatins with HPLC. After hydroponical exposure of V. faba roots to a range of cadmium concentrations and during different exposure times, the results of this approach showed large variations, according to the endpoint measured: after 48 h of exposure, genotoxic effects were found between 7.5 x 10(-8) and 5 x 10(-7)M CdCl(2), and cytotoxic effects were observed between 2.5 x 10(-7) and 5 x 10(-7)M CdCl(2). Statistically significant phytochelatin (PC) concentrations were measured at >or=10(-6)M CdCl(2) for PC(2), and at >or=10(-5)M CdCl(2) for PC3 and PC4.

Examining mechanism of toxicity of copper oxide nanoparticles to Saccharomyces cerevisiae and Caenorhabditis elegans

NASA Astrophysics Data System (ADS)

Mashock, Michael J.

Copper oxide nanoparticles (CuO NPs) are an up and coming technology increasingly being used in industrial and consumer applications and thus may pose risk to humans and the environment. In the present study, the toxic effects of CuO NPs were studied with two model organisms Saccharomyces cerevisiae and Caenorhabditis elegans. The role of released Cu ions during dissolution of CuO NPs in growth media were studied with freshly suspended, aged NPs, and the released Cu 2+ fraction. Exposures to the different Cu treatments showed significant inhibition of S. cerevisiae cellular metabolic activity. Inhibition from the NPs was inversely proportional to size and was not fully explained by the released Cu ions. S. cerevisiae cultures grown under respiring conditions demonstrated greater metabolic sensitivity when exposed to CuO NPs compared to cultures undergoing fermentation. The cellular response to both CuO NPs and released Cu ions on gene expression was analyzed via microarray analysis after an acute exposure. It was observed that both copper exposures resulted in an increase in carbohydrate storage, a decrease in protein production, protein misfolding, increased membrane permeability, and cell cycle arrest. Cells exposed to NPs up-regulated genes related to oxidative phosphorylation but also may be inducing cell cycle arrest by a different mechanism than that observed with released Cu ions. The effect of CuO NPs on C. elegans was examined by using several toxicological endpoints. The CuO NPs displayed a more inhibitory effect, compared to copper sulfate, on nematode reproduction, feeding, and development. We investigated the effects of copper oxide nanoparticles and copper sulfate on neuronal health, a known tissue vulnerable to heavy metal toxicity. In transgenic C. eleganswith neurons expressing a green fluorescent protein reporter, neuronal degeneration was observed in up to 10% of the population after copper oxide nanoparticle exposure. Additionally, nematode mutant strains containing gene knockouts in the divalent-metal transporters smf-1 and smf-2 showed increased tolerance to copper exposure. These results lend credence to the hypothesis that some toxicological effects to eukaryotic organisms from copper oxide nanoparticle exposure may be due to properties specific to the nanoparticles and not solely from the released copper ions.

Guidance on health effects of toxic chemicals. Safety Analysis Report Update Program

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

Foust, C.B.; Griffin, G.D.; Munro, N.B.

1994-02-01

Martin Marietta Energy Systems, Inc. (MMES), and Martin Marietta Utility Services, Inc. (MMUS), are engaged in phased programs to update the safety documentation for the existing US Department of Energy (DOE)-owned facilities. The safety analysis of potential toxic hazards requires a methodology for evaluating human health effects of predicted toxic exposures. This report provides a consistent set of health effects and documents toxicity estimates corresponding to these health effects for some of the more important chemicals found within MMES and MMUS. The estimates are based on published toxicity information and apply to acute exposures for an ``average`` individual. The healthmore » effects (toxicological endpoints) used in this report are (1) the detection threshold; (2) the no-observed adverse effect level; (3) the onset of irritation/reversible effects; (4) the onset of irreversible effects; and (5) a lethal exposure, defined to be the 50% lethal level. An irreversible effect is defined as a significant effect on a person`s quality of life, e.g., serious injury. Predicted consequences are evaluated on the basis of concentration and exposure time.« less

Spaceflight Sensorimotor Analogs: Simulating Acute and Adaptive Effects

NASA Technical Reports Server (NTRS)

Taylor, Laura C.; Harm, Deborah L.; Kozlovskaya, Inessa; Reschke, Millard F.; Wood, Scott J.

2009-01-01

Adaptive changes in sensorimotor function during spaceflight are reflected by spatial disorientation, motion sickness, gaze destabilization and decrements in balance, locomotion and eye-hand coordination that occur during and following transitions between different gravitational states. The purpose of this study was to conduct a meta-synthesis of data from spaceflight analogs to evaluate their effectiveness in simulating adaptive changes in sensorimotor function. METHODS. The analogs under review were categorized as either acute analogs used to simulate performance decrements accompanied with transient changes, or adaptive analogs used to drive sensorimotor learning to altered sensory feedback. The effectiveness of each analog was evaluated in terms of mechanisms of action, magnitude and time course of observed deficits compared to spaceflight data, and the effects of amplitude and exposure duration. RESULTS. Parabolic flight has been used extensively to examine effects of acute variation in gravitational loads, ranging from hypergravity to microgravity. More recently, galvanic vestibular stimulation has been used to elicit acute postural, locomotor and gaze dysfunction by disrupting vestibular afferents. Patient populations, e.g., with bilateral vestibular loss or cerebellar dysfunction, have been proposed to model acute sensorimotor dysfunction. Early research sponsored by NASA involved living onboard rotating rooms, which appeared to approximate the time course of adaptation and post-exposure recovery observed in astronauts following spaceflight. Exposure to different bed-rest paradigms (6 deg head down, dry immersion) result in similar motor deficits to that observed following spaceflight. Shorter adaptive analogs have incorporated virtual reality environments, visual distortion paradigms, exposure to conflicting tilt-translation cues, and exposure to 3Gx centrifugation. As with spaceflight, there is considerable variability in responses to most of the analogs reviewed. DISCUSSION. A true ground-based flight analog for sensorimotor function is not feasible. A combination of flight analogs; however, can be used to selectively mimic different aspects of the spaceflight-induced sensorimotor performance decrements.

Effects of Microcystis on development of early life stage Japanese medaka (Oryzias latipes): Comparative toxicity of natural blooms, cultured Microcystis and microcystin-LR.

PubMed

Saraf, Spencer R; Frenkel, Amy; Harke, Matthew J; Jankowiak, Jennifer G; Gobler, Christopher J; McElroy, Anne E

2018-01-01

Freshwater cyanobacterial harmful algal blooms (CyanoHABs) caused by algae in the genus Microcystis have been increasing in frequency and severity in recent decades. Microcystis blooms threaten aquatic organisms through effects associated with the rapid increase of biomass and the production of the hepatotoxin microcystin (MC) by toxic strains. Among fish, effects of blooms are likely to be more severe for early life stages, and physiological impacts on this life stage could significantly impact recruitment and fish populations. This study explores the effects of Microcystis blooms on the development of fish using the model organism, the Japanese medaka (Oryzias latipes), under realistic exposure conditions. Medaka embryos were exposed to natural blooms collected from New York City (USA) lakes, lab cultures of Microcystis, and MC-LR solutions. Field collected samples were more toxic than lab cultures (even when compared at the same algal density or MC concentration), causing decreased survival, premature time to hatch, reduced body length, yolk sac edema, and decreased heart rate, while lab culture exposures only resulted in bradycardia. Heart rate was the most sensitive endpoint measured, being depressed in embryos exposed to both lab cultures and field collected blooms. Generalized linear model analysis indicated bradycardia was statistically associated with both cell densities of blooms and MC concentrations, while single factor analysis indicated that MC concentrations had a stronger correlation compared to cell densities. However, MC exposure could not fully explain the effects observed, as exposures to MC-LR solutions alone were not able to reduce heart rate as severely as algal exposures. Collectively, these experiments indicate that factors beyond exposure to MC or even isolated Microcystis strains influence heart rate of fish exposed to Microcystis blooms. Enhanced mortality, depressed heart rate, and abnormal development observed in response to environmentally realistic exposures of Microcystis blooms could affect success of fish at both individual or population levels. Copyright © 2017 Elsevier B.V. All rights reserved.

Blending Model Output with satellite-based and in-situ observations to produce high-resolution estimates of population exposure to wildfire smoke

NASA Astrophysics Data System (ADS)

Lassman, William

In the western US, emissions from wildfires and prescribed fire have been associated with degradation of regional air quality. Whereas atmospheric aerosol particles with aerodynamic diameters less than 2.5 mum (PM2.5) have known impacts on human health, there is uncertainty in how particle composition, concentrations, and exposure duration impact the associated health response. Due to changes in climate and land-management, wildfires have increased in frequency and severity, and this trend is expected to continue. Consequently, wildfires are expected to become an increasingly important source of PM2.5 in the western US. While composition and source of the aerosol is thought to be an important factor in the resulting human health-effects, this is currently not well-understood; therefore, there is a need to develop a quantitative understanding of wildfire-smoke-specific health effects. A necessary step in this process is to determine who was exposed to wildfire smoke, the concentration of the smoke during exposure, and the duration of the exposure. Three different tools are commonly used to assess exposure to wildfire smoke: in-situ measurements, satellite-based observations, and chemical-transport model (CTM) simulations, and each of these exposure-estimation tools have associated strengths and weakness. In this thesis, we investigate the utility of blending these tools together to produce highly accurate estimates of smoke exposure during the 2012 fire season in Washington for use in an epidemiological case study. For blending, we use a ridge regression model, as well as a geographically weighted ridge regression model. We evaluate the performance of the three individual exposure-estimate techniques and the two blended techniques using Leave-One-Out Cross-Validation. Due to the number of in-situ monitors present during this time period, we find that predictions based on in-situ monitors were more accurate for this particular fire season than the CTM simulations and satellite-based observations, so blending provided only marginal improvements above the in-situ observations. However, we show that in hypothetical cases with fewer surface monitors, the two blending techniques can produce substantial improvement over any of the individual tools.

A study of the biological effect of continuous inhalation exposure of 1, 1, 1-trichloroethene (methyl chloroform) on animals

NASA Technical Reports Server (NTRS)

Macewen, J. D.; Kinkead, E. R.; Haun, C. C.

1974-01-01

The effects of continuous exposure to 1,1,1-trichloroethane on hepatic morphology and function are evaluated and compared with those produced by methylene chloride (dichloromethane) to determine environmental concentrations of each compound that would produce a similar biological response, i.e., a comparable increase in liver triglycerides over control levels. Experimental findings on mice, rats, dogs, and monkeys indicate that the pathological alternations observed with 1,1,1-trichloroethane are similar to those observed with dichloromethane except for different time courses of the effects and different degrees of recovery. A ten fold greater atmospheric concentration of 1,1,1-trichloroethane is required to produce the minimal liver changes found at 100 ppm dichloromethane.

Acetaldehyde Content and Oxidative Stress in the Deleterious Effects of Alcohol Drinking on Rat Uterine Horn

PubMed Central

Buthet, Lara Romina; Maciel, María Eugenia; Quintans, Leandro Néstor; Rodríguez de Castro, Carmen; Costantini, Martín Hernán; Castro, José Alberto

2013-01-01

After alcohol exposure through a standard Lieber and De Carli diet for 28 days, a severe atrophy in the rat uteirne horn was observed, accompanied by significant alterations in its epithelial cells. Microsomal pathway of acetaldehyde production was slightly increased. Hydroxyl radicals were detected in the cytosolic fraction, and this was attributed to participation of xanthine oxidoreductase. They were also observed in the microsomal fraction in the presence of NADPH generating system. No generation of 1-hydroxyethyl was evidenced. The t-butylhydroperoxide-induced chemiluminescence analysis of uterine horn homogenates revealed a significant increase in the chemiluminiscence emission due to ethanol exposure. In the animals repeatedly exposed to alcohol, sulfhydryl content from uterine horn proteins was decreased, but no significant changes were observed in the protein carbonyl content from the same samples. Minor but significant decreasing changes were observed in the GSH content accompanied by a tendency to decrease in the GSH/GSSG ratio. A highly significant finding was the diminished activity content of glutathione peroxidase. Results suggest that acetaldehyde accumulation plus the oxidative stress may play an additional effect to the alcohol-promoted hormonal changes in the uterus reported by others after chronic exposure to alcohol. PMID:24348548

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

PubMed Central

Frei, Patrizia; Mohler, Evelyn; Hug, Kerstin

2010-01-01

Abstract Objective To review and evaluate the recent literature on the health effects of exposure to mobile phone base station (MPBS) radiation. Methods We performed a systematic review of randomized human trials conducted in laboratory settings and of epidemiological studies that investigated the health effects of MPBS radiation in the everyday environment. Findings We included in the analysis 17 articles that met our basic quality criteria: 5 randomized human laboratory trials and 12 epidemiological studies. The majority of the papers (14) examined self-reported non-specific symptoms of ill-health. Most of the randomized trials did not detect any association between MPBS radiation and the development of acute symptoms during or shortly after exposure. The sporadically observed associations did not show a consistent pattern with regard to symptoms or types of exposure. We also found that the more sophisticated the exposure assessment, the less likely it was that an effect would be reported. Studies on health effects other than non-specific symptoms and studies on MPBS exposure in children were scarce. Conclusion The evidence for a missing relationship between MPBS exposure up to 10 volts per metre and acute symptom development can be considered strong because it is based on randomized, blinded human laboratory trials. At present, there is insufficient data to draw firm conclusions about health effects from long-term low-level exposure typically occurring in the everyday environment. PMID:21124713

Multigenerational exposure to dietary zearalenone (ZEA), an estrogenic mycotoxin, affects puberty and reproduction in female mice

PubMed Central

Zhao, Fei; Li, Rong; Xiao, Shuo; Honglu, Diao; El Zowalaty, Ahmed E.; Ye, Xiaoqin

2014-01-01

This study investigated potential cumulative effects of multiple pregnancy and multigenerational exposure to dietary ZEA (0, 0.8, 4, or 20 ppm) on female puberty and reproduction in C57BL/6J mice. Multiple pregnancies did not significantly affect litter size or offspring puberty. Significant effects were observed in 20 ppm ZEA-treated females: advanced puberty onset in F0, F1, and F2 generations; decreased implantation rate, pregnancy rate, and litter size, and increased pregnancy gap and gestation period in F1 and F2 generations; and reduced fertility index in F2 generation. F3 females from 0 and 20 ppm groups were split into 0 or 20 ppm ZEA diets at weaning, with advanced puberty onset seen in 0-20 and 20-20 groups and decreased implantation rate observed in 20-20 group. In summary, 20 ppm dietary ZEA advanced puberty onset without obvious cumulative effect and impaired fertility with multigenerational cumulative effect, which could be partially alleviated upon exposure cessation. PMID:24972337

Developmental Effects of Acute, Chronic, and Withdrawal from Chronic Nicotine on Fear Conditioning

PubMed Central

Portugal, George S.; Wilkinson, Derek S.; Turner, Jill R.; Blendy, Julie A.; Gould, Thomas J.

2012-01-01

Pre-adolescence and adolescence are developmental periods associated with increased vulnerability for tobacco addiction, and exposure to tobacco during these periods may lead to long-lasting changes in behavioral and neuronal plasticity. The present study examined the short- and long-term effects of nicotine and nicotine withdrawal on fear conditioning in pre-adolescent, adolescent, and adult mice, and potential underlying substrates that may mediate the developmental effects of nicotine, such as changes in nicotinic acetylcholine receptor (nAChR) binding, CREB expression, and nicotine metabolism. Age-related differences existed in sensitivity to the effects of acute nicotine, chronic nicotine and nicotine withdrawal on contextual fear conditioning (no changes in cued fear conditioning were seen); younger mice were more sensitive to the acute effects and less sensitive to the effects of nicotine withdrawal 24 hours post treatment cessation. Developmental differences in nAChR binding were associated with the effects of nicotine withdrawal on contextual learning. Developmental differences in nicotine metabolism and CREB expression were also observed, but were not related to the effects of nicotine withdrawal on contextual learning 24 hours post treatment. Chronic nicotine exposure during pre-adolescence or adolescence, however, produced long-lasting impairments in contextual learning that were observed during adulthood, whereas adult chronic nicotine exposure did not. These developmental effects could be related to changes in CREB. Overall, there is a developmental shift in the effects of nicotine on hippocampus-dependent learning and developmental exposure to nicotine results in adult cognitive deficits; these changes in cognition may play an important role in the development and maintenance of nicotine addiction. PMID:22521799

Exposure to bisphenol A, but not phthalates, increases spontaneous diabetes type 1 development in NOD mice.

PubMed

Bodin, Johanna; Kocbach Bølling, Anette; Wendt, Anna; Eliasson, Lena; Becher, Rune; Kuper, Frieke; Løvik, Martinus; Nygaard, Unni Cecilie

2015-01-01

Type 1 diabetes mellitus (T1DM) is an autoimmune destruction of insulin producing pancreatic beta-cells due to a genetic predisposition and can be triggered by environmental factors. We have previously shown that bisphenol A (BPA) accelerates the spontaneous development of diabetes in non-obese diabetic (NOD) mice. Here, we hypothesized that oral exposure to a mixture of the endocrine disruptors BPA and phthalates, relevant for human exposure, would accelerate diabetes development compared to BPA alone. NOD mice were exposed to BPA (1 mg/l), a mixture of phthalates (DEHP 1 mg/l, DBP 0.2 mg/l, BBP 10 mg/l and DiBP 20 mg/l) or a combination of BPA and the phthalate mixture through drinking water from conception and throughout life. Previous observations that BPA exposure increased the prevalence of diabetes and insulitis and decreased the number of tissue resident macrophages in pancreas were confirmed, and extended by demonstrating that BPA exposure also impaired the phagocytic activity of peritoneal macrophages. None of these effects were observed after phthalate exposure alone. The phthalate exposure in combination with BPA seemed to dampen the BPA effects on macrophage number and function as well as diabetes development, but not insulitis development. Exposure to BPA alone or in combination with phthalates decreased cytokine release (TNFα, IL-6, IL-10, IFNγ, IL-4) from in vitro stimulated splenocytes and lymph node cells, indicating systemic changes in immune function. In conclusion, exposure to BPA, but not to phthalates or mixed exposure to BPA and phthalates, accelerated diabetes development in NOD mice, apparently in part via systemic immune alterations including decreased macrophage function.

Toxicity and trophic transfer of P25 TiO2 NPs from Dunaliella salina to Artemia salina: Effect of dietary and waterborne exposure.

PubMed

Bhuvaneshwari, M; Thiagarajan, Vignesh; Nemade, Prateek; Chandrasekaran, N; Mukherjee, Amitava

2018-01-01

The recent increase in nanoparticle (P25 TiO 2 NPs) usage has led to concerns regarding their potential implications on environment and human health. The food chain is the central pathway for nanoparticle transfer from lower to high trophic level organisms. The current study relies on the investigation of toxicity and trophic transfer potential of TiO 2 NPs from marine algae Dunaliella salina to marine crustacean Artemia salina. Toxicity was measured in two different modes of exposure such as waterborne (exposure of TiO 2 NPs to Artemia) and dietary exposure (NP-accumulated algal cells are used to feed the Artemia). The toxicity and accumulation of TiO 2 NPs in marine algae D. salina were also studied. Artemia was found to be more sensitive to TiO 2 NPs (48h LC 50 of 4.21mgL -1 ) as compared to marine algae, D. salina (48h LC 50 of 11.35mgL -1 ). The toxicity, uptake, and accumulation of TiO 2 NPs were observed to be more in waterborne exposure as compared to dietary exposure. Waterborne exposure seemed to cause higher ROS production and antioxidant enzyme (SOD and CAT) activity as compared to dietary exposure of TiO 2 NPs in Artemia. There were no observed biomagnification (BMF) and trophic transfer from algae to Artemia through dietary exposure. Histopathological studies confirmed the morphological and internal damages in Artemia. This study reiterates the possible effects of the different modes of exposure on trophic transfer potential of TiO 2 NPs and eventually the consequences on aquatic environment. Copyright © 2017 Elsevier Inc. All rights reserved.

Circular swimming in mice after exposure to a high magnetic field.

PubMed

Houpt, Thomas A; Houpt, Charles E

2010-06-16

There is increasing evidence that exposure to high magnetic fields of 4T and above perturbs the vestibular system of rodents and humans. Performance in a swim test is a sensitive test of vestibular function. In order to determine the effect of magnet field exposure on swimming in mice, mice were exposed for 30 min within a 14.1T superconducting magnet and then tested at different times after exposure in a 2-min swim test. As previously observed in open field tests, mice swam in tight counter-clockwise circles when tested immediately after magnet exposure. The counter-clockwise orientation persisted throughout the 2-min swim test. The tendency to circle was transient, because no significant circling was observed when mice were tested at 3 min or later after magnet exposure. However, mice did show a decrease in total distance swum when tested between 3 and 40 min after magnet exposure. The decrease in swimming distance was accompanied by a pronounced postural change involving a counter-clockwise twist of the pelvis and hindlimbs that was particularly severe in the first 15s of the swim test. Finally, no persistent difference from sham-exposed mice was seen in the swimming of magnet-exposed mice when tested 60 min, 24h, or 96 h after magnet exposure. This suggests that there is no long-lasting effect of magnet exposure on the ability of mice to orient or swim. The transient deficits in swimming and posture seen shortly after magnet exposure are consistent with an acute perturbation of the vestibular system by the high magnetic field. (c) 2010 Elsevier Inc. All rights reserved.

Oral Bacterial Deactivation Using a Low-Temperature Atmospheric Argon Plasma Brush

PubMed Central

Yang, Bo; Chen, Jierong; Yu, Qingsong; Li, Hao; Lin, Mengshi; Mustapha, Azlin; Hong, Liang; Wang, Yong

2010-01-01

Summary Objectives To study the plasma treatment effects on deactivation effectiveness of oral bacteria. Methods A low temperature atmospheric argon plasma brush were used to study the oral bacterial deactivation effects in terms of plasma conditions, plasma exposure time, and bacterial supporting media. Oral bacteria of Streptococcus mutans and Lactobacillus acidophilus with an initial bacterial population density between 1.0 × 108 and 5.0 × 108 cfu/ml were seeded on various media and their survivability with plasma exposure was examined. Scanning electron microscopy was used to examine the morphological changes of the plasma treated bacteria. Optical absorption was used to determine the leakage of intracellular proteins and DNAs of the plasma treated bacteria. Results The experimental data indicated that the argon atmospheric plasma brush was very effective in deactivating oral bacteria. The plasma exposure time for a 99.9999% cell reduction was less than 15 seconds for S. mutans and within 5 minutes for L. acidophilus. It was found that the plasma deactivation efficiency was also dependent on the bacterial supporting media. With plasma exposure, significant damages to bacterial cell structures were observed with both bacterium species. Leakage of intracellular proteins and DNAs after plasma exposure was observed through monitoring the absorbance peaks at wavelengths of 280nm and 260nm, respectively. Conclusion The experimental results from this study indicated that low temperature atmospheric plasma treatment was very effective in deactivation of oral bacteria and could be a promising technique in various dental clinical applications such as bacterial disinfection and caries early prevention, etc. PMID:20951184

Cardiovascular and stress responses to short-term noise exposures-A panel study in healthy males.

PubMed

Walker, Erica D; Brammer, Anthony; Cherniack, Martin G; Laden, Francine; Cavallari, Jennifer M

2016-10-01

While previous epidemiological studies report adverse effects of long-term noise exposure on cardiovascular health, the mechanisms responsible for these effects are unclear. We sought to elucidate the cardiovascular and stress response to short-term, low (31.5-125Hz) and high (500-2000Hz) frequency noise exposures. Healthy male (n=10) participants were monitored on multiple visits during no noise, low- or high-frequency noise exposure scenarios lasting 40min. Participants were fitted with an ambulatory electrocardiogram (ECG) and blood pressure measures and saliva samples were taken before, during and after noise exposures. ECGs were processed for measures of heart rate variability (HRV): high-frequency power (HF), low-frequency power (LF), the root of the mean squared difference between adjacent normal heart beats (N-N) intervals (RMSSD), and the standard deviation of N-N intervals (SDNN). Systolic blood pressure (SBP), diastolic blood pressure (DPB), and pulse were reported and saliva was analyzed for salivary cortisol and amylase. Multivariate mixed-effects linear regression models adjusted for age were used to identify statistically significant difference in outcomes by no noise, during noise or after noise exposure periods and whether this differed by noise frequency. A total of 658, 205, and 122, HRV, saliva, and blood pressure measurements were performed over 41 person days. Reductions in HRV (LF and RMSSD) were observed during noise exposure (a reduction of 19% (-35,-3.5) and 9.1% (-17,-1.1), respectively). After adjusting for noise frequency, during low frequency noise exposure, HF, LF, and SDNN were reduced (a reduction of 32% (-57,-6.2), 34% (-52,-15), and 16% (-26,-6.1), respectively) and during high frequency noise exposure, a 21% (-39,-2.3) reduction in LF, as compared to during no noise exposure, was found. No significant (p<0.05) changes in blood pressure, salivary cortisol, or amylase were observed. These results suggest that exposure to noise, and in particular, to low-frequency noise, negatively impacts HRV. The frequencies of noise should be considered when evaluating the cardiovascular health impacts of exposure. Copyright © 2016 Elsevier Inc. All rights reserved.

Hidden Hearing Loss? No Effect of Common Recreational Noise Exposure on Cochlear Nerve Response Amplitude in Humans

PubMed Central

Grinn, Sarah K.; Wiseman, Kathryn B.; Baker, Jason A.; Le Prell, Colleen G.

2017-01-01

This study tested hypothesized relationships between noise exposure and auditory deficits. Both retrospective assessment of potential associations between noise exposure history and performance on an audiologic test battery and prospective assessment of potential changes in performance after new recreational noise exposure were completed. Methods: 32 participants (13M, 19F) with normal hearing (25-dB HL or better, 0.25–8 kHz) were asked to participate in 3 pre- and post-exposure sessions including: otoscopy, tympanometry, distortion product otoacoustic emissions (DPOAEs) (f2 frequencies 1–8 kHz), pure-tone audiometry (0.25–8 kHz), Words-in-Noise (WIN) test, and electrocochleography (eCochG) measurements at 70, 80, and 90-dB nHL (click and 2–4 kHz tone-bursts). The first session was used to collect baseline data, the second session was collected the day after a loud recreational event, and the third session was collected 1-week later. Of the 32 participants, 26 completed all 3 sessions. Results: The retrospective analysis did not reveal statistically significant relationships between noise exposure history and any auditory deficits. The day after new exposure, there was a statistically significant correlation between noise “dose” and WIN performance overall, and within the 4-dB signal-to-babble ratio. In contrast, there were no statistically significant correlations between noise dose and changes in threshold, DPOAE amplitude, or AP amplitude the day after new noise exposure. Additional analyses revealed a statistically significant relationship between TTS and DPOAE amplitude at 6 kHz, with temporarily decreased DPOAE amplitude observed with increasing TTS. Conclusions: There was no evidence of auditory deficits as a function of previous noise exposure history, and no permanent changes in audiometric, electrophysiologic, or functional measures after new recreational noise exposure. There were very few participants with TTS the day after exposure - a test time selected to be consistent with previous animal studies. The largest observed TTS was approximately 20-dB. The observed pattern of small TTS suggests little risk of synaptopathy from common recreational noise exposure, and that we should not expect to observe changes in evoked potentials for this reason. No such changes were observed in this study. These data do not support suggestions that common, recreational noise exposure is likely to result in “hidden hearing loss”. PMID:28919848

Evaluating Exposure-Response Associations for Non-Hodgkin Lymphoma with Varying Methods of Assigning Cumulative Benzene Exposure in the Shanghai Women's Health Study.

PubMed

Friesen, Melissa C; Bassig, Bryan A; Vermeulen, Roel; Shu, Xiao-Ou; Purdue, Mark P; Stewart, Patricia A; Xiang, Yong-Bing; Chow, Wong-Ho; Ji, Bu-Tian; Yang, Gong; Linet, Martha S; Hu, Wei; Gao, Yu-Tang; Zheng, Wei; Rothman, Nathaniel; Lan, Qing

2017-01-01

To provide insight into the contributions of exposure measurements to job exposure matrices (JEMs), we examined the robustness of an association between occupational benzene exposure and non-Hodgkin lymphoma (NHL) to varying exposure assessment methods. NHL risk was examined in a prospective population-based cohort of 73087 women in Shanghai. A mixed-effects model that combined a benzene JEM with >60000 short-term, area benzene inspection measurements was used to derive two sets of measurement-based benzene estimates: 'job/industry-specific' estimates (our presumed best approach) were derived from the model's fixed effects (year, JEM intensity rating) and random effects (occupation, industry); 'calibrated JEM' estimates were derived using only the fixed effects. 'Uncalibrated JEM' (using the ordinal JEM ratings) and exposure duration estimates were also calculated. Cumulative exposure for each subject was calculated for each approach based on varying exposure definitions defined using the JEM's probability ratings. We examined the agreement between the cumulative metrics and evaluated changes in the benzene-NHL associations. For our primary exposure definition, the job/industry-specific estimates were moderately to highly correlated with all other approaches (Pearson correlation 0.61-0.89; Spearman correlation > 0.99). All these metrics resulted in statistically significant exposure-response associations for NHL, with negligible gain in model fit from using measurement-based estimates. Using more sensitive or specific exposure definitions resulted in elevated but non-significant associations. The robust associations observed here with varying benzene assessment methods provide support for a benzene-NHL association. While incorporating exposure measurements did not improve model fit, the measurements allowed us to derive quantitative exposure-response curves. Published by Oxford University Press on behalf of the British Occupational Hygiene Society 2017.

Investigation of the effect of occupational noise exposure on blood pressure and heart rate of steel industry workers.

PubMed

Zamanian, Zahra; Rostami, Reza; Hasanzadeh, Jafar; Hashemi, Hassan

2013-01-01

This study aimed to investigate the effect of noise exposure on blood pressure and heart rate of steel industry workers. In the present cross-sectional study, 50 workers were selected from a steel company in Fars province, Iran, and exposed to 85, 95, and 105 dB noise levels for 5 minutes. The participants' blood pressure and heart rate were measured using Beurer BC16 pulse meter both before and after the exposure. The study results showed no significant difference in blood pressure and heart rate before and after the exposure. However, the workers' systolic blood pressure had increased compared to before the exposure; of course, the difference was not statistically significant (P > 0.05). Besides, although the subjects' heart rate had reduced in comparison to before the exposure, the difference was not statistically significant (P > 0.05). No significant change was observed in blood pressure and heart rate after acute exposure to 85, 95, and 105 dB noise levels.

The Molecular Epidemiology of Chronic Aflatoxin Driven Impaired Child Growth

PubMed Central

Turner, Paul Craig

2013-01-01

Aflatoxins are toxic secondary fungal metabolites that contaminate dietary staples in tropical regions; chronic high levels of exposure are common for many of the poorest populations. Observations in animals indicate that growth and/or food utilization are adversely affected by aflatoxins. This review highlights the development of validated exposure biomarkers and their use here to assess the role of aflatoxins in early life growth retardation. Aflatoxin exposure occurs in utero and continues in early infancy as weaning foods are introduced. Using aflatoxin-albumin exposure biomarkers, five major studies clearly demonstrate strong dose response relationships between exposure in utero and/or early infancy and growth retardation, identified by reduced birth weight and/or low HAZ and WAZ scores. The epidemiological studies include cross-sectional and longitudinal surveys, though aflatoxin reduction intervention studies are now required to further support these data and guide sustainable options to reduce the burden of exposure. The use of aflatoxin exposure biomarkers was essential in understanding the observational data reviewed and will likely be a critical monitor of the effectiveness of interventions to restrict aflatoxin exposure. Given that an estimated 4.5 billion individuals live in regions at risk of dietary contamination the public health concern cannot be over stated. PMID:24455429

The effects of a reminder of underwater trauma on behaviour and memory-related mechanisms in the rat dentate gyrus.

PubMed

Ardi, Ziv; Ritov, Gilad; Lucas, Morgan; Richter-Levin, Gal

2014-04-01

Intrusive re-experiencing is a core symptom in post-traumatic stress disorder (PTSD), often triggered by contextual cues associated with the trauma. It is not yet clear if intrusive re-experiencing is only the result, or whether it may contribute to the establishment of PTSD following acute stress. This study aimed at examining the impact of an underwater trauma (UWT) reminder on anxiety-like behaviour and on neuronal activity and plasticity in the hippocampus and the amygdala. Sprague-Dawley rats were exposed to UWT and 24 h later were re-exposed to the context. The effects on behaviour, activation of the amygdala (BLA) and dentate gyrus (DG), and on long-term potentiation (LTP) and local circuit activity (frequency-dependent inhibition (FDI) and paired-pulse inhibition (PPI)) in the DG were assessed. The exposure to UWT by itself resulted in increased anxiety behaviour in the open field, together with increased PPI. Upon exposure to the UWT reminder, an additional increase in anxiety was also observed in the EPM and in FDI. Moreover, reminder exposure resulted in impaired DG LTP and a significant BLA extracellular-signal-regulated kinases (ERK) 2 activation. In conclusion, these observed effects of exposure to a trauma reminder, following the exposure to the initial trauma, might be associated with the progression of trauma-related pathologies and the development of related disorders.

Effects of ethanol, molasses and Lactobacillus plantarum on the fermentation quality, in vitro digestibility and aerobic stability of total mixed ration silages in the Tibetan plateau of China.

PubMed

Yuan, Xianjun; Wen, Aiyou; Wang, Jian; Guo, Gang; Desta, Seare T; Shao, Tao

2016-05-01

In Tibet, it is common practice to make and relocate total mixed ration (TMR) silages before feeding due to the uneven distribution of forages temporally and spatially. This study was conducted to investigate the effects of Lactobacillus plantarum (L), molasses (M) or ethanol (E) on the fermentation quality and aerobic stability of local adaptive TMR silage. After 45 days of ensiling, pH and ammonia nitrogen in inoculated TMR silages were significantly lower than control. During the first 6 days of the aerobic exposure test, a small fluctuation in lactic acid concentration for all TMR silages was observed, and then silages with ethanol continued this trend, while lactic acid in silage without ethanol sharply decreased until the end of the aerobic exposure period. Meanwhile, pH gradually increased along the aerobic exposure; silages treated with ethanol showed lower pH after 9 days of aerobic exposure. The population of yeast gradually increased during 6 days of aerobic exposure, after that an accelerated rise was observed in TMR silages without ethanol. The combinational beneficial effect of L. plantarum and ethanol was found in combined addition of ethanol and Lactobacillus plantarum silages (EL), indicated by intermediate fermentation quality and higher aerobic stability. © 2015 Japanese Society of Animal Science.

A longitudinal study of smokers' exposure to cigarette smoke and the effects of spontaneous product switching.

PubMed

Cunningham, Anthony; Sommarström, Johan; Camacho, Oscar M; Sisodiya, Ajit S; Prasad, Krishna

2015-06-01

A challenge in investigating the effect of public health policies on cigarette consumption and exposure arises from variation in a smoker's exposure from cigarette to cigarette and the considerable differences between smokers. In addition, limited data are available on the effects of spontaneous product switching on a smoker's cigarette consumption and exposure to smoke constituents. Over 1000 adult smokers of the same commercial 10mg International Organization for Standardization (ISO) tar yield cigarette were recruited into the non-residential, longitudinal study across 10 cities in Germany. Cigarette consumption, mouth level exposure to tar and nicotine and biomarkers of exposure to nicotine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone were measured every 6months over a 3 and a half year period. Cigarette consumption remained stable through the study period and did not vary significantly when smokers spontaneously switched products. Mouth level exposure decreased for smokers (n=111) who switched to cigarettes of 7mg ISO tar yield or lower. In addition, downward trends in mouth level exposure estimates were observed for smokers who did not switch cigarettes. Data from this study illustrate some of the challenges in measuring smokers' long-term exposure to smoke constituents in their everyday environment. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

A Simulation Study of Categorizing Continuous Exposure Variables Measured with Error in Autism Research: Small Changes with Large Effects.

PubMed

Heavner, Karyn; Burstyn, Igor

2015-08-24

Variation in the odds ratio (OR) resulting from selection of cutoffs for categorizing continuous variables is rarely discussed. We present results for the effect of varying cutoffs used to categorize a mismeasured exposure in a simulated population in the context of autism spectrum disorders research. Simulated cohorts were created with three distinct exposure-outcome curves and three measurement error variances for the exposure. ORs were calculated using logistic regression for 61 cutoffs (mean ± 3 standard deviations) used to dichotomize the observed exposure. ORs were calculated for five categories with a wide range for the cutoffs. For each scenario and cutoff, the OR, sensitivity, and specificity were calculated. The three exposure-outcome relationships had distinctly shaped OR (versus cutoff) curves, but increasing measurement error obscured the shape. At extreme cutoffs, there was non-monotonic oscillation in the ORs that cannot be attributed to "small numbers." Exposure misclassification following categorization of the mismeasured exposure was differential, as predicted by theory. Sensitivity was higher among cases and specificity among controls. Cutoffs chosen for categorizing continuous variables can have profound effects on study results. When measurement error is not too great, the shape of the OR curve may provide insight into the true shape of the exposure-disease relationship.

Research Review: Environmental exposures, neurodevelopment and child mental health – new paradigms for the study of brain and behavioral effects

PubMed Central

Rauh, Virginia A.; Margolis, Amy

2016-01-01

Background Environmental exposures play a critical role in the genesis of some child mental health problems. Methods We open with a discussion of children’s vulnerability to neurotoxic substances, changes in the distribution of toxic exposures, and co-occurrence of social and physical exposures. We address trends in prevalence of mental health disorders, and approaches to the definition of disorders that are sensitive to the subtle effects of toxic exposures. We suggest broadening outcomes to include dimensional measures of autism spectrum disorders, attention deficit hyperactivity disorder, and child learning capacity, as well as direct assessment of brain function. Findings We consider the impact of two important exposures on children’s mental health: lead and pesticides. We argue that longitudinal research designs may capture the cascading effects of exposures across biological systems and the full-range of neuropsychological endpoints. Neuroimaging is a valuable tool for observing brain maturation under varying environmental conditions. A dimensional approach to measurement may be sensitive to subtle sub-clinical toxic effects, permitting the development of exposure-related profiles and testing of complex functional relationships between brain and behavior. Questions about the neurotoxic effects of chemicals become more pressing when viewed through the lens of environmental justice. Conclusions Reduction in the burden of child mental health disorders will require longitudinal study of neurotoxic exposures, incorporating dimensional approaches to outcome assessment and measures of brain function. Research that seeks to identify links between toxic exposures and mental health outcomes has enormous public health and societal value. PMID:26987761

Research Review: Environmental exposures, neurodevelopment, and child mental health - new paradigms for the study of brain and behavioral effects.

PubMed

Rauh, Virginia A; Margolis, Amy E

2016-07-01

Environmental exposures play a critical role in the genesis of some child mental health problems. We open with a discussion of children's vulnerability to neurotoxic substances, changes in the distribution of toxic exposures, and cooccurrence of social and physical exposures. We address trends in prevalence of mental health disorders, and approaches to the definition of disorders that are sensitive to the subtle effects of toxic exposures. We suggest broadening outcomes to include dimensional measures of autism spectrum disorders, attention-deficit hyperactivity disorder, and child learning capacity, as well as direct assessment of brain function. We consider the impact of two important exposures on children's mental health: lead and pesticides. We argue that longitudinal research designs may capture the cascading effects of exposures across biological systems and the full-range of neuropsychological endpoints. Neuroimaging is a valuable tool for observing brain maturation under varying environmental conditions. A dimensional approach to measurement may be sensitive to subtle subclinical toxic effects, permitting the development of exposure-related profiles and testing of complex functional relationships between brain and behavior. Questions about the neurotoxic effects of chemicals become more pressing when viewed through the lens of environmental justice. Reduction in the burden of child mental health disorders will require longitudinal study of neurotoxic exposures, incorporating dimensional approaches to outcome assessment, and measures of brain function. Research that seeks to identify links between toxic exposures and mental health outcomes has enormous public health and societal value. © 2016 Association for Child and Adolescent Mental Health.

Clinical progression of ocular injury following arsenical vesicant lewisite exposure.

PubMed

Tewari-Singh, Neera; Croutch, Claire R; Tuttle, Richard; Goswami, Dinesh G; Kant, Rama; Peters, Eric; Culley, Tara; Ammar, David A; Enzenauer, Robert W; Petrash, J Mark; Casillas, Robert P; Agarwal, Rajesh

2016-12-01

Ocular injury by lewisite (LEW), a potential chemical warfare and terrorist agent, results in edema of eyelids, inflammation, massive corneal necrosis and blindness. To enable screening of effective therapeutics to treat ocular injury from LEW, useful clinically-relevant endpoints are essential. Hence, we designed an efficient exposure system capable of exposing up to six New-Zealand white rabbits at one time, and assessed LEW vapor-induced progression of clinical ocular lesions mainly in the cornea. The right eye of each rabbit was exposed to LEW (0.2 mg/L) vapor for 2.5, 5.0, 7.5 and 10.0 min and clinical progression of injury was observed for 28 days post-exposure (dose-response study), or exposed to same LEW dose for 2.5 and 7.5 min and clinical progression of injury was observed for up to 56 days post-exposure (time-response study); left eye served as an unexposed control. Increasing LEW exposure caused corneal opacity within 6 h post-exposure, which increased up to 3 days, slightly reduced thereafter till 3 weeks, and again increased thereafter. LEW-induced corneal ulceration peaked at 1 day post-exposure and its increase thereafter was observed in phases. LEW exposure induced neovascularization starting at 7 days which peaked at 22-35 days post-exposure, and remained persistent thereafter. In addition, LEW exposure caused corneal thickness, iris redness, and redness and swelling of the conjunctiva. Together, these findings provide clinical sequelae of ocular injury following LEW exposure and for the first time establish clinically-relevant quantitative endpoints, to enable the further identification of histopathological and molecular events involved in LEW-induced ocular injury.

Exposure Science: A View of the Past and Milestones for the Future

PubMed Central

Lioy, Paul J.

2010-01-01

Background The study of human exposure to environmental toxicants has evolved as a scientific field over the past 30 years. Objectives This review provides a historical perspective on the growth of exposure science as a field, with some emphasis on the results from initial observational studies in obtaining information needed for generating hypotheses on significant human contact with environmental agents, testing the performance of models, and reducing exposures to protect public health. Discussion Advances in activity pattern and behavioral research that established a suite of variables needed to accurately define contact and factors that influence contact are also discussed. The identification and characterization of these factors have played a pivotal role in the growth of the field and in developing exposure reduction strategies. Answers to two key questions on the relevance and fundamental value of exposure science to the fields of environmental health and risk management are presented as a path forward: a) What does one do with such exposure information? b) What roles does exposure science play in situations beyond observational analyses and interpretation? Conclusions The discussion identifies the need for more focused use of observational studies of exposure for epidemiologic analyses. Further, the introduction and use of new tools and approaches for hypothesis testing that can improve the use of exposure science in prevention research for risk management is needed to affect the source-to-effect continuum. A major restructuring of the field is not required to achieve innovation. However, additional resources for training and education are required to ensure that the potential for exposure science to play a central role in reducing and preventing excess risk within environmental/occupational health is achieved. PMID:20308034

Time dependency of strainrange partitioning life relationships

NASA Technical Reports Server (NTRS)

Kalluri, S.; Manson, S. S.

1984-01-01

The effect of exposure time (or creep rate) on the CP life relationship is established by conducting isothermal CP tests at varying exposure times on 316 Ss at 1300 and 1500 F. A reduction in the CP cycle life is observed with an increase in the exposure time of the CP test at a given inelastic strain-range. This phenomenon is characterized by modifying the Manson-Coffin type of CP relationship. Two new life relationships: (1) the Steady State Creep Rate (SSRC) Modified CP life relationship, and (2) the Failure Time (FT) Modified CP life relationship, are developed in this report. They account for the effect of creep rate and exposure time within the CP type of waveform. The reduction in CP cyclic life in the long exposure time tests is attributed to oxidation and the precipitation of carbides along the grain boundaries.

The Effect of D-cycloserine on Subliminal Cue Exposure in Spider Fearful Individuals

PubMed Central

Gutner, Cassidy A.; Weinberger, Joel; Hofmann, Stefan G.

2012-01-01

Research on d-cycloserine (DCS) has demonstrated a significant effect on symptom reduction in human studies that utilized conventional exposure-based approaches. Recent studies have offered promising results for targeting fears through subliminal paradigms. In this double-blind, randomized placebo controlled study, 45 spider fearful individuals received DCS or placebo pills prior to completing a subliminal cue exposure task to images of spiders. Participants completed self-report questionnaires and a behavioral approach task to a live caged tarantula. After repeated exposure to subliminal spider cues, participants in the DCS group reported a greater reduction in disgust than individuals in the placebo group. No difference was observed in fear ratings. These findings suggest that DCS augments the reduction in disgust in spider fearful subjects after subliminal exposure to spider cues. PMID:22992160

The effects of selected air pollutants on clearance of titanic oxide particles from the lungs of rats.

PubMed

Ferin, J; Leach, L J

1975-09-01

A procedure utilizing the lung clearance kinetics of titanic oxide (TiO2) particles was used to determine the effects of inhaled sulphur dioxide (SO2) and nitrogen oxides (NO x) on particle clearance. The procedure is reproducible and mainly tests clearance mechanisms involving alveolar macrophages and the mucociliary transport system at the alveolobronchial clearance pathway. At low SO2 or NOx exposures enhanced particle clearance was observed. Lung clearance was depressed at 15 and 24 ppm of NO2 after 22 exposures as well as at 20 ppm of SO2 after 11 exposures, and also at 1 ppm of SO2 after 25 exposures. Dose-response curves for the SO2 and NOx exposures showed differences explainable by the routes by which these gases reach the alveolar macrophages.

An emission-weighted proximity model for air pollution exposure assessment.

PubMed

Zou, Bin; Wilson, J Gaines; Zhan, F Benjamin; Zeng, Yongnian

2009-08-15

Among the most common spatial models for estimating personal exposure are Traditional Proximity Models (TPMs). Though TPMs are straightforward to configure and interpret, they are prone to extensive errors in exposure estimates and do not provide prospective estimates. To resolve these inherent problems with TPMs, we introduce here a novel Emission Weighted Proximity Model (EWPM) to improve the TPM, which takes into consideration the emissions from all sources potentially influencing the receptors. EWPM performance was evaluated by comparing the normalized exposure risk values of sulfur dioxide (SO(2)) calculated by EWPM with those calculated by TPM and monitored observations over a one-year period in two large Texas counties. In order to investigate whether the limitations of TPM in potential exposure risk prediction without recorded incidence can be overcome, we also introduce a hybrid framework, a 'Geo-statistical EWPM'. Geo-statistical EWPM is a synthesis of Ordinary Kriging Geo-statistical interpolation and EWPM. The prediction results are presented as two potential exposure risk prediction maps. The performance of these two exposure maps in predicting individual SO(2) exposure risk was validated with 10 virtual cases in prospective exposure scenarios. Risk values for EWPM were clearly more agreeable with the observed concentrations than those from TPM. Over the entire study area, the mean SO(2) exposure risk from EWPM was higher relative to TPM (1.00 vs. 0.91). The mean bias of the exposure risk values of 10 virtual cases between EWPM and 'Geo-statistical EWPM' are much smaller than those between TPM and 'Geo-statistical TPM' (5.12 vs. 24.63). EWPM appears to more accurately portray individual exposure relative to TPM. The 'Geo-statistical EWPM' effectively augments the role of the standard proximity model and makes it possible to predict individual risk in future exposure scenarios resulting in adverse health effects from environmental pollution.

Effects of dietary exposure to brominated flame retardant BDE-47 on thyroid condition, gonadal development and growth of zebrafish

USGS Publications Warehouse

Torres, Leticia; Orazio, Carl E.; Peterman, Paul H.; Patino, Reynaldo

2013-01-01

Little is known about the effects of brominated flame retardants in teleosts and some of the information currently available is inconsistent. This study examined effects of dietary exposure to 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) on thyroid condition, body mass and size, and gonadal development of zebrafish. Pubertal, 49-day-old (posthatch) fish were fed diets without BDE-47 (control) or with 1, 5 or 25 μg/g BDE-47/diet. Treatments were conducted in triplicate 30-L tanks each containing 50 zebrafish, and 15 fish per treatment (5 per tank) were sampled at days 40, 80 and 120 of exposure. Measurements were taken of body mass, standard length, head depth and head length. Sex (at 40–120 days of exposure), germ cell stage (at 40 days) and thyroid condition (at 120 days; follicular cell height, colloid depletion, angiogenesis) were histologically determined. Whole-body BDE-47 levels at study completion were within the high end of levels reported in environmentally exposed (wild) fishes. Analysis of variance was used to determine differences among treatments at each sampling time. No effects were observed on thyroid condition or germ cell stage in either sex. Reduced head length was observed in females exposed to BDE-47 at 80 days but not at 40 or 120 days. In males, no apparent effects of BDE-47 were observed at 40 and 80 days, but fish exposed to 25 μg/g had lower body mass at 120 days compared to control fish. These observations suggest that BDE-47 at environmentally relevant whole-body concentrations does not affect thyroid condition or pubertal development of zebrafish but does affect growth during the juvenile-to-adult transition, especially in males.

Chronic health effects in people exposed to arsenic via the drinking water: dose-response relationships in review.

PubMed

Yoshida, Takahiko; Yamauchi, Hiroshi; Fan Sun, Gui

2004-08-01

Chronic arsenic (As) poisoning has become a worldwide public health issue. Most human As exposure occurs from consumption of drinking water containing high amounts of inorganic As (iAs). In this paper, epidemiological studies conducted on the dose-response relationships between iAs exposure via the drinking water and related adverse health effects are reviewed. Before the review, the methods for evaluation of the individual As exposure are summarized and classified into two types, that is, the methods depending on As concentration of the drinking water and the methods depending on biological monitoring for As exposure; certain methods may be applied as optimum As exposure indexes to study dose-response relationship based on various As exposure situation. Chronic effects of iAs exposure via drinking water include skin lesions, neurological effects, hypertension, peripheral vascular disease, cardiovascular disease, respiratory disease, diabetes mellitus, and malignancies including skin cancer. The skin is quite sensitive to arsenic, and skin lesions are some of the most common and earliest nonmalignant effects related to chronic As exposure. The increase of prevalence in the skin lesions has been observed even at the exposure levels in the range of 0.005-0.01 mg/l As in drinking waters. Skin, lung, bladder, kidney, liver, and uterus are considered as sites As-induced malignancies, and the skin is though to be perhaps the most sensitive site. Prospective studies in large area of endemic As poisoning, like Bangladesh or China, where the rate of malignancies is expected to increase within the next several decades, will help to clarify the dose-response relationship between As exposure levels and adverse health effects with enhanced accuracy.

Estrogen-Like Disruptive Effects of Dietary Exposure to Bisphenol A or 17α-Ethinyl Estradiol in CD1 Mice

PubMed Central

Kendig, Eric L.; Buesing, Dana R.; Christie, Susie M.; Cookman, Clifford J.; Gear, Robin B.; Hugo, Eric R.; Kasper, Susan N.; Kendziorski, Jessica A.; Ungi, Kevin R.; Williams, Karin; Belcher, Scott M.

2017-01-01

Bisphenol A (BPA) is an endocrine disrupting chemical that is ubiquitous in wild and built environments. Due to variability in study design, the disruptive effects of BPA have proven difficult to experimentally replicate. This study was designed to assess the disruptive actions of dietary BPA exposure, while carefully controlling for known confounders. Parental CD1 mice were acclimated to defined diet containing BPA (0.03, 0.3, 3, 30, or 300 ppm) or 17α-ethinyl estradiol (EE; 0.0001, 0.001, and 0.01 ppm) and bred to produce progeny (F1) that were maintained through adulthood on the same diet as the parents. In F1 females, uterine weights were increased in all EE and the 30-ppm BPA-exposure groups, demonstrating model sensitivity and estrogen-like actions of BPA. In BPA-exposed females, no treatment-related differences were observed in parental reproductive function, or in the timing of puberty and metabolic function in female offspring. In F1 males, modest changes in body weight, adiposity and glucose tolerance, consistent with improved metabolic function, were observed. Associated with increased prolactin and increased circulating testosterone levels, balanopreputial separation was accelerated by 0.03 and 3.0 ppm BPA and anogenital distance at postnatal day 21 was increased in males by 0.03 ppm BPA. Sperm counts were also increased with 3.0 ppm BPA exposures. Overall, BPA was found to have modest, sex specific endocrine disruptive effects on a variety of end points below the established no observed adverse effect level. The dose response characteristics for many of the effects were nonmonotonic and not predictable from high-dose extrapolations. PMID:23160314

Response and recovery of the macrophytes Elodea canadensis and Myriophyllum spicatum following a pulse exposure to the herbicide iofensulfuron-sodium in outdoor stream mesocosms.

PubMed

Wieczorek, Matthias V; Bakanov, Nikita; Lagadic, Laurent; Bruns, Eric; Schulz, Ralf

2017-04-01

Interest in stream mesocosms has recently revived for higher tier aquatic macrophyte risk assessment of plant protection products mainly because 1) the highest predicted environmental concentrations for the assessment of effects are frequently derived from stream scenarios, and 2) they allow an effect assessment using stream-typical pulse exposures. Therefore, the present stream mesocosm study used an herbicide pulse exposure and evaluated the responses of Elodea canadensis and Myriophyllum spicatum. Macrophytes were exposed for 24 h to 1 μg/L, 3 μg/L, 10 μg/L, and 30 μg/L of the herbicide iofensulfuron-sodium with a subsequent recovery period of 42 d. Biological endpoints were growth rates of the main, side, and total shoot length, the shoot number, the maximum root length, and the dry weight. The total shoot length was identified as the most sensitive endpoint; the growth rate of the total shoot length was inhibited by up to 66% and 45% in M. spicatum and E. canadensis, respectively. The lowest no observed effect concentrations (NOECs) were observed at day 7 and/or day 14 after herbicide treatment and were 1 μg/L for M. spicatum and 3 μg/L for E. canadensis. The no-observed-ecologically-adverse-effect concentrations (NOEAECs) were 10 μg/L and 30 μg/L for M. spicatum and E. canadensis, respectively. Such or similar mesocosm designs are useful to simulate typical stream exposures and estimate herbicide effects on aquatic macrophytes in stream systems. Environ Toxicol Chem 2017;36:1090-1100. © 2016 SETAC. © 2016 SETAC.

Understanding litter decomposition in semiarid ecosystems: linking leaf traits, UV exposure and rainfall variability

PubMed Central

Gaxiola, Aurora; Armesto, Juan J.

2015-01-01

Differences in litter quality, microbial activity or abiotic conditions cannot fully account for the variability in decomposition rates observed in semiarid ecosystems. Here we tested the role of variation in litter quality, water supply, and UV radiation as drivers of litter decomposition in arid lands. And show that carry-over effects of litter photodegradation during dry periods can regulate decomposition during subsequent wet periods. We present data from a two-phase experiment, where we first exposed litter from a drought-deciduous and an evergreen shrub to natural UV levels during five, rainless summer months and, subsequently, in the laboratory, we assessed the carry-over effects of photodegradation on biomass loss under different irrigation treatments representing the observed range of local rainfall variation among years (15–240 mm). Photodegradation of litter in the field produced average carbon losses of 12%, but deciduous Proustia pungens lost >25%, while evergreen Porlieria chilensis less than 5%. Natural exposure to UV significantly reduced carbon-to-nitrogen and lignin:N ratios in Proustia litter but not in Porlieria. During the subsequent wet phase, remaining litter biomass was lower in Proustia than in Porlieria. Indeed UV exposure increased litter decomposition of Proustia under low and medium rainfall treatments, whereas no carry-over effects were detected under high rainfall treatment. Consequently, for deciduous Proustia carry-over effects of UV exposure were negligible under high irrigation. Litter decomposition of the evergreen Porlieria depended solely on levels of rainfall that promote microbial decomposers. Our two-phase experiment revealed that both the carry-over effects of photodegradation and litter quality, modulated by inter-annual variability in rainfall, can explain the marked differences in decomposition rates and the frequent decoupling between rainfall and litter decomposition observed in semiarid ecosystems. PMID:25852705

Glutaraldehyde inhalation exposure of rats: effects on lung morphology, Clara-cell protein, and hyaluronic acid levels in BAL.

PubMed

Halatek, T; Opalska, B; Swiercz, R; Palczynski, C; Gorski, P; Rydzynski, K; Bernard, A

2003-01-01

Glutaraldehyde (GA) is a biocide widely used in hospital and laboratory practice. GA is a volatile substance and, under certain circumstances, significant airborne concentrations may be generated at room temperature. Occupational exposure to GA by inhalation is suspected of causing delayed irritating effects. In recent years, GA has emerged as the main cause of occupational asthma among health-care workers. The aim of the present study was to evaluate effects of GA inhalatory exposure (0.025 ppm or 0.1 ppm, for 28 days) in rats exposed corresponding to the occupational shift cycle, at time point 24 h, 48 h, and 7 days postexposure (PE). Numerous vacuoles and dilated spaces in epithelial cells in bronchioles showing a destructive effect of GA on the cellular membrane were observed at 24 h PE in 0.1 ppm exposed rats. Lipid vacuoles observed after 48 h PE in higher GA exposure, in the Clara cells of the bronchial epithelium, and in endothelial cells of the alveolar capillaries are probably attributable to disturbed lipid metabolism. Many foci of collagen fibers were observed already after 7 days postexposure. Monitoring of inflammatory response and repair was made possible by using two biomarkers: Clara-cell protein (CC16) and hyaluronic acid (HA). Our results show that the inflammatory repair response contributed to progenitor Clara cells and HA plays a role in the development of fibrotic changes in the lung of rats. Glutaraldehyde in rats causes fibrotic effects at the actual threshold limit value-time weighted average (TLV-TWA) level for GA as specified by current Polish and other national regulations.

Understanding litter decomposition in semiarid ecosystems: linking leaf traits, UV exposure and rainfall variability.

PubMed

Gaxiola, Aurora; Armesto, Juan J

2015-01-01

Differences in litter quality, microbial activity or abiotic conditions cannot fully account for the variability in decomposition rates observed in semiarid ecosystems. Here we tested the role of variation in litter quality, water supply, and UV radiation as drivers of litter decomposition in arid lands. And show that carry-over effects of litter photodegradation during dry periods can regulate decomposition during subsequent wet periods. We present data from a two-phase experiment, where we first exposed litter from a drought-deciduous and an evergreen shrub to natural UV levels during five, rainless summer months and, subsequently, in the laboratory, we assessed the carry-over effects of photodegradation on biomass loss under different irrigation treatments representing the observed range of local rainfall variation among years (15-240 mm). Photodegradation of litter in the field produced average carbon losses of 12%, but deciduous Proustia pungens lost >25%, while evergreen Porlieria chilensis less than 5%. Natural exposure to UV significantly reduced carbon-to-nitrogen and lignin:N ratios in Proustia litter but not in Porlieria. During the subsequent wet phase, remaining litter biomass was lower in Proustia than in Porlieria. Indeed UV exposure increased litter decomposition of Proustia under low and medium rainfall treatments, whereas no carry-over effects were detected under high rainfall treatment. Consequently, for deciduous Proustia carry-over effects of UV exposure were negligible under high irrigation. Litter decomposition of the evergreen Porlieria depended solely on levels of rainfall that promote microbial decomposers. Our two-phase experiment revealed that both the carry-over effects of photodegradation and litter quality, modulated by inter-annual variability in rainfall, can explain the marked differences in decomposition rates and the frequent decoupling between rainfall and litter decomposition observed in semiarid ecosystems.

Does acute radio-frequency electromagnetic field exposure affect visual event-related potentials in healthy adults?

PubMed

Dalecki, Anna; Loughran, Sarah P; Verrender, Adam; Burdon, Catriona A; Taylor, Nigel A S; Croft, Rodney J

2018-05-01

To use improved methods to address the question of whether acute exposure to radio-frequency (RF) electromagnetic fields (RF-EMF) affects early (80-200 ms) sensory and later (180-600 ms) cognitive processes as indexed by event-related potentials (ERPs). Thirty-six healthy subjects completed a visual discrimination task during concurrent exposure to a Global System for Mobile Communications (GSM)-like, 920 MHz signal with peak-spatial specific absorption rate for 10 g of tissue of 0 W/kg of body mass (Sham), 1 W/kg (Low RF) and 2 W/kg (High RF). A fully randomised, counterbalanced, double-blind design was used. P1 amplitude was reduced (p = .02) and anterior N1 latency was increased (p = .04) during Exposure compared to Sham. There were no effects on any other ERP latencies or amplitudes. RF-EMF exposure may affect early perceptual (P1) and preparatory motor (anterior N1) processes. However, only two ERP indices, out of 56 comparisons, were observed to differ between RF-EMF exposure and Sham, suggesting that these observations may be due to chance. These observations are consistent with previous findings that RF-EMF exposure has no reliable impact on cognition (e.g., accuracy and response speed). Copyright © 2018 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Endocrine concomitants of sweating and sweat depression.

PubMed

Candas, V; Brandenberger, G; Lutz-Bucher, B; Follenius, M; Libert, J P

1984-01-01

The effect of humid heat (Ta = 43 degrees C, Pa = 32 Torr) on sweat rate, plasma renin activity and plasma levels of aldosterone and antidiuretic hormone (ADH) was studied in four male subjects before and after repeated heat exposures. Over-sweating and sweat drippage followed by hidromeiosis were observed in three subjects during initial heat exposure. With repeated humid heat exposures increased sweat rates were accompanied by a more intense sweat depression (hidromeiosis) in all four subjects. In our conditions, no changes in plasma levels of aldosterone and ADH or plasma renin activity were observed with hidromeiosis. Plasma renin activity was slightly depressed by repeated exposures, whereas plasma volumes were enhanced, with no significant changes in plasma Na or K. The results suggest that neither ADH nor the components of the renin-angiotensin aldosterone system are involved in the hidromeiotic phenomenon.

Nitric Oxide and Superoxide Mediate Diesel Particle Effects in Cytokine-Treated Mice and Murine Lung Epithelial Cells ─ Implications for Susceptibility to Traffic-Related Air Pollution

EPA Science Inventory

Abstract Background: Epidemiologic studies associate childhood exposure to traffic-related air pollution with increased respiratory infections and asthmatic and allergic symptoms. The strongest associations between traffic exposure and negative health impacts are observed in in...

USE OF HAZARD MODELS IN EVALUATING THE EFFECT OF EXPOSURE DURATION ON THE ACUTE TOXICITY OF THREE PESTICIDES

EPA Science Inventory

Renewal toxicity tests (96 h) were conducted with the emulsifiable concentrates of three pesticides: azinphosmethyl, endosulfan, and fenvalerate. econd test design, which incorporated a 6-h period of exposure followed by 90 h of observation, was also conducted on these three pest...

Reducing attenuation in exposure-response relationships by exposure modeling and grouping: the relationship between wood dust exposure and lung function.

PubMed

Teschke, Kay; Spierings, Judith; Marion, Stephen A; Demers, Paul A; Davies, Hugh W; Kennedy, Susan M

2004-12-01

In a study of wood dust exposure and lung function, we tested the effect on the exposure-response relationship of six different exposure metrics using the mean measured exposure of each subject versus the mean exposure based on various methods of grouping subjects, including job-based groups and groups based on an empirical model of the determinants of exposure. Multiple linear regression was used to examine the association between wood dust concentration and forced expiratory volume in 1s (FEV(1)), adjusting for age, sex, height, race, pediatric asthma, and smoking. Stronger point estimates of the exposure-response relationships were observed when exposures were based on increasing levels of aggregation, allowing the relationships to be found statistically significant in four of the six metrics. The strongest point estimates were found when exposures were based on the determinants of exposure model. Determinants of exposure modeling offers the potential for improvement in risk estimation equivalent to or beyond that from job-based exposure grouping.

Silent latency periods in methylmercury poisoning and in neurodegenerative disease.

PubMed Central

Weiss, Bernard; Clarkson, Thomas W; Simon, William

2002-01-01

This article discusses three examples of delay (latency) in the appearance of signs and symptoms of poisoning after exposure to methylmercury. First, a case is presented of a 150-day delay period before the clinical manifestations of brain damage after a single brief (<1 day) exposure to dimethylmercury. The second example is taken from the Iraq outbreak of methylmercury poisoning in which the victims consumed contaminated bread for several weeks without any ill effects. Indeed, signs of poisoning did not appear until weeks or months after exposure stopped. The last example is drawn from observations on nonhuman primates and from the sequelae of the Minamata, Japan, outbreak in which low chronic doses of methylmercury may not have produced observable behavioral effects for periods of time measured in years. The mechanisms of these latency periods are discussed for both acute and chronic exposures. Parallels are drawn with other diseases that affect the central nervous system, such as Parkinson disease and post-polio syndrome, that also reflect the delayed appearance of central nervous system damage. PMID:12426145

DNA damage and oxidative stress induced by imidacloprid exposure in the earthworm Eisenia fetida.

PubMed

Wang, Juan; Wang, Jinhua; Wang, Guangchi; Zhu, Lusheng; Wang, Jun

2016-02-01

To investigate the soil ecological effect of imidacloprid, earthworm Eisenia fetida was exposed to various concentrations of imidacloprid (0.10, 0.50, and 1.00 mg kg(-1) soil) respectively after 7, 14, 21, and 28 d. The effect of imidacloprid on reactive oxygen species (ROS) generation, antioxidant enzymes activity [superoxide dismutase (SOD) and catalase (CAT), glutathione S-transferase enzyme (GST)], malondialdehyde (MDA) content and DNA damage of the E. fetida was investigated. Significant increase of the ROS level was observed. The SOD and GST activity were significantly induced at most exposure intervals. CAT activity was inhibited and reflected a dose-dependent relationship on days 7, 14 and 21. High MDA levels were observed and the olive tail moment (OTM) as well as the percentage of DNA in the comet tail (tail DNA%) in comet assay declined with increasing concentrations and exposure time after 7 d. Our results suggested that the sub-chronic exposure of imidacloprid caused DNA damage and lipid peroxidation (LPO) leading to antioxidant responses in earthworm E. fetida. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Observation of the L929 cell membrane after infrasound exposure with atomic force microscope].

PubMed

Wang, Bing-shui; Chen, Jing-zao; Liu, Bin; Li, Ling; Yi, Nan; Liu, Jing; Zhang, Sa

2005-12-01

To observe the changes of L929 cell membrane with atomic force microscope (AFM) after infrasound exposure and to explore the mechanisms of effect of infrasound on cell membrane. After primary culture, the L929 cells were exposed to infrasound with intensity output of 130 dB and frequency of 16 Hz 2 hours each day for 3 days. The subsequent changes in the membrane of the control cells and the cells exposed to the infrasound were determined by nano-scale scanning with AFM. After infrasound exposure, the normal prominence of the membrane became short and the dent became shallow in the 7.5 microm x 7.5 microm and 4.0 microm x 4.0 microm photographs. The prominence appeared as cobblestones. The surface of the membrane became smooth. The membrane structure of the L929 cells can be changed by infrasound exposure with intensity of 130 dB and frequency of 16 Hz. The change might be one of the characteristics of effect of infrasound on cell membrane.

Assessing the toxic effects of DMSO on cord blood to determine exposure time limits and the optimum concentration for cryopreservation.

PubMed

Fry, L J; Querol, S; Gomez, S G; McArdle, S; Rees, R; Madrigal, J A

2015-08-01

Advantages of using cord blood (CB) over other sources of haematopoietic progenitor cells, such as bone marrow, include the ability to cryopreserve and bank the samples until requested for a transplant. Cryopreservation requires the addition of a cryoprotectant to prevent the formation of intracellular ice during freezing. Dimethyl sulphoxide (DMSO) is commonly used at a concentration of 10% (v/v); however, there is evidence to suggest this chemical is toxic to cells as well as to patients after infusion. The toxic effects of DMSO were assessed through cell viability and in vitro functional assays in fresh and post-thaw CB samples before determining the maximum exposure time and optimal concentration for cryopreservation. A dose-dependent toxicity of DMSO was observed in fresh samples with 40% removing all viable and functional haematopoietic progenitor cells (HPC). In fresh and post-thaw analysis, minimal toxic effect was observed when cryopreservation was delayed for up to 1 h after 10% DMSO addition. After thawing, DMSO washout was superior to dilution or unmanipulated when maintained for long periods (advantage observed 1 h after thawing). Finally, the optimum concentration for cryopreserving CB was found to be 7.5 to 10% with detrimental effects observed outside of this range. These results support the use of 7.5-10% as the optimal DMSO concentration and the maximum exposure time should be limited to <1 h prior to freezing and 30 min post-thaw. © 2015 International Society of Blood Transfusion.

Carbon monoxide and lethal arrhythmias. Research report, Jul 85-Jan 89

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

Farber, J.P.; Schwartz, P.J.; Vanoli, E.

1990-01-01

The effect of acute exposure to carbon monoxide on ventricular arrhythmias was studied in dogs with a healed anterior myocardial infarction. The combination of mild exercise and acute myocardial ischemia induces ventricular fibrillation in 60 percent of the animals. Dogs that develop ventricular fibrillation are considered at high risk for sudden death and are defined as susceptible; dogs that survive the test without fatal arrhythmia are considered at low risk and are defined as 'resistant.' The effects of carboxyhemoglobin levels ranging from 5 to 15 percent were tested in resistant and susceptible dogs. A trend toward higher heart rates wasmore » observed at rest and during exercise in both resistant and susceptible dogs at all levels of carboxyhemoglobin, although significant differences were observed only with 15 percent carboxyhemoglobin. In resistant animals, in which acute myocardial ischemia is typically associated with bradycardia even under the control condition, the reflex response occurred earlier and was augmented after exposure to carbon monoxide. In both resistant and susceptible dogs, carbon monoxide exposure induced a worsening of ventricular arrhythmias in a minority of cases. The worsening was not reproducible in subsequent trials. These data indicate that acute exposure to carbon monoxide is seldom arrhythmogenic in dogs that have survived myocardial infarction. Nevertheless, the observation that carbon monoxide exposure increases heart rate at rest and during moderate exercise may have clinical implications relevant to patients with coronary artery disease.« less

Tungsten oxide thin film exposed to low energy D and He plasma: evidence for a thermal enhancement of the erosion yield

NASA Astrophysics Data System (ADS)

Hijazi, Hussein; Martin, C.; Roubin, P.; Addab, Y.; Cabie, C.; Pardanaud, C.; Bannister, M.; Meyer, F.

2017-10-01

Nanocrystalline tungsten oxide thin films (25 nm - 250 nm thickness) produced by thermal oxidation of a tungsten substrate were exposed to low energy D and He plasma. Low energy D plasma exposure (11 eV/D+) of these films have resulted in the formation of a tungsten bronze (DxWO3) clearly observed by Raman microscopy. D plasma bombardment (4 1021 m-2) has also induced a color change of the oxide layer which is similar to the well-known electro-chromic effect and has been named ``plasma-chromic effect''. To unravel physical and chemical origins of the modifications observed under exposure, similar tungsten oxide films were also exposed to low energy helium plasma (20 eV/He+) . Due to the low fluence (4 1021 m-2) and low ion energy (20 eV), at room temperature, He exposure has induced only very few morphological and structural modifications. On the contrary, at 673 K, significant erosion is observed, which gives evidence for an unexpected thermal enhancement of the erosion yield. We present here new results concerning He beam exposures at low fluence (4 1021 m-2) varying the He+ energy from 20 eV to 320 eV to measure the tungsten oxide sputtering threshold energy. Detailed analyses before/after exposure to describe the D and He interaction with the oxide layer, its erosion and structural modification at the atomic and micrometer scale will be presented.

Cortical and sub-cortical effects in primate models of cocaine use: implications for addiction and the increased risk of psychiatric illness.

PubMed

Bradberry, Charles W

2011-02-01

Drug abuse is a serious risk factor for the incidence and severity of multiple psychiatric illnesses. Understanding the neurobiological consequences of repeated exposure to abused drugs can help to inform how those risks are manifested in terms of specific neurochemical mechanisms and brain networks. This review examines selective studies in non-human primates that employed a cocaine self-administration model. Neurochemical consequences of chronic exposure appear to differ from observations in rodent studies. Whereas chronic intermittent exposure in the rodent is usually associated with a dose-dependent increase in dopaminergic response to a cocaine challenge, in the rhesus monkey, high cumulative exposure was not observed to cause a sensitized dopamine response. These non-human primate observations are concordant with clinical findings in human users. The results of cue exposure studies on dopaminergic transmission are also reviewed. Direct microdialysis measurements indicate that there is not a sustained increase in dopamine associated with cocaine-linked cues. As an alternative to striatal dopaminergic mechanisms mediating cue effects, single unit studies in prefrontal cortex during self-administration in monkeys suggests the orbitofrontal and anterior cingulate cortex are strongly engaged by cocaine cues. Based on the strong clinical imaging literature on cortical and cognitive dysfunction associated with addiction, it is proposed that the strong engagement of cortical systems during repeated cocaine reinforcement results in maladaptive changes that contribute to the risks of drug use for exacerbation of other psychiatric disorders.

Can plastic bag derived-microplastics act as vectors for metal exposure in terrestrial invertebrates?

NASA Astrophysics Data System (ADS)

E Hodson, Mark; Duffus-Hodson, Calum A.; Prendergast-Miller, Miranda; Thorpe, Karen

2017-04-01

Microplastics are widely reported contaminants in marine and freshwater ecosystems and studies have shown that they can be ingested by aquatic organisms and lead to potential negative effects on health. The effects can arise from the physical effects of the plastics (e.g. food displacement and blockages of the digestive tract) and from their potential to adsorb contaminants, primarily organic compounds, resulting in an increased exposure of the organism to toxic contaminants. Studies are beginning to emerge that also show a high abundance of microplastics in the terrestrial environment but there remains a lack of data on the impacts of these terrestrial microplastics or their interaction with other terrestrial pollutants. We conducted Zn adsorption experiments using HDPE microplastics, derived from plastic bags. Zinc adsorption to microplastics was similar to that observed in soils, but in the presence of both soil and microplastics, preferential adsorption onto the soil was observed. In desorption experiments, desorption of Zn from microplastics and soils was minimal (< 10 %) in 0.01 M CaCl2 solution, but in synthetic earthworm guts desorption of 40 - 60% was observed for the microplastics compared to 2 - 15 % for the soils. In earthworm exposure experiments Lumbricus terrestris earthworms cultivated in soils containing 0.35% by mass of Zn-bearing plastic (236 - 4505 mg kg-1) ingested the microplastics with no evidence for either preferential feeding or avoidance. There was no evidence for an accumulation of the microplastics in the earthworm gut or for signs of toxicity. Our experiments demonstrate that earthworms will ingest microplastics and that microplastics can adsorb metals and act as vectors for metal exposure in soil invertebrates. However, for Zn, the risk associated with this exposure appears to be minimal.

Prenatal exposure to bisphenol a at environmentally relevant doses adversely affects the murine female reproductive tract later in life.

PubMed

Newbold, Retha R; Jefferson, Wendy N; Padilla-Banks, Elizabeth

2009-06-01

Exposure to endocrine-disrupting chemicals during critical developmental periods causes adverse consequences later in life; an example is prenatal exposure to the pharmaceutical diethylstilbestrol (DES). Bisphenol A (BPA), an environmental estrogen used in the synthesis of plastics, is of concern because its chemical structure resembles that of DES, and it is a "high-volume production" chemical with widespread human exposure. In this study we investigated whether prenatal BPA causes long-term adverse effects in female reproductive tissues in an experimental animal model previously shown useful in studying effects of prenatal DES. Timed pregnant CD-1 mice were treated on days 9-16 of gestation with BPA (0.1, 1, 10, 100, or 1,000 mug/kg/day). After delivery, pups were held for 18 months; reproductive tissues were then evaluated. Ovarian cysts were significantly increased in the 1-mug/kg BPA group; ovarian cyst-adenomas were seen in the other three BPA-treated groups but not in corn-oil controls. We observed increased progressive proliferative lesions of the oviduct after BPA treatment, similar to those described in response to DES. Further, although not statistically different from the controls, prominent mesonephric (Wolffian) remnants and squamous metaplasia of the uterus, as well as vaginal adenosis, were present in BPA-treated mice, similar to lesions reported following DES treatment. More severe pathologies observed in some BPA-treated animals included atypical hyperplasia and stromal polyps of the uterus; sarcoma of the uterine cervix; and mammary adenocarcinoma. We did not observe these lesions in controls. These data suggest that BPA causes long-term adverse reproductive and carcinogenic effects if exposure occurs during critical periods of differentiation.

Prenatal Exposure to Bisphenol A at Environmentally Relevant Doses Adversely Affects the Murine Female Reproductive Tract Later in Life

PubMed Central

Newbold, Retha R.; Jefferson, Wendy N.; Padilla-Banks, Elizabeth

2009-01-01

Background Exposure to endocrine-disrupting chemicals during critical developmental periods causes adverse consequences later in life; an example is prenatal exposure to the pharmaceutical diethylstilbestrol (DES). Bisphenol A (BPA), an environmental estrogen used in the synthesis of plastics, is of concern because its chemical structure resembles that of DES, and it is a “high-volume production” chemical with widespread human exposure. Objectives In this study we investigated whether prenatal BPA causes long-term adverse effects in female reproductive tissues in an experimental animal model previously shown useful in studying effects of prenatal DES. Methods Timed pregnant CD-1 mice were treated on days 9–16 of gestation with BPA (0.1, 1, 10, 100, or 1,000 μg/kg/day). After delivery, pups were held for 18 months; reproductive tissues were then evaluated. Results Ovarian cysts were significantly increased in the 1-μg/kg BPA group; ovarian cyst-adenomas were seen in the other three BPA-treated groups but not in corn-oil controls. We observed increased progressive proliferative lesions of the oviduct after BPA treatment, similar to those described in response to DES. Further, although not statistically different from the controls, prominent mesonephric (Wolffian) remnants and squamous metaplasia of the uterus, as well as vaginal adenosis, were present in BPA-treated mice, similar to lesions reported following DES treatment. More severe pathologies observed in some BPA-treated animals included atypical hyperplasia and stromal polyps of the uterus; sarcoma of the uterine cervix; and mammary adenocarcinoma. We did not observe these lesions in controls. Conclusions These data suggest that BPA causes long-term adverse reproductive and carcinogenic effects if exposure occurs during critical periods of differentiation. PMID:19590677

Hazard assessment of three haloacetic acids, as byproducts of water disinfection, in human urothelial cells.

PubMed

Marsà, Alicia; Cortés, Constanza; Hernández, Alba; Marcos, Ricard

2018-05-15

Disinfection by-products (DBPs) are compounds produced in the raw water disinfection processes. Although increased cancer incidence has been associated with exposure to this complex mixture, the carcinogenic potential of individual DBPs remains not well known; thus, further studies are required. Haloacetic acids (HAAs) constitute an important group among DBPs. In this study, we have assessed the in vitro carcinogenic potential of three HAAs namely chloro-, bromo-, and iodoacetic acids. Using a long-term (8 weeks) and sub-toxic doses exposure scenario, different in vitro transformation markers were evaluated using a human urothelial cell line (T24). Our results indicate that long-term exposure to low doses of HAAs did not reproduce the genotoxic effects observed in acute treatments, where oxidative DNA damage was induced. No changes in the transformation endpoints analyzed were observed, as implied by the absence of significant morphological, cell growth rate and anchorage-independent cell growth pattern modifications. Interestingly, HAA-long-term exposed cells developed resistance to oxidative stress damage, what would explain the observed differences between acute and long-term exposure conditions. Accordingly, data obtained under long-term exposure to sub-toxic doses of HAAs could be more accurate, in terms of risk assessment, than under acute exposure scenarios. Copyright © 2018 Elsevier Inc. All rights reserved.

Effects of metsulfuron methyl and cypermethrin exposure on freshwater model ecosystems.

PubMed

Wendt-Rasch, L; Pirzadeh, P; Woin, P

2003-05-08

The aim of this study was to investigate the short-term (2 weeks) effects of the herbicide metsulfuron methyl alone and in combination with the insecticide cypermethrin in freshwater enclosures (80 l). We used a factorial design with four levels of herbicide (0, 1, 5, 20 microg/l) and two levels of insecticide (0 and 0.05 microg/l). The root growth of the macrophyte species Elodea canadensis and Myriophyllum spicatum decreased following exposure to the lowest concentration of metsulfuron methyl tested. Metsulfuron methyl exposure resulted in a decreased pH in the aquatic enclosure at the lowest concentration tested, which is most likely a further indication of decreased macrophyte primary production. The biomass of periphytic algae growing on the leaves of M. spicatum increased in the enclosures exposed to metsulfuron methyl. The species composition of the periphytic algae differed significantly from the controls in the enclosures exposed to 20 microg/l of the herbicide. The increased biomass of periphytic algae on the leaves of the macrophytes is probably an indirect effect of the herbicide exposure. The exposure to metsulfuron methyl possibly induced a leakage of nutrients from the macrophyte leaves, which promoted an increased algal growth. The exposure to metsulfuron methyl did not alter the biomass or the species composition of the phytoplankton community. The zooplankton communities in the enclosures were dominated by rotifers, which were not affected by the exposure to cypermethrin. However, a cypermethrin exposure of 0.05 microg/l initially decreased the abundance of copepod nauplii. Ten days after exposure, the abundance of nauplii was significantly higher in the insecticide-exposed enclosures compared with the non-exposed enclosures. This might be an indication of a sub-lethal stress response, which either increased the number of offspring produced or induced an increased hatching of copepod resting stages. No combined effects of the herbicide and insecticide exposure, either direct or indirect, were observed in the enclosure study. Significant effects on the macrophytes were observed following exposure to 1 microg metsulfuron methyl per litre in the enclosure study. Furthermore, a single species laboratory assay indicated that the shoot elongation of E. canadensis decreased following exposure to >or=0.1 microg metsulfuron methyl per litre. These concentrations are well within the range of expected environmental concentrations, thus this study shows that aquatic ecosystems, in particular those which are macrophyte-dominated, may be affected by metsulfuron methyl at concentrations that may well occur in water bodies adjacent to agricultural land.

Sex specific impact of perinatal bisphenol A (BPA) exposure over a range of orally administered doses on rat hypothalamic sexual differentiation.

PubMed

McCaffrey, Katherine A; Jones, Brian; Mabrey, Natalie; Weiss, Bernard; Swan, Shanna H; Patisaul, Heather B

2013-05-01

Bisphenol A (BPA) is a high volume production chemical used in polycarbonate plastics, epoxy resins, thermal paper receipts, and other household products. The neural effects of early life BPA exposure, particularly to low doses administered orally, remain unclear. Thus, to better characterize the dose range over which BPA alters sex specific neuroanatomy, we examined the impact of perinatal BPA exposure on two sexually dimorphic regions in the anterior hypothalamus, the sexually dimorphic nucleus of the preoptic area (SDN-POA) and the anterioventral periventricular (AVPV) nucleus. Both are sexually differentiated by estradiol and play a role in sex specific reproductive physiology and behavior. Long Evans rats were prenatally exposed to 10, 100, 1000, 10,000μg/kg bw/day BPA through daily, non-invasive oral administration of dosed-cookies to the dams. Offspring were reared to adulthood. Their brains were collected and immunolabeled for tyrosine hydroxylase (TH) in the AVPV and calbindin (CALB) in the SDN-POA. We observed decreased TH-ir cell numbers in the female AVPV across all exposure groups, an effect indicative of masculinization. In males, AVPV TH-ir cell numbers were significantly reduced in only the BPA 10 and BPA 10,000 groups. SDN-POA endpoints were unaltered in females but in males SDN-POA volume was significantly lower in all BPA exposure groups. CALB-ir was significantly lower in all but the BPA 1000 group. These effects are consistent with demasculinization. Collectively these data demonstrate that early life oral exposure to BPA at levels well below the current No Observed Adverse Effect Level (NOAEL) of 50mg/kg/day can alter sex specific hypothalamic morphology in the rat. Copyright © 2013 Elsevier Inc. All rights reserved.

Sex specific impact of perinatal bisphenol A (BPA) exposure over a range of orally administered doses on rat hypothalamic sexual differentiation

PubMed Central

McCaffrey, Katherine A.; Jones, Brian; Mabrey, Natalie; Weiss, Bernard; Swan, Shanna H.; Patisaul, Heather B.

2013-01-01

Bisphenol A (BPA) is a high volume production chemical used in polycarbonate plastics, epoxy resins, thermal paper receipts, and other household products. The neural effects of early life BPA exposure, particularly to low doses administered orally, remain unclear. Thus, to better characterize the dose range over which BPA alters sex specific neuroanatomy, we examined the impact of perinatal BPA exposure on two sexually dimorphic regions in the anterior hypothalamus, the sexually dimorphic nucleus of the preoptic area (SDN-POA) and the anterioventral periventricular (AVPV) nucleus. Both are sexually differentiated by estradiol and play a role in sex specific reproductive physiology and behavior. Long Evans rats were prenatally exposed to 10, 100, 1000, 10,000 mg/kg bw/day BPA through daily, noninvasive oral administration of dosed-cookies to the dams. Offspring were reared to adulthood. Their brains were collected and immunolabeled for tyrosine hydroxylase (TH) in the AVPV and calbindin (CALB) in the SDN-POA. We observed decreased TH-ir cell numbers in the female AVPV across all exposure groups, an effect indicative of masculinization. In males, AVPV TH-ir cell numbers were significantly reduced in only the BPA 10 and BPA 10,000 groups. SDN-POA endpoints were unaltered in females but in males SDN-POA volume was significantly lower in all BPA exposure groups. CALB-ir was significantly lower in all but the BPA 1000 group. These effects are consistent with demasculinization. Collectively these data demonstrate that early life oral exposure to BPA at levels well below the current No Observed Adverse Effect Level (NOAEL) of 50 mg/kg/day can alter sex specific hypothalamic morphology in the rat. PMID:23500335

Gestational Toluene Exposure Effects on Spontaneous and Amphetamine-Induced Locomotor Behavior in Rats

PubMed Central

Mohammadi, Michael H.; Batis, Jeffery C.; Hannigan, John H.

2007-01-01

The abuse of volatile organic solvents (inhalants) continues to be a major health concern throughout the world. Toluene, which is found in many products such as glues and household cleaners, is among the most commonly abused organic solvents. The neurobehavioral teratogenic sequelae of solvent abuse (i.e., repeated, brief inhalation exposures to very high concentrations of solvents) have not been examined thoroughly. In a preclinical model of inhalant abuse, timed-pregnant Sprague-Dawley rats were exposed to 0, 8,000, or 12,000 parts per million (ppm) for 15 min twice daily from gestation day 8 (GD8) through GD20. In the first experiment, separate groups of offspring were observed individually in an open-field on postnatal day 22 (PN22), PN42 or PN63. In the second experiment, other offspring given identical prenatal toluene exposures were observed in an “open-field” following an acute i.p. injection of amphetamine (0, 0.56, 1.78 mg/kg) on PN28. Automated measurements of distance traveled and ambulatory time were recorded. Prenatal toluene exposure resulted in small alterations in spontaneous activity compared to non-exposed rats. Prenatal exposure to 12,000 ppm toluene resulted in significant hyposensitivity to the locomotor stimulatory effects of the amphetamine challenge in male but not female rats on PN28. The results demonstrate that prenatal exposure to abuse patterns of high concentrations of toluene through inhalation can alter spontaneous and amphetamine-induced locomotor behavior in rats. The expression of these effects also appears to depend upon the postnatal age of testing. These results imply that abuse of organic solvents during pregnancy in humans may also produce long-lasting effects on biobehavioral development. PMID:17112700

Elemental composition of particulate matter and the association with lung function.

PubMed

Eeftens, Marloes; Hoek, Gerard; Gruzieva, Olena; Mölter, Anna; Agius, Raymond; Beelen, Rob; Brunekreef, Bert; Custovic, Adnan; Cyrys, Josef; Fuertes, Elaine; Heinrich, Joachim; Hoffmann, Barbara; de Hoogh, Kees; Jedynska, Aleksandra; Keuken, Menno; Klümper, Claudia; Kooter, Ingeborg; Krämer, Ursula; Korek, Michal; Koppelman, Gerard H; Kuhlbusch, Thomas A J; Simpson, Angela; Smit, Henriëtte A; Tsai, Ming-Yi; Wang, Meng; Wolf, Kathrin; Pershagen, Göran; Gehring, Ulrike

2014-09-01

Negative effects of long-term exposure to particulate matter (PM) on lung function have been shown repeatedly. Spatial differences in the composition and toxicity of PM may explain differences in observed effect sizes between studies. We conducted a multicenter study in 5 European birth cohorts-BAMSE (Sweden), GINIplus and LISAplus (Germany), MAAS (United Kingdom), and PIAMA (The Netherlands)-for which lung function measurements were available for study subjects at the age of 6 or 8 years. Individual annual average residential exposure to copper, iron, potassium, nickel, sulfur, silicon, vanadium, and zinc within PM smaller than 2.5 μm (PM2.5) and smaller than 10 μm (PM10) was estimated using land-use regression models. Associations between air pollution and lung function were analyzed by linear regression within cohorts, adjusting for potential confounders, and then combined by random effects meta-analysis. We observed small reductions in forced expiratory volume in the first second, forced vital capacity, and peak expiratory flow related to exposure to most elemental pollutants, with the most substantial negative associations found for nickel and sulfur. PM10 nickel and PM10 sulfur were associated with decreases in forced expiratory volume in the first second of 1.6% (95% confidence interval = 0.4% to 2.7%) and 2.3% (-0.1% to 4.6%) per increase in exposure of 2 and 200 ng/m, respectively. Associations remained after adjusting for PM mass. However, associations with these elements were not evident in all cohorts, and heterogeneity of associations with exposure to various components was larger than for exposure to PM mass. Although we detected small adverse effects on lung function associated with annual average levels of some of the evaluated elements (particularly nickel and sulfur), lower lung function was more consistently associated with increased PM mass.

Pulmonary biochemical effects of inhaled phosgene in rats.

PubMed

Franch, S; Hatch, G E

1986-01-01

Three exposure regimens were used to study the time course of indicators of lung damage and recovery response to single or repeated exposures to phosgene (COCl2). Rats were sacrificed immediately or throughout a 38-d recovery period after inhalation of 1 ppm COCl2 for 4 h, at intervals during a 7-h exposure to 1 ppm phosgene, or at several time points throughout a 17-d exposure to 0.125 and 0.25 ppm COCl2 (4 h/d, 5 d/wk) and during a 21-d recovery period. Regimen 1 revealed significantly elevated lung wet weight, lung nonprotein sulfhydryl (NPSH) content, and glucose-6-phosphate dehydrogenase (G6PD) activity that stayed elevated for up to 14 d. A significant decrease in body weight and food intake was observed 1 d after exposure. Regimen 2 caused a slight depression in NPSH content but did not affect G6PD activity. Regimen 3 animals showed sustained elevations in lung wet weight, NPSH content, and G6PD activity after 7 d of exposure. No significant changes in these endpoints were observed for the 0.125 ppm COCl2 group. No consistent elevation in hydroxyproline content was seen at either exposure concentration. Light microscopic examination of lung tissue exposed to 0.25 ppm COCl2 for 17 d revealed moderate multifocal accumulation of mononuclear cells in the centriacinar region. In summary, exposure to COCl2 caused changes similar in most ways to those observed for other lower-respiratory-tract irritants.

Intercellular Communication of Tumor Cells and Immune Cells after Exposure to Different Ionizing Radiation Qualities.

PubMed

Diegeler, Sebastian; Hellweg, Christine E

2017-01-01

Ionizing radiation can affect the immune system in many ways. Depending on the situation, the whole body or parts of the body can be acutely or chronically exposed to different radiation qualities. In tumor radiotherapy, a fractionated exposure of the tumor (and surrounding tissues) is applied to kill the tumor cells. Currently, mostly photons, and also electrons, neutrons, protons, and heavier particles such as carbon ions, are used in radiotherapy. Tumor elimination can be supported by an effective immune response. In recent years, much progress has been achieved in the understanding of basic interactions between the irradiated tumor and the immune system. Here, direct and indirect effects of radiation on immune cells have to be considered. Lymphocytes for example are known to be highly radiosensitive. One important factor in indirect interactions is the radiation-induced bystander effect which can be initiated in unexposed cells by expression of cytokines of the irradiated cells and by direct exchange of molecules via gap junctions. In this review, we summarize the current knowledge about the indirect effects observed after exposure to different radiation qualities. The different immune cell populations important for the tumor immune response are natural killer cells, dendritic cells, and CD8+ cytotoxic T-cells. In vitro and in vivo studies have revealed the modulation of their functions due to ionizing radiation exposure of tumor cells. After radiation exposure, cytokines are produced by exposed tumor and immune cells and a modulated expression profile has also been observed in bystander immune cells. Release of damage-associated molecular patterns by irradiated tumor cells is another factor in immune activation. In conclusion, both immune-activating and -suppressing effects can occur. Enhancing or inhibiting these effects, respectively, could contribute to modified tumor cell killing after radiotherapy.

Review of the health effects of wildland fire smoke on wildland firefighters and the public.

PubMed

Adetona, Olorunfemi; Reinhardt, Timothy E; Domitrovich, Joe; Broyles, George; Adetona, Anna M; Kleinman, Michael T; Ottmar, Roger D; Naeher, Luke P

2016-01-01

Each year, the general public and wildland firefighters in the US are exposed to smoke from wildland fires. As part of an effort to characterize health risks of breathing this smoke, a review of the literature was conducted using five major databases, including PubMed and MEDLINE Web of Knowledge, to identify smoke components that present the highest hazard potential, the mechanisms of toxicity, review epidemiological studies for health effects and identify the current gap in knowledge on the health impacts of wildland fire smoke exposure. Respiratory events measured in time series studies as incidences of disease-caused mortality, hospital admissions, emergency room visits and symptoms in asthma and chronic obstructive pulmonary disease patients are the health effects that are most commonly associated with community level exposure to wildland fire smoke. A few recent studies have also determined associations between acute wildland fire smoke exposure and cardiovascular health end-points. These cardiopulmonary effects were mostly observed in association with ambient air concentrations of fine particulate matter (PM2.5). However, research on the health effects of this mixture is currently limited. The health effects of acute exposures beyond susceptible populations and the effects of chronic exposures experienced by the wildland firefighter are largely unknown. Longitudinal studies of wildland firefighters during and/or after the firefighting career could help elucidate some of the unknown health impacts of cumulative exposure to wildland fire smoke, establish occupational exposure limits and help determine the types of exposure controls that may be applicable to the occupation.

Occupational solvent exposure and adult chronic lymphocytic leukemia: No risk in a population-based case-control study in four Nordic countries.

PubMed

Talibov, Madar; Auvinen, Anssi; Weiderpass, Elisabete; Hansen, Johnni; Martinsen, Jan-Ivar; Kjaerheim, Kristina; Tryggvadottir, Laufey; Pukkala, Eero

2017-09-15

The aim of this study was to assess the effect of occupational solvent exposure on the risk of adult chronic lymphocytic leukemia (CLL). The current case-control study was nested in the Nordic Occupational Cancer Study (NOCCA) cohort. 20,615 CLL cases diagnosed in 1961-2005 in Finland, Iceland, Norway, and Sweden, and 103,075 population-based controls matched by year of birth, sex, and country were included. Occupational histories for cases and controls were obtained from census records in 1960, 1970, 1980/1981, and 1990. Exposure to selected solvents was estimated by using the NOCCA job-exposure matrix (NOCCA-JEM). Odds ratios (OR) and 95% confidence intervals (95% CI) were estimated by using conditional logistic regression models. Overall, nonsignificant CLL risk elevations were observed for methylene chloride, perchloroethylene, and 1,1,1-trichloroethane. Compared to unexposed, significantly increased risks were observed for cumulative perchloroethylene exposure ≤13.3 ppm-years (OR = 1.85, 95% CI 1.16-2.96) and average life-time perchloroethylene exposure ≤2.5 ppm (1.61, 95% CI 1.01-2.56) among women, and cumulative methylene chloride exposure ≤12.5 ppm-years (OR = 1.19, 95% CI 1.01-1.41) and 12.5-74.8 ppm-years (OR = 1.23, 95% CI 1.01-1.51) among men in an analysis with 5 years lag-time, though without dose-response pattern. Decreased CLL risk was observed for aliphatic and alicyclic hydrocarbon solvents and toluene. This study did not support associations for solvent exposure and CLL. Observed weak associations for methylene chloride, perchloroethylene, 1,1,1-trichloroethane exposures, aliphatic and alicyclic hydrocarbons and toluene were not consistent across sexes, and showed no gradient with amount of exposure. © 2017 UICC.

Effects of bisphenol A on incidence and severity of cardiac lesions in the NCTR-Sprague-Dawley rat: A CLARITY-BPA study.

PubMed

Gear, Robin; Kendziorski, Jessica A; Belcher, Scott M

2017-06-05

The goal of this study was to determine whether bisphenol A (BPA) had adverse effects indicative of cardiac toxicity. As part of the "Consortium Linking Academic and Regulatory Insights on BPA Toxicity" (CLARITY-BPA), study dams and offspring were exposed by daily gavage to five doses of BPA ranging from 2.5 to 25000μg/kg/day, 0.05 or 0.5μg/kg/day 17α-ethinyl-estradiol (EE) or 0.3% carboxymethylcellulose vehicle. Exposure-related effects were analyzed in isolated hearts by quantitative morphometry and histopathology. No dose-related changes in body weight were detected. Across all exposure groups including vehicle controls, body weight of continuously dosed males was reduced compared to males dosed only until PND21. Heart weight was increased only in females exposed to EE, and consistent alterations in LV wall thickness were not observed. Exposure-related changes in collagen accumulation were minor and limited to highest EE exposure groups with increased collagen accumulation in PND21 males. Decreased collagen was observed in hearts of BPA or EE exposed females at PND90 and PND180. In BPA or EE treated females cardiomyopathy incidence and severity was significantly increased compared to control females at PND21 with myocardial degeneration observed in both males and females at PND21 and PND90. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of Gender on the Radiation Sensitivity of Murine Blood Cells

PubMed Central

Billings, Paul C; Romero-Weaver, Ana L; Kennedy, Ann R

2014-01-01

Space travel beyond the Earth’s protective magnetosphere risks exposing astronauts to ionizing radiation, such as that generated during a solar particle event (SPE). Ionizing radiation has well documented effects on blood cells and it is generally assumed that these effects contribute to the hematopoietic syndrome (HS), observed in animals and humans, following exposure to total body irradiation (TBI). The purpose of the current study was to assess the role of gender on the effects of gamma radiation on blood cells. C3H/HeN mice were irradiated with a 137Cs gamma source. Radiation had similar effects on white blood cells (WBCs), lymphocytes, and granulocytes in male and female C3H/HeN mice, while red blood cell (RBC) counts and hematocrit values remained stable following radiation exposure. Non-irradiated male mice had 13% higher platelet counts, compared with their female counterparts, and showed enhanced recovery of platelets on day 16 following radiation exposure. Hence, gender differences influence the response of platelets to TBI exposure. PMID:25221782

Ozone personal exposures and health effects for selected groups residing in the Fraser Valley

NASA Astrophysics Data System (ADS)

Brauer, Michael; Brook, Jeffrey R.

Due to concern regarding poor ambient air quality in the Fraser Valley, a series of exposure and health effects assessments were performed to evaluate the impact of summer photochemical air pollution. In 1992 and 1993, three groups of individuals were selected for personal monitoring of ozone exposure, based on prior expectations of their activity patterns. The first group spent a majority of the work day indoors or commuting, the second group spent more time outdoors and the third group spent the entire personal monitoring period outdoors. Time-activity data were collected for the first two groups and differences in personal ozone exposures were found to be associated with the fraction of time a person spent outdoors. Similarly, differences among groups in the mean ozone exposure were associated with time spent outdoors. These results and other exposure information were used to design a study of the health impacts of summer ambient air pollution that was conducted during the time period of the Pacific'93 field campaign. Aerosol acidity levels in the Fraser Valley were observed to be very low in 1992 so the health study focused on the effects of ozone exposure. The subjects were adult farm workers (26 male, 32 female; mean age 44.4, range 10-69) who spent the entire working day outdoors (a subset of group 3 above). Lung function measurements were made twice daily on each subject, once before and once after their work shift, from 23 June-26 August 1993. Ambient O 3 concentrations were measured continuously at several nearby locations. In a regression model including individual lung function level, date, temperature and daily maximum O 3, a statistically significant ( p < 0.001) negative association was observed between ozone and lung function. This association between ozone and reduced lung function was still apparent the following day, suggesting a persistent ozone effect. These results indicate that exposure to ambient O 3 concentrations below either the U.S. NAAQS (120 ppb) or the Canadian Air Quality Objective (82 ppb) may have an adverse effect on the lung function of people engaged in outdoor work for several hours a day.

Interim results of long-term environmental exposures of advanced composites for aircraft applications

NASA Technical Reports Server (NTRS)

Pride, R. A.

1978-01-01

Interim results from a number of ongoing, long-term environmental effects programs for composite materials are reported. The flight service experience is evaluated for 142 composite aircraft components after more than five years and one million successful component flight hours. Ground-based outdoor exposures of composite material coupons after 3 years of exposure at five sites have reached equilibrium levels of moisture pickup which are predictable. Solar ultraviolet-induced material loss is discussed for these same exposures. No significant degradation has been observed in residual strength for either stressed or unstressed specimens, or for exposures to aviation fuels and fluids.

Status update: is smoke on your mind? Using social media to assess smoke exposure

NASA Astrophysics Data System (ADS)

Ford, Bonne; Burke, Moira; Lassman, William; Pfister, Gabriele; Pierce, Jeffrey R.

2017-06-01

Exposure to wildland fire smoke is associated with negative effects on human health. However, these effects are poorly quantified. Accurately attributing health endpoints to wildland fire smoke requires determining the locations, concentrations, and durations of smoke events. Most current methods for assessing these smoke events (ground-based measurements, satellite observations, and chemical transport modeling) are limited temporally, spatially, and/or by their level of accuracy. In this work, we explore using daily social media posts from Facebook regarding smoke, haze, and air quality to assess population-level exposure for the summer of 2015 in the western US. We compare this de-identified, aggregated Facebook dataset to several other datasets that are commonly used for estimating exposure, such as satellite observations (MODIS aerosol optical depth and Hazard Mapping System smoke plumes), daily (24 h) average surface particulate matter measurements, and model-simulated (WRF-Chem) surface concentrations. After adding population-weighted spatial smoothing to the Facebook data, this dataset is well correlated (R2 generally above 0.5) with the other methods in smoke-impacted regions. The Facebook dataset is better correlated with surface measurements of PM2. 5 at a majority of monitoring sites (163 of 293 sites) than the satellite observations and our model simulation. We also present an example case for Washington state in 2015, for which we combine this Facebook dataset with MODIS observations and WRF-Chem-simulated PM2. 5 in a regression model. We show that the addition of the Facebook data improves the regression model's ability to predict surface concentrations. This high correlation of the Facebook data with surface monitors and our Washington state example suggests that this social-media-based proxy can be used to estimate smoke exposure in locations without direct ground-based particulate matter measurements.

Effect of sorption on exposures to organic gases from environmental tobacco smoke (ETS)

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

Singer, B.C.; Hodgson, A.T.; Nazaroff, W.W.

The effects of sorption processes on dynamic ETS organic gas concentrations and potential exposures were studied in a carpeted and furnished 50-m{sup 3} room ventilated at 0.6 h{sup -1}. Ten cigarettes were machine-smoked on six of every seven days over four weeks. Concentrations of ETS-specific tracers and regulated toxic compounds were quantified during daily smoking, post-smoking and background periods. Potential exposures were calculated by period and day. Large sorption effects were observed for the widely used tracers 3-ethenylpyridine and nicotine, and for several toxic compounds including naphthalene and cresol isomers. Short-term adsorption to indoor surfaces reduced concentrations and potential exposuresmore » during smoking, while later reemission increased concentrations and exposures hours after smoking ended. Concentrations during nonsmoking periods rose from day to day over the first few weeks, presumably from increased reemission associated with increased sorbed mass concentrations. For sorbing compounds, more than half of daily potential exposures occurred during nonsmoking periods.« less

Exploring associations between prenatal solvent exposures and teenage drug and alcohol use: a retrospective cohort study.

PubMed

Gallagher, Lisa G; Webster, Thomas F; Aschengrau, Ann

2017-03-11

Investigating the effects of prenatal and childhood exposures on behavioral health outcomes in adolescence is challenging given the lengthy period between the exposure and outcomes. We conducted a retrospective cohort study in Cape Cod, Massachusetts to evaluate the impact of prenatal and early childhood exposure to tetrachloroethylene (PCE)-contaminated drinking water on the occurrence of risk-taking behaviors as a teenager. An increased occurrence of risk-taking behaviors, particularly illicit drug use, was observed in those highly exposed to PCE. We hypothesized that there may be other sources of prenatal solvent exposure such as maternal consumption of alcoholic beverages during pregnancy which might modify the previously observed associations between PCE and risk-taking behaviors and so we conducted an exploratory analysis using available cohort data. The current report presents the results of these analyses and describes the difficulties in conducting research on long-term behavioral effects of early life exposures. The exploratory analysis compared a referent group of subjects with no early life exposure to PCE or alcohol (n = 242) to subjects with only alcohol exposure (n = 201), subjects with only PCE exposure (n = 361), and subjects with exposure to both PCE and alcohol (n = 302). Surveys completed by the subject's mother included questions on prenatal alcoholic beverage consumption and available confounding variables such as cigarette smoking and marijuana use. Surveys completed by the subjects included questions on risk-taking behaviors such as alcoholic beverage consumption and illicit drug use as a teenager and available confounding variables. PCE exposure was modeled using a leaching and transport algorithm embedded in water distribution system modeling software that estimated the amount of PCE delivered to a subject's residence during gestation and early childhood. Subjects with early life exposure to both PCE and alcohol had an increased risk of using two or more major drugs as a teen (RR = 1.9 (95% CI 1.2, 3.0)) compared to unexposed subjects. Increased risks for only PCE exposure (RR = 1.6 (95% CI 1.0, 2.4) and only alcohol exposure (RR = 1.3 (95% CI 0.7, 2.1)) were also evident but were smaller than the increased risk associated with both exposures. While available confounding variables were controlled, many relevant social risk factors were not obtained due to limitations in the retrospective study design. This exploratory analysis found evidence for an additive effect of early life exposure to PCE and alcohol on the risk of use of multiple illicit drugs as a teenager. Because of numerous limitations in this retrospective study, further research is needed to examine longstanding behavioral effects of early life exposures. To be most informative, this research should involve long-term prospective data collection.

Acute exposure to wood smoke from incomplete combustion--indications of cytotoxicity.

PubMed

Muala, Ala; Rankin, Gregory; Sehlstedt, Maria; Unosson, Jon; Bosson, Jenny A; Behndig, Annelie; Pourazar, Jamshid; Nyström, Robin; Pettersson, Esbjörn; Bergvall, Christoffer; Westerholm, Roger; Jalava, Pasi I; Happo, Mikko S; Uski, Oskari; Hirvonen, Maija-Riitta; Kelly, Frank J; Mudway, Ian S; Blomberg, Anders; Boman, Christoffer; Sandström, Thomas

2015-10-29

Smoke from combustion of biomass fuels is a major risk factor for respiratory disease, but the underlying mechanisms are poorly understood. The aim of this study was to determine whether exposure to wood smoke from incomplete combustion would elicit airway inflammation in humans. Fourteen healthy subjects underwent controlled exposures on two separate occasions to filtered air and wood smoke from incomplete combustion with PM1 concentration at 314 μg/m(3) for 3 h in a chamber. Bronchoscopy with bronchial wash (BW), bronchoalveolar lavage (BAL) and endobronchial mucosal biopsies was performed after 24 h. Differential cell counts and soluble components were analyzed, with biopsies stained for inflammatory markers using immunohistochemistry. In parallel experiments, the toxicity of the particulate matter (PM) generated during the chamber exposures was investigated in vitro using the RAW264.7 macrophage cell line. Significant reductions in macrophage, neutrophil and lymphocyte numbers were observed in BW (p < 0.01, <0.05, <0.05, respectively) following the wood smoke exposure, with a reduction in lymphocytes numbers in BAL fluid (<0.01. This unexpected cellular response was accompanied by decreased levels of sICAM-1, MPO and MMP-9 (p < 0.05, <0.05 and <0.01). In contrast, significant increases in submucosal and epithelial CD3+ cells, epithelial CD8+ cells and submucosal mast cells (p < 0.01, <0.05, <0.05 and <0.05, respectively), were observed after wood smoke exposure. The in vitro data demonstrated that wood smoke particles generated under these incomplete combustion conditions induced cell death and DNA damage, with only minor inflammatory responses. Short-term exposure to sooty PAH rich wood smoke did not induce an acute neutrophilic inflammation, a classic hallmark of air pollution exposure in humans. While minor proinflammatory lymphocytic and mast cells effects were observed in the bronchial biopsies, significant reductions in BW and BAL cells and soluble components were noted. This unexpected observation, combined with the in vitro data, suggests that wood smoke particles from incomplete combustion could be potentially cytotoxic. Additional research is required to establish the mechanism of this dramatic reduction in airway leukocytes and to clarify how this acute response contributes to the adverse health effects attributed to wood smoke exposure. NCT01488500.

Implications of sequence and timing of exposure for synergy between the pyrethroid insecticide alpha-cypermethrin and the entomopathogenic fungus Beauveria bassiana.

PubMed

Meyling, Nicolai V; Arthur, Samuel; Pedersen, Kathrine E; Dhakal, Suraj; Cedergreen, Nina; Fredensborg, Brian L

2018-03-30

Combining low doses of chemical insecticides with entomopathogens constitutes a sustainable pest control method, but the significance of the timing and sequence of exposures needs clarification. We studied lethal effects of combinations of the entomopathogenic fungus Beauveria bassiana (KVL03-122) and the pyrethroid alpha-cypermethrin on the beetle Tenebrio molitor under varying timing and sequence of exposure. Synergy over time was evaluated in relation to the model of independent action (IA). We expected that increased progression of disease caused by B. bassiana would make beetles more susceptible to the insecticide, leading to enhanced synergy. Synergistic effects between B. bassiana and alpha-cypermethrin were observed when B. bassiana was applied first, but only when the interval between applications was >48 h. With 72 h between exposures, mortality had increased to 100% after 8 days, in contrast to the 60% mortality expected. No synergy was observed when the insecticide was applied prior to fungal exposure within 24 h. The sequence and timing of exposure do matter to achieve synergistic mortality by combining B. bassiana and alpha-cypermethrin, and the IA model proved to be a strong tool with which to evaluate the interactions of the two stressors over time. Pest control strategies could include B. bassiana followed by low-dose exposures to alpha-cypermethrin after 2-3 days. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

Brief Exposure to Secondhand Smoke Reversibly Impairs Endothelial Vasodilatory Function

PubMed Central

2014-01-01

Introduction: We sought to determine the effects of brief exposures to low concentrations of tobacco secondhand smoke (SHS) on arterial flow-mediated dilation (FMD, a nitric oxide-dependent measure of vascular endothelial function), in a controlled animal model never before exposed to smoke. In humans, SHS exposure for 30min impairs FMD. It is important to gain a better understanding of the acute effects of exposure to SHS at low concentrations and for brief periods of time. Methods: We measured changes in FMD in rats exposed to a range of real-world levels of SHS for durations of 30min, 10min, 1min, and 4 breaths (roughly 15 s). Results: We observed a dose-response relationship between SHS particle concentration over 30min and post-exposure impairment of FMD, which was linear through the range typically encountered in smoky restaurants and then saturated at higher concentrations. One min of exposure to SHS at moderate concentrations was sufficient to impair FMD. Conclusions: Brief SHS exposure at real-world levels reversibly impairs FMD. Even 1min of SHS exposure can cause reduction of endothelial function. PMID:24302638

Understanding the exposure-time effect on speckle contrast measurements for laser displays

NASA Astrophysics Data System (ADS)

Suzuki, Koji; Kubota, Shigeo

2018-02-01

To evaluate the influence of exposure time on speckle noise for laser displays, speckle contrast measurement method was developed observable at a human eye response time using a high-sensitivity camera which has a signal multiplying function. The nonlinearity of camera light sensitivity was calibrated to measure accurate speckle contrasts, and the measuring lower limit noise of speckle contrast was improved by applying spatial-frequency low pass filter to the captured images. Three commercially available laser displays were measured over a wide range of exposure times from tens of milliseconds to several seconds without adjusting the brightness of laser displays. The speckle contrast of raster-scanned mobile projector without any speckle-reduction device was nearly constant over various exposure times. On the contrary to this, in full-frame projection type laser displays equipped with a temporally-averaging speckle-reduction device, some of their speckle contrasts close to the lower limits noise were slightly increased at the shorter exposure time due to the noise. As a result, the exposure-time effect of speckle contrast could not be observed in our measurements, although it is more reasonable to think that the speckle contrasts of laser displays, which are equipped with the temporally-averaging speckle-reduction device, are dependent on the exposure time. This discrepancy may be attributed to the underestimation of temporal averaging factor. We expected that this method is useful for evaluating various laser displays and clarify the relationship between the speckle noise and the exposure time for a further verification of speckle reduction.

Steel dust in the New York City subway system as a source of manganese, chromium, and iron exposures for transit workers.

PubMed

Chillrud, Steven N; Grass, David; Ross, James M; Coulibaly, Drissa; Slavkovich, Vesna; Epstein, David; Sax, Sonja N; Pederson, Dee; Johnson, David; Spengler, John D; Kinney, Patrick L; Simpson, H James; Brandt-Rauf, Paul

2005-03-01

The United States Clean Air Act Amendments of 1990 reflected increasing concern about potential effects of low-level airborne metal exposure on a wide array of illnesses. Here we summarize results demonstrating that the New York City (NYC) subway system provides an important microenvironment for metal exposures for NYC commuters and subway workers and also describe an ongoing pilot study of NYC transit workers' exposure to steel dust. Results from the TEACH (Toxic Exposure Assessment, a Columbia and Harvard) study in 1999 of 41 high-school students strongly suggest that elevated levels of iron, manganese, and chromium in personal air samples were due to exposure to steel dust in the NYC subway. Airborne concentrations of these three metals associated with fine particulate matter were observed to be more than 100 times greater in the subway environment than in home indoor or outdoor settings in NYC. While there are currently no known health effects at the airborne levels observed in the subway system, the primary aim of the ongoing pilot study is to ascertain whether the levels of these metals in the subway air affect concentrations of these metals or related metabolites in the blood or urine of exposed transit workers, who due to their job activities could plausibly have appreciably higher exposures than typical commuters. The study design involves recruitment of 40 transit workers representing a large range in expected exposures to steel dust, the collection of personal air samples of fine particulate matter, and the collection of blood and urine samples from each monitored transit worker.

Immunotoxicity of gallium arsenide on antigen presentation: comparative study of intratracheal and intraperitoneal exposure routes.

PubMed

Hartmann, Constance B; Harrison, M Travis; McCoy, Kathleen L

2005-01-01

Gallium arsenide (GaAs) is a semiconductor utilized in electronics and computer industries. GaAs exposure of animals causes local inflammation and systemic immune suppression. Mice were administered 2 to 200 mg/kg GaAs. On day 5, intratracheal instillation increased lung weights in a dose-dependent manner and induced pulmonary inflammation exemplified by mononuclear cell infiltration and mild epithelial hyperplasia. No fibrosis, pneumocyte hyperplasia, proteinosis, or bronchial epithelial damage was observed in the lungs. Splenic cellularity and composition were unaffected. GaAs' effect on antigen presentation by macrophages was similar after intratracheal and intraperitoneal exposure, although the lowest observable adverse effect levels differed. Macrophages from the exposure site displayed an enhanced ability to activate an antigen-specific CD4(+) helper T-cell hybridoma compared with vehicle controls, whereas splenic macrophages were defective in this function. The chemical's impact on peritoneal macrophages depended on the exposure route. GaAs exposure augmented thiol cathepsins B and L activities in macrophages from the exposure site, but decreased proteolytic activities in splenic macrophages. Alveolar macrophages had increased expression of major histocompatibility complex (MHC) Class II molecules, whereas MHC Class II expression on splenic and peritoneal macrophages was unaffected. Modified thiol cathepsin activities statistically correlated with altered efficiency of antigen presentation, whereas MHC Class II expression did not. Our study is the first one to examine the functional capability of alveolar macrophages after intratracheal GaAs instillation. Therefore, thiol cathepsins may be potential target molecules by which GaAs exposure modulates antigen presentation.

[Effects of infrasound on activities of 3beta hydroxysteroid dehydrogenase and acid phosphatase of polygonal cells in adrenal cortex zona fasciculate in mice].

PubMed

Dang, Wei-min; Wang, Sheng; Tian, Shi-xiu; Chen, Bing; Sun, Fei; Li, Wei; Jiao, Yan; He, Li-hua

2007-02-01

To explore the biological effects of infrasound on the polygonal cells in adrenal cortex zona fasciculation in mice. The biological effects of infrasound on the activities of 3beta hydroxysteroid dehydrogenase (3-betaHSDH) and acid phosphatase(ACP) of the polygonal cells in adrenal cortex zona fasciculate were observed when exposure to 8 and 16 Hz infrasound at 80, 90, 100, 110, 120 and 130 dB for 1 day, 7 days and 14 days or 14 days after the exposure. When exposure to 8 Hz infrasound, the enzyme activities of 3-betaHSDH increase as the sound pressure levels increase. Only when the sound pressure levels reach 130 dB, the enzyme activities began to decrease exceptionally. When exposure to 16 Hz, 80 dB infrasound, no significant difference between the treatment and control group in the activities of 3-betaHSDH could be observed, but the injury of the polygonal cells had appeared. When exposure to 16 Hz, 100 dB infrasound, the activities of 3-betaHSDH started to increase. The cell injury still existed. When exposed to 16 Hz, 120 dB infrasound, the local tissue damage represented. Fourteen days after the mice exposure to 8 Hz, 90 dB and 130 dB infrasound for 14 days continuously, the local tissue injury of the adrenal cortex zona fasciculation began to recover at certain extent, but the higher the exposure sound pressure level, the poorer the tissue recovery. The biological effects of infrasound on the polygonal cells in adrenal cortex zona fasciculation response to the frequency of the infrasound are found at certain action strength range, but this characteristic usually is covered by the severe tissue injury. When exposure to infrasound is stopped for a period of time, the local tissue injury of the adrenal cortex zona fasciculation could recovers at certain extent, but the higher the exposure sound pressure level, the more poorer the tissue recovery.

Space environment effects (M0006)

NASA Technical Reports Server (NTRS)

Angelo, J. A., Jr.; Madonna, R. G.; Altadonna, L. P.; Dagostino, M. D.; Chang, J. Y.; Alfano, R. R.; Caplan, V. L.

1984-01-01

The effects of long term exposure to the near Earth space environment on advanced electrooptical and radiation sensor components were examined. The effect of long duration spaceflight on the germination rate of selected terrestrial plant seeds is observed in exobiological experiments.

Cigarette smoke increases Staphylococcus aureus biofilm formation via oxidative stress.

PubMed

Kulkarni, Ritwij; Antala, Swati; Wang, Alice; Amaral, Fábio E; Rampersaud, Ryan; Larussa, Samuel J; Planet, Paul J; Ratner, Adam J

2012-11-01

The strong epidemiological association between cigarette smoke (CS) exposure and respiratory tract infections is conventionally attributed to immunosuppressive and irritant effects of CS on human cells. Since pathogenic bacteria such as Staphylococcus aureus are members of the normal microbiota and reside in close proximity to human nasopharyngeal cells, we hypothesized that bioactive components of CS might affect these organisms and potentiate their virulence. Using Staphylococcus aureus as a model organism, we observed that the presence of CS increased both biofilm formation and host cell adherence. Analysis of putative molecular pathways revealed that CS exposure decreased expression of the quorum-sensing agr system, which is involved in biofilm dispersal, and increased transcription of biofilm inducers such as sarA and rbf. CS contains bioactive compounds, including free radicals and reactive oxygen species, and we observed transcriptional induction of bacterial oxidoreductases, including superoxide dismutase, following exposure. Moreover, pretreatment of CS with an antioxidant abrogated CS-mediated enhancement of biofilms. Exposure of bacteria to hydrogen peroxide alone increased biofilm formation. These observations are consistent with the hypothesis that CS induces staphylococcal biofilm formation in an oxidant-dependent manner. CS treatment induced transcription of fnbA (encoding fibronectin binding protein A), leading to increased binding of CS-treated staphylococci to immobilized fibronectin and increased adherence to human cells. These observations indicate that the bioactive effects of CS may extend to the resident microbiota of the nasopharynx, with implications for the pathogenesis of respiratory infection in CS-exposed humans.

Indirect associations of combat exposure with post-deployment physical symptoms in U.S. soldiers: roles of post-traumatic stress disorder, depression and insomnia.

PubMed

Quartana, Phillip J; Wilk, Joshua E; Balkin, Thomas J; Hoge, Charles W

2015-05-01

To characterize the indirect associations of combat exposure with post-deployment physical symptoms through shared associations with post-traumatic stress disorder (PTSD), depression and insomnia symptoms. Surveys were administered to a sample of U.S. soldiers (N = 587) three months after a 15-month deployment to Iraq. A multiple indirect effects model was used to characterize direct and indirect associations between combat exposure and physical symptoms. Despite a zero-order correlation between combat exposure and physical symptoms, the multiple indirect effects analysis did not provide evidence of a direct association between these variables. Evidence for a significant indirect association of combat exposure and physical symptoms was observed through PTSD, depression, and insomnia symptoms. In fact, 92% of the total effect of combat exposure on physical symptoms scores was indirect. These findings were evident even after adjusting for the physical injury and relevant demographics. This is the first empirical study to suggest that PTSD, depression and insomnia collectively and independently contribute to the association between combat exposure and post-deployment physical symptoms. Limitations, future research directions, and potential policy implications are discussed. Published by Elsevier Inc.

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

PubMed Central

Fleury, Naomi; Geldenhuys, Sian; Gorman, Shelley

2016-01-01

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

Effects of fetal microwave radiation exposure on offspring behavior in mice

PubMed Central

Zhang, Yanchun; Li, Zhihui; Gao, Yan; Zhang, Chenggang

2015-01-01

Abstract The recent rapid development of electronic communication techniques is resulting in a marked increase in exposure of humans to electromagnetic fields (EMFs). This has raised public concerns about the health hazards of long-term environmental EMF exposure for fetuses and children. Some studies have suggested EMF exposure in children could induce nervous system disorders. However, gender-dependent effects of microwave radiation exposure on cognitive dysfunction have not previously been reported. Here we investigated whether in utero exposure to 9.417-GHz microwave throughout gestation (Days 3.5–18) affected behavior, using the open field test (OFT), elevated-plus maze (EPM), tail suspension test (TST), forced swimming test (FST) and Morris water maze (MWM). We found that mice showed less movement in the center of an open field (using the OFT) and in an open arm (using the EPM) after in utero exposure to 9.417-GHz radiation, which suggested that the mice had increased anxiety-related behavior. Mice demonstrated reduced immobility in TST and FST after in utero exposure to 9.417-GHz radiation, which suggested that the mice had decreased depression-related behavior. From the MWM test, we observed that male offspring demonstrated decreased learning and memory, while females were not affected in learning and memory, which suggested that microwaves had gender-dependent effects. In summary, we have provided the first experimental evidence of microwaves inducing gender-dependent effects. PMID:25359903

Cardiovascular and Stress Responses to Short-Term Noise Exposures—A Panel Study in Healthy Males

PubMed Central

Walker, Erica D; Brammer, Anthony; Cherniack, Martin G; Laden, Francine; Cavallari, Jennifer M

2016-01-01

Background While previous epidemiological studies report adverse effects of long-term noise exposure on cardiovascular health, the mechanisms responsible for these effects are unclear. We sought to elucidate the cardiovascular and stress response to short-term, low (31.5-125 Hz) and high (500 – 2000 Hz) frequency noise exposures. Methods Healthy male (n = 10) participants were monitored on multiple visits during no noise, low- or high-frequency noise exposure scenarios lasting 40 minutes. Participants were fitted with an ambulatory electrocardiogram (ECG) and blood pressure measures and saliva samples were taken before, during and after noise exposures. ECGs were processed for measures of heart rate variability (HRV): high-frequency power (HF), low-frequency power (LF), the root of the mean squared difference between adjacent normal heart beats (N-N) intervals (RMSSD), and the standard deviation of N-N intervals (SDNN). Systolic blood pressure (SBP), diastolic blood pressure (DPB), and pulse were reported and saliva was analyzed for salivary cortisol and amylase. Multivariate mixed-effects linear regression models adjusted for age were used to identify statistically significant difference in outcomes by no noise, during noise or after noise exposure periods and whether this differed by noise frequency. Results A total of 658, 205, and 122, HRV, saliva,and blood pressure measurements were performed over 41 person days. Reductions in HRV (LF and RMSSD) were observed during noise exposure (a reduction of 19%(−35,−3.5) and 9.1%(−17,−1.1), respectively). After adjusting for noise frequency, during low frequency noise exposure, HF, LF, and SDNN were reduced (a reduction of 32%(−57,−6.2), 34%(−52,−15), and 16%(−26,−6.1), respectively and during high frequency noise exposure, a 21%(−39,−2.3) reduction in LF, as compared to during no noise exposure was found. No significant (p>0.05) changes in blood pressure,salivary cortisol or amylase were observed. Conclusions These results suggest that exposure to noise, and in particular, to low-frequency noise negatively impacts HRV. The frequencies of noise should be considered when evaluating the cardiovascular health impacts of exposure. PMID:27371930

Lung Cancer in Chinese Women: Evidence for an Interaction between Tobacco Smoking and Exposure to Inhalants in the Indoor Environment

PubMed Central

Tang, Li; Lim, Wei-Yen; Eng, Philip; Leong, Swan Swan; Lim, Tow Keang; Ng, Alan W.K.; Tee, Augustine; Seow, Adeline

2010-01-01

Background Epidemiologic data suggest that Chinese women have a high incidence of lung cancer in relation to their smoking prevalence. In addition to active tobacco smoke exposure, other sources of fumes and airborne particles in the indoor environment, such as cooking and burning of incense and mosquito coils, have been considered potential risk factors for lung cancer. Objectives We used a case–control study to explore effects of inhalants from combustion sources common in the domestic environment on lung cancer and their modification by active tobacco smoking. Methods We analyzed 703 primary lung cancer cases and 1,578 controls. Data on demographic background and relevant exposures were obtained by face-to-face interviews in the hospital. Results We observed a positive relationship with daily exposure to incense or mosquito coils and to cooking fumes only among smokers, and no association among lifetime nonsmokers. Interactions between smoking and frequency of cooking, or exposure to incense or mosquito coils were statistically significant and consistent with synergistic effects on lung cancer. The odds ratio (OR) comparing smokers without daily incense or mosquito coil exposure with nonsmokers without daily exposure was 2.80 [95% confidence interval (CI), 1.86–4.21], whereas the OR comparing smokers with daily exposure to the same referent group was 4.61 (95% CI, 3.41–6.24). In contrast, daily exposure to incense or mosquito coils was not associated with lung cancer among nonsmokers (OR = 0.91; 95% CI, 0.72–1.16). We observed the same pattern of associations for smokers without (OR = 2.31; 95% CI, 1.52–3.51) and with (OR = 4.50; 95% CI, 3.21–6.30) daily cooking exposure compared with nonsmokers, with no evidence of an association with daily cooking exposure among nonsmokers. Conclusion Our results suggest that active tobacco smoking not only is an important risk factor for development of lung cancer, but also may cause smokers to be more susceptible to the risk-enhancing effects of other inhalants. PMID:20472525

Aluminium exposure disrupts elemental homeostasis in Caenorhabditis elegans†

PubMed Central

Page, Kathryn E.; White, Keith N.; McCrohan, Catherine R.

2013-01-01

Aluminium (Al) is highly abundant in the environment and can elicit a variety of toxic responses in biological systems. Here we characterize the effects of Al on Caenorhabditis elegans by identifying phenotypic abnormalities and disruption in whole-body metal homeostasis (metallostasis) following Al exposure in food. Widespread changes to the elemental content of adult nematodes were observed when chronically exposed to Al from the first larval stage (L1). Specifically, we saw increased barium, chromium, copper and iron content, and a reduction in calcium levels. Lifespan was decreased in worms exposed to low levels of Al, but unexpectedly increased when the Al concentration reached higher levels (4.8 mM). This bi-phasic phenotype was only observed when Al exposure occurred during development, as lifespan was unaffected by Al exposure during adulthood. Lower levels of Al slowed C. elegans developmental progression, and reduced hermaphrodite self-fertility and adult body size. Significant developmental delay was observed even when Al exposure was restricted to embryogenesis. Similar changes in Al have been noted in association with Al toxicity in humans and other mammals, suggesting that C. elegans may be of use as a model for understanding the mechanisms of Al toxicity in mammalian systems. PMID:22534883

Neurotoxicity produced by dibromoacetic acid in drinking water of rats.

PubMed

Moser, V C; Phillips, P M; Levine, A B; McDaniel, K L; Sills, R C; Jortner, B S; Butt, M T

2004-05-01

An evaluation of potential adverse human health effects of disinfection byproducts requires study of both cancer and noncancer endpoints; however, no studies have evaluated the neurotoxic potential of a common haloacetic acid, dibromoacetic acid (DBA). This study characterized the neurotoxicity of DBA during 6-month exposure in the drinking water of rats. Adolescent male and female Fischer 344 rats were administered DBA at 0, 0.2, 0.6, and 1.5 g/l. On a mg/kg/day basis, the consumed dosages decreased greatly over the exposure period, with average intakes of 0, 20, 72, and 161 mg/kg/day. Weight gain was depressed in the high-concentration group, and concentration-related diarrhea and hair loss were observed early in exposure. Testing with a functional observational battery and motor activity took place before dosing and at 1, 2, 4, and 6 months. DBA produced concentration-related neuromuscular toxicity (mid and high concentrations) characterized by limb weakness, mild gait abnormalities, and hypotonia, as well as sensorimotor depression (all concentrations), with decreased responses to a tail-pinch and click. Other signs of toxicity at the highest concentration included decreased activity and chest clasping. Neurotoxicity was evident as early as one month, but did not progress with continued exposure. The major neuropathological finding was degeneration of spinal cord nerve fibers (mid and high concentrations). Cellular vacuolization in spinal cord gray matter (mostly) and in white matter (occasionally) tracts was also observed. No treatment-related changes were seen in brain, eyes, peripheral nerves, or peripheral ganglia. The lowest-observable effect level for neurobehavioral changes was 20 mg/kg/day (produced by 0.2 g/l, lowest concentration tested), whereas this dosage was a no-effect level for neuropathological changes. These studies suggest that neurotoxicity should be considered in the overall hazard evaluation of haloacetic acids.

Effects of Mangifera indica L. aqueous extract (Vimang) on primary culture of rat hepatocytes.

PubMed

Rodeiro, I; Donato, M T; Jiménez, N; Garrido, G; Delgado, R; Gómez-Lechón, M J

2007-12-01

Vimang is an aqueous extract from stem bark of Mangifera indica L. (Mango) with pharmacological properties. It is a mixture of polyphenols (as main components), terpenoids, steroids, fatty acids and microelements. In the present work we studied the cytotoxic effects of Vimang on rat hepatocytes, possible interactions of the extract with drug-metabolizing enzymes and its effects on GSH levels and lipid peroxidation. No cytotoxic effects were observed after 24 h exposure to Vimang of up to 1000 microg/mL, while a moderate cytotoxicity was observed after 48 and 72 h of exposure at higher concentrations (500 and 1000 microg/mL). The effect of the extract (50-400 microg/mL) on several P450 isozymes was evaluated. Exposure of hepatocytes to Vimang at concentrations of up to 100 microg/mL produced a significant reduction (60%) in 7-methoxyresorufin-O-demethylase (MROD; CYP1A2) activity, an increase (50%) in 7-penthoxyresorufin-O-depentylase (PROD; CYP2B1) activity, while no significant effect was observed with other isozymes. To our knowledge, this is the first report regarding the modulation of the activity of the P450 system by an extract of Mangifera indica L. The antioxidant properties of Vimang were also evaluated in t-butyl-hydroperoxide-treated hepatocytes. A 36-h pre-treatment of cells with Vimang (25-200 microg/mL) strongly inhibited the decrease of GSH levels and lipid peroxidation induced by t-butyl-hydroperoxide dose- and time-dependently.

Effects of the statin antihyperlipidemic agent simvastatin on grass shrimp, Palaemonetes pugio.

PubMed

Key, Peter B; Hoguet, Jennifer; Reed, Lou Ann; Chung, Katy W; Fulton, Michael H

2008-04-01

This study investigated lethal effects (i.e., survival) and sublethal effects (glutathione, GSH; lipid peroxidation, LPx; cholesterol, CHL; and acetylcholinesterase, AChE) of the antihyperlipidemic drug simvastatin on larval and adult grass shrimp (Palaemonetes pugio). The 96-h LC50 test for larvae resulted in an estimated LC50 of 1.18 mg/L (95% confidence interval 0.98-1.42 mg/L). The adult 96-h LC50 was >10.0 mg/L. GSH and AChE levels for both the larvae and the adults were not significantly affected by simvastatin exposure. LPx levels in the larvae were significantly higher than controls in the lowest and the highest simvastatin exposures. In adult grass shrimp, LPx levels were highest in the three lowest simvastatin exposures. CHL levels were significantly reduced in larvae at the highest simvastatin exposure level of 1 mg/L while adult CHL was not affected. Both lethal and sublethal effects associated with simvastatin exposure were only observed at concentrations well above those reported in the environment. (Copyright) 2008 Wiley Periodicals, Inc.

The Pregnancy Exposome: Multiple Environmental Exposures in the INMA-Sabadell Birth Cohort.

PubMed

Robinson, Oliver; Basagaña, Xavier; Agier, Lydiane; de Castro, Montserrat; Hernandez-Ferrer, Carles; Gonzalez, Juan R; Grimalt, Joan O; Nieuwenhuijsen, Mark; Sunyer, Jordi; Slama, Rémy; Vrijheid, Martine

2015-09-01

The "exposome" is defined as "the totality of human environmental exposures from conception onward, complementing the genome" and its holistic approach may advance understanding of disease etiology. We aimed to describe the correlation structure of the exposome during pregnancy to better understand the relationships between and within families of exposure and to develop analytical tools appropriate to exposome data. Estimates on 81 environmental exposures of current health concern were obtained for 728 women enrolled in The INMA (INfancia y Medio Ambiente) birth cohort, in Sabadell, Spain, using biomonitoring, geospatial modeling, remote sensors, and questionnaires. Pair-wise Pearson's and polychoric correlations were calculated and principal components were derived. The median absolute correlation across all exposures was 0.06 (5th-95th centiles, 0.01-0.54). There were strong levels of correlation within families of exposure (median = 0.45, 5th-95th centiles, 0.07-0.85). Nine exposures (11%) had a correlation higher than 0.5 with at least one exposure outside their exposure family. Effectively all the variance in the data set (99.5%) was explained by 40 principal components. Future exposome studies should interpret exposure effects in light of their correlations to other exposures. The weak to moderate correlation observed between exposure families will permit adjustment for confounding in future exposome studies.

Exposure and effect assessment of aerosolized red tide toxins (brevetoxins) and asthma.

PubMed

Fleming, Lora E; Bean, Judy A; Kirkpatrick, Barbara; Cheng, Yung Sung; Pierce, Richard; Naar, Jerome; Nierenberg, Kate; Backer, Lorraine C; Wanner, Adam; Reich, Andrew; Zhou, Yue; Watkins, Sharon; Henry, Mike; Zaias, Julia; Abraham, William M; Benson, Janet; Cassedy, Amy; Hollenbeck, Julie; Kirkpatrick, Gary; Clarke, Tainya; Baden, Daniel G

2009-07-01

In previous studies we demonstrated statistically significant changes in reported symptoms for lifeguards, general beach goers, and persons with asthma, as well as statistically significant changes in pulmonary function tests (PFTs) in asthmatics, after exposure to brevetoxins in Florida red tide (Karenia brevis bloom) aerosols. In this study we explored the use of different methods of intensive ambient and personal air monitoring to characterize these exposures to predict self-reported health effects in our asthmatic study population. We evaluated health effects in 87 subjects with asthma before and after 1 hr of exposure to Florida red tide aerosols and assessed for aerosolized brevetoxin exposure using personal and ambient samplers. After only 1 hr of exposure to Florida red tide aerosols containing brevetoxin concentrations > 57 ng/m(3), asthmatics had statistically significant increases in self-reported respiratory symptoms and total symptom scores. However, we did not see the expected corresponding changes in PFT results. Significant increases in self-reported symptoms were also observed for those not using asthma medication and those living >/= 1 mile from the coast. These results provide additional evidence of health effects in asthmatics from ambient exposure to aerosols containing very low concentrations of brevetoxins, possibly at the lower threshold for inducing a biologic response (i.e., toxicity). Consistent with the literature describing self-reported symptoms as an accurate measure of asthmatic distress, our results suggest that self-reported symptoms are a valuable measure of the extent of health effects from exposure to aerosolized brevetoxins in asthmatic populations.

Innate Immunity and the Inter-exposure Interval Determine the Dynamics of Secondary Influenza Virus Infection and Explain Observed Viral Hierarchies.

PubMed

Cao, Pengxing; Yan, Ada W C; Heffernan, Jane M; Petrie, Stephen; Moss, Robert G; Carolan, Louise A; Guarnaccia, Teagan A; Kelso, Anne; Barr, Ian G; McVernon, Jodie; Laurie, Karen L; McCaw, James M

2015-08-01

Influenza is an infectious disease that primarily attacks the respiratory system. Innate immunity provides both a very early defense to influenza virus invasion and an effective control of viral growth. Previous modelling studies of virus-innate immune response interactions have focused on infection with a single virus and, while improving our understanding of viral and immune dynamics, have been unable to effectively evaluate the relative feasibility of different hypothesised mechanisms of antiviral immunity. In recent experiments, we have applied consecutive exposures to different virus strains in a ferret model, and demonstrated that viruses differed in their ability to induce a state of temporary immunity or viral interference capable of modifying the infection kinetics of the subsequent exposure. These results imply that virus-induced early immune responses may be responsible for the observed viral hierarchy. Here we introduce and analyse a family of within-host models of re-infection viral kinetics which allow for different viruses to stimulate the innate immune response to different degrees. The proposed models differ in their hypothesised mechanisms of action of the non-specific innate immune response. We compare these alternative models in terms of their abilities to reproduce the re-exposure data. Our results show that 1) a model with viral control mediated solely by a virus-resistant state, as commonly considered in the literature, is not able to reproduce the observed viral hierarchy; 2) the synchronised and desynchronised behaviour of consecutive virus infections is highly dependent upon the interval between primary virus and challenge virus exposures and is consistent with virus-dependent stimulation of the innate immune response. Our study provides the first mechanistic explanation for the recently observed influenza viral hierarchies and demonstrates the importance of understanding the host response to multi-strain viral infections. Re-exposure experiments provide a new paradigm in which to study the immune response to influenza and its role in viral control.

Innate Immunity and the Inter-exposure Interval Determine the Dynamics of Secondary Influenza Virus Infection and Explain Observed Viral Hierarchies

PubMed Central

Cao, Pengxing; Yan, Ada W. C.; Heffernan, Jane M.; Petrie, Stephen; Moss, Robert G.; Carolan, Louise A.; Guarnaccia, Teagan A.; Kelso, Anne; Barr, Ian G.; McVernon, Jodie; Laurie, Karen L.; McCaw, James M.

2015-01-01

Influenza is an infectious disease that primarily attacks the respiratory system. Innate immunity provides both a very early defense to influenza virus invasion and an effective control of viral growth. Previous modelling studies of virus–innate immune response interactions have focused on infection with a single virus and, while improving our understanding of viral and immune dynamics, have been unable to effectively evaluate the relative feasibility of different hypothesised mechanisms of antiviral immunity. In recent experiments, we have applied consecutive exposures to different virus strains in a ferret model, and demonstrated that viruses differed in their ability to induce a state of temporary immunity or viral interference capable of modifying the infection kinetics of the subsequent exposure. These results imply that virus-induced early immune responses may be responsible for the observed viral hierarchy. Here we introduce and analyse a family of within-host models of re-infection viral kinetics which allow for different viruses to stimulate the innate immune response to different degrees. The proposed models differ in their hypothesised mechanisms of action of the non-specific innate immune response. We compare these alternative models in terms of their abilities to reproduce the re-exposure data. Our results show that 1) a model with viral control mediated solely by a virus-resistant state, as commonly considered in the literature, is not able to reproduce the observed viral hierarchy; 2) the synchronised and desynchronised behaviour of consecutive virus infections is highly dependent upon the interval between primary virus and challenge virus exposures and is consistent with virus-dependent stimulation of the innate immune response. Our study provides the first mechanistic explanation for the recently observed influenza viral hierarchies and demonstrates the importance of understanding the host response to multi-strain viral infections. Re-exposure experiments provide a new paradigm in which to study the immune response to influenza and its role in viral control. PMID:26284917

Toxicity of the conventional energetics TNT and RDX relative to new insensitive munitions constituents DNAN and NTO in Rana pipiens tadpoles.

PubMed

Stanley, Jacob K; Lotufo, Guilherme R; Biedenbach, James M; Chappell, Pornsawan; Gust, Kurt A

2015-04-01

An initiative within the US military is targeting the replacement of traditional munitions constituents with insensitive munitions to reduce risk of accidental detonation. The purpose of the present study was to comparatively assess toxicity of the traditional munitions constituents 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) with the new insensitive munitions constituents 2,4-dinitroanisole (DNAN) and 3-nitro-1,2,4-triazol-5-one (NTO). The following exposure durations were performed with Rana pipiens (leopard frog) tadpoles: TNT and DNAN, 96 h and 28 d; RDX, 10 d and 28 d; NTO, 28 d. The 96-h 50% lethal concentration (LC50) values and 95% confidence intervals for TNT and DNAN were 4.4 mg/L (4.2 mg/L, 4. 7 mg/L) and 24.3 mg/L (21.3 mg/L, 27.6 mg/L), respectively. No significant impacts on survival were observed in the 10-d exposure to RDX up to 25.3 mg/L. Effects on tadpole swimming distance were observed with a lowest-observed-effect concentration (LOEC) of 5.9 mg/L RDX. In the 28-d exposures, the LOECs for survival for TNT, DNAN, and NTO were 0.003 mg/L, 2.4 mg/L, and 5.0 mg/L, respectively. No significant mortality was observed in the RDX chronic 28-d exposure up to the highest treatment level tested of 28.0 mg/L. Neither tadpole developmental stage nor growth was significantly affected in any of the 28-d exposures. Rana pipiens were very sensitive to chronic TNT exposure, with an LOEC 3 orders of magnitude lower than those for insensitive munitions constituents DNAN and NTO. © 2015 SETAC.

The effect of exposure to media campaign messages on adult cessation.

PubMed

Nonnemaker, James M; Dench, Daniel; Homsi, Ghada; MacMonegle, Anna; Duke, Jennifer

2015-10-01

Numerous studies have examined the relationship between antitobacco mass-media campaigns and quit attempts. However, less is known about the effect of these campaigns on relapse. This paper evaluates the effect of media exposure on smokers' quit attempts and relapse. We used data from the Florida Adult Cohort Survey, a telephone follow-up survey of adult smokers and recent quitters, who completed the Florida Adult Tobacco Survey. For this study, 1823 unique smokers and recent quitters from baseline first observed between July 2008 and October 2012 were surveyed through up to seven follow-up interviews between October 2009 and October 2013. Media exposure during this period primarily represents exposure to Florida's Tobacco Free Florida (TFF) campaign, although it also includes exposure to the Centers for Disease Control and Prevention's Tips From Former Smokers media campaign in 2012-2013. A multiple-spell discrete-time survival model was estimated using logistic regression. Each spell represents a quit attempt or relapse event. The odds of the first observed quit attempt are higher at higher levels of target rating points (TRPs) (aOR=1.02, p=0.023). The odds ratio for relapse and second quit and second relapse was not statistically significant. The results suggest that exposure to media campaign messages in Florida has led to increases in quit attempts. Although the estimates were not statistically significant for relapse or the second spell of quit attempts or relapse, the results suggest that media messages might also influence subsequent quit attempts or relapses after an initial quit attempt. Copyright © 2015 Elsevier Ltd. All rights reserved.

Gestational exposure to yellow fever vaccine at different developmental stages induces behavioral alterations in the progeny.

PubMed

Marianno, P; Salles, M J S; Sonego, A B; Costa, G A; Galvão, T C; Lima, G Z; Moreira, E G

2013-01-01

The most effective method to prevent yellow fever and control the disease is a vaccine made with attenuated live virus. Due to the neurological tropism of the virus, preventive vaccination is not recommended for infants under 6 months and for pregnant women. However there is a paucity of data regarding the safety for pregnant women and there are no experimental studies investigating adverse effects to the offspring after maternal exposure to the vaccine. This study aimed to investigate, in mice, the effects of maternal exposure to the yellow fever vaccine at three different gestational ages on the physical and behavioral development of the offspring. Pregnant Swiss mice received a single subcutaneous injection of water for injection (control groups) or 2 log Plaque Forming Units (vaccine-treated groups) of the yellow fever vaccine on gestational days (GD) 5, 10 or 15. Neither maternal signs of toxicity nor alterations in physical development and reflex ontogeny of the offspring were observed in any of the groups. Data from behavioral evaluation indicated that yellow fever vaccine exposure induced motor hypoactivity in 22-day-old females independent of the day of exposure; and in 60-day-old male and female pups exposed at GD 10. Moreover, 22-day-old females also presented with a deficit in habituation memory. Altogether, these results indicate that in utero exposure to the yellow fever vaccine may induce behavioral alterations in the pups that may persist to adulthood in the absence of observed maternal toxicity or disruption of physical development milestones or reflex ontogeny. Copyright © 2013 Elsevier Inc. All rights reserved.

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

PubMed

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

2010-01-01

Systemic inflammation may be one of the mechanisms mediating the association between ambient air pollution and cardiovascular morbidity and mortality. Interleukin-6 (IL-6) and fibrinogen are biomarkers of systemic inflammation that are independent risk factors for cardio-vascular disease. We investigated the association between ambient air pollution and systemic inflammation using baseline measurements of IL-6 and fibrinogen from controlled human exposure studies. In this retrospective analysis we used repeated-measures data in 45 nonsmoking subjects. Hourly and daily moving averages were calculated for ozone, nitrogen dioxide, sulfur dioxide, and particulate matter

The impact of composite AUC estimates on the prediction of systemic exposure in toxicology experiments.

PubMed

Sahota, Tarjinder; Danhof, Meindert; Della Pasqua, Oscar

2015-06-01

Current toxicity protocols relate measures of systemic exposure (i.e. AUC, Cmax) as obtained by non-compartmental analysis to observed toxicity. A complicating factor in this practice is the potential bias in the estimates defining safe drug exposure. Moreover, it prevents the assessment of variability. The objective of the current investigation was therefore (a) to demonstrate the feasibility of applying nonlinear mixed effects modelling for the evaluation of toxicokinetics and (b) to assess the bias and accuracy in summary measures of systemic exposure for each method. Here, simulation scenarios were evaluated, which mimic toxicology protocols in rodents. To ensure differences in pharmacokinetic properties are accounted for, hypothetical drugs with varying disposition properties were considered. Data analysis was performed using non-compartmental methods and nonlinear mixed effects modelling. Exposure levels were expressed as area under the concentration versus time curve (AUC), peak concentrations (Cmax) and time above a predefined threshold (TAT). Results were then compared with the reference values to assess the bias and precision of parameter estimates. Higher accuracy and precision were observed for model-based estimates (i.e. AUC, Cmax and TAT), irrespective of group or treatment duration, as compared with non-compartmental analysis. Despite the focus of guidelines on establishing safety thresholds for the evaluation of new molecules in humans, current methods neglect uncertainty, lack of precision and bias in parameter estimates. The use of nonlinear mixed effects modelling for the analysis of toxicokinetics provides insight into variability and should be considered for predicting safe exposure in humans.

Tobacco smoke modulates ozone-induced toxicity in rat lungs and central nervous system.

PubMed

Bhoopalan, Vanitha; Han, Sung Gu; Shah, Mrudang M; Thomas, David M; Bhalla, Deepak K

2013-01-01

Adult Sprague-Dawley (SD) male rats were exposed for a single 3 h period to air, ozone (O₃) or O₃) followed by tobacco smoke (O₃/TS). For pulmonary effects, bronchoalveolar lavage (BAL) cells and fluid were analyzed. Data revealed a significant increase in polymorphonuclear leukocytes (PMN), total protein and albumin concentrations in the O₃ group, reflecting inflammatory and toxic responses. A subsequent exposure to TS attenuated PMN infiltration into the airspaces and their recovery in the BAL. A similar reduction was observed for BAL protein and albumin in the O₃/TS group, but it was not statistically significant. We also observed a significant increase in BAL total antioxidant capacity following O₃ exposure, suggesting development of protective mechanisms for oxidative stress damage from O₃. Exposure to TS attenuated the levels of total antioxidant capacity. Lung tissue protein analysis showed a significant reduction of extracellular superoxide dismutase (EC-SOD) in the O₃ or O₃/TS group and catalase in the O₃/TS group. TS further altered O₃-induced EC-SOD and catalase protein expression, but the reductions were not significant. For effects in the central nervous system (CNS), we measured striatal dopamine levels by HPLC with electrochemical detection. O₃ exposure produced a nonsignificant decrease in the striatal dopamine content. The effect was partially reversed in the O₃/TS group. Overall, the results show that the toxicity of O₃ in the lung is modulated by TS exposure, and the attenuating trend, though nonsignificant in many cases, is contrary to the synergistic toxicity predicted for TS and O₃, suggesting limited cross-tolerance following such exposures.

Sex differences in the long-lasting effects of a single exposure to immobilization stress in rats.

PubMed

Gagliano, Humberto; Nadal, Roser; Armario, Antonio

2014-11-01

In male rats, a single exposure to a severe stressor such as immobilization (IMO) results in marked activation of the HPA axis and reduction of body weight gain. In addition, the HPA response to the same (homotypic) stressor is reduced, whereas the response to a different (heterotypic) stressor is enhanced for days. Although sex differences in the responsiveness of the HPA axis have been described, there are few studies about the influence of sex on long-lasting effects of stress. Thus, we have compared the consequences of a single exposure to IMO in male and female rats. Females showed a similar ACTH response to the first IMO associated with higher corticosterone, but they were more resistant than males to stress-induced loss of body weight. Unstressed females showed higher resting levels of ACTH and corticosterone, but they did not show the increase in the resting levels of HPA hormones observed in males on the day after IMO. During exposure to a different stressor (open-field) two days after IMO, enhanced corticosterone response and hypoactivity was observed in males, but not in females. Finally, a second exposure to IMO 8 days after the first one resulted in a reduction of the HPA response and of the negative impact on body weight as compared to the first exposure, and this protective effect was greater in females. In sum, IMO-exposed females showed a greater reduction of the response to a second IMO and appear to be more resistant than males to some of the negative impacts of IMO. Copyright © 2014. Published by Elsevier Inc.

Post—September 11, 2001, Incidence of Systemic Autoimmune Diseases in World Trade Center—Exposed Firefighters and Emergency Medical Service Workers

PubMed Central

Webber, Mayris P.; Moir, William; Crowson, Cynthia S.; Cohen, Hillel W.; Zeig-Owens, Rachel; Hall, Charles B.; Berman, Jessica; Qayyum, Basit; Jaber, Nadia; Matteson, Eric L.; Liu, Yang; Kelly, Kerry; Prezant, David J.

2016-01-01

Objective To estimate the incidence of selected systemic autoimmune diseases (SAIDs) in approximately 14,000 male rescue/recovery workers enrolled in the Fire Department of the City of New York (FDNY) World Trade Center (WTC) Health Program and to compare FDNY incidence to rates from demographically similar men in the Rochester Epidemiology Project (REP), a population-based database in Olmsted County, Minnesota. Patients and Methods We calculated incidence for specific SAIDs (rheumatoid arthritis, psoriatic arthritis, systemic lupus erythematosus, and others) and combined SAIDs diagnosed from September 12, 2001, through September 11, 2014, and generated expected sex- and age-specific rates based on REP rates. Rates were stratified by level of WTC exposure (higher vs lower). Standardized incidence ratios (SIRs), which are the ratios of the observed number of cases in the FDNY group to the expected number of cases based on REP rates, and 95% CIs were calculated. Results We identified 97 SAID cases. Overall, FDNY rates were not significantly different from expected rates (SIR, 0.97; 95% CI, 0.77–1.21). However, the lower WTC exposure group had 9.9 fewer cases than expected, whereas the higher WTC exposure group had 7.7 excess cases. Conclusion Most studies indicate that the healthy worker effect reduces the association between exposure and outcome by about 20%, which we observed in the lower WTC exposure group. Overall rates masked differences in incidence by level of WTC exposure, especially because the higher WTC exposure group was relatively small. Continued surveillance for early detection of SAIDs in high WTC exposure populations is required to identify and treat exposure-related adverse effects. PMID:26682920

Impact of UVA exposure on psychological parameters and circulating serotonin and melatonin

PubMed Central

Gambichler, Thilo; Bader, Armin; Vojvodic, Mirjana; Bechara, Falk G; Sauermann, Kirsten; Altmeyer, Peter; Hoffmann, Klaus

2002-01-01

Background People tend to feel better after exposure to ultraviolet (UV) radiation. This study was performed to investigate the impact of UVA exposure on psychological and neuroendocrine parameters. Methods Fifty-three volunteers were separated into 42 individuals who had UVA exposure and 11 individuals who had no UVA exposure. The UVA-exposed volunteers had irradiation sessions six times in a three-week period. All volunteers completed two questionnaires at baseline (T1) and at the end of the study (T3). For the determination of serotonin and melatonin serum levels of all volunteers blood samples were collected at baseline (T1), after the first UVA exposure (T2), and at the end of the study after the sixth exposure (T3). Results UVA-exposed volunteers felt significantly more balanced, less nervous, more strengthened, and more satisfied with their appearance at T3. By contrast, the controls did not show significant changes of psychological parameters. In comparison to T1 and T3, serum serotonin was significantly higher and the serum melatonin was significantly lower for the volunteers exposed to UVA at T2. Both, for exposed and non-exposed volunteers serotonin and melatonin levels did not significantly differ at T1 and T3. Conclusions It remains obscure, whether the exposure to UVA or other components of the treatment were responsible for the psychological benefits observed. The changes of circulating neuroendocrine mediators found after UVA exposure at T2 may be due to an UVA-induced effect via a cutaneous pathway. Nevertheless, the positive psychological effects observed in our study cannot be attributed to circulating serotonin or melatonin. PMID:11952999

Post-September 11, 2001, Incidence of Systemic Autoimmune Diseases in World Trade Center-Exposed Firefighters and Emergency Medical Service Workers.

PubMed

Webber, Mayris P; Moir, William; Crowson, Cynthia S; Cohen, Hillel W; Zeig-Owens, Rachel; Hall, Charles B; Berman, Jessica; Qayyum, Basit; Jaber, Nadia; Matteson, Eric L; Liu, Yang; Kelly, Kerry; Prezant, David J

2016-01-01

To estimate the incidence of selected systemic autoimmune diseases (SAIDs) in approximately 14,000 male rescue/recovery workers enrolled in the Fire Department of the City of New York (FDNY) World Trade Center (WTC) Health Program and to compare FDNY incidence to rates from demographically similar men in the Rochester Epidemiology Project (REP), a population-based database in Olmsted County, Minnesota. We calculated incidence for specific SAIDs (rheumatoid arthritis, psoriatic arthritis, systemic lupus erythematosus, and others) and combined SAIDs diagnosed from September 12, 2001, through September 11, 2014, and generated expected sex- and age-specific rates based on REP rates. Rates were stratified by level of WTC exposure (higher vs lower). Standardized incidence ratios (SIRs), which are the ratios of the observed number of cases in the FDNY group to the expected number of cases based on REP rates, and 95% CIs were calculated. We identified 97 SAID cases. Overall, FDNY rates were not significantly different from expected rates (SIR, 0.97; 95% CI, 0.77-1.21). However, the lower WTC exposure group had 9.9 fewer cases than expected, whereas the higher WTC exposure group had 7.7 excess cases. Most studies indicate that the healthy worker effect reduces the association between exposure and outcome by about 20%, which we observed in the lower WTC exposure group. Overall rates masked differences in incidence by level of WTC exposure, especially because the higher WTC exposure group was relatively small. Continued surveillance for early detection of SAIDs in high WTC exposure populations is required to identify and treat exposure-related adverse effects. Copyright © 2016. Published by Elsevier Inc.

Cigarette Smoking and the Risk of Bladder Cancer in Men and Women

PubMed Central

Quirk, Jeffrey T; Li, Qiang; Natarajan, Nachimuthu; Mettlin, Curtis J; Cummings, K Michael

2004-01-01

Although cigarette smoking is a principal risk factor for bladder cancer in both men and women, few studies have statistically evaluated whether gender modifies the effect of smoking on bladder cancer risk. We initiated the present case-control study at Roswell Park Cancer Institute in Buffalo, New York, U.S., to provide further data on this important issue. We observed similar risk estimates for men and women with comparable smoking exposures, but did not observe a statistically significant interaction between gender and lifetime smoking exposure. We conclude that cigarette smoking is a major risk factor for bladder cancer in both sexes, but that gender does not modify the effect of smoking on bladder cancer risk.

A strong static-magnetic field alters operant responding by rats.

PubMed

Nakagawa, M; Matsuda, Y

1988-01-01

Forty male rats of the Wistar ST strain were trained and observed for Sidman avoidance (SA) for 7 weeks or for discriminative avoidance (DA) for 14 weeks to determine the effects of exposure to a strong static-magnetic field. Before avoidance conditioning was completed, rats in the SA group were exposed to the static field at 0.6 T, 16 h/day for 4 days during the fifth week, and those in the DA group were exposed for 6 h/day for 4 days during the seventh week. In the SA conditioning, frequency of lever-pressing by exposed rats gradually decreased during 1 week of exposure and stayed low for at least 2 weeks after exposure. Frequencies of electric shocks received by the rats increased dramatically during the second day of exposure and consistently stayed higher than those of control rats. In the DA condition, exposed rats responded at lower rates than did control rats throughout the observation period. They received more shocks during the 2 weeks following exposure. The data indicate that performance of avoidance responses was inhibited by a comparatively long exposure to a strong magnetic field.

Integrative assessment of multiple pesticides as risk factors for non-Hodgkin's lymphoma among men.

PubMed

De Roos, A J; Zahm, S H; Cantor, K P; Weisenburger, D D; Holmes, F F; Burmeister, L F; Blair, A

2003-09-01

An increased rate of non-Hodgkin's lymphoma (NHL) has been repeatedly observed among farmers, but identification of specific exposures that explain this observation has proven difficult. During the 1980s, the National Cancer Institute conducted three case-control studies of NHL in the midwestern United States. These pooled data were used to examine pesticide exposures in farming as risk factors for NHL in men. The large sample size (n = 3417) allowed analysis of 47 pesticides simultaneously, controlling for potential confounding by other pesticides in the model, and adjusting the estimates based on a prespecified variance to make them more stable. Reported use of several individual pesticides was associated with increased NHL incidence, including organophosphate insecticides coumaphos, diazinon, and fonofos, insecticides chlordane, dieldrin, and copper acetoarsenite, and herbicides atrazine, glyphosate, and sodium chlorate. A subanalysis of these "potentially carcinogenic" pesticides suggested a positive trend of risk with exposure to increasing numbers. Consideration of multiple exposures is important in accurately estimating specific effects and in evaluating realistic exposure scenarios.

Sublethal Effects of ActiveGuard Exposure on Feeding Behavior and Fecundity of the Bed Bug (Hemiptera: Cimicidae).

PubMed

Jones, Susan C; Bryant, Joshua L; Sivakoff, Frances S

2015-05-01

Sublethal exposure to pesticides can alter insect behavior with potential for population-level consequences. We investigated sublethal effects of ActiveGuard, a permethrin-impregnated fabric, on feeding behavior and fecundity of bed bugs (Cimex lectularius L.) from five populations that ranged from susceptible to highly pyrethroid resistant. After exposure to ActiveGuard fabric or untreated fabric for 1 or 10 min, adult virgin female bed bugs were individually observed when offered a blood meal to determine feeding attempts and weight gain. Because bed bug feeding behavior is tightly coupled with its fecundity, all females were then mated, and the number of eggs laid and egg hatch rate were used as fecundity measures. We observed that pyrethroid-resistant and -susceptible bugs were not significantly different for all feeding and fecundity parameters. Bed bugs exposed to ActiveGuard for 10 min were significantly less likely to attempt to feed or successfully feed, and their average blood meal size was significantly smaller compared with individuals in all other groups. Independent of whether or not feeding occurred, females exposed to ActiveGuard for 10 min were significantly more likely to lay no eggs. Only a single female exposed to ActiveGuard for 10 min laid any eggs. Among the other fabric treatment-exposure time groups, there were no observable differences in egg numbers or hatch rates. Brief exposure of 10 min to ActiveGuard fabric appeared to decrease feeding and fecundity of pyrethroid-resistant and susceptible bed bugs, suggesting the potentially important role of sublethal exposure for the control of this ectoparasitic insect. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Associations between urinary biomarkers of oxidative stress and air pollutants observed in a randomized crossover exposure to steel mill emissions.

PubMed

Pelletier, Guillaume; Rigden, Marc; Kauri, Lisa Marie; Shutt, Robin; Mahmud, Mamun; Cakmak, Sabit; Kumarathasan, Premkumari; Thomson, Errol M; Vincent, Renaud; Broad, Gayle; Liu, Ling; Dales, Robert

2017-04-01

The effects of industrial air pollution on human health have not been as thoroughly investigated as those of urban air pollution which originates mostly from automotive transport. To better assess the health impacts of point sources of industrial air pollution, a randomized crossover exposure study was conducted. Sixty one young and healthy volunteers were randomly assigned to spend five consecutive eight-hour days near a steel mill or at a location five kilometres away. After a nine or sixteen-day washout period, volunteers spent another five consecutive days at the second site. Meteorological conditions and air pollutants were monitored at both exposure sites. On each exposure day, the first morning urine was collected along with a second urine sample obtained immediately before leaving the exposure site at the end of the day. Urinary levels of biomarkers of oxidative stress 8-hydroxy-2'-deoxyguanosine (8-OHdG, a biomarker of oxidative DNA damage), malondialdehyde (MDA, a biomarker of lipid peroxidation), 8-isoprostane (8-IsoP, a bioactive metabolite resulting from the peroxidation of arachidonic acid) and Vascular Endothelial Growth Factor (VEGF, involved in response to oxidative stress) were measured. According to mixed-effects linear regression models, intra-individual variations in 8-OHdG urinary levels were significantly associated with exposure site, but surprisingly, lower levels were observed at the steel mill site. Delayed, temporally-defined associations with specific air pollutants were observed for 8-OHdG, 8-IsoP and VEGF. However, these associations were subtle, presented complex patterns and their biological consequences remain unclear. Crown Copyright © 2016. Published by Elsevier GmbH. All rights reserved.

Effects of tributyltin and benzo[a]pyrene on the immune-associated activities of hemocytes and recovery responses in the gastropod abalone, Haliotis diversicolor.

PubMed

Gopalakrishnan, Singaram; Huang, Wei-Bin; Wang, Qiang-Wei; Wu, Man-Li; Liu, Jie; Wang, Ke-Jian

2011-08-01

Our previous study reports that short-term exposure to sublethal concentrations of benzo[a]pyrene (BaP) induces immunomodulation in the gastropod abalone, Haliotis diversicolor. In the present study, it was further observed that long-term chronic exposure to sublethal concentrations of BaP modulated the immunocompetence of abalones in terms of the change in activity of the antioxidant and immune associated parameters tested. In addition, the effect of tributyltin (TBT), another important genotoxicant in the aquatic environment, was investigated. Exposure of abalones to sublethal concentrations of TBT and BaP for 21 days resulted in significant decrease of total hemocyte count, phagocytosis, membrane stability and lysozyme activity. Conversely induction of extra and intra cellular superoxide generation, nitric oxide, nitric oxide synthase and myeloperoxidase activity was present when the abalones were exposed to TBT and BaP. Most of the immune associated parameters tested showed clear time dependent response to both toxicants. Within 14 days after the 21 day exposure to BaP, recovery was observed as evidenced by most of the parameters returning to their normal level. However, no recovery was observed within 14 days after the 21 day exposure to TBT as evidenced by continued elevation of intra cellular superoxide and nitrite production and decrease in THC, membrane stability and lysozyme activity. This suggested a prolonged TBT-induced impact on the immune reaction and possibly more damage than that caused by BaP. Overall the results suggest that chronic exposure to sublethal concentrations of TBT or BaP causes modulations in the immunocompetence of abalones with most of the immune associated parameters tested being stimulated, and this might be harmful to the host. Copyright © 2011 Elsevier Inc. All rights reserved.

Shape, Color and the Other-Race Effect in the Infant Brain

ERIC Educational Resources Information Center

Balas, Benjamin; Westerlund, Alissa; Hung, Katherine; Nelson, Charles A., III

2011-01-01

The "other-race" effect describes the phenomenon in which faces are difficult to distinguish from one another if they belong to an ethnic or racial group to which the observer has had little exposure. Adult observers typically display multiple forms of recognition error for other-race faces, and infants exhibit behavioral evidence of a developing…

Acute Lung Injury and Persistent Small Airway Disease in a Rabbit Model of Chlorine Inhalation

PubMed Central

Musah, Sadiatu; Schlueter, Connie F.; Humphrey, David M.; Powell, Karen S.; Roberts, Andrew M.; Hoyle, Gary W.

2016-01-01

Chlorine is a pulmonary toxicant to which humans can be exposed through accidents or intentional releases. Acute effects of chlorine inhalation in humans and animal models have been well characterized, but less is known about persistent effects of acute, high-level chlorine exposures. In particular, animal models that reproduce the long-term effects suggested to occur in humans are lacking. Here, we report the development of a rabbit model in which both acute and persistent effects of chlorine inhalation can be assessed. Male New Zealand White rabbits were exposed to chlorine while the lungs were mechanically ventilated. After chlorine exposure, the rabbits were extubated and were allowed to survive for up to 24 h after exposure to 800 ppm chlorine for 4 min to study acute effects or up to 7 days after exposure to 400 ppm for 8 min to study longer term effects. Acute effects observed 6 or 24 h after inhalation of 800 ppm chlorine for 4 min included hypoxemia, pulmonary edema, airway epithelial injury, inflammation, altered baseline lung mechanics, and airway hyperreactivity to inhaled methacholine. Seven days after recovery from inhalation of 400 ppm chlorine for 8 min, rabbits exhibited mild hypoxemia, increased area of pressure-volume loops, and airway hyperreactivity. Lung histology 7 days after chlorine exposure revealed abnormalities in the small airways, including inflammation and sporadic bronchiolitis obliterans lesions. Immunostaining showed a paucity of club and ciliated cells in the epithelium at these sites. These results suggest that small airway disease may be an important component of persistent respiratory abnormalities that occur following acute chlorine exposure. This non-rodent chlorine exposure model should prove useful for studying persistent effects of acute chlorine exposure and for assessing efficacy of countermeasures for chlorine-induced lung injury. PMID:27913141

Combined effect of short-term dehydration and sublethal acute oral dicrotophos exposure confounds the diagnosis of anticholinesterase exposure in common quail (Coturnix coturnix) using plasma cholinesterase activity.

PubMed

Heffernan, James; Mineau, Pierre; Falk, Ramona; Wickstrom, Mark

2012-07-01

Common Quail (Coturnix coturnix) were subjected to controlled and replicated experiments in the summer of 2008 to investigate the effects of short-term dehydration on cholinesterase activity in brain and plasma and the interaction between dehydration and exposure to the organophosphorus pesticide dicrotophos in these same tissues. Our objective was to determine if dehydration could confound the diagnosis of anticholinesterase exposure using inhibition of cholinesterase activity in quail tissues. The effect of dehydration was quantified using measures of plasma osmolality and hematocrit. Dicrotophos exposure caused significant inhibition of cholinesterase activity in brain, while the effects of dehydration and interaction were not significant. Dehydration caused significant duration-dependent increases in plasma osmolality and hematocrit. Dehydration also caused a significant increase in plasma cholinesterase activity. Variation in the change in plasma cholinesterase activity in response to dehydration was significantly and positively correlated with dehydration-induced variation in both the change in plasma osmolality and the change in hematocrit. These correlations suggest that plasma cholinesterase activity in quail is not limited to plasma but occupies some larger pool of the extracellular fluid volume, and we suggest lymph is part of that pool. The effects of dehydration on plasma cholinesterase activity masked the inhibitory effects of dicrotophos. Here, the combination of dehydration and dicrotophos exposure produced plasma cholinesterase activity that was not significantly different from reference and pre-exposure values, confounding the diagnosis of anticholinesterase exposure in dehydrated, dicrotophos-exposed quail. A method to adjust plasma cholinesterase activities for the confounding effects of dehydration and enable the diagnosis of anticholinesterase exposure in dehydrated, dicrotophos-exposed quail was developed. Clinicians and practitioners responsible for the diagnosis of anticholinesterase exposure in birds are cautioned that dehydration, commonly observed in sick wildlife, may mask the effect of anticholinesterases on plasma cholinesterase activity.

Cancer incidence among welders: possible effects of exposure to extremely low frequency electromagnetic radiation (ELF) and to welding fumes.

PubMed Central

Stern, R M

1987-01-01

Epidemiological studies of cancer incidence among welders disclose a pooled total of 146 cases of leukemia observed versus 159.46 expected, a risk ratio of 0.92, and 40 cases of acute leukemia observed versus 43.39 expected, a risk ratio of 0.92. For respiratory tract cancer, the pooled total is 1789 cases observed versus 1290.7 expected, a risk ratio of 1.39. Most electric welders are exposed to extremely low frequency electromagnetic radiation (ELF) (magnetic flux densities of up to 100,000 microT), a suspected leukemogen, and to concentrated metallic aerosols (up to 200 mg/m3), which can contain the putative respiratory tract carcinogens Cr(VI) and Ni. The two exposures are usually coincident, since welding with an electric current produces welding fumes. The observation of an excess risk for respiratory tract cancer strongly suggests significant exposure both to fumes and to ELF. The absence of increased risk for all leukemia or for acute leukemia among ELF-exposed welders does not support the hypothesis that the observed excess risk for leukemia or acute leukemia among workers in the electrical trades is due to their ELF exposure, which on the average is lower than that of welders. PMID:3447902

Acute and chronic toxicity of buprofezin on Daphnia magna and the recovery evaluation.

PubMed

Liu, Yong; Qi, Suzhen; Zhang, Wen; Li, Xuefeng; Qiu, Lihong; Wang, Chengju

2012-11-01

The toxic effects of buprofezin on Daphnia magna after both chronic and acute exposures were evaluated according to OECD guidelines. A 48-h acute exposure of buprofezin resulted in daphnid immobility at an EC(50) of 0.44 mg/L. In a 14 days chronic exposure of buprofezin (0, 0.025, 0.05, 0.10 and 0.15 mg/L), the development and reproduction of daphnids were all significantly affected and the body length was more sensitive than other observed parameters. However, the adverse effects of buprofezin on parental daphnids can be passed on to their offspring and cannot be recovered in a short time.

Biomarker assessment of the effects of coal strip-mine contamination on channel catfish.

PubMed

Martin, L K; Black, M C

1998-11-01

A suite of biomarkers was used to evaluate acute (1-day) to semichronic (3-month) heavy metal-induced toxicity in channel catfish, lctalurus punctatus, caged at an abandoned strip mine and a noncontaminated reference site. Assays performed include indicators of metabolic, hematological, osmoregulatory, and genotoxic stress. Two cage designs were used to evaluate the importance of exposure routes: one excluding contact with the sediments and the other allowing contact with water and sediments. Significant DNA strand breakage was observed in catfish exposed to both exposure regimens, but evidence of DNA repair was observed only in water-exposed catfish. Transient increases in hemoglobin, delta-aminolevulinic acid dehydratase, and hematocrit levels were observed at 1 month's exposure for both exposure regimens, followed by a return to control levels for the duration of the study. Environmental conditions (i.e., weather-related changes in water quality) may have contributed to the variable plasma chloride and glucose levels observed in all catfish exposed to strip-mine wastes. The transient changes in biomarkers followed by a return to reference values represent an initial stress and an acclimation to normal levels. Copyright 1998 Academic Press.

The effects analysis of two neonicotinoid insecticides on in vitro maturation of porcine oocytes using hanging drop monoculture method.

PubMed

Ishikawa, Sadamasa; Hiraga, Kou; Hiradate, Yuuki; Tanemura, Kentaro

2015-06-01

Acetamiprid (ACE) and imidacroprid (IMI) are known neonicotinoid insecticides with strong affinities for the insect-selective nicotinic acetylcholine receptor. These provide insect control by hyperstimulating insect nerves and are used for agricultural pest management. However, it has also been reported that ACE and IMI affect mammalian reproductive function. We determined the effects of ACE and IMI on the in vitro maturation of porcine oocytes. Significant decreases in nuclear maturation rates were observed in the ACE or IMI-exposed groups. Also, in matured oocytes from the ACE or IMI-exposed groups, irregular chromosomes were observed. Our results suggest that ACE and IMI exposure was detrimental to porcine oocytes and the extent of the effects depends on the concentration of exposure.

Exposure to time varying magnetic fields associated with magnetic resonance imaging reduces fentanyl-induced analgesia in mice

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

Teskey, G.C.; Prato, F.S.; Ossenkopp, K.P.

The effects of exposure to clinical magnetic resonance imaging (MRI) on analgesia induced by the mu opiate agonist, fentanyl, was examined in mice. During the dark period, adult male mice were exposed for 23.2 min to the time-varying (0.6 T/sec) magnetic field (TVMF) component of the MRI procedure. Following this exposure, the analgesic potency of fentanyl citrate (0.1 mg/kg) was determined at 5, 10, 15, and 30 min post-injection, using a thermal test stimulus (hot-plate 50 degrees C). Exposure to the magnetic-field gradients attenuated the fentanyl-induced analgesia in a manner comparable to that previously observed with morphine. These results indicatemore » that the time-varying magnetic fields associated with MRI have significant inhibitory effects on the analgesic effects of specific mu-opiate-directed ligands.« less

Are men talking their reproductive health away?

PubMed

Agarwal, Ashok; Durairajanayagam, Damayanthi

2015-01-01

The advent of mobile phones has revolutionized communication trends across the globe. As the popularity of mobile phone usage continues to escalate, there is now growing concern about the effects of radiofrequency electromagnetic waves (RF-EMW) exposure on biological tissues, such as the brain and testes. Researchers have sought to link the much debated decline in human sperm quality in the last decade, with increased exposure to RF-EMW, particularly through mobile phone usage. In a recent systematic review and meta-analysis on the effect of mobile phone RF-EMW radiation on sperm quality, Adams et al. [1] demonstrated an association between mobile phone exposure and reduced sperm motility and viability, with inconsistent effects on sperm concentration. [1] Results from 10 pooled experimental (in vitro) and observational (in vivo)human studies (n = 1492) led these researchers to suggest that exposure to RF-EMW radiation from carrying a mobile phone in the trouser pocket negatively impacts sperm quality.

Leaky vaccines protect highly exposed recipients at a lower rate: implications for vaccine efficacy estimation and sieve analysis.

PubMed

Edlefsen, Paul T

2014-01-01

"Leaky" vaccines are those for which vaccine-induced protection reduces infection rates on a per-exposure basis, as opposed to "all-or-none" vaccines, which reduce infection rates to zero for some fraction of subjects, independent of the number of exposures. Leaky vaccines therefore protect subjects with fewer exposures at a higher effective rate than subjects with more exposures. This simple observation has serious implications for analysis methodologies that rely on the assumption that the vaccine effect is homogeneous across subjects. We argue and show through examples that this heterogeneous vaccine effect leads to a violation of the proportional hazards assumption, to incomparability of infected cases across treatment groups, and to nonindependence of the distributions of the competing failure processes in a competing risks setting. We discuss implications for vaccine efficacy estimation, correlates of protection analysis, and mark-specific efficacy analysis (also known as sieve analysis).

Differential respiratory health effects from the 2008 northern California wildfires: A spatiotemporal approach.

PubMed

Reid, Colleen E; Jerrett, Michael; Tager, Ira B; Petersen, Maya L; Mann, Jennifer K; Balmes, John R

2016-10-01

We investigated health effects associated with fine particulate matter during a long-lived, large wildfire complex in northern California in the summer of 2008. We estimated exposure to PM2.5 for each day using an exposure prediction model created through data-adaptive machine learning methods from a large set of spatiotemporal data sets. We then used Poisson generalized estimating equations to calculate the effect of exposure to 24-hour average PM2.5 on cardiovascular and respiratory hospitalizations and ED visits. We further assessed effect modification by sex, age, and area-level socioeconomic status (SES). We observed a linear increase in risk for asthma hospitalizations (RR=1.07, 95% CI=(1.05, 1.10) per 5µg/m(3) increase) and asthma ED visits (RR=1.06, 95% CI=(1.05, 1.07) per 5µg/m(3) increase) with increasing PM2.5 during the wildfires. ED visits for chronic obstructive pulmonary disease (COPD) were associated with PM2.5 during the fires (RR=1.02 (95% CI=(1.01, 1.04) per 5µg/m(3) increase) and this effect was significantly different from that found before the fires but not after. We did not find consistent effects of wildfire smoke on other health outcomes. The effect of PM2.5 during the wildfire period was more pronounced in women compared to men and in adults, ages 20-64, compared to children and adults 65 or older. We also found some effect modification by area-level median income for respiratory ED visits during the wildfires, with the highest effects observed in the ZIP codes with the lowest median income. Using a novel spatiotemporal exposure model, we found some evidence of differential susceptibility to exposure to wildfire smoke. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Mechanism of biological effects observed in honey bees (Apis mellifera, L. ) hived under extra-high-voltage transmission lines: implications derived from bee exposure to simulated intense electric fields and shocks

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

Bindokas, V.P.; Gauger, J.R.; Greenberg, B.

This work explores mechanisms for disturbance of honey bee colonies under a 765 kV, 60-Hz transmission line (electric (E) field = 7 kV/m) observed in previous studies. Proposed mechanisms fell into two categories: direct bee perception of enhanced in-hive E fields and perception of shock from induced currents. The adverse biological effects could be reproduced in simulations where only the worker bees were exposed to shock or to E field in elongated hive entranceways (= tunnels). We now report the results of full-scale experiments using the tunnel exposure scheme, which assesses the contribution of shock and intense E field tomore » colony disturbance. Exposure of worker bees (1400 h) to 60-Hz E fields including 100 kV/m under moisture-free conditions within a nonconductive tunnel causes no deleterious affect on colony behavior. Exposure of bees in conductive (e.g., wet) tunnels produces bee disturbance, increased mortality, abnormal propolization, and possible impairment of colony growth. We propose that this substrate dependence of bee disturbance is the result of perception of shock from coupled body currents and enhanced current densities postulated to exist in the legs and thorax of bees on conductors. Similarly, disturbance occurs when bees are exposed to step-potential-induced currents. At 275-350 nA single bees are disturbed; at 600 nA bees begin abnormal propolization behavior; and stinging occurs at 900 nA. We conclude that biological effects seen in bee colonies under a transmission line are primarily the result of electric shock from induced hive currents. This evaluation is based on the limited effects of E-field exposure in tunnels, the observed disturbance thresholds caused by shocks in tunnels, and the ability of hives exposed under a transmission line to source currents 100-1,000 times the shock thresholds.« less

Comparative toxic potential of market formulation of two organophosphate pesticides in transgenic Drosophila melanogaster (hsp70-lacZ).

PubMed

Gupta, S C; Siddique, H R; Saxena, D K; Chowdhuri, D Kar

2005-01-01

This study investigated the working hypothesis that two widely used organophosphate pesticides; Nuvan and Dimecron, exert toxic effects in Drosophila. Transgenic D. melanogaster (hsp70-lacZ) was used as a model for assaying stress gene expression and AchE activity as an endpoint for toxicity and also to evaluate whether stress gene expression is sufficient to protect against toxic insult of the chemicals and to prevent tissue damage. The study was extended to investigate the effect of the pesticides on the life cycle and reproduction of the organism. The study showed that Nuvan affected emergence of the exposed flies more drastically than Dimecron and the effect was lethal at the highest tested concentration (0.075 ppm). While Nuvan at 0.0075 and 0.015 ppm concentrations affected reproduction of the flies significantly, the effect of Dimecron was significant only at 0.015 and 0.075 ppm. Nuvan-exposed third-instar larvae exhibited a 1.2-fold to 1.5-fold greater hsp70 expression compared to Dimecron at concentrations ranging from 0.0075 to 0.075 ppm following 12 and 18 h exposure. While maximum expression of hsp70 was observed in Nuvan-exposed third-instar larval tissues following 18 h exposure at 0.075 ppm, Dimecron at the same dietary concentration induced a maximum expression of hsp70 following 24 h exposure. Further, concomitant with a significant induction of hsp70, significant inhibition of AchE was observed following chemical exposure and temperature shock. Concurrent with a significant decline in hsp70 expression in Nuvan-exposed larvae after 48 h at 0.075 ppm, tissue damage was evident. Dimecron-exposed larvae exhibited a plateau in hsp70 induction even after 48 h exposure and moderate tissue damage was observed in these larvae. The present study suggests that Nuvan is more cytotoxic than Dimecron in transgenic Drosophila melanogaster.

The effect of electromagnetic radiation emitted by display screens on cell oxygen metabolism – in vitro studies

PubMed Central

Henrykowska, Gabriela A.; Pacholski, Krzysztof; Śmigielski, Janusz; Rutkowski, Maciej; Dziedziczak-Buczyńska, Maria; Buczyński, Andrzej

2015-01-01

Introduction Research studies carried out for decades have not solved the problem of the effect of electromagnetic radiation of various frequency and strength on the human organism. Due to this fact, we decided to investigate the changes taking place in human blood platelets under the effect of electromagnetic radiation (EMR) emitted by LCD monitors. Material and methods The changes of selected parameters of oxygen metabolism were measured, i.e. reactive oxygen species concentration, enzymatic activity of antioxidant defence proteins – superoxide dismutase (SOD-1) and catalase (CAT) – and malondialdehyde concentration (MDA). A suspension of human blood platelets was exposed to electromagnetic radiation of 1 kHz frequency and 150 V/m and 220 V/m intensity for 30 and 60 min. The level of changes of the selected parameters of oxidative stress was determined after the exposure and compared to the control samples (not exposed). Results The measurements revealed an increase of the concentration of reactive oxygen species. The largest increase of ROS concentration vs. the control sample was observed after exposure to EMF of 220 V/m intensity for 60 min (from x = 54.64 to x = 72.92). The measurement of MDA concentration demonstrated a statistically significant increase after 30-min exposure to an EMF of 220 V/m intensity in relation to the initial values (from x = 3.18 to x = 4.41). The enzymatic activity of SOD-1 decreased after exposure (the most prominent change was observed after 60-min and 220 V/m intensity from x = 3556.41 to x = 1084.83). The most significant change in activity of catalase was observed after 60 min and 220 v/m exposure (from x = 6.28 to x = 4.15). Conclusions The findings indicate that exposure to electromagnetic radiation of 1 kHz frequency and 150 V/m and 220 V/m intensity may cause adverse effects within blood platelets’ oxygen metabolism and thus may lead to physiological dysfunction of the organism. PMID:26788099

The Cellular and Molecular Carcinogenic Effects of Radon Exposure: A Review

PubMed Central

Robertson, Aaron; Allen, James; Laney, Robin; Curnow, Alison

2013-01-01

Radon-222 is a naturally occurring radioactive gas that is responsible for approximately half of the human annual background radiation exposure globally. Chronic exposure to radon and its decay products is estimated to be the second leading cause of lung cancer behind smoking, and links to other forms of neoplasms have been postulated. Ionizing radiation emitted during the radioactive decay of radon and its progeny can induce a variety of cytogenetic effects that can be biologically damaging and result in an increased risk of carcinogenesis. Suggested effects produced as a result of alpha particle exposure from radon include mutations, chromosome aberrations, generation of reactive oxygen species, modification of the cell cycle, up or down regulation of cytokines and the increased production of proteins associated with cell-cycle regulation and carcinogenesis. A number of potential biomarkers of exposure, including translocations at codon 249 of TP53 in addition to HPRT mutations, have been suggested although, in conclusion, the evidence for such hotspots is insufficient. There is also substantial evidence of bystander effects, which may provide complications when calculating risk estimates as a result of exposure, particularly at low doses where cellular responses often appear to deviate from the linear, no-threshold hypothesis. At low doses, effects may also be dependent on cellular conditions as opposed to dose. The cellular and molecular carcinogenic effects of radon exposure have been observed to be both numerous and complex and the elevated chronic exposure of man may therefore pose a significant public health risk that may extend beyond the association with lung carcinogenesis. PMID:23880854

Daytime Effect of Monochromatic Blue Light on EEG Activity Depends on Duration and Timing of Exposure in Young Men

PubMed Central

Iskra-Golec, Irena; Golonka, Krystyna; Wyczesany, Miroslaw; Smith, Lawrence; Siemiginowska, Patrycja; Wątroba, Joanna

2017-01-01

Growing evidence suggests an alerting effect of monochromatic blue light on brain activity. Little is known about the moderation of those effects by timing and duration of exposure. The present electroencephalography (EEG ) study examined such moderations on delta, theta, alpha1, alpha2, and beta EEG bands. A counterbalanced repeated-measures design was applied. The 16-hr daytime period was divided into three sessions: 07:00-12:20, 12:20-17:40, and 17:40-23:00 (timing of exposure). Two light conditions comparable in luminance but differing in wavelength were applied, namely polychromatic white light and monochromatic blue light (460 nm). There were two durations of exposure—the shorter one lasting 30 min and the longer one lasting 4 hrs. Thirty male students participated in the study. Four factors analyses of variance (ANOV As, for light conditions, timing of exposure, duration of exposure, and brain area) were performed on each EEG band. Results indicated an alerting effect of short exposure to monochromatic blue light at midday and in the evening, which was demonstrated by a decrease in lower frequency bands (alpha1, delta, and theta, respectively). Long exposure to blue light may have a reverse effect, especially in the morning and at midday, when increases in lower frequency bands (theta in the morning and theta and alpha1 at midday) were observed. It can be concluded that the daytime effect of monochromatic blue light on EEG activity depends on timing and duration of exposure. PMID:29062437

Exposure to nitrogen dioxide and chronic obstructive pulmonary disease (COPD) in adults: a systematic review and meta-analysis.

PubMed

Zhang, Zili; Wang, Jian; Lu, Wenju

2018-05-01

Exposure to nitrogen dioxide (NO 2 ) has long been linked to elevated mortality and morbidity from epidemiological evidences. However, questions remain unclear whether NO 2 acts directly on human health or being an indicator of other ambient pollutants. In this study, random-effect meta-analyses were performed on examining exposure to nitrogen oxide (NO x ) and its association with chronic obstructive pulmonary disease (COPD). The overall relative risk (RR) of COPD risk related to a 10 μg/m 3 increase in NO 2 exposure increased by 2.0%. The pooled effect on prevalence was 17% with an increase of 10 μg/m 3 in NO 2 concentration, and 1.3% on hospital admissions, and 2.6% on mortality. The RR of COPD cases related to NO 2 long-term exposure was 2.5 and 1.4% in short-term exposure. The COPD effect related with a 10 μg/m 3 increase in exposure to a general outdoor-sourced NO 2 was 1.7 and 17.8% to exposure to an exclusively traffic-sourced NO 2 ; importantly, we did observe the effect of NO 2 on COPD mortality with a large majority in lag0. Long-term traffic exerted more severe impairments on COPD prevalence than long-term or short-term outdoor effect; long-term mortality effect on COPD was serious in single model from this meta-analysis. Overall, our study reported consistent evidence of the potential positive association between NO 2 and COPD risk.

Long term effects of radiation exposure on telomere lengths of leukocytes and its associated biomarkers among atomic-bomb survivors

PubMed Central

Lustig, Ana; Shterev, Ivo; Geyer, Susan; Shi, Alvin; Hu, Yiqun; Morishita, Yukari; Nagamura, Hiroko; Sasaki, Keiko; Maki, Mayumi; Hayashi, Ikue; Furukawa, Kyoji; Yoshida, Kengo; Kajimura, Junko; Kyoizumi, Seishi; Kusunoki, Yoichiro; Ohishi, Waka; Nakachi, Kei; Weng, Nan-ping; Hayashi, Tomonori

2016-01-01

Ionizing radiation (IR) is a major source of cellular damage and the immediate cellular response to IR has been well characterized. But the long-term impact of IR on cell function and its relationship with aging are not known. Here, we examined the IR effects on telomere length and other biomarkers 50 to 68 years post-exposure (two time points per person) in survivors of the atomic bombing at Hiroshima during WWII. We found that telomere length of leukocytes was inversely correlated with the dose of IR (p=0.008), and this effect was primarily found in survivors who were exposed at younger ages; specifically those <12 years old (p=0.0004). Although a dose-related retardation of telomere shortening with age was observed in the cross-sectional data, longitudinal follow-up after 11 years did not show IR exposure-related alteration of the rate of telomere shortening with age. In addition, IR diminished the associations between telomere length and selected aging biomarkers that were observed in survivors with no dose. These included uric acid metabolism, cytokines, and blood T cell counts. These findings showed long-lasting detrimental effects of IR on telomere length of leukocytes in both dose- and age-at-exposure dependent manner, and on alterations of biomarkers with aging. PMID:27102155

Associations of Mortality with Long-Term Exposures to Fine and Ultrafine Particles, Species and Sources: Results from the California Teachers Study Cohort

PubMed Central

Hu, Jianlin; Goldberg, Debbie; Reynolds, Peggy; Hertz, Andrew; Bernstein, Leslie; Kleeman, Michael J.

2015-01-01

Background Although several cohort studies report associations between chronic exposure to fine particles (PM2.5) and mortality, few have studied the effects of chronic exposure to ultrafine (UF) particles. In addition, few studies have estimated the effects of the constituents of either PM2.5 or UF particles. Methods We used a statewide cohort of > 100,000 women from the California Teachers Study who were followed from 2001 through 2007. Exposure data at the residential level were provided by a chemical transport model that computed pollutant concentrations from > 900 sources in California. Besides particle mass, monthly concentrations of 11 species and 8 sources or primary particles were generated at 4-km grids. We used a Cox proportional hazards model to estimate the association between the pollutants and all-cause, cardiovascular, ischemic heart disease (IHD), and respiratory mortality. Results We observed statistically significant (p < 0.05) associations of IHD with PM2.5 mass, nitrate, elemental carbon (EC), copper (Cu), and secondary organics and the sources gas- and diesel-fueled vehicles, meat cooking, and high-sulfur fuel combustion. The hazard ratio estimate of 1.19 (95% CI: 1.08, 1.31) for IHD in association with a 10-μg/m3 increase in PM2.5 is consistent with findings from the American Cancer Society cohort. We also observed significant positive associations between IHD and several UF components including EC, Cu, metals, and mobile sources. Conclusions Using an emissions-based model with a 4-km spatial scale, we observed significant positive associations between IHD mortality and both fine and ultrafine particle species and sources. Our results suggest that the exposure model effectively measured local exposures and facilitated the examination of the relative toxicity of particle species. Citation Ostro B, Hu J, Goldberg D, Reynolds P, Hertz A, Bernstein L, Kleeman MJ. 2015. Associations of mortality with long-term exposures to fine and ultrafine particles, species and sources: results from the California Teachers Study cohort. Environ Health Perspect 123:549–556; http://dx.doi.org/10.1289/ehp.1408565 PMID:25633926

Troubled or Traumatized Youth? The Relations Between Psychopathy, Violence Exposure, Posttraumatic Stress Disorder, and Antisocial Behavior Among Juvenile Offenders.

PubMed

Tsang, Siny

2018-01-01

The current study examined how psychopathy, exposure to violence, and posttraumatic stress disorder (PTSD) are associated with antisocial behavior among 1,354 serious delinquent adolescents from the Pathways to Desistance study. Results showed that psychopathy, violence exposure, and PTSD are independently linked to self-reported involvement of delinquency, even after controlling for respondents' demographic characteristics. However, the effect of PTSD on antisocial behavior was small. Differential associations were observed between the 2 factors of psychopathy, interpersonal/affective and social deviance, and PTSD symptoms. Specifically, the effect of social deviance characteristics on delinquency was above and beyond that of interpersonal/affective features. In addition, exposure to violence as a victim or witness were uniquely associated with increased delinquent behavior. Findings clarified the relations among psychopathy, violence exposure, PTSD, and antisocial behavior, and highlighted the differential links between psychopathy factors and delinquency.

Changes in CR-39 proton sensitivity due to prolonged exposure to high vacuums relevant to the National Ignition Facility and OMEGA.

PubMed

Manuel, M J-E; Rosenberg, M J; Sinenian, N; Rinderknecht, H; Zylstra, A B; Séguin, F H; Frenje, J; Li, C K; Petrasso, R D

2011-09-01

When used at facilities like OMEGA and the NIF, CR-39 is exposed to high vacuum environments before and after irradiation by charged particles and neutrons. Using an electrostatic linear accelerator at MIT, studies have been conducted to investigate the effects of high vacuum exposure on the sensitivity of CR-39 to fusion protons in the ~1-9 MeV energy range. High vacuum conditions, of order 10(-5) Torr, experienced by CR-39 samples at these facilities were emulated. It is shown that vacuum exposure times longer than ~16 h before proton irradiation result in a decrease in proton sensitivity, whereas no effect was observed for up to 67 h of vacuum exposure after proton irradiation. CR-39 sensitivity curves are presented for samples with prolonged exposure to high vacuum before and after proton irradiation. © 2011 American Institute of Physics

Changes in background impair fluency-triggered positive affect: a cross-cultural test using a mere-exposure paradigm.

PubMed

Ishii, Keiko

2011-04-01

This study examined whether repeated exposure would enhance positive evaluations when only a part of a stimulus (e.g., the central object) was identical to a previously presented stimulus. Japanese and American participants were exposed to photographs of animals with scenery, then asked their preferences for each of four types of photographs of animals (photographs of animals with the original scenery, photographs of animals without scenery, photographs of animals with novel scenery, and photographs of animals not depicted previously). Finally, their recognition of the animals presented in the exposure phase was tested. Members of both groups showed the mere-exposure effect for the first two types of stimuli, irrespective of stimulus recognition accuracy, whereas this effect was not observed for animals presented with novel scenery. This suggests that changes in background impair positive affect as a result of repeated exposure.

Agricultural pesticide use and adverse birth outcomes in the San Joaquin Valley of California.

PubMed

Larsen, Ashley E; Gaines, Steven D; Deschênes, Olivier

2017-08-29

Virtually all agricultural communities worldwide are exposed to agricultural pesticides. Yet, the health consequences of such exposure are poorly understood, and the scientific literature remains ambiguous. Using individual birth and demographic characteristics for over 500 000 birth observations between 1997-2011 in the agriculturally dominated San Joaquin Valley, California, we statistically investigate if residential agricultural pesticide exposure during gestation, by trimester, and by toxicity influences birth weight, gestational length, or birth abnormalities. Overall, our analysis indicates that agricultural pesticide exposure increases adverse birth outcomes by 5-9%, but only among the population exposed to very high quantities of pesticides (e.g., top 5th percentile, i.e., ~4200 kg applied over gestation). Thus, policies and interventions targeting the extreme right tail of the pesticide distribution near human habitation could largely eliminate the adverse birth outcomes associated with agricultural pesticide exposure documented in this study.The health consequences of exposure to pesticides are uncertain and subject to much debate. Here, the effect of exposure during pregnancy is investigated in an agriculturally dominated residential area, showing that an increase in adverse birth outcomes is observed with very high levels of pesticide exposure.

[Reliability and validity of a generic job exposure matrix applied on a small-business].

PubMed

Haro-García, Luis; Celis-Quintal, Germán; López-Rojas, Pablo; Sánchez-Román, Francisco Raúl; Juárez-Pérez, Cuauhtémoc Arturo

2007-01-01

to evaluate the reliability and validity of a generic job exposure matrix (JEM) applied in a small business. procedures to evaluate a JEM integrated by six sections: the number of exposed workers per area, frequency of exposure, time of exposure time, level of exposure, safety controls, and proximity to source of exposure, was evaluated. The JEM also obtains information about possible health effects from exposure to occupational/environment agents. Two observers estimated the risk of exposure to epoxy resins on 31 workers of an epoxy resin facility in Mexico City. The rater agreements between the two observers were assessed through percent agreement (PA), weighted kappa (kappa(w)) and the intraclass correlation coefficient (ICC). disagreements were greater for the number of exposed workers (PA = 61.3, kappa(w) = 0.24, ICC = 0.33), level of exposure (PA= 66.7, kappa(w) = 0.25, ICC= 0.56), and safety controls (PA = 54.8, kappa(w) = 0.23, ICC = 0.69) sections. Percent agreement and kappa(w) were 64% and 0.58, respectively. In accordance with Landis and Koch, Altman, Fleiss, and Byrt classifications for the interpretation of kappa value, the weighted kappa (0.58) ranged from moderate to a fair good level. despite the discordance in some sections, the JEM proved to be useful to identify the risk of exposure in this type of small business.

The Effect of Early Mosquito Insecticides Exposure on Spraque Dawley Rat Testis: A Histopathological Feature Towards Malignancy?

NASA Astrophysics Data System (ADS)

Indah Winarni, Tri; Auzan Aziman, Milzam; Abshar Andar, Anindyo; Pawitra, Ika

2017-02-01

The incidence of health problems associated with endocrine-disruption have increased. Many studies suggesting that endocrine disruptor chemicals (EDC) do contribute to cancer through estrogen-related receptors. Many chemicals have EDCs properties including insecticides. Early life exposure to EDCs can increased the risk of testicular cancer have been reported in the last decade. This study was aimed to determine the effect of insecticides exposure on histopathological tumor cell development of germ and Leydig cell. True experiment research design with posttest only control group design was applied. Sprague Dawley (SD) rat (n = 25) were randomly divided into 5 groups (control group, 25 mg β estradiol 3-benzoate, spiral mosquito coil repellent, 3 ml of liquid mosquito repellent, and 4 ml of liquid mosquito repellent). The exposure were administered for 20 days started at aged 3 days. At the age of 100 days (older adult), testis was stained using Hematoxyllin Eosin (HE) and histological features predicting malignancy were observed. The number of tumor cell development in both testicular germ cells and Leydig cells significantly increased in all treated group compared to those of control and the changes towards malignancy were also observed in all treated group. Exposure to mosquito insecticides causes significant changes in testicular germ and Leydig cell histological features that leads to malignancy.

Hypoxia Treatment of Callosobruchus maculatus Females and Its Effects on Reproductive Output and Development of Progeny Following Exposure.

PubMed

Yan, Yan; Williams, Scott B; Baributsa, Dieudonne; Murdock, Larry L

2016-06-17

Modified atmospheres present a residue-free alternative to fumigants for controlling postharvest pests of grain during storage. How sub-lethal applications of this method affects the reproductive fitness of target pests, however, is still not fully understood. We examined how low levels of ambient oxygen influence the reproduction of the female cowpea bruchid (Callosobruchus maculatus), a pest of cowpea. We used three low-oxygen atmospheres-2%, 5% and 10% (v/v) oxygen-and observed their effects on: (1) the number of eggs laid by bruchids compared to insects held in normoxic (~20% oxygen) conditions; (2) the total number of eggs laid; and (3) the number of progeny that reached maturity. Low oxygen did not significantly affect the number of eggs laid during 48 or 72 h of exposure, but 2% and 5% oxygen did negatively affected total egg production. Increasing the exposure time from 48 to 72 h further depressed lifetime reproductive output. Maternal and egg exposure to hypoxia reduced the number of progeny that reached adulthood. Lower adult emergence was observed from eggs laid under low oxygen and longer exposure times. These data demonstrate that hermetic conditions depress the egg-laying behavior of cowpea bruchids and the successful development of their progeny.

Hypoxia Treatment of Callosobruchus maculatus Females and Its Effects on Reproductive Output and Development of Progeny Following Exposure

PubMed Central

Yan, Yan; Williams, Scott B.; Baributsa, Dieudonne; Murdock, Larry L.

2016-01-01

Modified atmospheres present a residue-free alternative to fumigants for controlling postharvest pests of grain during storage. How sub-lethal applications of this method affects the reproductive fitness of target pests, however, is still not fully understood. We examined how low levels of ambient oxygen influence the reproduction of the female cowpea bruchid (Callosobruchus maculatus), a pest of cowpea. We used three low-oxygen atmospheres—2%, 5% and 10% (v/v) oxygen—and observed their effects on: (1) the number of eggs laid by bruchids compared to insects held in normoxic (~20% oxygen) conditions; (2) the total number of eggs laid; and (3) the number of progeny that reached maturity. Low oxygen did not significantly affect the number of eggs laid during 48 or 72 h of exposure, but 2% and 5% oxygen did negatively affected total egg production. Increasing the exposure time from 48 to 72 h further depressed lifetime reproductive output. Maternal and egg exposure to hypoxia reduced the number of progeny that reached adulthood. Lower adult emergence was observed from eggs laid under low oxygen and longer exposure times. These data demonstrate that hermetic conditions depress the egg-laying behavior of cowpea bruchids and the successful development of their progeny. PMID:27322332

A model for the effects of germanium on silica biomineralization in choanoflagellates

PubMed Central

Chappell, Helen; Ratcliffe, Sarah; Goldstein, Raymond E.

2016-01-01

Silica biomineralization is a widespread phenomenon of major biotechnological interest. Modifying biosilica with substances like germanium (Ge) can confer useful new properties, although exposure to high levels of Ge disrupts normal biosilicification. No clear mechanism explains why this disruption occurs. Here, we study the effect of Ge on loricate choanoflagellates, a group of protists that construct a species-specific extracellular lorica from multiple siliceous costal strips. High Ge exposures were toxic, whereas lower Ge exposures produced cells with incomplete or absent loricae. These effects can be ameliorated by restoring the germanium : silicon ratio, as observed in other biosilicifying organisms. We developed simulations of how Ge interacts with polymerizing silica. In our models, Ge is readily incorporated at the ends of silica forming from silicic acid condensation, but this prevents further silica polymerization. Our ‘Ge-capping’ model is supported by observations from loricate choanoflagellates. Ge exposure terminates costal strip synthesis and lorica formation, resulting in disruption to cytokinesis and fatal build-up of silicic acid. Applying the Ge-capping model to other siliceous organisms explains the general toxicity of Ge and identifies potential protective responses in metalloid uptake and sensing. This can improve the design of new silica biomaterials, and further our understanding of silicon metabolism. PMID:27655668

Inhalation Toxicity of Bisphenol A and Its Effect on Estrous Cycle, Spatial Learning, and Memory in Rats upon Whole-Body Exposure

PubMed Central

Chung, Yong Hyun; Han, Jeong Hee; Lee, Sung-Bae; Lee, Yong-Hoon

2017-01-01

Bisphenol A (BPA) is a monomer used in a polymerization reaction in the production of polycarbonate plastics. It has been used in many consumer products, including plastics, polyvinyl chloride, food packaging, dental sealants, and thermal receipts. However, there is little information available on the inhalation toxicity of BPA. Therefore, the aim of this study was to determine its inhalation toxicity and effects on the estrous cycle, spatial learning, and memory. Sprague-Dawley rats were exposed to 0, 10, 30, and 90 mg/m3 BPA, 6 hr/day, 5 days/week for 8 weeks via whole-body inhalation. Mortality, clinical signs, body weight, hematology, serum chemistry, estrous cycle parameters, performance in the Morris water maze test, and organ weights, as well as gross and histopathological findings, were compared between the control and BPA exposure groups. Statistically significant changes were observed in serum chemistry and organ weights upon exposure to BPA. However, there was no BPA-related toxic effect on the body weight, food consumption, hematology, serum chemistry, organ weights, estrous cycle, performance in the Morris water maze test, or gross or histopathological lesions in any male or female rats in the BPA exposure groups. In conclusion, the results of this study suggested that the no observable adverse effect level (NOAEL) for BPA in rats is above 90 mg/m3/6 hr/day, 5 days/week upon 8-week exposure. Furthermore, BPA did not affect the estrous cycle, spatial learning, or memory in rats. PMID:28503266

Space environmental effects on the integrity of chromic acid anodized coatings

NASA Technical Reports Server (NTRS)

Plagemann, W. L.

1993-01-01

This report describes the condition of chromic acid anodized aluminum subsequent to a 69-month exposure to low Earth orbit (LEO) on the Long Duration Exposure Facility. Optical properties and the condition of anodized coating are reported. This material was exposed to each environmental parameter present in LEO. Only slight changes in the material were observed.

The effect of 1800MHz radio-frequency radiation on NMDA receptor subunit NR1 expression and peroxidation in the rat brain in healthy and inflammatory states.

PubMed

Bodera, Paweł; Makarova, Katerina; Zawada, Katarzyna; Antkowiak, Bożena; Paluch, Małgorzata; Sobiczewska, Elżbieta; Sirav, Bahriye; Siwicki, Andrzej K; Stankiewicz, Wanda

2017-08-01

The aim of this study was to evaluate the effect of repeated exposure (5 times for 15min) of 1800MHz radio-frequency radiation (RFR) on N-methyl-d-aspartate receptor subunit NR1 (NMDA-NR1) expression in the brains of rats in a persistent inflammatory state. We also measured the effect of RFR combined with tramadol (TRAM) to determine the potential antioxidant capacity of this agent. The effects of the Global System for Mobile Communication (GSM) modulated 1800MHz RFR exposure on the expression and activity of glutamate receptor channels with antioxidative activity in brain tissue was measured using oxygen radical absorbance capacity (ORAC) and electron spin resonance (ESR) detection of the hydroxyl radical generated by the Fenton reaction. NMDA-NR1 was measured in the cerebral tissue of rats with inflammation (complete Freund's adjuvent) and those injected with tramadol after RFR exposure (RFR, RFR/TRAM) and in non-exposed (baseline, TRAM) rats. No differences between the baseline group and the exposed group (RFR) were observed. NMDA-NR1 expression decreased after CFA injection and RFR exposure, and an elevated expression of NMDA-NR1 was observed in healthy control rats of both groups: TRAM/RFR and RFR. ORAC assessment revealed a robust effect of RFR, however the other experiments revealed equivocal effects. Further studies examining the combination of ORAC with NMDA are warranted to elucidate more clearly the effect of RFR on the brain. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

The utility of naphthyl-keratin adducts as biomarkers for jet-fuel exposure

PubMed Central

Kang-Sickel, Juei-Chuan C.; Butler, Mary Ann; Frame, Lynn; Serdar, Berrin; Chao, Yi-Chun E.; Egeghy, Peter; Rappaport, Stephen M.; Toennis, Christine A.; Li, Wang; Borisova, Tatyana; French, John E.; Nylander-French, Leena A.

2014-01-01

We investigated the association between biomarkers of dermal exposure, naphthyl-keratin adducts (NKA), and urine naphthalene biomarker levels in 105 workers routinely exposed to jet-fuel. A moderate correlation was observed between NKA and urine naphthalene levels (p = 0.061). The NKA, post-exposure breath naphthalene, and male gender were associated with an increase, while CYP2E1*6 DD and GSTT1-plus (++/+−) genotypes were associated with a decrease in urine naphthalene level (p < 0.0001). The NKA show great promise as biomarkers for dermal exposure to naphthalene. Further studies are warranted to characterize the relationship between NKA, other exposure biomarkers, and/or biomarkers of biological effects due to naphthalene and/or PAH exposure. PMID:21961652

The utility of naphthyl-keratin adducts as biomarkers for jet-fuel exposure.

PubMed

Kang-Sickel, Juei-Chuan C; Butler, Mary Ann; Frame, Lynn; Serdar, Berrin; Chao, Yi-Chun E; Egeghy, Peter; Rappaport, Stephen M; Toennis, Christine A; Li, Wang; Borisova, Tatyana; French, John E; Nylander-French, Leena A

2011-11-01

We investigated the association between biomarkers of dermal exposure, naphthyl-keratin adducts (NKA), and urine naphthalene biomarker levels in 105 workers routinely exposed to jet-fuel. A moderate correlation was observed between NKA and urine naphthalene levels (p = 0.061). The NKA, post-exposure breath naphthalene, and male gender were associated with an increase, while CYP2E1*6 DD and GSTT1-plus (++/+-) genotypes were associated with a decrease in urine naphthalene level (p < 0.0001). The NKA show great promise as biomarkers for dermal exposure to naphthalene. Further studies are warranted to characterize the relationship between NKA, other exposure biomarkers, and/or biomarkers of biological effects due to naphthalene and/or PAH exposure.

Inhaled ozone as a mutagen. II - Effect on the frequency of chromosome aberrations observed in irradiated Chinese hamsters.

NASA Technical Reports Server (NTRS)

Zelac, R. E.; Cromroy, H. L.; Bolch, W. E., Jr.; Dunavant, B. G.; Bevis, H. A.

1971-01-01

Exposure-adjusted break frequencies for chromosome aberrations produced in Chinese hamster circulating blood lymphocytes were the quantitative indicator of damage from 5 hrs of exposure to X-radiation and/or to ozone. Radiation produced 5.51 x 0.0001 breaks/cell rad for cells withdrawn 2 weeks after exposure, a reasonable value when compared with data from in vivo exposure of human lymphocytes and Chinese hamster bone marrow cells. Animals exposed to the two agents simultaneously exhibited more than 70% of the total breaks anticipated assuming the expected equal contributions to be additive. Extending to humans, at presently permitted levels, exposure to ozone would be much more detrimental than exposure to radiati*n.

[Combined effect of cisplatin and caffeine on murine B16-BL6 melanoma cells].

PubMed

Yasutake, H; Tsuchiya, H; Sugihara, M; Tomita, K; Ueda, Y; Tanaka, M; Sasaki, T

1989-05-01

Combined effect of cisplatin and caffeine on murine B16-BL6 melanoma cells was studied. Synergistic inhibition of the cell growth was observed when caffeine (2 mM) was added continuously after one hour exposure of cisplatin. On the other hand, when caffeine was added before one hour exposure of cisplatin or one hour simultaneous exposure with cisplatin, synergistic effect was not shown. In the analysis of DNA histogram obtained from flow cytometry, S and G2/M accumulation was observed by the treatment of cisplatin and that accumulation was reduced by the combination of cisplatin and caffeine. From this findings, it was suggested that caffeine would inhibit DNA repair process. Furthermore, according to morphological studies with hematoxylin-eosin stain and Fontana-Masson stain, the addition of caffeine alone resulted in mild swelling of melanoma cells and the decrease of nuclear-cytoplasmic ratio. The combination of cisplatin and caffeine caused marked swelling of melanoma cells and remarkable increase of dendrite-like processes. Melanogenesis was also enhanced by the addition of these two drugs. Many matured melanosomes, increases of mitochondria, Golgi's apparatus and endoplasmic reticula were observed by the use of electron microscope. These findings implied that the combination of cisplatin and caffeine induced a differentiation of murine melanoma cells.

Effects of inhalation exposure to SRC-II heavy and middle distillates

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

Springer, D.L.; Miller, R.A.; Weimer, W.C.

1984-11-01

To expand the data base on potential health effects of coal liquefaction materials, we have performed studies with both solvent refined coal (SRC)-II heavy distillate (HD) and middle distillate (MD). Weight gain for exposed animals was less than that of controls and was dose-related, ranging from no significant difference for animals in the low-exposure group to failure to gain in the high-dose animals. Liver weights increased significantly over controls, and thymus weights decreased for animals sacrificed at 5 and 13 weeks. After both exposure periods, there were significant treatment-related decreases in erythrocyte parameters and in certain types of white bloodmore » cells (WBC). Bone marrow cellularity, and numbers of megakaryocytes consistently decreased, suggesting that bone marrow is a target tissue for high-boiling coal liquids. Microscopic evaluation of tissue indicated exposure-related changes is listed. In contrast to the reported mutagenic and carcinogenic effects observed for the high-boiling coal liquids, middle-boiling-range materials lacked such activity in these assays. These data demonstrate a great deal of similarity in the kinds of effects observed following exposure to middle- and high-boiling-range coal liquids. However, the significance of changes in organ weights and peripheral blood parameters are not always readily apparent following a subchronic study. Because of this, we exposed animals to HD in a manner similar to that for the subchronic experiment and have followed these animals throughout their lives for the development of adverse effects such as reduced longevity and the appearance of tumors. Results from this study will be available for mice in FY 1985 and for rats in FY 1986.« less

Mortality, Temporary Sterilization, and Maternal Effects of Sublethal Heat in Bed Bugs

PubMed Central

Rukke, Bjørn Arne; Aak, Anders; Edgar, Kristin Skarsfjord

2015-01-01

Adult bed bugs were exposed to the sublethal temperatures 34.0°C, 35.5°C, 37.0°C, 38.5°C, or 40.0°C for 3, 6, or 9 days. The two uppermost temperatures induced 100% mortality within 9 and 2 days, respectively, whereas 34.0°C had no observable effect. The intermediate temperatures interacted with time to induce a limited level of mortality but had distinct effects on fecundity, reflected by decreases in the number of eggs produced and hatching success. Adult fecundity remained low for up to 40 days after heat exposure, and the time until fertility was restored correlated with the temperature-sum experienced during heat exposure. Three or 6 days of parental exposure to 38.5°C significantly lowered their offspring’s feeding and moulting ability, which consequently led to a failure to continue beyond the third instar. Eggs that were deposited at 22.0°C before being exposed to 37.0°C for 3 or 6 days died, whereas eggs that were exposed to lower temperatures were not significantly affected. Eggs that were deposited during heat treatment exhibited high levels of mortality also at 34.0°C and 35.5°C. The observed negative effects of temperatures between 34.0°C and 40.0°C may be utilized in pest management, and sublethal temperature exposure ought to be further investigated as an additional tool to decimate or potentially eradicate bed bug populations. The effect of parental heat exposure on progeny demonstrates the importance of including maternal considerations when studying bed bug environmental stress reactions. PMID:25996999

Aluminium sulfate exposure: A set of effects on hydrolases from brain, muscle and digestive tract of juvenile Nile tilapia (Oreochromis niloticus).

PubMed

Oliveira, Vagne Melo; Assis, Caio Rodrigo Dias; Costa, Helane Maria Silva; Silva, Raquel Pereira Freitas; Santos, Juliana Ferreira; Carvalho, Luiz Bezerra; Bezerra, Ranilson Souza

2017-01-01

Aluminium is a major pollutant due to its constant disposal in aquatic environments through anthropogenic activities. The physiological effects of this metal in fish are still scarce in the literature. This study investigated the in vivo and in vitro effects of aluminium sulfate on the activity of enzymes from Nile tilapia (Oreochromis niloticus): brain acetylcholinesterase (AChE), muscle cholinesterases (AChE-like and BChE-like activities), pepsin, trypsin, chymotrypsin and amylase. Fish were in vivo exposed during 14days when the following experimental groups were assayed: control group (CG), exposure to Al 2 (SO 4 ) 3 at 1μg·mL -1 (G1) and 3μg·mL -1 (G3) (concentrations compatible with the use of aluminium sulfate as coagulant in water treatment). In vitro exposure was performed using animals of CG treatment. Both in vivo and in vitro exposure increased cholinesterase activity in relation to controls. The highest cholinesterase activity was observed for muscle BChE-like enzyme in G3. In contrast, the digestive enzymes showed decreased activity in both in vivo and in vitro exposures. The highest inhibitory effect was observed for pepsin activity. The inhibition of serine proteases was also quantitatively analyzed in zymograms using pixel optical densitometry as area under the peaks (AUP) and integrated density (ID). These results suggest that the inhibition of digestive enzymes in combination with activation of cholinesterases in O. niloticus is a set of biochemical effects that evidence the presence of aluminium in the aquatic environment. Moreover, these enzymatic alterations may support further studies on physiological changes in this species with implications for its neurological and digestive metabolisms. Copyright © 2016 Elsevier Inc. All rights reserved.

Modeling indoor particulate exposures in inner city school classrooms

PubMed Central

Gaffin, Jonathan M.; Petty, Carter R.; Hauptman, Marissa; Kang, Choong-Min; Wolfson, Jack M.; Awad, Yara Abu; Di, Qian; Lai, Peggy S.; Sheehan, William J.; Baxi, Sachin; Coull, Brent A.; Schwartz, Joel D.; Gold, Diane R.; Koutrakis, Petros; Phipatanakul, Wanda

2016-01-01

Outdoor air pollution penetrates buildings and contributes to total indoor exposures. We investigated the relationship of indoor to outdoor particulate matter in inner-city school classrooms. The School Inner City Asthma Study investigates the effect of classroom-based environmental exposures on students with asthma in the northeast United States. Mixed-effects linear models were used to determine the relationships between indoor PM2.5 and BC and their corresponding outdoor concentrations, and to develop a model for predicting exposures to these pollutants. The indoor-outdoor sulfur ratio was used as an infiltration factor of outdoor fine particles. Weeklong concentrations of PM2.5 and BC in 199 samples from 136 classrooms (30 school buildings) were compared to those measured at a central monitoring site averaged over the same timeframe. Mixed effects regression models found significant random intercept and slope effects, which indicate that: 1) there are important PM2.5 sources in classrooms; 2) the penetration of outdoor PM2.5 particles varies by school, and 3) the site-specific outside PM2.5 levels (inferred by the models) differ from those observed at the central monitor site. Similar results were found for BC except for lack of indoor sources. The fitted predictions from the sulfur-adjusted models were moderately predictive of observed indoor pollutant levels (Out of sample correlations: PM2.5: r2 = 0.68, BC; r2 = 0.61). Our results suggest that PM2.5 has important classroom sources, which vary by school. Furthermore, using these mixed effects models, classroom exposures can be accurately predicted for dates when central site measures are available but indoor measures are not available. PMID:27599884

Analysis of proteome response to the mobile phone radiation in two types of human primary endothelial cells.

PubMed

Nylund, Reetta; Kuster, Niels; Leszczynski, Dariusz

2010-10-18

Use of mobile phones has widely increased over the past decade. However, in spite of the extensive research, the question of potential health effects of the mobile phone radiation remains unanswered. We have earlier proposed, and applied, proteomics as a tool to study biological effects of the mobile phone radiation, using as a model human endothelial cell line EA.hy926. Exposure of EA.hy926 cells to 900 MHz GSM radiation has caused statistically significant changes in expression of numerous proteins. However, exposure of EA.hy926 cells to 1800 MHz GSM signal had only very small effect on cell proteome, as compared with 900 MHz GSM exposure. In the present study, using as model human primary endothelial cells, we have examined whether exposure to 1800 MHz GSM mobile phone radiation can affect cell proteome. Primary human umbilical vein endothelial cells and primary human brain microvascular endothelial cells were exposed for 1 hour to 1800 MHz GSM mobile phone radiation at an average specific absorption rate of 2.0 W/kg. The cells were harvested immediately after the exposure and the protein expression patterns of the sham-exposed and radiation-exposed cells were examined using two dimensional difference gel electrophoresis-based proteomics (2DE-DIGE). There were observed numerous differences between the proteomes of human umbilical vein endothelial cells and human brain microvascular endothelial cells (both sham-exposed). These differences are most likely representing physiological differences between endothelia in different vascular beds. However, the exposure of both types of primary endothelial cells to mobile phone radiation did not cause any statistically significant changes in protein expression. Exposure of primary human endothelial cells to the mobile phone radiation, 1800 MHz GSM signal for 1 hour at an average specific absorption rate of 2.0 W/kg, does not affect protein expression, when the proteomes were examined immediately after the end of the exposure and when the false discovery rate correction was applied to analysis. This observation agrees with our earlier study showing that the 1800 MHz GSM radiation exposure had only very limited effect on the proteome of human endothelial cell line EA.hy926, as compared with the effect of 900 MHz GSM radiation.

Pulmonary tolerance in man to continuous oxygen exposure at 3.0, 2.5, 2.0, and 1.5 ATA in Predictive Studies V

NASA Technical Reports Server (NTRS)

Clark, J. M.; Gelfand, R.; Flores, N. D.; Lambertsen, C. J.; Pisarello, J. B.

1987-01-01

Oxygen effects on pulmonary function were measured in normal, resting men who breathed oxygen continuously at 3.0, 2.5, 2.0, and 1.5 ATA to predefined limits of CNS, cardiac, or pulmonary tolerance. Rates of pulmonary symptom intensification and decrease in vital capacity (VC) increased progressively with elevation of inspired oxygen pressure. Although VC decrements occurred concurrently with symptoms, the lung volume changes became prominent when symptoms were still mild. The observed effects were consistent with the interpretation that small airway function is impaired more selectively by oxygen exposure at 3.0 and 2.5 ATA than by exposure at 2.0 and 1.5 ATA. Despite similar VC changes after oxygen exposure at 2.0 ATA for nearly 10 hr and exposure at 1.5 ATA for almost 18 hr, the 2.0 ATA exposure caused greater impairment of pulmonary function and required a longer recovery period.

Effect of continuous gamma-ray exposure on performance of learned tasks and effect of subsequent fractionated exposures on blood-forming tissue

NASA Technical Reports Server (NTRS)

Spalding, J. F.; Holland, L. M.; Prine, J. R.; Farrer, D. N.; Braun, R. G.

1972-01-01

Sixteen monkeys trained to perform continuous and discrete-avoidance and fixed-ratio tasks with visual and auditory cues were performance-tested before, during, and after 10-day gamma-ray exposures totaling 0, 500, 750, and 1000 rads. Approximately 14 months after the performance-test exposures, surviving animals were exposed to 100-rad gamma-ray fractions at 56-day intervals to observe injury and recovery patterns of blood-forming tissues. The fixed-ratio, food-reward task performance showed a transient decline in all dose groups within 24 hours of the start of gamma-ray exposure, followed by recovery to normal food-consumption levels within 48 to 72 hours. Avoidance tasks were performed successfully by all groups during the 10-day exposure, but reaction times of the two higher dose-rate groups in which animals received 3 and 4 rads per hour or total doses of 750 and 1000 rads, respectively, were somewhat slower.

Adaptive Changes In Postural Equilibrium And Motion Sickness Following Repeated Exposures To Virtual Environments

NASA Technical Reports Server (NTRS)

Harm, D. L.; Taylor, L. C.

2006-01-01

Virtual environments offer unique training opportunities, particularly for training astronauts and preadapting them to the novel sensory conditions of microgravity. Two unresolved human factors issues in virtual reality (VR) systems are: 1) potential "cybersickness", and 2) maladaptive sensorimotor performance following exposure to VR systems. Interestingly, these aftereffects are often quite similar to adaptive sensorimotor responses observed in astronauts during and/or following space flight. Changes in the environmental sensory stimulus conditions and the way we interact with the new stimuli may result in motion sickness, and perceptual, spatial orientation and sensorimotor disturbances. Initial interpretation of novel sensory information may be inappropriate and result in perceptual errors. Active exploratory behavior in a new environment, with resulting feedback and the formation of new associations between sensory inputs and response outputs, promotes appropriate perception and motor control in the new environment. Thus, people adapt to consistent, sustained alterations of sensory input such as those produced by microgravity, unilateral labyrinthectomy and experimentally produced stimulus rearrangements. Adaptation is revealed by aftereffects including perceptual disturbances and sensorimotor control disturbances. The purpose of the current study was to compare disturbances in postural control produced by dome and head-mounted virtual environment displays, and to examine the effects of exposure duration, and repeated exposures to VR systems. Forty-one subjects (21 men, 20 women) participated in the study with an age range of 21-49 years old. One training session was completed in order to achieve stable performance on the posture and VR tasks before participating in the experimental sessions. Three experimental sessions were performed each separated by one day. The subjects performed a navigation and pick and place task in either a dome or head-mounted display (HMD) VR system for either 30 or 60 min. The environment was a square room with 15 pedestals on two opposite walls. The objects appeared on one set of pedestals and the subject s objective was to move the objects to the other set of pedestals. After the subject picked up an object, a pathway appeared and they were required to follow the pathway to the other side of the room. The subject was instructed to perform the task as quickly and accurately as possible, avoiding hitting walls and other any obstacles and placing the object on the center of the pedestal. Postural equilibrium was measured (using the Equitest CDP balance system, Neurocom, International) before, immediately after, and at 1 hr, 2 hr, 4 hr and 6 hr following exposure to VR. Postural equilibrium was measured during quiet stance with eyes open, eyes closed and vision and/or ankle proprioceptive inputs selectively altered by servo-controlling the visual surround and/or support surface to the subject s center of mass sway. Posture data was normalized using a log transformation and motion sickness data were normalized using the square root. In general, we found that exposure to VR resulted in decrements in postural stability. The largest decrements were observed in the tests performed immediately following exposure to VR and showed a fairly rapid recovery across the remaining test sessions. In addition, subjects generally showed improvement across days. We found significant main effects for day and time for the composite equilibrium score and for sensory organization tests (SOT) 1, 2 and 6. Significant main effects were observed for day for SOT 3 and 5. Although we found no significant main effects for gender (when center of gravity was used as a covariate), we did observe significant gender X time interaction effects for composite equilibrium and for SOT 1, 3, 4 and 5. Women appeared to show larger decrements in postural stability immediately after exposure to VR than men, but recover more quickly than n. Finally, we found no significant main effects for type of VR device or for exposure duration, however, these factors did interact with other factors during some of the SOTs. Subjects exhibited rapid recovery of motion sickness symptoms across time following exposure to VR and significantly less severe symptoms across days. We did not observe main effects for gender, type of device or duration of exposure. Individuals recovered from the detrimental effects of exposure to virtual reality on postural control and motion sickness within one hour. Sickness severity and initial decrements in postural equilibrium decreases over days, which suggests that subjects become dual-adapted over time. These findings provide some direction for developing training schedules for VR users that facilitate adaptation, and support the idea that preflight training of astronauts may serve as useful countermeasure for the sensorimotor effects of space flight.

Assessing Health Outcomes After Environmental Exposures Associated With Open Pit Burning in Deployed US Service Members.

PubMed

Rohrbeck, Patricia; Hu, Zheng; Mallon, Col Timothy M

2016-08-01

This study assessed the long-term health impact of environmental exposures associated with open pit burning in deployed US service members. Two hundred individuals deployed to Balad, Iraq, and Bagram, Afghanistan, with known exposure to open pits, were matched to 200 non-deployed service members. Both cohorts were observed for adverse health outcomes after returning from deployment. Slight increased risks were observed for respiratory diseases in the Bagram cohort (adj RR: 1.259), and for cardiovascular disease in the Balad cohort (adj RR: 1.072), but the findings were not significant. The combined deployed cohort showed lower risks for adverse health outcomes, suggesting a healthy deployer effect. In conclusion, this study did not find significantly increased risks for selected health outcomes after burn pit exposure during deployment among two deployed cohorts compared with a non-deployed cohort.

Cognitive and emotional alterations in periadolescent mice exposed to 2 g hypergravity field.

PubMed

Francia, Nadia; Santucci, Daniela; Chiarotti, Flavia; Alleva, Enrico

2004-12-15

The development of the nervous system is a dynamic process where epigenetic factors play a fundamental role. Both ground-based and space research indicate that exposure to an altered gravitational environment affects rodent neurobehavioral profile and stage of development as well as duration of exposure appear to be critical for the observed effects. The behavioral profile of adolescent (28-day-old) male and female CD-1 mice upon acute 2 g exposure was characterized and emotional/anxiety responses (plus-maze), as well as spatial learning performance (Morris water-maze), were assessed respectively 24 and 48 h after hypergravity exposure. Behavioral observation indicated a transient mild sickness associated with hypergravity, with a decrease in spontaneous activity. Rotation per se induced an increase in emotional/anxious responses and a deterioration of spatial learning acquisition, while hypergravity specifically improved flexibility of spatial orientation.

Oxidative Stress Response Induced by Butachlor in Zebrafish Embryo/Larvae: The Protective Effect of Vitamin C.

PubMed

Xiang, Qingqing; Xu, Bofan; Ding, Yilun; Liu, Xiaoyi; Zhou, Ying; Ahmad, Farooq

2018-02-01

The widespread contamination and persistence of the herbicide butachlor in the environment resulted in the exposure of non-target organisms. The present study investigated the toxicity effect of butachlor (1-15 µmol/L) and the protective effect of vitamin C (VC) against butachlor-induced toxicity in zebrafish. It was found that butachlor significantly increased the mortality and malformation rates in a dose-dependent manner, which caused elevation in reactive oxygen species (ROS) and malondialdehyde (MDA) after 72 h exposure. Compared with butachlor treatment group, the protective effect of VC against butachlor-induced toxicity were observed after adding 40, 80 mg/L VC respectively. VC significantly decreased the mortality, malformation rates, ROS, MDA, and normalized antioxidant enzymes activities of zebrafish after 72 h exposure. The result shows VC has mitigative effect on butachlor-induced toxicity and it can be used as an effective antioxidant in aquaculture.

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 particular, male mice were highly sensitive to MeHg. The MeHg and Hg(0) + MeHg exposure groups showed similar neurobehavioral effects. Concerning the effects of prenatal mercury exposure under the conditions of this study, the effects of MeHg exposure may be more marked than those of Hg(0) exposure.

Bias and power in group-based epidemiologic studies of low-back pain exposure and outcome--effects of study size and exposure measurement efforts.

PubMed

Coenen, Pieter; Mathiassen, Svend Erik; Kingma, Idsart; Boot, Cécile R L; Bongers, Paulien M; van Dieën, Jaap H

2015-05-01

Exposure-outcome studies, for instance on work-related low-back pain (LBP), often classify workers into groups for which exposures are estimated from measurements on a sample of workers within or outside the specific study. The present study investigated the influence on bias and power in exposure-outcome associations of the sizes of the total study population and the sample used to estimate exposures. At baseline, lifting, trunk flexion, and trunk rotation were observed for 371 of 1131 workers allocated to 19 a-priori defined occupational groups. LBP (dichotomous) was reported by all workers during 3 years of follow-up. All three exposures were associated with LBP in this parent study (P < 0.01). All 21 combinations of n = 10, 20, 30 workers per group with an outcome, and k = 1, 2, 3, 5, 10, 15, 20 workers actually being observed were investigated using bootstrapping, repeating each combination 10000 times. Odds ratios (OR) with P values were determined for each of these virtual studies. Average OR and statistical power (P < 0.05 and P < 0.01) was determined from the bootstrap distributions at each (n, k) combination. For lifting and flexed trunk, studies including n ≥ 20 workers, with k ≥ 5 observed, led to an almost unbiased OR and a power >0.80 (P level = 0.05). A similar performance required n ≥ 30 workers for rotated trunk. Small numbers of observed workers (k) resulted in biased OR, while power was, in general, more sensitive to the total number of workers (n). In epidemiologic studies using a group-based exposure assessment strategy, statistical performance may be sufficient if outcome is obtained from a reasonably large number of workers, even if exposure is estimated from only few workers per group. © The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

A meta-analysis of the effects of exposure to microplastics on fish and aquatic invertebrates.

PubMed

Foley, Carolyn J; Feiner, Zachary S; Malinich, Timothy D; Höök, Tomas O

2018-08-01

Microplastics are present in aquatic ecosystems the world over and may influence the feeding, growth, reproduction, and survival of freshwater and marine biota; however, the extent and magnitude of potential effects of microplastics on aquatic organisms is poorly understood. In the current study, we conducted a meta-analysis of published literature to examine impacts of exposure to microplastics on consumption (and feeding), growth, reproduction, and survival of fish and aquatic invertebrates. While we did observe within-taxa negative effects for all four categories of responses, many of the effects summarized in our study were neutral, indicating that the effects of exposure to microplastics are highly variable across taxa. The most consistent effect was a reduction in consumption of natural prey when microplastics were present. For some taxa, negative effects on growth, reproduction and even survival were also evident. Organisms that serve as prey to larger predators, e.g., zooplankton, may be particularly susceptible to negative impacts of exposure to microplastic pollution, with potential for ramifications throughout the food web. Future work should focus on whether microplastics may be affecting aquatic organisms more subtly, e.g., by influencing exposure to contaminants and pathogens, or by acting at a molecular level. Copyright © 2018 Elsevier B.V. All rights reserved.

Perspectives on repeated low-level blast and the measurement of neurotrauma in humans as an occupational exposure risk

NASA Astrophysics Data System (ADS)

Carr, W.; Dell, K. C.; Yanagi, M. A.; Hassan, D. M.; LoPresti, M. L.

2017-11-01

A pressing question in military medical research is the nature and degree of effects on the human brain from occupational repeated exposure to low-level explosive blast, but reliable and effective means to objectively measure such effects remain elusive. In survey results, headache, difficulty sleeping, irritability, cognitive impairment, and a variety of other symptoms consistent with post-concussive syndrome have been reported by those exposed to blast and there was positive correlation between degree of blast exposure and degree of symptomology, but an important goal is to obtain more objective evidence of an effect than self-report alone. This review reflects recent efforts to measure and evaluate such hypothesized effects and current recommendations for ongoing study. Optimal measures are likely those with sensitivity and specificity to systemic effects in mild neurotrauma, that have minimal to no volitional component, and that can be sampled relatively quickly with minimal intrusion in prospective, observational field studies during routine training with explosives. An understanding of an association between parameters of exposure to repeated low-level blast and negative neurologic effects would support the evaluation of clinical implications and development of protective equipment and surveillance protocols where warranted. At present, low-level blast exposure surveillance measurements do not exist as a systematic record for any professional community.

Secondhand tobacco smoke exposure and heart rate variability and inflammation among non-smoking construction workers: a repeated measures study.

PubMed

Zhang, Jinming; Fang, Shona C; Mittleman, Murray A; Christiani, David C; Cavallari, Jennifer M

2013-10-02

Although it has been well recognized that exposure to secondhand tobacco smoke (SHS) is associated with cardiovascular mortality, the mechanisms and time course by which SHS exposure may lead to cardiovascular effects are still being explored. Non-smoking workers were recruited from a local union and monitored inside a union hall while exposed to SHS over approximately 6 hours. Participants were fitted with a continuous electrocardiographic monitor upon enrollment which was removed at the end of a 24-hr monitoring period. A repeated measures study design was used where resting ECGs and blood samples were taken from individuals before SHS exposure (baseline), immediately following SHS exposure (post) and the morning following SHS exposure (next-morning).Inflammatory markers, including high sensitivity C-reactive protein (CRP) and white blood cell count (WBC) were analyzed. Heart rate variability (HRV) was analyzed from the ECG recordings in time (SDNN, rMSSD) and frequency (LF, HF) domain parameters over 5-minute periods. SHS exposure was quantified using a personal fine particulate matter (PM2.5) monitor.Linear mixed effects regression models were used to examine within-person changes in inflammatory and HRV parameters across the 3 time periods. Exposure-response relationships with PM2.5 were examined using mixed effects models. All models were adjusted for age, BMI and circadian variation. A total of 32 male non-smokers were monitored between June 2010 and June 2012. The mean PM2.5 from SHS exposure was 132 μg/m3. Immediately following SHS exposure, a 100 μg/m3 increase in PM2.5 was associated with declines in HRV (7.8% [standard error (SE) =3%] SDNN, 8.0% (SE = 3.9%) rMSSD, 17.2% (SE = 6.3%) LF, 29.0% (SE = 10.1%) HF) and increases in WBC count 0.42 (SE = 0.14) k/μl. Eighteen hours following SHS exposure, a 100 μg/m3 increase in PM2.5 was associated with 24.2% higher CRP levels. Our study suggest that short-term SHS exposure is associated with significantly lower HRV and higher levels of inflammatory markers. Exposure-associated declines in HRV were observed immediately following exposure while higher levels of CRP were not observed until 18 hours following exposure. Cardiovascular autonomic and inflammation responses may contribute to the pathophysiologic pathways that link SHS exposure with adverse cardiovascular outcomes.

Effects of GSM-Frequency Electromagnetic Radiation on Some Physiological and Biochemical Parameters in Rats.

PubMed

Khirazova, E E; Baizhumanov, A A; Trofimova, L K; Deev, L I; Maslova, M V; Sokolova, N A; Kudryashova, N Yu

2012-10-01

Single exposure of white outbred rats to electromagnetic radiation with a frequency 905 MHz (GSM frequency) for 2 h increased anxiety, reduced locomotor, orientation, and exploration activities in females and orientation and exploration activities in males. Glucocorticoid levels and antioxidant system activity increased in both males and females. In addition to acute effects, delayed effects of radiation were observed in both males and females 1 day after the exposure. These results demonstrated significant effect of GSM-range radiation on the behavior and activity of stress-realizing and stress-limiting systems of the body.

Exposure and non-fear emotions: A randomized controlled study of exposure-based and rescripting-based imagery in PTSD treatment.

PubMed

Langkaas, Tomas Formo; Hoffart, Asle; Øktedalen, Tuva; Ulvenes, Pål G; Hembree, Elizabeth A; Smucker, Mervin

2017-10-01

Interventions involving rescripting-based imagery have been proposed as a better approach than exposure-based imagery when posttraumatic stress disorder (PTSD) is associated with emotions other than fear. Prior research led to the study's hypotheses that (a) higher pretreatment non-fear emotions would predict relatively better response to rescripting as compared to exposure, (b) rescripting would be associated with greater reduction in non-fear emotions, and (c) pretreatment non-fear emotions would predict poor response to exposure. A clinically representative sample of 65 patients presenting a wide range of traumas was recruited from patients seeking and being offered PTSD treatment in an inpatient setting. Subjects were randomly assigned to 10 weeks of treatment involving either rescripting-based imagery (Imagery Rescripting; IR) or exposure-based imagery (Prolonged Exposure; PE). Patients were assessed on outcome and emotion measures at pretreatment, posttreatment and 12 months follow-up. Comparison to control benchmarks indicated that both treatments were effective, but no outcome differences between them appeared. None of the initial hypotheses were supported. The results from this study challenge previous observations and hypotheses about exposure mainly being effective for fear-based PTSD and strengthen the notion that exposure-based treatment is a generally effective treatment for all types of PTSD. Copyright © 2017 Elsevier Ltd. All rights reserved.

Physiological Stress Responses to Prolonged Exposure to MS-222 and Surgical Implantation in Juvenile Chinook Salmon

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

Wagner, Katie A.; Woodley, Christa M.; Seaburg, Adam

While many studies have investigated the effects of transmitters on fish condition, behavior, and survival, to our knowledge, no studies have taken into account anesthetic exposure time in addition to tag and surgery effects. We investigated stress responses to prolonged MS-222 exposure after stage 4 induction in surgically implanted juvenile Chinook salmon (Oncorhynchus tshawytscha). Survival, tag loss, plasma cortisol concentration, and blood Na +, K +, Ca 2+, and pH were measured immediately following anesthetic exposure and surgical implantation and 1, 7, and 14 days post-treatment. Despite the prolonged anesthetic exposure, 3-15 minutes post Stage 4 induction, there were nomore » mortalities or tag loss in any treatment. MS-222 was effective at delaying immediate cortisol release during surgical implantation; however, osmotic disturbances resulted, which were more pronounced in longer anesthetic time exposures. From day 1 to day 14, Na +, Ca 2+, and pH significantly decreased, while cortisol significantly increased. The cortisol increase was exacerbated by surgical implantation. There was a significant interaction between MS-222 time exposure and observation day for Na +, Ca 2+, K +, and pH; variations were seen in the longer time exposures, although not consistently. In conclusion, stress response patterns suggest stress associated with surgical implantation is amplified with increased exposure to MS-222.« less

Extending the Distributed Lag Model framework to handle chemical mixtures.

PubMed

Bello, Ghalib A; Arora, Manish; Austin, Christine; Horton, Megan K; Wright, Robert O; Gennings, Chris

2017-07-01

Distributed Lag Models (DLMs) are used in environmental health studies to analyze the time-delayed effect of an exposure on an outcome of interest. Given the increasing need for analytical tools for evaluation of the effects of exposure to multi-pollutant mixtures, this study attempts to extend the classical DLM framework to accommodate and evaluate multiple longitudinally observed exposures. We introduce 2 techniques for quantifying the time-varying mixture effect of multiple exposures on an outcome of interest. Lagged WQS, the first technique, is based on Weighted Quantile Sum (WQS) regression, a penalized regression method that estimates mixture effects using a weighted index. We also introduce Tree-based DLMs, a nonparametric alternative for assessment of lagged mixture effects. This technique is based on the Random Forest (RF) algorithm, a nonparametric, tree-based estimation technique that has shown excellent performance in a wide variety of domains. In a simulation study, we tested the feasibility of these techniques and evaluated their performance in comparison to standard methodology. Both methods exhibited relatively robust performance, accurately capturing pre-defined non-linear functional relationships in different simulation settings. Further, we applied these techniques to data on perinatal exposure to environmental metal toxicants, with the goal of evaluating the effects of exposure on neurodevelopment. Our methods identified critical neurodevelopmental windows showing significant sensitivity to metal mixtures. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of exercise training on pulmonary vessel muscularization and right ventricular function in an animal model of COPD.

PubMed

Hassel, Erlend; Berre, Anne Marie; Skjulsvik, Anne Jarstein; Steinshamn, Sigurd

2014-09-28

Right ventricular dysfunction in COPD is common, even in the absence of pulmonary hypertension. The aim of the present study was to examine the effects of high intensity interval training (HIIT) on right ventricular (RV) function, as well as pulmonary blood vessel remodeling in a mouse model of COPD. 42 female A/JOlaHsd mice were randomized to exposure to either cigarette smoke or air for 6 hours/day, 5 days/week for 14 weeks. Mice from both groups were further randomized to sedentariness or HIIT for 4 weeks. Cardiac function was evaluated by echocardiography and muscularization of pulmonary vessel walls by immunohistochemistry. Smoke exposure induced RV systolic dysfunction demonstrated by reduced tricuspid annular plane systolic excursion. HIIT in smoke-exposed mice reversed RV dysfunction. There were no significant effects on the left ventricle of neither smoke exposure nor HIIT. Muscularization of the pulmonary vessels was reduced after exercise intervention, but no significant effects on muscularization were observed from smoke exposure. RV function was reduced in mice exposed to cigarette smoke. No Increase in pulmonary vessel muscularization was observed in these mice, implying that other mechanisms caused the RV dysfunction. HIIT attenuated the RV dysfunction in the smoke exposed mice. Reduced muscularization of the pulmonary vessels due to HIIT suggests that exercise training not only affects the heart muscle, but also has important effects on the pulmonary vasculature.

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

Long-term effects of the rain exposure shortly after the atomic bombings in Hiroshima and Nagasaki.

PubMed

Sakata, Ritsu; Grant, Eric J; Furukawa, Kyoji; Misumi, Munechika; Cullings, Harry; Ozasa, Kotaro; Shore, Roy E

2014-12-01

The "black rain" that fell after the atomic bombings of Hiroshima and Nagasaki has been generally believed to contain radioactive materials. During 1949-1961 the Atomic Bomb Casualty Commission conducted surveys that included a query about exposure to the rain that fell a short time after the bombings. This article presents the first report of those data in relation to possible adverse health outcomes. This study looked at Life Span Study subjects who were in either city at the time of bombing and had an estimated direct radiation dose from the bombs (n = 86,609). The mortality data from 1950-2005 and cancer incidence data from 1958-2005 were used. Excess relative risks (ERRs) of subjects who were exposed to rain compared to those who reported no rain exposure were calculated using a Poisson regression model. In Hiroshima 11,661 subjects (20%) reported that they were exposed to rain, while in Nagasaki only 733 subjects (2.6%) reported rain exposure. To avoid outcome dependent biases (i.e., recall of exposure after a health outcome has already occurred), the primary analyses were based on events that occurred during 1962-2005. No significant risks due to rain exposure were observed for death due to all causes, all solid cancer or leukemia in Hiroshima. In Nagasaki there was no significantly elevated rain exposure-associated risks for 1962-2005, however, for 1950-2005 there was a weak association for all-cause mortality (ERR = 0.08; 95% confidence interval 0.00006, 0.17; P = 0.05). For incidence of solid cancer and leukemia, no significantly elevated rain exposure risks were observed in either city. These results failed to show deleterious health effects from rain exposure. While these data represent the most extensive set of systematically collected data on rain exposure of the atomic bomb survivors, they are limited by substantial uncertainties regarding exposures and missing individual data, so cautious interpretation is advised.

On the evolution of cured voxel in bulk photopolymerization upon focused Gaussian laser exposure

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

Bhole, Kiran, E-mail: kirandipali@gmail.com; Gandhi, Prasanna; Kundu, T.

Unconstrained depth photopolymerization is emerging as a promising technique for fabrication of several polymer microstructures such as self propagating waveguides, 3D freeform structures by bulk lithography, and polymer nanoparticles by flash exposure. Experimental observations reveal governing physics beyond Beer Lambert's law and scattering effects. This paper seeks to model unconstrained depth photopolymerization using classical nonlinear Schrödinger equation coupled with transient diffusion phenomenon. The beam propagation part of the proposed model considers scattering effects induced due to spatial variation of the refractive index as a function of the beam intensity. The critical curing energy model is used to further predict profilemore » of polymerized voxel. Profiles of photopolymerized voxel simulated using proposed model are compared with the corresponding experimental results for several cases of exposure dose and duration. The comparison shows close match leading to conclusion that the experimentally observed deviation from Beer Lambert's law is indeed due to combined effect of diffusion of photoinitiator and scattering of light because of change in the refractive index.« less

Causal Methods for Observational Research: A Primer.

PubMed

Almasi-Hashiani, Amir; Nedjat, Saharnaz; Mansournia, Mohammad Ali

2018-04-01

The goal of many observational studies is to estimate the causal effect of an exposure on an outcome after adjustment for confounders, but there are still some serious errors in adjusting confounders in clinical journals. Standard regression modeling (e.g., ordinary logistic regression) fails to estimate the average effect of exposure in total population in the presence of interaction between exposure and covariates, and also cannot adjust for time-varying confounding appropriately. Moreover, stepwise algorithms of the selection of confounders based on P values may miss important confounders and lead to bias in effect estimates. Causal methods overcome these limitations. We illustrate three causal methods including inverse-probability-of-treatment-weighting (IPTW) and parametric g-formula, with an emphasis on a clever combination of these 2 methods: targeted maximum likelihood estimation (TMLE) which enjoys a double-robust property against bias. © 2018 The Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Estimating human-equivalent no observed adverse-effect levels for VOCs (volatile organic compounds) based on minimal knowledge of physiological parameters. Technical paper

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

Overton, J.H.; Jarabek, A.M.

1989-01-01

The U.S. EPA advocates the assessment of health-effects data and calculation of inhaled reference doses as benchmark values for gauging systemic toxicity to inhaled gases. The assessment often requires an inter- or intra-species dose extrapolation from no observed adverse effect level (NOAEL) exposure concentrations in animals to human equivalent NOAEL exposure concentrations. To achieve this, a dosimetric extrapolation procedure was developed based on the form or type of equations that describe the uptake and disposition of inhaled volatile organic compounds (VOCs) in physiologically-based pharmacokinetic (PB-PK) models. The procedure assumes allometric scaling of most physiological parameters and that the value ofmore » the time-integrated human arterial-blood concentration must be limited to no more than to that of experimental animals. The scaling assumption replaces the need for most parameter values and allows the derivation of a simple formula for dose extrapolation of VOCs that gives equivalent or more-conservative exposure concentrations values than those that would be obtained using a PB-PK model in which scaling was assumed.« less

Incorporation of multiple cloud layers for ultraviolet radiation modeling studies

NASA Technical Reports Server (NTRS)

Charache, Darryl H.; Abreu, Vincent J.; Kuhn, William R.; Skinner, Wilbert R.

1994-01-01

Cloud data sets compiled from surface observations were used to develop an algorithm for incorporating multiple cloud layers into a multiple-scattering radiative transfer model. Aerosol extinction and ozone data sets were also incorporated to estimate the seasonally averaged ultraviolet (UV) flux reaching the surface of the Earth in the Detroit, Michigan, region for the years 1979-1991, corresponding to Total Ozone Mapping Spectrometer (TOMS) version 6 ozone observations. The calculated UV spectrum was convolved with an erythema action spectrum to estimate the effective biological exposure for erythema. Calculations show that decreasing the total column density of ozone by 1% leads to an increase in erythemal exposure by approximately 1.1-1.3%, in good agreement with previous studies. A comparison of the UV radiation budget at the surface between a single cloud layer method and a multiple cloud layer method presented here is discussed, along with limitations of each technique. With improved parameterization of cloud properties, and as knowledge of biological effects of UV exposure increase, inclusion of multiple cloud layers may be important in accurately determining the biologically effective UV budget at the surface of the Earth.

Biogenic-Anthropogenic Interactions in Secondary Organic Aerosol Formation and Health Effects of Atmospheric Organic Aerosol

NASA Astrophysics Data System (ADS)

Ye, Jianhuai

Secondary organic aerosol (SOA) formed from oxidation of volatile organic compounds (VOCs), comprises a major fraction of atmospheric submicron particulate matter, which is crucial for global climate change and human health. While biogenic VOCs are naturally emitted and cannot be directly controlled, field measurements and satellite observations have shown that biogenic SOA (BSOA) formation correlates well with anthropogenic pollutants and may be anthropogenically controlled. In this work, the formation of the "anthropogenically controllable BSOA" was examined. BSOA from alpha-pinene ozonolysis was investigated in the presence of laboratory-generated or ambient organic aerosol such as Toronto ambient particles. It is shown that SOA was not equally miscible with all organic species. Aerosol mixing thermodynamics in the atmosphere is composition dependent. Based on laboratory observations, an empirical framework using bulk elemental ratios was developed to predict atmospheric organic miscibility and SOA yield enhancements. Besides organic aerosol, interactions between BSOA formation and SO2 was also examined. Synergistic effects were observed between BSOA formation and SO2 oxidation through Criegee and peroxide chemistry under atmospherically relevant RH conditions. In addition to the physicochemical properties of SOA, health impacts of SOA were examined. An atmospheric simulation reactor (ASR) was developed to investigate the health effects of air pollutants by permitting controlled chronic in vivo exposure of mice to combine particulate and gaseous pollutants at 'real-life' concentrations. Results show that daily exposure to SOA from naphthalene photooxidation led to increased airway hyperresponsiveness (AHR) to methacholine in a dose-dependent manner. Multi-pollutant exposures with ozone and/or NO2 in conjunction with a sub-toxic concentration of SOA resulted in additive effects on AHR to methacholine. Inflammatory cell recruitment to the airways was not observed in any of the exposure conditions, indicating the increased AHR was not associated with airway inflammation and may occur through other mechanisms.

Week Long Topography Study of Young Adults Using Electronic Cigarettes in Their Natural Environment.

PubMed

Robinson, R J; Hensel, E C; Roundtree, K A; Difrancesco, A G; Nonnemaker, J M; Lee, Y O

2016-01-01

Results of an observational, descriptive study quantifying topography characteristics of twenty first generation electronic nicotine delivery system users in their natural environment for a one week observation period are presented. The study quantifies inter-participant variation in puffing topography between users and the intra-participant variation for each user observed during one week of use in their natural environment. Puff topography characteristics presented for each user include mean puff duration, flow rate and volume for each participant, along with descriptive statistics of each quantity. Exposure characteristics including the number of vaping sessions, total number of puffs and cumulative volume of aerosol generated from ENDS use (e-liquid aerosol) are reported for each participant for a one week exposure period and an effective daily average exposure. Significant inter-participant and intra-participant variation in puff topography was observed. The observed range of natural use environment characteristics is used to propose a set of topography protocols for use as command inputs to drive machine-puffed electronic nicotine delivery systems in a controlled laboratory environment.

Week Long Topography Study of Young Adults Using Electronic Cigarettes in Their Natural Environment

PubMed Central

Roundtree, K. A.; Difrancesco, A. G.; Nonnemaker, J. M.; Lee, Y. O.

2016-01-01

Results of an observational, descriptive study quantifying topography characteristics of twenty first generation electronic nicotine delivery system users in their natural environment for a one week observation period are presented. The study quantifies inter-participant variation in puffing topography between users and the intra-participant variation for each user observed during one week of use in their natural environment. Puff topography characteristics presented for each user include mean puff duration, flow rate and volume for each participant, along with descriptive statistics of each quantity. Exposure characteristics including the number of vaping sessions, total number of puffs and cumulative volume of aerosol generated from ENDS use (e-liquid aerosol) are reported for each participant for a one week exposure period and an effective daily average exposure. Significant inter-participant and intra-participant variation in puff topography was observed. The observed range of natural use environment characteristics is used to propose a set of topography protocols for use as command inputs to drive machine-puffed electronic nicotine delivery systems in a controlled laboratory environment. PMID:27736944

Organometallic exposure dependence on organic–inorganic hybrid material formation in polyethylene terephthalate and polyamide 6 polymer fibers

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

Akyildiz, Halil I.; Jur, Jesse S., E-mail: jsjur@ncsu.edu

2015-03-15

The effect of exposure conditions and surface area on hybrid material formation during sequential vapor infiltrations of trimethylaluminum (TMA) into polyamide 6 (PA6) and polyethylene terephthalate (PET) fibers is investigated. Mass gain of the fabric samples after infiltration was examined to elucidate the reaction extent with increasing number of sequential TMA single exposures, defined as the times for a TMA dose and a hold period. An interdependent relationship between dosing time and holding time on the hybrid material formation is observed for TMA exposure PET, exhibited as a linear trend between the mass gain and total exposure (dose time ×more » hold time × number of sequential exposures). Deviation from this linear relationship is only observed under very long dose or hold times. In comparison, amount of hybrid material formed during sequential exposures to PA6 fibers is found to be highly dependent on amount of TMA dosed. Increasing the surface area of the fiber by altering its cross-sectional dimension is shown to have little on the reaction behavior but does allow for improved diffusion of the TMA into the fiber. This work allows for the projection of exposure parameters necessary for future high-throughput hybrid modifications to polymer materials.« less

Evaluation of the Tobacco Heating System 2.2. Part 4: 90-day OECD 413 rat inhalation study with systems toxicology endpoints demonstrates reduced exposure effects compared with cigarette smoke.

PubMed

Wong, Ee Tsin; Kogel, Ulrike; Veljkovic, Emilija; Martin, Florian; Xiang, Yang; Boue, Stephanie; Vuillaume, Gregory; Leroy, Patrice; Guedj, Emmanuel; Rodrigo, Gregory; Ivanov, Nikolai V; Hoeng, Julia; Peitsch, Manuel C; Vanscheeuwijck, Patrick

2016-11-30

The objective of the study was to characterize the toxicity from sub-chronic inhalation of test atmospheres from the candidate modified risk tobacco product (MRTP), Tobacco Heating System version 2.2 (THS2.2), and to compare it with that of the 3R4F reference cigarette. A 90-day nose-only inhalation study on Sprague-Dawley rats was performed, combining classical and systems toxicology approaches. Reduction in respiratory minute volume, degree of lung inflammation, and histopathological findings in the respiratory tract organs were significantly less pronounced in THS2.2-exposed groups compared with 3R4F-exposed groups. Transcriptomics data obtained from nasal epithelium and lung parenchyma showed concentration-dependent differential gene expression following 3R4F exposure that was less pronounced in the THS2.2-exposed groups. Molecular network analysis showed that inflammatory processes were the most affected by 3R4F, while the extent of THS2.2 impact was much lower. Most other toxicological endpoints evaluated did not show exposure-related effects. Where findings were observed, the effects were similar in 3R4F- and THS2.2-exposed animals. In summary, toxicological changes observed in the respiratory tract organs of THS2.2 aerosol-exposed rats were much less pronounced than in 3R4F-exposed rats while other toxicological endpoints either showed no exposure-related effects or were comparable to what was observed in the 3R4F-exposed rats. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

Air pollution exposure and adverse pregnancy outcomes in a large UK birth cohort: use of a novel spatio-temporal modelling technique.

PubMed

Hannam, Kimberly; McNamee, Roseanne; Baker, Philip; Sibley, Colin; Agius, Raymond

2014-09-01

Previous work suggests an association between air pollution exposure and adverse pregnancy outcomes, even at relatively low concentrations. Our aim was to quantify the effect of air pollution having an adverse effect on preterm birth (PTB) and fetal growth in a large UK cohort using a novel exposure estimation technique [spatio-temporal (S-T) model] alongside a traditional nearest stationary monitor technique (NSTAT). All available postcodes from a Northwest England birth outcome dataset during 2004-2008 were geocoded (N=203 562 deliveries). Pollution estimates were linked to corresponding pregnancy periods using temporally adjusted background modelled concentrations as well as NSTAT. Associations with PTB, small for gestational age (SGA), and birth weight were investigated using regression models adjusting for maternal age, ethnicity, parity, birth season, socioeconomic status (SES), body mass index (BMI), and smoking. Based on the novel S-T model, a small statistically significant association was observed for particulate matter (PM10) and SGA, particularly with exposure in the first and third trimesters. Similar effects on SGA were also found for nitrogen dioxide (NO 2), particulate matter (PM 2,5), and carbon monoxide (CO) in later pregnancy, but no overall increased risk was observed. No associations were found with NO xor the outcomes PTB and reduction in birth weight. Our findings suggest an association between air pollution exposure and birth of a SGA infant, particularly in the later stages of pregnancy but not with PTB or mean birth weight change.

Chronic exposure to adverse psychosocial work factors and high psychological distress among white-collar workers: A 5-year prospective study.

PubMed

Ndjaboue, Ruth; Brisson, Chantal; Talbot, Denis; Vézina, Michel

2017-03-01

Prospective studies which evaluated whether the effects of chronic exposure to psychosocial work factors on mental health persisted over time are scarce. For the first time, this study evaluated: 1) the effect of chronic exposure to effort-reward imbalance over 5years on the prevalence of high psychological distress among men and women, and 2) the persistence of this effect over time. Overall, 1747 white-collar workers from three public organizations participated in a prospective study. Psychological distress and effort-reward imbalance were measured using validated questionnaires at baseline, and at 3- and 5-year follow-ups. Prevalence ratios (PRs) of high psychological distress were estimated using log-binomial regression according to baseline and repeated exposure. Compared to unexposed workers, those with repeated exposure to effort-reward imbalance had a higher prevalence of high psychological distress. Workers exposed only at some time-points also had a higher prevalence. The deleterious effect of repeated exposure observed at the 3-year follow-up persisted at the 5-year follow-up among women (PR=2.48 95% confidence interval (CI) 1.97-3.11) and men (PR=1.91 95% CI 1.20-3.04). These effects were greater than those found using a single baseline measurement. The current study supported a deleterious effect of repeated exposure to effort-reward imbalance on psychological distress, and a lack of adaptation to these effects over time among men and women. Since psychological distress may later lead to severe mental problems, current results highlight the need to consider exposure to these adverse work factors in primary and secondary preventions aimed at reducing mental health problems at work. Copyright © 2017 Elsevier Inc. All rights reserved.

Prenatal exposure to amphetamines. Risks and adverse outcomes in pregnancy.

PubMed

Plessinger, M A

1998-03-01

Based on findings in humans and the confirmation of prenatal exposures in animals, amphetamines and methamphetamines increase the risk of an adverse outcome when abused during pregnancy. Clefting, cardiac anomalies, and fetal growth reduction deficits that have been seen in infants exposed to amphetamines during pregnancy have all been reproduced in animal studies involving prenatal exposures to amphetamines. The differential effects of amphetamines between genetic strains of mice and between species demonstrate that pharmacokinetics and the genetic disposition of the mother and developing embryo can have an enormous influence on enhancing or reducing these potential risks. The effects of prenatal exposure to amphetamines in producing altered behavior in humans appear less compelling when one considers other confounding variables of human environment, genetics, and polydrug abuse. In view of the animal data concerning altered behavior and learning tasks in comparison with learning deficits observed in humans, the influence of the confounding variables in humans may serve to increase the sensitivity of the developing embryo/fetus to prenatal exposure to amphetamines. These factors and others may predispose the developing conceptus to the damaging effects of amphetamines by actually lowering the threshold of susceptibility at the sites where damage occurs. Knowledge of the effects of prenatal exposure of the fetus and the mother to designer amphetamines is lacking. Based on the few studies in which designer drugs have been examined in animal models, more questions are raised than answered. Possible reasons why no malformations or significant fetal effects were found in the study by St. Omer include the genetic strain of rat used, the conservative exposure profile, or the fact that the placenta metabolized MDMA before reaching the embryo. These questions underscore the need for further investigations concerning the prenatal exposure effects of designer compounds and the effects of amphetamine and methamphetamine in general.

Weight-of-evidence evaluation of short-term ozone exposure and cardiovascular effects.

PubMed

Goodman, Julie E; Prueitt, Robyn L; Sax, Sonja N; Lynch, Heather N; Zu, Ke; Lemay, Julie C; King, Joseph M; Venditti, Ferdinand J

2014-10-01

There is a relatively large body of research on the potential cardiovascular (CV) effects associated with short-term ozone exposure (defined by EPA as less than 30 days in duration). We conducted a weight-of-evidence (WoE) analysis to assess whether it supports a causal relationship using a novel WoE framework adapted from the US EPA's National Ambient Air Quality Standards causality framework. Specifically, we synthesized and critically evaluated the relevant epidemiology, controlled human exposure, and experimental animal data and made a causal determination using the same categories proposed by the Institute of Medicine report Improving the Presumptive Disability Decision-making Process for Veterans ( IOM 2008). We found that the totality of the data indicates that the results for CV effects are largely null across human and experimental animal studies. The few statistically significant associations reported in epidemiology studies of CV morbidity and mortality are very small in magnitude and likely attributable to confounding, bias, or chance. In experimental animal studies, the reported statistically significant effects at high exposures are not observed at lower exposures and thus not likely relevant to current ambient ozone exposures in humans. The available data also do not support a biologically plausible mechanism for CV effects of ozone. Overall, the current WoE provides no convincing case for a causal relationship between short-term exposure to ambient ozone and adverse effects on the CV system in humans, but the limitations of the available studies preclude definitive conclusions regarding a lack of causation. Thus, we categorize the strength of evidence for a causal relationship between short-term exposure to ozone and CV effects as "below equipoise."

Effects of short term and long term Extremely Low Frequency Magnetic Field on depressive disorder in mice: Involvement of nitric oxide pathway.

PubMed

Madjid Ansari, Alireza; Farzampour, Shahrokh; Sadr, Ali; Shekarchi, Babak; Majidzadeh-A, Keivan

2016-02-01

Previous reports on the possible effects of Extremely Low Frequency Magnetic Fields (ELF MF) on mood have been paradoxical in different settings while no study has yet been conducted on animal behavior. In addition, it was shown that ELF MF exposure makes an increase in brain nitric oxide level. Therefore, in the current study, we aimed to assess the possible effect(s) of ELF MF exposure on mice Forced Swimming Test (FST) and evaluate the probable role of the increased level of nitric oxide in the observed behavior. Male adult mice NMRI were recruited to investigate the short term and long term ELF MF exposure (0.5 mT and 50 Hz, single 2h and 2 weeks 2h a day). Locomotor behavior was assessed by using open-field test (OFT) followed by FST to evaluate the immobility time. Accordingly, NΩ-nitro-l-arginine methyl ester 30 mg/kg was used to exert anti-depressant like effect. According to the results, short term exposure did not alter the immobility time, whereas long term exposure significantly reduces immobility time (p<0.01). However, it was revealed that the locomotion did not differ among all experimental groups. Short term exposure reversed the anti-depressant like effect resulting from 30 mg/kg of NΩ-nitro-l-arginine methyl ester (p<0.01). It has been concluded that long term exposure could alter the depressive disorder in mice, whereas short term exposure has no significant effect. Also, reversing the anti-depressant activity of L-NAME indicates a probable increase in the brain nitric oxide. Copyright © 2016 Elsevier Inc. All rights reserved.

A long-term copper exposure in a freshwater ecosystem using lotic mesocosms: Invertebrate community responses

USGS Publications Warehouse

Joachim, Sandrine; Roussel, Hélène; Bonzom, Jean-Marc; Thybaud, Eric; Mebane, Christopher A.; Brink, Paul Van den; Gauthier, Laury

2017-01-01

A lotic mesocosm study was carried out in 20-m-long channels, under continuous, environmentally realistic concentrations of copper (Cu) in low, medium, and high exposures (nominally 0, 5, 25, and 75 μg L−1; average effective concentrations <0.5, 4, 20, and 57 μg L−1 respectively) for 18 mo. Total abundance, taxa richness, and community structure of zooplankton, macroinvertebrates, and emerging insects were severely affected at Cu treatment levels of 25 and 75 μg L−1. Some taxa were sensitive to Cu, including gastropods such as Lymnaea spp. and Physasp., crustaceans such as Chydorus sphaericus, Gammarus pulex, and Asellus aquaticus, rotifers such as Mytilina sp. and Trichocerca sp., leeches such as Erpobdella sp., and the emergence of dipteran insects such as Chironomini. Other taxa appeared to be tolerant or favored by indirect effects, as in Chironimidae larvae, the emergence of Orthocladiinae, and the zooplankter Vorticella sp., which increased in the 25 and 75 μg L−1 treatments. After approximately 8 mo of Cu exposure, the macroinvertebrate community in the high treatment was decimated to the point that few organisms could be detected, with moderate effects in the medium treatment, and very slight effects in the low-Cu treatment. Subsequently, most taxa in the high-Cu exposure began a gradual and partial recovery. By the end of the study at 18 mo, macroinvertebrate taxa richness was similar to control richness, although overall abundances remained lower than controls. After 18 mo of copper exposure, a no-observed-effect concentration at the community level for consumers was set at 5 μg L−1 (4 μg L−1 as average effective concentration), and a lowest-observed-effect concentration at 25 μg L−1(20 μg L−1 as average effective concentration).