Comparative international analysis of radiofrequency exposure surveys of mobile communication radio base stations.

PubMed

Rowley, Jack T; Joyner, Ken H

2012-01-01

This paper presents analyses of data from surveys of radio base stations in 23 countries across five continents from the year 2000 onward and includes over 173,000 individual data points. The research compared the results of the national surveys, investigated chronological trends and compared exposures by technology. The key findings from this data are that irrespective of country, the year and cellular technology, exposures to radio signals at ground level were only a small fraction of the relevant human exposure standards. Importantly, there has been no significant increase in exposure levels since the widespread introduction of 3G mobile services, which should be reassuring for policy makers and negate the need for post-installation measurements at ground level for compliance purposes. There may be areas close to antennas where compliance levels could be exceeded. Future potential work includes extending the study to additional countries, development of cumulative exposure distributions and investigating the possibility of linking exposure measurements to population statistics to assess the distribution of exposure levels relative to population percentiles.

Association Between Cd Exposure and Risk of Prostate Cancer: A PRISMA-Compliant Systematic Review and Meta-Analysis.

PubMed

Ju-Kun, Song; Yuan, Dong-Bo; Rao, Hao-Fu; Chen, Tian-Fei; Luan, Bo-Shi; Xu, Xiao-Ming; Jiang, Fu-Neng; Zhong, Wei-De; Zhu, Jian-Guo

2016-02-01

Several observational studies on the association between Cd exposure and risk of prostate cancer have yielded inconsistent results. To address this issue, we conducted a meta-analysis to evaluate the correlation between Cd exposure and risk of prostate cancer.Relevant studies in PubMed and Embase databases were retrieved until October 2015. We compared the highest and lowest meta-analyses to quantitatively evaluate the relationship between Cd exposure and risk of prostate cancer. Summary estimates were obtained using a random-effects model.In the general population, high Cd exposure was not associated with increased prostate cancer (OR 1.21; 95% CI 0.91-1.64), whereas the combined standardized mortality ratio of the association between Cd exposure and risk of prostate cancer was 1.66 (95% CI 1.10-2.50) in populations exposed to occupational Cd. In addition, high D-Cd intake (OR 1.07; 95% CI 0.96-1.20) and U-Cd concentration (OR 0.86; 95% CI 0.48-1.55) among the general population was not related to the increased risk of prostate cancer. In the dose analysis, the summary relative risk was 1.07 (95% CI 0.73-1.57) for each 0.5 μg/g creatinine increase in U-Cd and 1.02 (95% CI 0.99-1.06) for each 10 μg/day increase of dietary Cd intake. However, compared with nonoccupational exposure, high occupational Cd exposure may be associated with the increased risk of prostate cancer.This meta-analysis suggests high Cd exposure as a risk factor for prostate cancer in occupational rather than nonoccupational populations. However, these results should be carefully interpreted because of the significant heterogeneity among studies. Additional large-scale and high-quality prospective studies are needed to confirm the association between Cd exposure and risk of prostate cancer.

Safety and tolerability of exenatide twice daily in patients with type 2 diabetes: integrated analysis of 5594 patients from 19 placebo-controlled and comparator-controlled clinical trials

PubMed Central

MacConell, Leigh; Brown, Carl; Gurney, Kate; Han, Jenny

2012-01-01

Background Exenatide twice daily is a first-in-class glucagon-like peptide receptor agonist approved for the treatment of type 2 diabetes. The objective of this analysis was to evaluate the safety profile of exenatide twice daily and to compare its profile with that of a pooled comparator (placebo and insulin) in patients with type 2 diabetes. Methods Data from 19 completed, randomized, controlled clinical trials of exenatide twice daily (5 μg and 10 μg) were pooled and analyzed; the pooled data included 5594 intent-to-treat patients who were followed for 12–52 weeks. Incidence rates, exposure-adjusted incidence rates, and 95% confidence intervals around risk differences between groups were calculated. Results Baseline demographics and exposure time were comparable between groups (exenatide, N = 3261; pooled comparator, N = 2333; mean exposure time 166–171 days). Transient, mild- to-moderate nausea was the most frequent adverse event with exenatide (36.9% versus 8.3% in the pooled comparator). The incidence of hypoglycemia (minor or major) with concomitant sulfonylurea (exenatide 26.5%, pooled comparator 20.7%) was higher than that without sulfonylurea (exenatide 3.1%, pooled comparator 2.7%) in all groups. Serious adverse events, discontinuations due to serious adverse events, and deaths were reported with similar frequency in the exenatide and pooled comparator groups. Composite exposure-adjusted incidence rates were not statistically different between groups for pancreatitis, renal impairment, or major adverse cardiac events; there was a difference in incidence rates for benign thyroid neoplasm (0.3% versus 0%). Conclusion Overall, this analysis, representing over 1500 patient-years of exposure, demonstrated that exenatide twice daily was safe and generally well tolerated in patients with type 2 diabetes. The incidence of most adverse events, including serious adverse events, was similar in both exenatide-treated and comparator-treated patients. The most distinct differences between groups were in gastrointestinal-related adverse events, which is consistent with other therapies within the glucagon-like peptide class. PMID:22375098

Effects of a sublethal concentration of sodium lauryl sulphate on the morphology and Na+/K+ ATPase activity in the gill of the ornate wrasse (Thalassoma pavo).

PubMed

Brunelli, Elvira; Talarico, Erminia; Corapi, Barbara; Perrotta, Ida; Tripepi, Sandro

2008-10-01

We analysed the morphology and ultrastructure of the gill apparatus of the ornate wrasse, Thalassoma pavo, under normal conditions and after exposure to a sublethal concentration of sodium lauryl sulphate (3.5 mg/l, which is one-third of the 96LC99 value). To identify the biochemical mechanisms affected by this pollutant, we evaluated and compared the localisation of Na(+)/K(+) ATPase in normal and experimental conditions. Immunocytochemical analysis revealed that this enzyme was active in the chloride cells (CCs), which were distributed in clusters in the interlamellar region of the filament. Ultrastructural analysis revealed conspicuous alterations on the epithelium after 96 and 192 h of exposure to sodium lauryl sulphate: structural features of the surface cells were lost, the appearance of intercellular lacunae changed, and cellular degeneration occurred. Statistical analysis comparing the number and dimensions of CCs in normal conditions and after 96 h of exposure showed that the CC area decreased after exposure to the detergent.

Exposure to second-hand smoke and direct healthcare costs in children - results from two German birth cohorts, GINIplus and LISAplus.

PubMed

Batscheider, Ariane; Zakrzewska, Sylwia; Heinrich, Joachim; Teuner, Christina M; Menn, Petra; Bauer, Carl Peter; Hoffmann, Ute; Koletzko, Sibylle; Lehmann, Irina; Herbarth, Olf; von Berg, Andrea; Berdel, Dietrich; Krämer, Ursula; Schaaf, Beate; Wichmann, H-Erich; Leidl, Reiner

2012-10-02

Although the negative health consequences of the exposure to second hand tobacco smoke during childhood are already known, evidence on the economic consequences is still rare. The aim of this study was to estimate excess healthcare costs of exposure to tobacco smoke in German children. The study is based on data from two birth cohort studies of 3,518 children aged 9-11 years with information on healthcare utilisation and tobacco smoke exposure: the GINIplus study (German Infant Study On The Influence Of Nutrition Intervention Plus Environmental And Genetic Influences On Allergy Development) and the LISAplus study (Influence of Life-Style Factors On The Development Of The Immune System And Allergies In East And West Germany Plus The Influence Of Traffic Emissions And Genetics). Direct medical costs were estimated using a bottom-up approach (base year 2007). We investigated the impact of tobacco smoke exposure in different environments on the main components of direct healthcare costs using descriptive analysis and a multivariate two-step regression analysis. Descriptive analysis showed that average annual medical costs (physician visits, physical therapy and hospital treatment) were considerably higher for children exposed to second-hand tobacco smoke at home (indoors or on patio/balcony) compared with those who were not exposed. Regression analysis confirmed these descriptive trends: the odds of positive costs and the amount of total costs are significantly elevated for children exposed to tobacco smoke at home after adjusting for confounding variables. Combining the two steps of the regression model shows smoking attributable total costs per child exposed at home of €87 [10-165] (patio/balcony) and €144 [6-305] (indoors) compared to those with no exposure. Children not exposed at home but in other places showed only a small, but not significant, difference in total costs compared to those with no exposure. This study shows adverse economic consequences of second-hand smoke in children depending on proximity of exposure. Tobacco smoke exposure seems to affect healthcare utilisation in children who are not only exposed to smoke indoors but also if parents reported exclusively smoking on patio or balcony. Preventing children from exposure to second-hand tobacco smoke might thus be desirable not only from a health but also from an economic perspective.

Fumonisin B1 Toxicity in Grower-Finisher Pigs: A Comparative Analysis of Genetically Engineered Bt Corn and non-Bt Corn by Using Quantitative Dietary Exposure Assessment Modeling

PubMed Central

Delgado, James E.; Wolt, Jeffrey D.

2011-01-01

In this study, we investigate the long-term exposure (20 weeks) to fumonisin B1 (FB1) in grower-finisher pigs by conducting a quantitative exposure assessment (QEA). Our analytical approach involved both deterministic and semi-stochastic modeling for dietary comparative analyses of FB1 exposures originating from genetically engineered Bacillus thuringiensis (Bt)-corn, conventional non-Bt corn and distiller’s dried grains with solubles (DDGS) derived from Bt and/or non-Bt corn. Results from both deterministic and semi-stochastic demonstrated a distinct difference of FB1 toxicity in feed between Bt corn and non-Bt corn. Semi-stochastic results predicted the lowest FB1 exposure for Bt grain with a mean of 1.5 mg FB1/kg diet and the highest FB1 exposure for a diet consisting of non-Bt grain and non-Bt DDGS with a mean of 7.87 mg FB1/kg diet; the chronic toxicological incipient level of concern is 1.0 mg of FB1/kg of diet. Deterministic results closely mirrored but tended to slightly under predict the mean result for the semi-stochastic analysis. This novel comparative QEA model reveals that diet scenarios where the source of grain is derived from Bt corn presents less potential to induce FB1 toxicity than diets containing non-Bt corn. PMID:21909298

The effect of duration of exposure on sulfuric acid-induced pulmonary function changes in asthmatic adolescent subjects: A dose-response study

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

Koenig, J.Q.; Covert, D.S.; Larson, T.V.

To evaluate the pulmonary effects of varying doses of sulfuric acid, adolescent subjects with asthma were exposed to 35 or 70 micrograms/m3 sulfuric acid for 45 or 90 min. Exposure was carried out during intermittent moderate exercise. The pulmonary functions measured before and after exposure were FEV1, FVC, and total respiratory resistance. The 45 min exposures were associated with larger decreases in FEV1 (-6% or -3%) than the 90 min exposures (-1% or +2%). Analysis of variance of the change in FEV1 among the exposures revealed that the 45 min exposure to 35 micrograms/m3 was significant (p = 0.03). Themore » p value for 45 min exposure to 70 micrograms/m3 was not significant (p = 0.08). Using analysis of variance, neither of the 90 min exposures was associated with a significant decrease in FEV1 compared to air exposure. Also, none of the changes in FVC or RT was significant. When baseline to post-exposure changes were compared for each of the five test atmospheres using paired t tests, both of the 45 min exposures were associated with statistical significance (p < 0.001 for 35 micrograms/m3 and p < 0.005 for 70 micrograms/m3). This baseline to post exposure change was not statistically significant for the 90 min exposures. The reason for the lesser effect on pulmonary function at increased exposure duration is not known; it may be due to changes in either varying deposition patterns or changes in buffering capacity of the cells lining the airways. With respect to individual sensitivities to H2SO4, the data showed a significant consistency across test atmospheres.« less

Sensitivity analysis of the near-road dispersion model RLINE - An evaluation at Detroit, Michigan

NASA Astrophysics Data System (ADS)

Milando, Chad W.; Batterman, Stuart A.

2018-05-01

The development of accurate and appropriate exposure metrics for health effect studies of traffic-related air pollutants (TRAPs) remains challenging and important given that traffic has become the dominant urban exposure source and that exposure estimates can affect estimates of associated health risk. Exposure estimates obtained using dispersion models can overcome many of the limitations of monitoring data, and such estimates have been used in several recent health studies. This study examines the sensitivity of exposure estimates produced by dispersion models to meteorological, emission and traffic allocation inputs, focusing on applications to health studies examining near-road exposures to TRAP. Daily average concentrations of CO and NOx predicted using the Research Line source model (RLINE) and a spatially and temporally resolved mobile source emissions inventory are compared to ambient measurements at near-road monitoring sites in Detroit, MI, and are used to assess the potential for exposure measurement error in cohort and population-based studies. Sensitivity of exposure estimates is assessed by comparing nominal and alternative model inputs using statistical performance evaluation metrics and three sets of receptors. The analysis shows considerable sensitivity to meteorological inputs; generally the best performance was obtained using data specific to each monitoring site. An updated emission factor database provided some improvement, particularly at near-road sites, while the use of site-specific diurnal traffic allocations did not improve performance compared to simpler default profiles. Overall, this study highlights the need for appropriate inputs, especially meteorological inputs, to dispersion models aimed at estimating near-road concentrations of TRAPs. It also highlights the potential for systematic biases that might affect analyses that use concentration predictions as exposure measures in health studies.

Statistical modeling of crystalline silica exposure by trade in the construction industry using a database compiled from the literature.

PubMed

Sauvé, Jean-François; Beaudry, Charles; Bégin, Denis; Dion, Chantal; Gérin, Michel; Lavoué, Jérôme

2012-09-01

A quantitative determinants-of-exposure analysis of respirable crystalline silica (RCS) levels in the construction industry was performed using a database compiled from an extensive literature review. Statistical models were developed to predict work-shift exposure levels by trade. Monte Carlo simulation was used to recreate exposures derived from summarized measurements which were combined with single measurements for analysis. Modeling was performed using Tobit models within a multimodel inference framework, with year, sampling duration, type of environment, project purpose, project type, sampling strategy and use of exposure controls as potential predictors. 1346 RCS measurements were included in the analysis, of which 318 were non-detects and 228 were simulated from summary statistics. The model containing all the variables explained 22% of total variability. Apart from trade, sampling duration, year and strategy were the most influential predictors of RCS levels. The use of exposure controls was associated with an average decrease of 19% in exposure levels compared to none, and increased concentrations were found for industrial, demolition and renovation projects. Predicted geometric means for year 1999 were the highest for drilling rig operators (0.238 mg m(-3)) and tunnel construction workers (0.224 mg m(-3)), while the estimated exceedance fraction of the ACGIH TLV by trade ranged from 47% to 91%. The predicted geometric means in this study indicated important overexposure compared to the TLV. However, the low proportion of variability explained by the models suggests that the construction trade is only a moderate predictor of work-shift exposure levels. The impact of the different tasks performed during a work shift should also be assessed to provide better management and control of RCS exposure levels on construction sites.

Paediatric x-ray radiation dose reduction and image quality analysis.

PubMed

Martin, L; Ruddlesden, R; Makepeace, C; Robinson, L; Mistry, T; Starritt, H

2013-09-01

Collaboration of multiple staff groups has resulted in significant reduction in the risk of radiation-induced cancer from radiographic x-ray exposure during childhood. In this study at an acute NHS hospital trust, a preliminary audit identified initial exposure factors. These were compared with European and UK guidance, leading to the introduction of new factors that were in compliance with European guidance on x-ray tube potentials. Image quality was assessed using standard anatomical criteria scoring, and visual grading characteristics analysis assessed the impact on image quality of changes in exposure factors. This analysis determined the acceptability of gradual radiation dose reduction below the European and UK guidance levels. Chest and pelvis exposures were optimised, achieving dose reduction for each age group, with 7%-55% decrease in critical organ dose. Clinicians confirmed diagnostic image quality throughout the iterative process. Analysis of images acquired with preliminary and final exposure factors indicated an average visual grading analysis result of 0.5, demonstrating equivalent image quality. The optimisation process and final radiation doses are reported for Carestream computed radiography to aid other hospitals in minimising radiation risks to children.

Agent Orange exposure and prevalence of self-reported diseases in Korean Vietnam veterans.

PubMed

Yi, Sang-Wook; Ohrr, Heechoul; Hong, Jae-Seok; Yi, Jee-Jeon

2013-09-01

The aim of this study was to evaluate the association between Agent Orange exposure and self-reported diseases in Korean Vietnam veterans. A postal survey of 114 562 Vietnam veterans was conducted. The perceived exposure to Agent Orange was assessed by a 6-item questionnaire. Two proximity-based Agent Orange exposure indices were constructed using division/brigade-level and battalion/company-level unit information. Adjusted odds ratios (ORs) for age and other confounders were calculated using a logistic regression model. The prevalence of all self-reported diseases showed monotonically increasing trends as the levels of perceived self-reported exposure increased. The ORs for colon cancer (OR, 1.13), leukemia (OR, 1.56), hypertension (OR, 1.03), peripheral vasculopathy (OR, 1.07), enterocolitis (OR, 1.07), peripheral neuropathy (OR, 1.07), multiple nerve palsy (OR, 1.14), multiple sclerosis (OR, 1.24), skin diseases (OR, 1.05), psychotic diseases (OR, 1.07) and lipidemia (OR, 1.05) were significantly elevated for the high exposure group in the division/brigade-level proximity-based exposure analysis, compared to the low exposure group. The ORs for cerebral infarction (OR, 1.08), chronic bronchitis (OR, 1.05), multiple nerve palsy (OR, 1.07), multiple sclerosis (OR, 1.16), skin diseases (OR, 1.05), and lipidemia (OR, 1.05) were significantly elevated for the high exposure group in the battalion/company-level analysis. Korean Vietnam veterans with high exposure to Agent Orange experienced a higher prevalence of several self-reported chronic diseases compared to those with low exposure by proximity-based exposure assessment. The strong positive associations between perceived self-reported exposure and all self-reported diseases should be evaluated with discretion because the likelihood of reporting diseases was directly related to the perceived intensity of Agent Orange exposure.

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.

Fault tree analysis for exposure to refrigerants used for automotive air conditioning in the United States.

PubMed

Jetter, J J; Forte, R; Rubenstein, R

2001-02-01

A fault tree analysis was used to estimate the number of refrigerant exposures of automotive service technicians and vehicle occupants in the United States. Exposures of service technicians can occur when service equipment or automotive air-conditioning systems leak during servicing. The number of refrigerant exposures of service technicians was estimated to be 135,000 per year. Exposures of vehicle occupants can occur when refrigerant enters passenger compartments due to sudden leaks in air-conditioning systems, leaks following servicing, or leaks caused by collisions. The total number of exposures of vehicle occupants was estimated to be 3,600 per year. The largest number of exposures of vehicle occupants was estimated for leaks caused by collisions, and the second largest number of exposures was estimated for leaks following servicing. Estimates used in the fault tree analysis were based on a survey of automotive air-conditioning service shops, the best available data from the literature, and the engineering judgement of the authors and expert reviewers from the Society of Automotive Engineers Interior Climate Control Standards Committee. Exposure concentrations and durations were estimated and compared with toxicity data for refrigerants currently used in automotive air conditioners. Uncertainty was high for the estimated numbers of exposures, exposure concentrations, and exposure durations. Uncertainty could be reduced in the future by conducting more extensive surveys, measurements of refrigerant concentrations, and exposure monitoring. Nevertheless, the analysis indicated that the risk of exposure of service technicians and vehicle occupants is significant, and it is recommended that no refrigerant that is substantially more toxic than currently available substitutes be accepted for use in vehicle air-conditioning systems, absent a means of mitigating exposure.

A Comparison between the Second Korean Working Conditions Survey (KWCS) and the First KWCS.

PubMed

Kim, Young Sun; Park, Jungsun; Rhee, Kyung Yong; Kim, Hye Min

2015-06-01

The study was designed to assess the changes in working conditions through a comparative analysis of the characteristics of working conditions in 2006 and 2010. We performed a comparative analysis of the data related to the first Korean Working Conditions Survey (KWCS) and the second KWCS in the categories of demographic characteristics, quality of labor, exposure to hazards, and health problems. From our analysis of the demographic characteristics, we saw an increase in labor force participation rate of women and elderly people. As a result of the investigation with regards to working hours, the ratio of employees who worked for ≥ 49 hours per week was decreased and the ratio of employees who worked for ≥ 40 h/wk increased. As for exposure to hazards, exposure to tobacco smoke notably decreased in 2010 compared with 2006. With regards to health problems, there was a sharp increase in the number of people who complained of muscle pain in their arms and legs. KWCS data included many aspects of working conditions as a nationwide sample. In addition, because this is a periodic nationwide survey, the labor force, working hours, harmful factor exposure, and the change in health problems characteristics according to the flow of time could be investigated. The information comparing the main results of the first survey conducted in 2006 and the second survey conducted in 2010 obtained through this study can be used as an important base material for the establishment of the national policy.

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.

Comparison of electric field exposure monitoring instrumentation. Final report

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

Bracken, T.D.

1985-06-01

Electric field exposure monitoring instrumentation was compared and evaluated during three days of tests performed in 60-Hz electric fields. A conducting vest exposure meter and a small electric field exposure meter (EFEM) located in a shirt pocket, arm band or hard hat were compared in a series of static and dynamic tests. In some tests, the devices were worn simultaneously without interference to provide separate measures of identical exposure. Tests with stationary subjects wearing the instruments were used to measure the effects of grounding, and to establish the meter response in a standard posture for each subject. Dynamic occupational exposuremore » simulations were used to compare accumulated measurements of exposure between instruments and to compare measurements with predicted exposures. The simulations were based on analysis of the work-related behavior of substation electricians and operators. Electrician's tasks at ground level and in a bucket truck were simulated near an energized test line. A simulated substation inspection was performed in a 230 kV substation. The exposure measurements demonstrated an overall consistency between the meters. The vest demonstrated less intersubject variability and less detailed exposure characterization. Measurements with the shirt pocket EFEM were below those made with the vest and with the EFEM in other locations. Insulation provided by shoe soles appeared to be the largest factor in reducing measured exposures during the substation inspection below those predicted from the unperturbed field. Improvements in meter design and additional measurements are suggested. 11 refs., 20 figs., 28 tabs.« less

Mycological studies housed in the Apollo 16 microbial ecology evaluation device

NASA Technical Reports Server (NTRS)

Volz, P. A.

1973-01-01

Survival, death, and phenotype count have yielded variation in the number of fungi recovered from the controls and the flight exposed cuvettes during preliminary analysis of postflight first phase data. Also the preliminary analysis was indicative that fungi exposed to specific space flight conditions demonstrated variable survival rates and phenotype counts. Specific space flight conditions included full light space exposure for Chaetomium globosum, exposure at 300- and 254-nanometer wavelengths for Rhodotorula rubra, full light and 280-nanometer wavelength exposure for Trichophyton terrestre, and 254-nanometer wavelength exposure for Saccharomyces cerevisiae. In general, phenotype counts for flight cuvettes and survival rates for control cuvettes were higher compared with the remaining cuvettes.

Analysis of the Asbestos Permissible Exposure Level Threshold Standard

DTIC Science & Technology

1991-06-01

Risks from Smoki in. . .. . . .. ... .. 44 4. Is Society Paying Too Much? . . . . . . . . 44 a. Death Rates Compared to Lung Cancer .. 44 C. Conclusions...risk of death. Table 2 compares age-standardized lung cancer death rates (per 100,000 man-years) for cigarette smoking and/or occupational exposure to...Cancer Death Rates for Cigarette Smoking and Asbestos ZZposuze Group Exposed to Smoker Mortality Asbestos Ratio * Control No No 1.00 Asbestos Worker

Environmental hazards and stress: evidence from the Texas City Stress and Health Study.

PubMed

Peek, M K; Cutchin, M P; Freeman, D; Stowe, R P; Goodwin, J S

2009-10-01

Substantial research has suggested that exposure to environmental health hazards, such as polluting industrial activity, has deleterious effects on psychological and physiological well-being. However, one gap in the existing literature is comparative analysis of objective and subjective exposure's relative association with various measurable outcomes of exposure. These relationships were explored within a community sample of 2604 respondents living near a large petrochemical complex in Texas City, Texas, USA. Objective exposure was investigated using distance of residence from a cluster of petrochemical plants and subjective exposure using residents' concern about potential health effects from those plants. Regression models were then used to examine how each type of exposure predicts perceived stress, physiological markers of stress and perceived health. Results suggest that objective exposure was associated primarily with markers of physiological stress (interleukin-6 and viral reactivation), and subjective exposure (concern about petrochemical health risk) was associated with variables assessing perceived health. From the analysis, it can be inferred that, in the context of an environmental hazard of this type, subjective exposure may be at least as important a predictor of poor health outcomes as objective exposure.

A study on quantitative analysis of exposure dose caused by patient depending on time and distance in nuclear medicine examination

NASA Astrophysics Data System (ADS)

Kim, H. S.; Cho, J. H.; Shin, S. G.; Dong, K. R.; Chung, W. K.; Chung, J. E.

2013-01-01

This study evaluated possible actions that can help protect against and reduce radiation exposure by measuring the exposure dose for each type of isotope that is used frequently in nuclear medicine before performing numerical analysis of the effective half-life based on the measurement results. From July to August in 2010, the study targeted 10, 6 and 5 people who underwent an 18F-FDG (fludeoxyglucose) positron emission tomography (PET) scan, 99mTc-HDP bone scan, and 201Tl myocardial single-photon emission computed tomography (SPECT) scan, respectively, in the nuclear medicine department. After injecting the required medicine into the subjects, a survey meter was used to measure the dose depending on the distance from the heart and time elapsed. For the 18F-FDG PET scan, the dose decreased by approximately 66% at 90 min compared to that immediately after the injection and by 78% at a distance of 1 m compared to that at 0.3 m. In the 99mTc-HDP bone scan, the dose decreased by approximately 71% in 200 min compared to that immediately after the injection and by approximately 78% at a distance of 1 m compared to that at 0.3 m. In the 201Tl myocardial SPECT scan, the dose decreased by approximately 30% in 250 min compared to that immediately after the injection and by approximately 55% at a distance of 1 m compared to that at 0.3 m. In conclusion, the dose decreases by a large margin depending on the distance and time. In conclusion, this study measured the exposure doses by isotopes, distance from the heart and exposure time, and found that the doses were reduced significantly according the distance and the time.

Good research practices for comparative effectiveness research: approaches to mitigate bias and confounding in the design of nonrandomized studies of treatment effects using secondary data sources: the International Society for Pharmacoeconomics and Outcomes Research Good Research Practices for Retrospective Database Analysis Task Force Report--Part II.

PubMed

Cox, Emily; Martin, Bradley C; Van Staa, Tjeerd; Garbe, Edeltraut; Siebert, Uwe; Johnson, Michael L

2009-01-01

The goal of comparative effectiveness analysis is to examine the relationship between two variables, treatment, or exposure and effectiveness or outcome. Unlike data obtained through randomized controlled trials, researchers face greater challenges with causal inference with observational studies. Recognizing these challenges, a task force was formed to develop a guidance document on methodological approaches to addresses these biases. The task force was commissioned and a Chair was selected by the International Society for Pharmacoeconomics and Outcomes Research Board of Directors in October 2007. This report, the second of three reported in this issue of the Journal, discusses the inherent biases when using secondary data sources for comparative effectiveness analysis and provides methodological recommendations to help mitigate these biases. The task force report provides recommendations and tools for researchers to mitigate threats to validity from bias and confounding in measurement of exposure and outcome. Recommendations on design of study included: the need for data analysis plan with causal diagrams; detailed attention to classification bias in definition of exposure and clinical outcome; careful and appropriate use of restriction; extreme care to identify and control for confounding factors, including time-dependent confounding. Design of nonrandomized studies of comparative effectiveness face several daunting issues, including measurement of exposure and outcome challenged by misclassification and confounding. Use of causal diagrams and restriction are two techniques that can improve the theoretical basis for analyzing treatment effects in study populations of more homogeneity, with reduced loss of generalizability.

Meta-analysis of the association between short-term exposure to ambient ozone and respiratory hospital admissions

NASA Astrophysics Data System (ADS)

Ji, Meng; Cohan, Daniel S.; Bell, Michelle L.

2011-04-01

Ozone is associated with health impacts including respiratory outcomes; however, results differ across studies. Meta-analysis is an increasingly important approach to synthesizing evidence across studies. We conducted meta-analysis of short-term ozone exposure and respiratory hospitalizations to evaluate variation across studies and explore some of the challenges in meta-analysis. We identified 136 estimates from 96 studies and investigated how estimates differed by age, ozone metric, season, lag, region, disease category, and hospitalization type. Overall results indicate associations between ozone and various kinds of respiratory hospitalizations; however, study characteristics affected risk estimates. Estimates were similar, but higher, for the elderly compared to all ages and for previous day exposure compared to same day exposure. Comparison across studies was hindered by variation in definitions of disease categories, as some (e.g., asthma) were identified through >= 3 different sets of ICD codes. Although not all analyses exhibited evidence of publication bias, adjustment for publication bias generally lowered overall estimates. Emergency hospitalizations for total respiratory disease increased by 4.47% (95% interval: 2.48, 6.50%) per 10 ppb 24 h ozone among the elderly without adjustment for publication bias and 2.97% (1.05, 4.94%) with adjustment. Comparison of multi-city study results and meta-analysis based on single-city studies further suggested publication bias.

Maternal Voice and Short-Term Outcomes in Preterm Infants

PubMed Central

Krueger, Charlene; Parker, Leslie; Chiu, Sheau-Huey; Theriaque, Douglas

2013-01-01

This study explored effects of exposure to maternal voice on short-term outcomes in very low birth weight preterm infants cared for within an neonatal intensive care unit (NICU) without an ongoing program of developmental care. Using a comparative design, 53 infants born during their 27th to 28th postmenstrual week were sampled by convenience. Experimental groups were exposed to maternal voice during two developmental time periods. Group 1 listened to a recording of their mothers reciting a rhyme from 28 to 34 postmenstrual weeks. Group 2 waited 4 weeks and heard the recording from 32 to 34 weeks. The control group received routine care. The primary analysis of combined experimental groups compared to the control group revealed that the experimental infants experienced significantly fewer episodes of feeding intolerance and achieved full enteral feeds quicker compared to the control group. Further, in an analysis evaluating all three groups separately, it was noted that Group 1 experienced significantly fewer episodes of feeding intolerance compared to the control group. Study findings warrant further investigation of exposure to maternal voice and the developmental timing at which exposure is begun. PMID:20112262

Comparison of dust related respiratory effects in Dutch and Canadian grain handling industries: a pooled analysis.

PubMed Central

Peelen, S J; Heederik, D; Dimich-Ward, H D; Chan-Yeung, M; Kennedy, S M

1996-01-01

OBJECTIVES: Four previously conducted epidemiological studies in more than 1200 grain workers were used to compare exposure-response relations between exposure to grain dust and respiratory health. METHODS: The studies included Dutch workers from an animal feed mill and a transfer grain elevator and Canadian workers from a terminal grain elevator and the docks. Relations between forced expiratory volume in one second (FEV1) and exposure were analysed with multiple regression analysis corrected for smoking, age, and height. Exposure variables examined included cumulative and current dust exposure and the numbers of years a subject was employed in the industry. Sampling efficiencies of the Dutch and Canadian measurement techniques were compared in a pilot study. Results of this study were used to correct slopes of exposure-response relations for differences in dust fractions sampled by Dutch and Canadian personal dust samplers. RESULTS: Negative exposure-response relations were shown for regressions of FEV1 on cumulative and current exposure and years employed. Slopes of the exposure-response relations differed by a factor of three to five between industries, apart from results for cumulative exposure. Here the variation in slopes differed by a factor of 100, from -1 to -0.009 ml/mg.y/m3. The variation in slopes between industries reduced to between twofold to fivefold when the Dutch transfer elevator workers were not considered. There was evidence that the small exposure-response slope found for this group is caused by misclassification of exposure and a strong healthy worker effect. Alternative, but less likely explanations for the variation in slopes were differences in exposure concentrations, composition of grain dust, exposure characteristics, and measurement techniques. CONCLUSION: In conclusion, this study showed moderately similar negative exposure-response relations for four different populations from different countries, despite differences in methods of exposure assessment and exposure estimation. PMID:8983468

Comparison of dust related respiratory effects in Dutch and Canadian grain handling industries: a pooled analysis.

PubMed

Peelen, S J; Heederik, D; Dimich-Ward, H D; Chan-Yeung, M; Kennedy, S M

1996-08-01

Four previously conducted epidemiological studies in more than 1200 grain workers were used to compare exposure-response relations between exposure to grain dust and respiratory health. The studies included Dutch workers from an animal feed mill and a transfer grain elevator and Canadian workers from a terminal grain elevator and the docks. Relations between forced expiratory volume in one second (FEV1) and exposure were analysed with multiple regression analysis corrected for smoking, age, and height. Exposure variables examined included cumulative and current dust exposure and the numbers of years a subject was employed in the industry. Sampling efficiencies of the Dutch and Canadian measurement techniques were compared in a pilot study. Results of this study were used to correct slopes of exposure-response relations for differences in dust fractions sampled by Dutch and Canadian personal dust samplers. Negative exposure-response relations were shown for regressions of FEV1 on cumulative and current exposure and years employed. Slopes of the exposure-response relations differed by a factor of three to five between industries, apart from results for cumulative exposure. Here the variation in slopes differed by a factor of 100, from -1 to -0.009 ml/mg.y/m3. The variation in slopes between industries reduced to between twofold to fivefold when the Dutch transfer elevator workers were not considered. There was evidence that the small exposure-response slope found for this group is caused by misclassification of exposure and a strong healthy worker effect. Alternative, but less likely explanations for the variation in slopes were differences in exposure concentrations, composition of grain dust, exposure characteristics, and measurement techniques. In conclusion, this study showed moderately similar negative exposure-response relations for four different populations from different countries, despite differences in methods of exposure assessment and exposure estimation.

The risk of acute liver injury among users of antibiotic medications: a comparison of case-only studies.

PubMed

Brauer, Ruth; Ruigómez, Ana; Klungel, Olaf; Reynolds, Robert; Feudjo Tepie, Maurille; Smeeth, Liam; Douglas, Ian

2016-03-01

The aims of this study were two-fold: (i) to investigate the effect of exposure to antibiotic agents on the risk of acute liver injury using a self-controlled case series and case-crossover study and (ii) to compare the results between the case-only studies. For the self-controlled case series study relative incidence ratios (IRR) were calculated by dividing the rate of acute liver injury experienced during patients' periods of exposure to antibiotics to patients' rate of events during non-exposed time using conditional Poisson regression. For the case-crossover analysis we calculated Odds Ratios (OR) using conditional logistic regression by comparing exposure during 14- and 30-day risk windows with exposure during control moments. Using the self-controlled case series approach, the IRR was highest during the first 7 days after receipt of a prescription (10.01, 95% CI 6.59-15.18). Omitting post-exposure washout periods lowered the IRR to 7.2. The highest estimate in the case-crossover analysis was found when two 30-day control periods 1 year prior to the 30-day ALI risk period were retained in the analysis: OR = 6.5 (95% CI, 3.95-10.71). The lowest estimate was found when exposure in the 14-day risk period was compared to exposure in four consecutive 14-day control periods immediately prior to the risk period (OR = 3.05, 95% CI, 2.06-4.53). An increased relative risk of acute liver injury was consistently observed using both self-controlled case series and case-crossover designs. Case-only designs can be used as a viable alternative study design to study the risk of acute liver injury, albeit with some limitations. © 2015 The Authors Pharmacoepidemiology and Drug Safety Published by John Wiley & Sons Ltd.

Self-reported and laboratory evaluation of late pregnancy nicotine exposure and drugs of abuse.

PubMed

Hall, E S; Wexelblatt, S L; Greenberg, J M

2016-10-01

The objective of this study was to evaluate the prevalence of late pregnancy nicotine exposures, including secondhand smoke exposures, and to evaluate the associated risk of exposure to drugs of abuse. The study was a retrospective single-center cohort analysis of more than 18 months. We compared self-reported smoking status from vital birth records with mass spectrometry laboratory results of maternal urine using a chi-square test. Logistic regression estimated adjusted odds for detection of drugs of abuse based on nicotine detection. Compared with 8.6% self-reporting cigarette use, mass spectrometry detected high-level nicotine exposures for 16.5% of 708 women (P<0.001) and an additional 7.5% with low-level exposures. We identified an increased likelihood of exposure to drugs of abuse, presented as adjusted odds ratios, (95% confidence interval (CI), for both low-level (5.69, CI: 2.09 to 15.46) and high-level (13.93, CI: 7.06 to 27.49) nicotine exposures. Improved measurement tactics are critically needed to capture late pregnancy primary and passive nicotine exposures from all potential sources.

Association Between Cd Exposure and Risk of Prostate Cancer

PubMed Central

Ju-Kun, Song; Yuan, Dong-Bo; Rao, Hao-Fu; Chen, Tian-Fei; Luan, Bo-Shi; Xu, Xiao-Ming; Jiang, Fu-Neng; Zhong, Wei-De; Zhu, Jian-Guo

2016-01-01

Abstract Several observational studies on the association between Cd exposure and risk of prostate cancer have yielded inconsistent results. To address this issue, we conducted a meta-analysis to evaluate the correlation between Cd exposure and risk of prostate cancer. Relevant studies in PubMed and Embase databases were retrieved until October 2015. We compared the highest and lowest meta-analyses to quantitatively evaluate the relationship between Cd exposure and risk of prostate cancer. Summary estimates were obtained using a random-effects model. In the general population, high Cd exposure was not associated with increased prostate cancer (OR 1.21; 95% CI 0.91–1.64), whereas the combined standardized mortality ratio of the association between Cd exposure and risk of prostate cancer was 1.66 (95% CI 1.10–2.50) in populations exposed to occupational Cd. In addition, high D-Cd intake (OR 1.07; 95% CI 0.96–1.20) and U-Cd concentration (OR 0.86; 95% CI 0.48–1.55) among the general population was not related to the increased risk of prostate cancer. In the dose analysis, the summary relative risk was 1.07 (95% CI 0.73–1.57) for each 0.5 μg/g creatinine increase in U-Cd and 1.02 (95% CI 0.99–1.06) for each 10 μg/day increase of dietary Cd intake. However, compared with nonoccupational exposure, high occupational Cd exposure may be associated with the increased risk of prostate cancer. This meta-analysis suggests high Cd exposure as a risk factor for prostate cancer in occupational rather than nonoccupational populations. However, these results should be carefully interpreted because of the significant heterogeneity among studies. Additional large-scale and high-quality prospective studies are needed to confirm the association between Cd exposure and risk of prostate cancer. PMID:26871808

The changing patterns of psychosocial exposures at work in the south of Europe: Spain as a labor market laboratory.

PubMed

Utzet, Mireia; Moncada, Salvador; Molinero, Emilia; Llorens, Clara; Moreno, Neus; Navarro, Albert

2014-09-01

To examine the pattern of psychosocial risk exposures at work among wage-earners in Spain in 2005 and 2010, and to analyze changes in exposure inequalities by gender and job category. Psychosocial exposures were compared using the COPSOQ-ISTAS21 method, based on two surveys representative of the Spanish wage-earning population (2005 and 2010). Statistical analysis was conducted using correspondence analysis. There was an increase in exposure to high Double Presence, low Social Support, high Work Pace, and high Insecurity about finding a job; and reduction in exposure to high Insecurity about losing a job, and to high Insecurity over worsening of employment conditions. A gender- and occupation-related gradient was maintained. Although this study analyzes wage-earner "survivors" after the outbreak of the current economic crisis, it shows a worsening of harmful exposures to some psychosocial risks. In a context of job destruction, concerns about worsening working conditions appear to be subordinate to insecurity about job loss. © 2014 Wiley Periodicals, Inc.

Sensitivity analysis for direct and indirect effects in the presence of exposure-induced mediator-outcome confounders

PubMed Central

Chiba, Yasutaka

2014-01-01

Questions of mediation are often of interest in reasoning about mechanisms, and methods have been developed to address these questions. However, these methods make strong assumptions about the absence of confounding. Even if exposure is randomized, there may be mediator-outcome confounding variables. Inference about direct and indirect effects is particularly challenging if these mediator-outcome confounders are affected by the exposure because in this case these effects are not identified irrespective of whether data is available on these exposure-induced mediator-outcome confounders. In this paper, we provide a sensitivity analysis technique for natural direct and indirect effects that is applicable even if there are mediator-outcome confounders affected by the exposure. We give techniques for both the difference and risk ratio scales and compare the technique to other possible approaches. PMID:25580387

Analysis of Ingredient Lists to Quantitatively Characterize Chemicals in Consumer Products

EPA Science Inventory

The EPA’s ExpoCast program is developing high throughput (HT) approaches to generate the needed exposure estimates to compare against HT bioactivity data generated from the US inter-agency Tox21 and the US EPA ToxCast programs. Assessing such exposures for the thousands of...

Occupational styrene exposure for twelve product categories in the reinforced-plastics industry.

PubMed

Lemasters, G K; Carson, A; Samuels, S J

1985-08-01

Approximately 1500 occupational styrene exposure values from 28 reinforced-plastic manufacturers were collected retrospectively from companies and state and federal agencies. This report describes the major types of manufacturing processes within the reinforced-plastics industry and reports on the availability, collection and analysis of historical exposure information. Average exposure to styrene in most open-mold companies (24-82 ppm) was generally 2-3 times the exposure in press-mold companies (11-26 ppm). Manufacturers of smaller boats had mean styrene exposures of 82 ppm as compared to 37 ppm for yacht companies. There was considerable overlap in styrene exposure among job titles classified as directly exposed within open- and press-mold processing.

Comparison of modeling approaches to prioritize chemicals based on estimates of exposure and exposure potential

PubMed Central

Mitchell, Jade; Arnot, Jon A.; Jolliet, Olivier; Georgopoulos, Panos G.; Isukapalli, Sastry; Dasgupta, Surajit; Pandian, Muhilan; Wambaugh, John; Egeghy, Peter; Cohen Hubal, Elaine A.; Vallero, Daniel A.

2014-01-01

While only limited data are available to characterize the potential toxicity of over 8 million commercially available chemical substances, there is even less information available on the exposure and use-scenarios that are required to link potential toxicity to human and ecological health outcomes. Recent improvements and advances such as high throughput data gathering, high performance computational capabilities, and predictive chemical inherency methodology make this an opportune time to develop an exposure-based prioritization approach that can systematically utilize and link the asymmetrical bodies of knowledge for hazard and exposure. In response to the US EPA’s need to develop novel approaches and tools for rapidly prioritizing chemicals, a “Challenge” was issued to several exposure model developers to aid the understanding of current systems in a broader sense and to assist the US EPA’s effort to develop an approach comparable to other international efforts. A common set of chemicals were prioritized under each current approach. The results are presented herein along with a comparative analysis of the rankings of the chemicals based on metrics of exposure potential or actual exposure estimates. The analysis illustrates the similarities and differences across the domains of information incorporated in each modeling approach. The overall findings indicate a need to reconcile exposures from diffuse, indirect sources (far-field) with exposures from directly, applied chemicals in consumer products or resulting from the presence of a chemical in a microenvironment like a home or vehicle. Additionally, the exposure scenario, including the mode of entry into the environment (i.e. through air, water or sediment) appears to be an important determinant of the level of agreement between modeling approaches. PMID:23707726

Comparison of modeling approaches to prioritize chemicals based on estimates of exposure and exposure potential.

PubMed

Mitchell, Jade; Arnot, Jon A; Jolliet, Olivier; Georgopoulos, Panos G; Isukapalli, Sastry; Dasgupta, Surajit; Pandian, Muhilan; Wambaugh, John; Egeghy, Peter; Cohen Hubal, Elaine A; Vallero, Daniel A

2013-08-01

While only limited data are available to characterize the potential toxicity of over 8 million commercially available chemical substances, there is even less information available on the exposure and use-scenarios that are required to link potential toxicity to human and ecological health outcomes. Recent improvements and advances such as high throughput data gathering, high performance computational capabilities, and predictive chemical inherency methodology make this an opportune time to develop an exposure-based prioritization approach that can systematically utilize and link the asymmetrical bodies of knowledge for hazard and exposure. In response to the US EPA's need to develop novel approaches and tools for rapidly prioritizing chemicals, a "Challenge" was issued to several exposure model developers to aid the understanding of current systems in a broader sense and to assist the US EPA's effort to develop an approach comparable to other international efforts. A common set of chemicals were prioritized under each current approach. The results are presented herein along with a comparative analysis of the rankings of the chemicals based on metrics of exposure potential or actual exposure estimates. The analysis illustrates the similarities and differences across the domains of information incorporated in each modeling approach. The overall findings indicate a need to reconcile exposures from diffuse, indirect sources (far-field) with exposures from directly, applied chemicals in consumer products or resulting from the presence of a chemical in a microenvironment like a home or vehicle. Additionally, the exposure scenario, including the mode of entry into the environment (i.e. through air, water or sediment) appears to be an important determinant of the level of agreement between modeling approaches. Copyright © 2013 Elsevier B.V. All rights reserved.

Incorporating twitter-based human activity information in spatial analysis of crashes in urban areas.

PubMed

Bao, Jie; Liu, Pan; Yu, Hao; Xu, Chengcheng

2017-09-01

The primary objective of this study was to investigate how to incorporate human activity information in spatial analysis of crashes in urban areas using Twitter check-in data. This study used the data collected from the City of Los Angeles in the United States to illustrate the procedure. The following five types of data were collected: crash data, human activity data, traditional traffic exposure variables, road network attributes and social-demographic data. A web crawler by Python was developed to collect the venue type information from the Twitter check-in data automatically. The human activities were classified into seven categories by the obtained venue types. The collected data were aggregated into 896 Traffic Analysis Zones (TAZ). Geographically weighted regression (GWR) models were developed to establish a relationship between the crash counts reported in a TAZ and various contributing factors. Comparative analyses were conducted to compare the performance of GWR models which considered traditional traffic exposure variables only, Twitter-based human activity variables only, and both traditional traffic exposure and Twitter-based human activity variables. The model specification results suggested that human activity variables significantly affected the crash counts in a TAZ. The results of comparative analyses suggested that the models which considered both traditional traffic exposure and human activity variables had the best goodness-of-fit in terms of the highest R 2 and lowest AICc values. The finding seems to confirm the benefits of incorporating human activity information in spatial analysis of crashes using Twitter check-in data. Copyright © 2017 Elsevier Ltd. All rights reserved.

Optimization of camera exposure durations for multi-exposure speckle imaging of the microcirculation

PubMed Central

Kazmi, S. M. Shams; Balial, Satyajit; Dunn, Andrew K.

2014-01-01

Improved Laser Speckle Contrast Imaging (LSCI) blood flow analyses that incorporate inverse models of the underlying laser-tissue interaction have been used to develop more quantitative implementations of speckle flowmetry such as Multi-Exposure Speckle Imaging (MESI). In this paper, we determine the optimal camera exposure durations required for obtaining flow information with comparable accuracy with the prevailing MESI implementation utilized in recent in vivo rodent studies. A looping leave-one-out (LOO) algorithm was used to identify exposure subsets which were analyzed for accuracy against flows obtained from analysis with the original full exposure set over 9 animals comprising n = 314 regional flow measurements. From the 15 original exposures, 6 exposures were found using the LOO process to provide comparable accuracy, defined as being no more than 10% deviant, with the original flow measurements. The optimal subset of exposures provides a basis set of camera durations for speckle flowmetry studies of the microcirculation and confers a two-fold faster acquisition rate and a 28% reduction in processing time without sacrificing accuracy. Additionally, the optimization process can be used to identify further reductions in the exposure subsets for tailoring imaging over less expansive flow distributions to enable even faster imaging. PMID:25071956

Comparative Probabilistic Assessment of Occupational Pesticide Exposures Based on Regulatory Assessments.

PubMed

Pouzou, Jane G; Cullen, Alison C; Yost, Michael G; Kissel, John C; Fenske, Richard A

2017-11-06

Implementation of probabilistic analyses in exposure assessment can provide valuable insight into the risks of those at the extremes of population distributions, including more vulnerable or sensitive subgroups. Incorporation of these analyses into current regulatory methods for occupational pesticide exposure is enabled by the exposure data sets and associated data currently used in the risk assessment approach of the Environmental Protection Agency (EPA). Monte Carlo simulations were performed on exposure measurements from the Agricultural Handler Exposure Database and the Pesticide Handler Exposure Database along with data from the Exposure Factors Handbook and other sources to calculate exposure rates for three different neurotoxic compounds (azinphos methyl, acetamiprid, emamectin benzoate) across four pesticide-handling scenarios. Probabilistic estimates of doses were compared with the no observable effect levels used in the EPA occupational risk assessments. Some percentage of workers were predicted to exceed the level of concern for all three compounds: 54% for azinphos methyl, 5% for acetamiprid, and 20% for emamectin benzoate. This finding has implications for pesticide risk assessment and offers an alternative procedure that may be more protective of those at the extremes of exposure than the current approach. © 2017 Society for Risk Analysis.

Summary of ionizing radiation analysis on the Long Duration Exposure Facility

NASA Technical Reports Server (NTRS)

Parnell, T. A.

1991-01-01

The Ionizing Radiation Special Investigation Group (IRSIG) for the Long Duration Exposure Facility (LDEF) was established to perform radiation measurements and analysis not planned in the original experiments, and to assure availability of LDEF analysis results in a form useful to future missions. The IRSIG has organized extensive induced radioactivity measurements throughout LDEF, and a comprehensive program to compare the LDEF radiation measurements to values calculated using environment models. The activities and present status of the Group is described. The ionizing radiation results presented is summarized.

Environmental hazards and stress: evidence from the Texas City Stress and Health Study

PubMed Central

Peek, MK; Cutchin, MP; Freeman, D; Stowe, RP; Goodwin, JS

2013-01-01

Background Substantial research has suggested that exposure to environmental health hazards, such as polluting industrial activity, has deleterious effects on psychological and physiological well-being. However, one gap in the existing literature is comparative analysis of objective and subjective exposure's relative association with various measurable outcomes of exposure. Methods These relationships were explored within a community sample of 2604 respondents living near a large petrochemical complex in Texas City, Texas, USA. Objective exposure was investigated using distance of residence from a cluster of petrochemical plants and subjective exposure using residents' concern about potential health effects from those plants. Regression models were then used to examine how each type of exposure predicts perceived stress, physiological markers of stress and perceived health. Results Results suggest that objective exposure was associated primarily with markers of physiological stress (interleukin-6 and viral reactivation), and subjective exposure (concern about petrochemical health risk) was associated with variables assessing perceived health. Conclusions From the analysis, it can be inferred that, in the context of an environmental hazard of this type, subjective exposure may be at least as important a predictor of poor health outcomes as objective exposure. PMID:19282316

Farmworker Exposure to Pesticides: Methodologic Issues for the Collection of Comparable Data

PubMed Central

Arcury, Thomas A.; Quandt, Sara A.; Barr, Dana B.; Hoppin, Jane A.; McCauley, Linda; Grzywacz, Joseph G.; Robson, Mark G.

2006-01-01

The exposure of migrant and seasonal farmworkers and their families to agricultural and residential pesticides is a continuing public health concern. Pesticide exposure research has been spurred on by the development of sensitive and reliable laboratory techniques that allow the detection of minute amounts of pesticides or pesticide metabolites. The power of research on farmworker pesticide exposure has been limited because of variability in the collection of exposure data, the predictors of exposure considered, the laboratory procedures used in analyzing the exposure, and the measurement of exposure. The Farmworker Pesticide Exposure Comparable Data Conference assembled 25 scientists from diverse disciplinary and organizational backgrounds to develop methodologic consensus in four areas of farmworker pesticide exposure research: environmental exposure assessment, biomarkers, personal and occupational predictors of exposure, and health outcomes of exposure. In this introduction to this mini-monograph, first, we present the rationale for the conference and its organization. Second, we discuss some of the important challenges in conducting farmworker pesticide research, including the definition and size of the farmworker population, problems in communication and access, and the organization of agricultural work. Third, we summarize major findings from each of the conference’s four foci—environmental exposure assessment, biomonitoring, predictors of exposure, and health outcomes of exposure—as well as important laboratory and statistical analysis issues that cross-cut the four foci. PMID:16759996

Changes on lipid peroxidation,enzymatic activities and gene expression in planarian (Dugesia japonica) following exposure to perfluorooctanoic acid.

PubMed

Yuan, Zuoqing; Miao, Zili; Gong, Xiaoning; Zhao, Baoying; Zhang, Yuanyuan; Ma, Hongdou; Zhang, Jianyong; Zhao, Bosheng

2017-11-01

We investigated perfluorooctanoic acid (PFOA)-induced stress response in planarians. We administered different concentrations of PFOA to planarians for up to 10 d. PFOA exposure resulted in significant concentration-dependent elevations in lipid peroxidation, glutathione S-transferase and caspase-3 protease activities, and a significant decline in glutathione peroxidase activities compared with control groups. Exposure to PFOA significantly up-regulated the heat shock proteins hsp70 and hsp90, and p53, and down-regulated hsp40 compared with controls. PFOA exposure also increased HSP70 protein levels, as demonstrated by western blot analysis. These alterations indicated that PFOA exposure induced a stress response and affected the regulation of oxidative stress, enzymatic activities and gene expression. These results suggest that these sensitive parameters, together with other biomarkers, could be used for evaluating toxicity, for ecological risk assessment of PFOA in freshwaters. Copyright © 2017 Elsevier Inc. All rights reserved.

Additive Synergism between Asbestos and Smoking in Lung Cancer Risk: A Systematic Review and Meta-Analysis

PubMed Central

Ngamwong, Yuwadee; Tangamornsuksan, Wimonchat; Lohitnavy, Ornrat; Chaiyakunapruk, Nathorn; Scholfield, C. Norman; Reisfeld, Brad; Lohitnavy, Manupat

2015-01-01

Smoking and asbestos exposure are important risks for lung cancer. Several epidemiological studies have linked asbestos exposure and smoking to lung cancer. To reconcile and unify these results, we conducted a systematic review and meta-analysis to provide a quantitative estimate of the increased risk of lung cancer associated with asbestos exposure and cigarette smoking and to classify their interaction. Five electronic databases were searched from inception to May, 2015 for observational studies on lung cancer. All case-control (N = 10) and cohort (N = 7) studies were included in the analysis. We calculated pooled odds ratios (ORs), relative risks (RRs) and 95% confidence intervals (CIs) using a random-effects model for the association of asbestos exposure and smoking with lung cancer. Lung cancer patients who were not exposed to asbestos and non-smoking (A-S-) were compared with; (i) asbestos-exposed and non-smoking (A+S-), (ii) non-exposure to asbestos and smoking (A-S+), and (iii) asbestos-exposed and smoking (A+S+). Our meta-analysis showed a significant difference in risk of developing lung cancer among asbestos exposed and/or smoking workers compared to controls (A-S-), odds ratios for the disease (95% CI) were (i) 1.70 (A+S-, 1.31–2.21), (ii) 5.65; (A-S+, 3.38–9.42), (iii) 8.70 (A+S+, 5.8–13.10). The additive interaction index of synergy was 1.44 (95% CI = 1.26–1.77) and the multiplicative index = 0.91 (95% CI = 0.63–1.30). Corresponding values for cohort studies were 1.11 (95% CI = 1.00–1.28) and 0.51 (95% CI = 0.31–0.85). Our results point to an additive synergism for lung cancer with co-exposure of asbestos and cigarette smoking. Assessments of industrial health risks should take smoking and other airborne health risks when setting occupational asbestos exposure limits. PMID:26274395

Amygdala volume in combat-exposed veterans with and without posttraumatic stress disorder: a cross-sectional study.

PubMed

Kuo, Janice R; Kaloupek, Danny G; Woodward, Steven H

2012-10-01

Data from animal models demonstrate a link between stress exposure and hypertrophic changes in the amygdala; however, studies of adults with posttraumatic stress disorder (PTSD) have failed to find analogous structural alterations. To compare amygdala volumes between a sample of combat veterans with and without PTSD (analysis 1) and examine whether our observation of larger amygdala volume in individuals with PTSD could be accounted for by the presence of trauma exposure in childhood and the severity of combat exposure in adulthood (analysis 2). Cross-sectional magnetic resonance imaging. Veterans Affairs Palo Alto Health Care System Inpatient Trauma Recovery Program and Veterans Affairs New England Health Care System Outpatient PTSD program. Ninety-nine combat-exposed veterans from the Vietnam Conflict or the Persian Gulf War who had been exposed to substantial military operational stress. Amygdala volume adjusted for total cerebral volume, Life Events Checklist, and the Combat Exposure Scale. Analysis 1 indicated that combat-exposed individuals with PTSD exhibited larger total amygdala volume compared with their non-PTSD counterparts (99 individuals, P = .047). Analysis 2 indicated that greater severity of combat exposure (87 individuals, P = .02), as well as the interaction between the presence of early life trauma and the severity of combat exposure (87 individuals, P = .008), were significantly associated with smaller total amygdala volume. The PTSD diagnosis continued to explain larger amygdala volume (87 individuals, P = .006). Posttraumatic stress disorder is associated with enlarged amygdala volume, above the variance accounted for by a history of early life trauma and severity of adult trauma exposure. The discrepancy between our and prior findings may be explained by variability in these trauma indices in previous investigations. These findings support additional study of amygdala structure in human stress disorders and further delineation of the role of early and adult trauma on associated neurologic changes.

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.

Rating locomotive crew diesel emission exposure profiles using statistics and Bayesian Decision Analysis.

PubMed

Hewett, Paul; Bullock, William H

2014-01-01

For more than 20 years CSX Transportation (CSXT) has collected exposure measurements from locomotive engineers and conductors who are potentially exposed to diesel emissions. The database included measurements for elemental and total carbon, polycyclic aromatic hydrocarbons, aromatics, aldehydes, carbon monoxide, and nitrogen dioxide. This database was statistically analyzed and summarized, and the resulting statistics and exposure profiles were compared to relevant occupational exposure limits (OELs) using both parametric and non-parametric descriptive and compliance statistics. Exposure ratings, using the American Industrial Health Association (AIHA) exposure categorization scheme, were determined using both the compliance statistics and Bayesian Decision Analysis (BDA). The statistical analysis of the elemental carbon data (a marker for diesel particulate) strongly suggests that the majority of levels in the cabs of the lead locomotives (n = 156) were less than the California guideline of 0.020 mg/m(3). The sample 95th percentile was roughly half the guideline; resulting in an AIHA exposure rating of category 2/3 (determined using BDA). The elemental carbon (EC) levels in the trailing locomotives tended to be greater than those in the lead locomotive; however, locomotive crews rarely ride in the trailing locomotive. Lead locomotive EC levels were similar to those reported by other investigators studying locomotive crew exposures and to levels measured in urban areas. Lastly, both the EC sample mean and 95%UCL were less than the Environmental Protection Agency (EPA) reference concentration of 0.005 mg/m(3). With the exception of nitrogen dioxide, the overwhelming majority of the measurements for total carbon, polycyclic aromatic hydrocarbons, aromatics, aldehydes, and combustion gases in the cabs of CSXT locomotives were either non-detects or considerably less than the working OELs for the years represented in the database. When compared to the previous American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV) of 3 ppm the nitrogen dioxide exposure profile merits an exposure rating of AIHA exposure category 1. However, using the newly adopted TLV of 0.2 ppm the exposure profile receives an exposure rating of category 4. Further evaluation is recommended to determine the current status of nitrogen dioxide exposures. [Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Occupational and Environmental Hygiene for the following free supplemental resource: additional text on OELs, methods, results, and additional figures and tables.].

Visible lesion thresholds and model predictions for Q-switched 1318-nm and 1540-nm laser exposures to porcine skin

NASA Astrophysics Data System (ADS)

Zohner, Justin J.; Schuster, Kurt J.; Chavey, Lucas J.; Stolarski, David J.; Kumru, Semih S.; Rockwell, Benjamin A.; Thomas, Robert J.; Cain, Clarence P.

2006-02-01

Skin damage thresholds were measured and compared with theoretical predictions using a skin thermal model for near-IR laser pulses at 1318 nm and 1540 nm. For the 1318-nm data, a Q-switched, 50-ns pulse with a spot size of 5 mm was applied to porcine skin and the damage thresholds were determined at 1 hour and 24 hours postexposure using Probit analysis. The same analysis was conducted for a Q-switched, 30-ns pulse at 1540 nm with a spot size of 5 mm. The Yucatan mini-pig was used as the skin model for human skin due to its similarity to pigmented human skin. The ED 50 for these skin exposures at 24 hours postexposure was 10.5 J/cm2 for the 1318-nm exposures, and 6.1 J/cm2 for the 1540-nm exposures. These results were compared to thermal model predictions. We show that the thermal model fails to account for the ED 50 values observed. A brief discussion of the possible causes of this discrepancy is presented. These thresholds are also compared with previously published skin minimum visible lesion (MVL) thresholds and with the ANSI Standard's MPE for 1318-nm lasers at 50 ns and 1540-nm lasers at 30 ns.

Impact of temporal upscaling and chemical transport model horizontal resolution on reducing ozone exposure misclassification

NASA Astrophysics Data System (ADS)

Xu, Yadong; Serre, Marc L.; Reyes, Jeanette M.; Vizuete, William

2017-10-01

We have developed a Bayesian Maximum Entropy (BME) framework that integrates observations from a surface monitoring network and predictions from a Chemical Transport Model (CTM) to create improved exposure estimates that can be resolved into any spatial and temporal resolution. The flexibility of the framework allows for input of data in any choice of time scales and CTM predictions of any spatial resolution with varying associated degrees of estimation error and cost in terms of implementation and computation. This study quantifies the impact on exposure estimation error due to these choices by first comparing estimations errors when BME relied on ozone concentration data either as an hourly average, the daily maximum 8-h average (DM8A), or the daily 24-h average (D24A). Our analysis found that the use of DM8A and D24A data, although less computationally intensive, reduced estimation error more when compared to the use of hourly data. This was primarily due to the poorer CTM model performance in the hourly average predicted ozone. Our second analysis compared spatial variability and estimation errors when BME relied on CTM predictions with a grid cell resolution of 12 × 12 km2 versus a coarser resolution of 36 × 36 km2. Our analysis found that integrating the finer grid resolution CTM predictions not only reduced estimation error, but also increased the spatial variability in daily ozone estimates by 5 times. This improvement was due to the improved spatial gradients and model performance found in the finer resolved CTM simulation. The integration of observational and model predictions that is permitted in a BME framework continues to be a powerful approach for improving exposure estimates of ambient air pollution. The results of this analysis demonstrate the importance of also understanding model performance variability and its implications on exposure error.

Secondary traumatic stress among mental health providers working with the military: prevalence and its work- and exposure-related correlates.

PubMed

Cieslak, Roman; Anderson, Valerie; Bock, Judith; Moore, Bret A; Peterson, Alan L; Benight, Charles C

2013-11-01

Our research assessed the prevalence of secondary traumatic stress (STS) among mental health providers working with military patients. We also investigated personal, work-related, and exposure-related correlates of STS. Finally, using meta-analysis, the mean level of STS symptoms in this population was compared with the mean level of these symptoms in other groups. Participants (N = 224) completed measures of indirect exposure to trauma (i.e., diversity, volume, frequency, ratio), appraisal of secondary exposure impact, direct exposure to trauma, STS, and work characteristics. The prevalence of STS was 19.2%. Personal history of trauma, complaints about having too many patients, and more negative appraisals of the impact caused by an indirect exposure to trauma were associated with higher frequency of STS symptoms. A meta-analysis showed that the severity of intrusion, avoidance, and arousal symptoms of STS was similar across various groups of professionals indirectly exposed to trauma (e.g., mental health providers, rescue workers, social workers).

Hair analysis for the biomonitoring of pesticide exposure: comparison with blood and urine in a rat model.

PubMed

Appenzeller, Brice M R; Hardy, Emilie M; Grova, Nathalie; Chata, Caroline; Faÿs, François; Briand, Olivier; Schroeder, Henri; Duca, Radu-Corneliu

2017-08-01

Urine and plasma have been used to date for the biomonitoring of exposure to pollutants and are still the preferred fluids for this purpose; however, these fluids mainly provide information on the short term and may present a high level of variability regarding pesticide concentrations, especially for nonpersistent compounds. Hair analysis may provide information about chronic exposure that is averaged over several months; therefore, this method has been proposed as an alternative to solely relying on these fluids. Although the possibility of detecting pesticides in hair has been demonstrated over the past few years, the unknown linkage between exposure and pesticides concentration in hair has limited the recognition of this matrix as a relevant tool for assessing human exposure. Based on a rat model in which there was controlled exposure to a mixture of pesticides composed of lindane, β-hexachlorocyclohexane, β-endosulfan, p,p'-DDT, p,p'-DDE, dieldrin, pentachlorophenol, diazinon, chlorpyrifos, cyhalothrin, permethrin, cypermethrin, propiconazole, fipronil, oxadiazon, diflufenican, trifluralin, carbofuran, and propoxur, the current work demonstrates the association between exposure intensity and resulting pesticide concentration in hair. We also compared the results obtained from a hair analysis to urine and plasma collected from the same rats. Hair, blood, and urine were collected from rats submitted to 90-day exposure by gavage to the aforementioned mixture of common pesticides at different levels. We observed a linear relationship between exposure intensity and the concentration of pesticides in the rats' hair (R Pearson 0.453-0.978, p < 0.01). A comparison with results from urine and plasma samples demonstrated the relevance of hair analysis and, for many chemicals, its superiority over using fluids for differentiating animals from different groups and for re-attributing animals to their correct groups of exposure based on pesticide concentrations in the matrix. Therefore, this study strongly supports hair analysis as a reliable tool to be used during epidemiological studies to investigate exposure-associated adverse health effects.

The incidence and prevalence of ankle sprain injury: a systematic review and meta-analysis of prospective epidemiological studies.

PubMed

Doherty, Cailbhe; Delahunt, Eamonn; Caulfield, Brian; Hertel, Jay; Ryan, John; Bleakley, Chris

2014-01-01

Ankle sprain is one of the most common musculoskeletal injuries, yet a contemporary review and meta-analysis of prospective epidemiological studies investigating ankle sprain does not exist. Our aim is to provide an up-to-date account of the incidence rate and prevalence period of ankle sprain injury unlimited by timeframe or context activity. We conducted a systematic review and meta-analyses of English articles using relevant computerised databases. Search terms included Medical Search Headings for the ankle joint, injury and epidemiology. The following inclusion criteria were used: the study must report epidemiology findings of injuries sustained in an observed sample; the study must report ankle sprain injury with either incidence rate or prevalence period among the surveyed sample, or provide sufficient data from which these figures could be calculated; the study design must be prospective. Independent extraction of articles was performed by two authors using pre-determined data fields. One-hundred and eighty-one prospective epidemiology studies from 144 separate papers were included. The average rating of all the included studies was 6.67/11, based on an adapted version of the STROBE (STrengthening the Reporting of OBservational studies in Epidemiology) guidelines for rating observational studies. 116 studies were considered high quality and 65 were considered low quality. The main findings of the meta-analysis demonstrated a higher incidence of ankle sprain in females compared with males (13.6 vs 6.94 per 1,000 exposures), in children compared with adolescents (2.85 vs 1.94 per 1,000 exposures) and adolescents compared with adults (1.94 vs 0.72 per 1,000 exposures). The sport category with the highest incidence of ankle sprain was indoor/court sports, with a cumulative incidence rate of 7 per 1,000 exposures or 1.37 per 1,000 athlete exposures and 4.9 per 1,000 h. Low-quality studies tended to underestimate the incidence of ankle sprain when compared with high-quality studies (0.54 vs 11.55 per 1,000 exposures). Ankle sprain prevalence period estimates were similar across sub-groups. Lateral ankle sprain was the most commonly observed type of ankle sprain. Females were at a higher risk of sustaining an ankle sprain compared with males and children compared with adolescents and adults, with indoor and court sports the highest risk activity. Studies at a greater risk of bias were more likely to underestimate the risk of ankle sprain. Participants were at a significantly higher risk of sustaining a lateral ankle sprain compared with syndesmotic and medial ankle sprains.

Mediation analysis allowing for exposure-mediator interactions and causal interpretation: theoretical assumptions and implementation with SAS and SPSS macros

PubMed Central

Valeri, Linda; VanderWeele, Tyler J.

2012-01-01

Mediation analysis is a useful and widely employed approach to studies in the field of psychology and in the social and biomedical sciences. The contributions of this paper are several-fold. First we seek to bring the developments in mediation analysis for non linear models within the counterfactual framework to the psychology audience in an accessible format and compare the sorts of inferences about mediation that are possible in the presence of exposure-mediator interaction when using a counterfactual versus the standard statistical approach. Second, the work by VanderWeele and Vansteelandt (2009, 2010) is extended here to allow for dichotomous mediators and count outcomes. Third, we provide SAS and SPSS macros to implement all of these mediation analysis techniques automatically and we compare the types of inferences about mediation that are allowed by a variety of software macros. PMID:23379553

Mediation analysis allowing for exposure-mediator interactions and causal interpretation: theoretical assumptions and implementation with SAS and SPSS macros.

PubMed

Valeri, Linda; Vanderweele, Tyler J

2013-06-01

Mediation analysis is a useful and widely employed approach to studies in the field of psychology and in the social and biomedical sciences. The contributions of this article are several-fold. First we seek to bring the developments in mediation analysis for nonlinear models within the counterfactual framework to the psychology audience in an accessible format and compare the sorts of inferences about mediation that are possible in the presence of exposure-mediator interaction when using a counterfactual versus the standard statistical approach. Second, the work by VanderWeele and Vansteelandt (2009, 2010) is extended here to allow for dichotomous mediators and count outcomes. Third, we provide SAS and SPSS macros to implement all of these mediation analysis techniques automatically, and we compare the types of inferences about mediation that are allowed by a variety of software macros. (PsycINFO Database Record (c) 2013 APA, all rights reserved).

Virtual reality exposure therapy in anxiety disorders: a quantitative meta-analysis.

PubMed

Opriş, David; Pintea, Sebastian; García-Palacios, Azucena; Botella, Cristina; Szamosközi, Ştefan; David, Daniel

2012-02-01

Virtual reality exposure therapy (VRET) is a promising intervention for the treatment of the anxiety disorders. The main objective of this meta-analysis is to compare the efficacy of VRET, used in a behavioral or cognitive-behavioral framework, with that of the classical evidence-based treatments, in anxiety disorders. A comprehensive search of the literature identified 23 studies (n = 608) that were included in the final analysis. The results show that in the case of anxiety disorders, (1) VRET does far better than the waitlist control; (2) the post-treatment results show similar efficacy between the behavioral and the cognitive behavioral interventions incorporating a virtual reality exposure component and the classical evidence-based interventions, with no virtual reality exposure component; (3) VRET has a powerful real-life impact, similar to that of the classical evidence-based treatments; (4) VRET has a good stability of results over time, similar to that of the classical evidence-based treatments; (5) there is a dose-response relationship for VRET; and (6) there is no difference in the dropout rate between the virtual reality exposure and the in vivo exposure. Implications are discussed. © 2011 Wiley Periodicals, Inc.

Revisiting exposure: fatal and non-fatal traffic injury risk across different populations of travelers in Wisconsin, 2001-2009.

PubMed

McAndrews, Carolyn; Beyer, Kirsten; Guse, Clare E; Layde, Peter

2013-11-01

Comparing the injury risk of different travel modes requires using a travel-based measure of exposure. In this study we quantify injury risk by travel mode, age, race/ethnicity, sex, and injury severity using three different travel-based exposure measures (person-trips, person-minutes of travel, and person-miles of travel) to learn how these metrics affect the characterization of risk across populations. We used a linked database of hospital and police records to identify non-fatal injuries (2001-2009), the Fatality Analysis Reporting System for fatalities (2001-2009), and the 2001 Wisconsin Add-On to the National Household Travel Survey for exposure measures. In Wisconsin, bicyclists and pedestrians have a moderately higher injury risk compared to motor vehicle occupants (adjusting for demographic factors), but the risk is much higher when exposure is measured in distance. Although the analysis did not control for socio-economic status (a likely confounder) it showed that American Indian and Black travelers in Wisconsin face higher transportation injury risk than White travelers (adjusting for sex and travel mode), across all three measures of exposure. Working with multiple metrics to form comprehensive injury risk profiles such as this one can inform decision making about how to prioritize investments in transportation injury prevention. Copyright © 2013 Elsevier Ltd. All rights reserved.

Analysis of intervention strategies for inhalation exposure to polycyclic aromatic hydrocarbons and associated lung cancer risk based on a Monte Carlo population exposure assessment model.

PubMed

Zhou, Bin; Zhao, Bin

2014-01-01

It is difficult to evaluate and compare interventions for reducing exposure to air pollutants, including polycyclic aromatic hydrocarbons (PAHs), a widely found air pollutant in both indoor and outdoor air. This study presents the first application of the Monte Carlo population exposure assessment model to quantify the effects of different intervention strategies on inhalation exposure to PAHs and the associated lung cancer risk. The method was applied to the population in Beijing, China, in the year 2006. Several intervention strategies were designed and studied, including atmospheric cleaning, smoking prohibition indoors, use of clean fuel for cooking, enhancing ventilation while cooking and use of indoor cleaners. Their performances were quantified by population attributable fraction (PAF) and potential impact fraction (PIF) of lung cancer risk, and the changes in indoor PAH concentrations and annual inhalation doses were also calculated and compared. The results showed that atmospheric cleaning and use of indoor cleaners were the two most effective interventions. The sensitivity analysis showed that several input parameters had major influence on the modeled PAH inhalation exposure and the rankings of different interventions. The ranking was reasonably robust for the remaining majority of parameters. The method itself can be extended to other pollutants and in different places. It enables the quantitative comparison of different intervention strategies and would benefit intervention design and relevant policy making.

World Trade Center Disaster Exposure-Related Probable Posttraumatic Stress Disorder among Responders and Civilians: A Meta-Analysis

PubMed Central

Liu, Bian; Tarigan, Lukman H.; Bromet, Evelyn J.; Kim, Hyun

2014-01-01

The World Trade Center (WTC) disaster on September 11, 2001 was an unprecedented traumatic event with long-lasting health consequences among the affected populations in the New York metropolitan area. This meta-analysis aimed to estimate the risk of probable posttraumatic stress disorder (PTSD) associated with specific types of WTC exposures. Meta-analytical findings from 10 studies of 3,271 to 20,294 participants yielded 37 relevant associations. The pooled summary odds ratio (OR) was 2.05 (95% confidence interval (CI): 1.82, 2.32), with substantial heterogeneity linked to exposure classification, cohort type, data source, PTSD assessment instrument/criteria, and lapse time since 9/11. In general, responders (e.g. police, firefighters, rescue/recovery workers and volunteers) had a lower probable PTSD risk (OR = 1.61; 95% CI: 1.39, 1.87) compared to civilians (e.g. residents, office workers, and passersby; OR = 2.71, 95% CI: 2.35, 3.12). The differences in ORs between responders and civilians were larger for physical compared to psychosocial exposure types. We also found that injury, lost someone, and witnessed horror were the three (out of six) most pernicious exposures. These findings suggest that these three exposures should be a particular focus in psychological evaluation and treatment programs in WTC intervention and future emergency preparedness efforts. PMID:25047411

World Trade Center disaster exposure-related probable posttraumatic stress disorder among responders and civilians: a meta-analysis.

PubMed

Liu, Bian; Tarigan, Lukman H; Bromet, Evelyn J; Kim, Hyun

2014-01-01

The World Trade Center (WTC) disaster on September 11, 2001 was an unprecedented traumatic event with long-lasting health consequences among the affected populations in the New York metropolitan area. This meta-analysis aimed to estimate the risk of probable posttraumatic stress disorder (PTSD) associated with specific types of WTC exposures. Meta-analytical findings from 10 studies of 3,271 to 20,294 participants yielded 37 relevant associations. The pooled summary odds ratio (OR) was 2.05 (95% confidence interval (CI): 1.82, 2.32), with substantial heterogeneity linked to exposure classification, cohort type, data source, PTSD assessment instrument/criteria, and lapse time since 9/11. In general, responders (e.g. police, firefighters, rescue/recovery workers and volunteers) had a lower probable PTSD risk (OR = 1.61; 95% CI: 1.39, 1.87) compared to civilians (e.g. residents, office workers, and passersby; OR = 2.71, 95% CI: 2.35, 3.12). The differences in ORs between responders and civilians were larger for physical compared to psychosocial exposure types. We also found that injury, lost someone, and witnessed horror were the three (out of six) most pernicious exposures. These findings suggest that these three exposures should be a particular focus in psychological evaluation and treatment programs in WTC intervention and future emergency preparedness efforts.

Acquisition of HIV by African-Born Residents of Victoria, Australia: Insights from Molecular Epidemiology

PubMed Central

Lemoh, Chris; Ryan, Claire E.; Sekawi, Zamberi; Hearps, Anna C.; Aleksic, Eman; Chibo, Doris; Grierson, Jeffrey; Baho, Samia; Street, Alan; Hellard, Margaret; Biggs, Beverley-Ann; Crowe, Suzanne M.

2013-01-01

African-born Australians are a recognised “priority population” in Australia's Sixth National HIV/AIDS Strategy. We compared exposure location and route for African-born people living with HIV (PLHIV) in Victoria, Australia, with HIV-1 pol subtype from drug resistance assays and geographical origin suggested by phylogenetic analysis of env gene. Twenty adult HIV positive African-born Victorian residents were recruited via treating doctors. HIV exposure details were obtained from interviews and case notes. Viral RNA was extracted from participant stored plasma or whole blood. The env V3 region was sequenced and compared to globally representative reference HIV-1 sequences in the Los Alamos National Library HIV Database. Twelve participants reported exposure via heterosexual sex and two via iatrogenic blood exposures; four were men having sex with men (MSM); two were exposed via unknown routes. Eight participants reported exposure in their countries of birth, seven in Australia, three in other countries and two in unknown locations. Genotype results (pol) were available for ten participants. HIV env amplification was successful in eighteen cases. HIV-1 subtype was identified in all participants: eight both pol and env; ten env alone and two pol alone. Twelve were subtype C, four subtype B, three subtype A and one subtype CRF02_AG. Reported exposure location was consistent with the phylogenetic clustering of env sequences. African Australians are members of multiple transnational social and sexual networks influencing their exposure to HIV. Phylogenetic analysis may complement traditional surveillance to discern patterns of HIV exposure, providing focus for HIV prevention programs in mobile populations. PMID:24391866

Acute respiratory effects and biomarkers of inflammation due to welding-derived nanoparticle aggregates.

PubMed

Dierschke, Katrin; Isaxon, Christina; Andersson, Ulla B K; Assarsson, Eva; Axmon, Anna; Stockfelt, Leo; Gudmundsson, Anders; Jönsson, Bo A G; Kåredal, Monica; Löndahl, Jakob; Pagels, Joakim; Wierzbicka, Aneta; Bohgard, Mats; Nielsen, Jörn

2017-07-01

Welders are exposed to airborne particles from the welding environment and often develop symptoms work-related from the airways. A large fraction of the particles from welding are in the nano-size range. In this study we investigate if the welders' airways are affected by exposure to particles derived from gas metal arc welding in mild steel in levels corresponding to a normal welding day. In an exposure chamber, 11 welders with and 10 welders without work-related symptoms from the lower airways and 11 non-welders without symptoms, were exposed to welding fumes (1 mg/m 3 ) and to filtered air, respectively, in a double-blind manner. Symptoms from eyes and upper and lower airways and lung function were registered. Blood and nasal lavage (NL) were sampled before, immediately after and the morning after exposure for analysis of markers of oxidative stress. Exhaled breath condensate (EBC) for analysis of leukotriene B4 (LT-B4) was sampled before, during and immediately after exposure. No adverse effects of welding exposure were found regarding symptoms and lung function. However, EBC LT-B4 decreased significantly in all participants after welding exposure compared to filtered air. NL IL-6 increased immediately after exposure in the two non-symptomatic groups and blood neutrophils tended to increase in the symptomatic welder group. The morning after, neutrophils and serum IL-8 had decreased in all three groups after welding exposure. Remarkably, the symptomatic welder group had a tenfold higher level of EBC LT-B4 compared to the two groups without symptoms. Despite no clinical adverse effects at welding, changes in inflammatory markers may indicate subclinical effects even at exposure below the present Swedish threshold limit (8 h TWA respirable dust).

Individual and collective exposure to political violence: Palestinian adolescents coping with conflict.

PubMed

Giacaman, Rita; Shannon, Harry S; Saab, Hana; Arya, Neil; Boyce, Will

2007-08-01

We conducted a survey of Palestinian adolescents in school. We hypothesized that collective and individual exposures to violence would both negatively affect adolescents' mental health. We also anticipated that the negative effect of collective exposures on mental health would be less than that of individual exposures. Our analysis was designed to test these hypotheses. A representative sample of 3415 students of 10th and 11th grades from the Ramallah District of the West Bank participated in the survey. The primary independent variables were scales of individual and collective exposures to trauma/violence (ETV) by the Israeli military and settlers. Factor analysis revealed several sub-scales. Outcome measures were constructed and included: a binary measure of depressive-like states, and emotional, depressive-like state, and somatic scales. Several variables were identified as possible covariates: gender, age, school-type, residence, employment status of father, and identity documents held. Logistic and multiple regression analyses revealed a strong relationship between ETV and adolescents' mental health, with both individual and collective exposures having independent effects. There was a higher prevalence of depressive-like symptoms among girls compared with boys, and in adolescents living in Palestinian refugee camps compared with those living in cities, towns and villages. The findings confirmed our hypothesis that both individual and collective ETV independently affect the mental health of adolescents. Contrary to expectations, individual exposures did not consistently have a greater negative effect on health outcomes than collective exposures, although the sub-scale of direct personal exposures to violence consistently showed the strongest effect among sub-scales. The results emphasize the importance of going beyond individual experiences and including the health outcomes of collective violation when analyzing violent and traumatic contexts.

When is exposure to a natural disaster traumatic? Comparison of a trauma questionnaire and disaster exposure inventory.

PubMed

Harville, Emily W; Jacobs, Marni; Boynton-Jarrett, Renée

2015-01-01

Few studies have compared the sensitivity of trauma questionnaires to disaster inventories for assessing the prevalence of exposure to natural disaster or associated risk for post-disaster psychopathology. The objective of this analysis was to compare reporting of disaster exposure on a trauma questionnaire (Brief Trauma Questionnaire [BTQ]) to an inventory of disaster experience. Between 2011 and 2014, a sample of 841 reproductive-aged southern Louisiana women were interviewed using the BTQ and completed a detailed inventory about exposure to hurricanes and flooding. Post-traumatic stress disorder (PTSD) symptomology was measured with the Post-Traumatic Stress Checklist, and depression with the Edinburgh Depression Scale. The single question addressing disaster exposure on the BTQ had a sensitivity of between 65% and 70% relative to the more detailed questions. Reporting disaster exposure on the BTQ was more likely for those who reported illness/injury due to a hurricane or flood (74%-77%) or danger (77-79%), compared to those who reported damage (69-71%) or evacuation (64-68%). Reporting disaster exposure on the BTQ was associated with depression (odds ratio [OR] 2.29, 95% confidence interval [CI] 1.43-3.68). A single question is unlikely to be useful for assessing the degree of exposure to disaster across a broad population, and varies in utility depending on the mental health outcome of interest: the single trauma question is useful for assessing depression risk.

One-Session Exposure Treatment for Social Anxiety with Specific Fear of Public Speaking

ERIC Educational Resources Information Center

Hindo, Cindy S.; Gonzalez-Prendes, A. Antonio

2011-01-01

Objectives: This pilot study evaluated the effectiveness of one-session, exposure-based therapy, to treat social anxiety disorder (SAD) with specific fear of public speaking. Methods: A quasi-experimental pre-posttest design with repeated measures-within-subject Analysis of Variance and paired sample t-tests was used to compare pretest, posttest…

MPATHav: A software prototype for multiobjective routing in transportation risk assessment

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

Ganter, J.H.; Smith, J.D.

Most routing problems depend on several important variables: transport distance, population exposure, accident rate, mandated roads (e.g., HM-164 regulations), and proximity to emergency response resources are typical. These variables may need to be minimized or maximized, and often are weighted. `Objectives` to be satisfied by the analysis are thus created. The resulting problems can be approached by combining spatial analysis techniques from geographic information systems (GIS) with multiobjective analysis techniques from the field of operations research (OR); we call this hybrid multiobjective spatial analysis` (MOSA). MOSA can be used to discover, display, and compare a range of solutions that satisfymore » a set of objectives to varying degrees. For instance, a suite of solutions may include: one solution that provides short transport distances, but at a cost of high exposure; another solution that provides low exposure, but long distances; and a range of solutions between these two extremes.« less

Unbiased Scanning Method and Data Banking Approach Using Ultra-High Performance Liquid Chromatography Coupled with High-Resolution Mass Spectrometry for Quantitative Comparison of Metabolite Exposure in Plasma across Species Analyzed at Different Dates.

PubMed

Gao, Hongying; Deng, Shibing; Obach, R Scott

2015-12-01

An unbiased scanning methodology using ultra high-performance liquid chromatography coupled with high-resolution mass spectrometry was used to bank data and plasma samples for comparing the data generated at different dates. This method was applied to bank the data generated earlier in animal samples and then to compare the exposure to metabolites in animal versus human for safety assessment. With neither authentic standards nor prior knowledge of the identities and structures of metabolites, full scans for precursor ions and all ion fragments (AIF) were employed with a generic gradient LC method to analyze plasma samples at positive and negative polarity, respectively. In a total of 22 tested drugs and metabolites, 21 analytes were detected using this unbiased scanning method except that naproxen was not detected due to low sensitivity at negative polarity and interference at positive polarity; and 4'- or 5-hydroxy diclofenac was not separated by a generic UPLC method. Statistical analysis of the peak area ratios of the analytes versus the internal standard in five repetitive analyses over approximately 1 year demonstrated that the analysis variation was significantly different from sample instability. The confidence limits for comparing the exposure using peak area ratio of metabolites in animal plasma versus human plasma measured over approximately 1 year apart were comparable to the analysis undertaken side by side on the same days. These statistical analysis results showed it was feasible to compare data generated at different dates with neither authentic standards nor prior knowledge of the analytes.

Arrested neural and advanced mesenchymal differentiation of glioblastoma cells-comparative study with neural progenitors

PubMed Central

2009-01-01

Background Although features of variable differentiation in glioblastoma cell cultures have been reported, a comparative analysis of differentiation properties of normal neural GFAP positive progenitors, and those shown by glioblastoma cells, has not been performed. Methods Following methods were used to compare glioblastoma cells and GFAP+NNP (NHA): exposure to neural differentiation medium, exposure to adipogenic and osteogenic medium, western blot analysis, immunocytochemistry, single cell assay, BrdU incorporation assay. To characterize glioblastoma cells EGFR amplification analysis, LOH/MSI analysis, and P53 nucleotide sequence analysis were performed. Results In vitro differentiation of cancer cells derived from eight glioblastomas was compared with GFAP-positive normal neural progenitors (GFAP+NNP). Prior to exposure to differentiation medium, both types of cells showed similar multilineage phenotype (CD44+/MAP2+/GFAP+/Vimentin+/Beta III-tubulin+/Fibronectin+) and were positive for SOX-2 and Nestin. In contrast to GFAP+NNP, an efficient differentiation arrest was observed in all cell lines isolated from glioblastomas. Nevertheless, a subpopulation of cells isolated from four glioblastomas differentiated after serum-starvation with varying efficiency into derivatives indistinguishable from the neural derivatives of GFAP+NNP. Moreover, the cells derived from a majority of glioblastomas (7 out of 8), as well as GFAP+NNP, showed features of mesenchymal differentiation when exposed to medium with serum. Conclusion Our results showed that stable co-expression of multilineage markers by glioblastoma cells resulted from differentiation arrest. According to our data up to 95% of glioblastoma cells can present in vitro multilineage phenotype. The mesenchymal differentiation of glioblastoma cells is advanced and similar to mesenchymal differentiation of normal neural progenitors GFAP+NNP. PMID:19216795

Quantitative risk assessment of the aggregate dermal exposure to the sensitizing fragrance geraniol in personal care products and household cleaning agents.

PubMed

Nijkamp, M M; Bokkers, B G H; Bakker, M I; Ezendam, J; Delmaar, J E

2015-10-01

A quantitative risk assessment was performed to establish if consumers are at risk for being dermally sensitized by the fragrance geraniol. Aggregate dermal exposure to geraniol was estimated using the Probabilistic Aggregate Consumer Exposure Model, containing data on the use of personal care products and household cleaning agents. Consumer exposure to geraniol via personal care products appeared to be higher than via household cleaning agents. The hands were the body parts receiving the highest exposure to geraniol. Dermal sensitization studies were assessed to derive the point of departure needed for the estimation of the Acceptable Exposure Level (AEL). Two concentrations were derived, one based on human studies and the other from dose-response analysis of the available murine local lymph node assay data. The aggregate dermal exposure assessment resulted in body part specific median exposures up to 0.041 μg/cm(2) (highest exposure 102 μg/cm(2)) for hands. Comparing the exposure to the lowest AEL (55 μg/cm(2)), shows that a range of 0.02-0.86% of the population may have an aggregated exposure which exceeds the AEL. Furthermore, it is demonstrated that personal care products contribute more to the consumer's geraniol exposure compared to household cleaning agents. Copyright © 2015 Elsevier Inc. All rights reserved.

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 effect of electromagnetic radiation of wireless connections on morphology of amniotic fluid

NASA Astrophysics Data System (ADS)

Novikov, Vsevolod O.; Titova, Natalia; Azarhov, Olexand; Wójcik, Waldemar; GrÄ dz, Å.»aklin; Mussabekova, Assel

2016-09-01

The article considers the effect of wireless networks on the morphology of amniotic fluid (AF) to demonstrate possible risks involving pregnant women. The analysis of AF thesiograms after exposure of the model fluid to Wi-Fi, 3G and β- radiation was chosen as the research method. A comparative analysis of facies structures is carried out, and depth maps of the facies structure are created. This comparative analysis permits an evaluation of the efficiency of morphological changes. It is shown that AF control facies differ in the concentration of areas with a narrow peripheral area and ellipsoidal formations of crystalloids in circumferences center. After exposure of different types of radiation onto AF, the facies structures collapse and form their own conglomerates. The obtained results show that the considered types of radiation have a negative effect on AF.

Pharmacokinetics and pharmacogenetics of the MEK1/2 inhibitor, selumetinib, in Asian and Western healthy subjects: a pooled analysis.

PubMed

Dymond, Angela W; Elks, Cathy; Martin, Paul; Carlile, David J; Mariani, Gabriella; Lovick, Susan; Huang, Yifan; Lorch, Ulrike; Brown, Helen; So, Karen

2017-06-01

Emerging data on selumetinib, a MEK1/2 inhibitor in clinical development, suggest a possible difference in pharmacokinetics (PK) between Japanese and Western patients. This pooled analysis sought to assess the effect of ethnicity on selumetinib exposure in healthy Western and Asian subjects, and to identify any association between genetic variants in the UGT1A1, CYP2C19 and ABCG2 genes and observed differences in selumetinib PK. A pooled analysis of data from ten Phase I studies, one in Asian subjects (encompassing Japanese, non-Japanese Asian and Indian Asian subjects) and nine in Western subjects, was conducted. Key findings were derived from the collective exposure data across doses of 25, 35, 50 and 75 mg selumetinib; primary variables were dose-normalized AUC and C max . PK data from 308 subjects (10 studies) were available for the pooled analysis; genetic data from 87 subjects (3 studies) were available for the pharmacogenetic analysis. Dose-normalized AUC and C max were 35% (95% CI: 25-47%) and 39% (95% CI: 24-56%) higher in the pooled Asian group, respectively, compared with Western subjects. PK exposure parameters were similar between the Japanese, non-Japanese Asian and Indian groups. There was no evidence that the polymorphisms assessed in the genes UGT1A1, CYP2C19 and ABCG2 account for observed PK differences. Selumetinib exposure was higher in healthy Asian subjects compared with Western subjects, and these data provide valuable insight for clinicians to consider when treating patients of Asian ethnicity with selumetinib.

Signals for a promoting action of radiation in cancer incidence data.

PubMed

Heidenreich, W F

2002-09-01

The two-stage clonal expansion model allows us in principle to separate the initiating and promoting action of radiation. Features of the relative risk functions which indicate the action of promotion most clearly are identified for acute and for protracted exposures. They are compared with data: for acute exposure, some results of a preliminary analysis of the atomic-bomb survivor data are given; for protracted exposure, patterns in the fatal lung tumours of radon-exposed rats are discussed.

Combined analysis of job and task benzene air exposures among workers at four US refinery operations

PubMed Central

Shin, Jennifer (Mi); Unice, Ken M; Gaffney, Shannon H; Kreider, Marisa L; Gelatt, Richard H; Panko, Julie M

2016-01-01

Workplace air samples analyzed for benzene at four US refineries from 1976 to 2007 were pooled into a single dataset to characterize similarities and differences between job titles, tasks and refineries, and to provide a robust dataset for exposure reconstruction. Approximately 12,000 non-task (>180 min) personal samples associated with 50 job titles and 4000 task (<180 min) samples characterizing 24 tasks were evaluated. Personal air sample data from four individual refineries were pooled based on a number of factors including (1) the consistent sampling approach used by refinery industrial hygienists over time, (2) the use of similar exposure controls, (3) the comparability of benzene content of process streams and end products, (4) the ability to assign uniform job titles and task codes across all four refineries, and (5) our analysis of variance (ANOVA) of the distribution of benzene air concentrations for select jobs/tasks across all four refineries. The jobs and tasks most frequently sampled included those with highest potential contact with refinery product streams containing benzene, which reflected the targeted sampling approach utilized by the facility industrial hygienists. Task and non-task data were analyzed to identify and account for significant differences within job-area, task-job, and task-area categories. This analysis demonstrated that in general, areas with benzene containing process streams were associated with greater benzene air concentrations compared to areas with process streams containing little to no benzene. For several job titles and tasks analyzed, there was a statistically significant decrease in benzene air concentration after 1990. This study provides a job and task-focused analysis of occupational exposure to benzene during refinery operations, and it should be useful for reconstructing refinery workers’ exposures to benzene over the past 30 years. PMID:26862134

Combined analysis of job and task benzene air exposures among workers at four US refinery operations.

PubMed

Burns, Amanda; Shin, Jennifer Mi; Unice, Ken M; Gaffney, Shannon H; Kreider, Marisa L; Gelatt, Richard H; Panko, Julie M

2017-03-01

Workplace air samples analyzed for benzene at four US refineries from 1976 to 2007 were pooled into a single dataset to characterize similarities and differences between job titles, tasks and refineries, and to provide a robust dataset for exposure reconstruction. Approximately 12,000 non-task (>180 min) personal samples associated with 50 job titles and 4000 task (<180 min) samples characterizing 24 tasks were evaluated. Personal air sample data from four individual refineries were pooled based on a number of factors including (1) the consistent sampling approach used by refinery industrial hygienists over time, (2) the use of similar exposure controls, (3) the comparability of benzene content of process streams and end products, (4) the ability to assign uniform job titles and task codes across all four refineries, and (5) our analysis of variance (ANOVA) of the distribution of benzene air concentrations for select jobs/tasks across all four refineries. The jobs and tasks most frequently sampled included those with highest potential contact with refinery product streams containing benzene, which reflected the targeted sampling approach utilized by the facility industrial hygienists. Task and non-task data were analyzed to identify and account for significant differences within job-area, task-job, and task-area categories. This analysis demonstrated that in general, areas with benzene containing process streams were associated with greater benzene air concentrations compared to areas with process streams containing little to no benzene. For several job titles and tasks analyzed, there was a statistically significant decrease in benzene air concentration after 1990. This study provides a job and task-focused analysis of occupational exposure to benzene during refinery operations, and it should be useful for reconstructing refinery workers' exposures to benzene over the past 30 years.

Stratified probabilistic bias analysis for BMI-related exposure misclassification in postmenopausal women.

PubMed

Banack, Hailey R; Stokes, Andrew; Fox, Matthew P; Hovey, Kathleen M; Cespedes-Feliciano, Elizabeth M; LeBlanc, Erin; Bird, Chloe; Caan, Bette J; Kroenke, Candyce H; Allison, Matthew A; Going, Scott B; Snetslaar, Linda; Cheng, Ting-Yuan David; Chlebowski, Rowan T; Stefanick, Marcia L; LaMonte, Michael J; Wactawski-Wende, Jean

2018-06-01

There is widespread concern about the use of body mass index (BMI) to define obesity status in postmenopausal women because it may not accurately represent an individual's true obesity status. The objective of the present study is to examine and adjust for exposure misclassification bias from using an indirect measure of obesity (BMI) compared with a direct measure of obesity (percent body fat). We used data from postmenopausal non-Hispanic black and non-Hispanic white women in the Women's Health Initiative (WHI; n=126,459). Within the WHI, a sample of 11,018 women were invited to participate in a sub-study involving dual-energy x-ray absorptiometry (DXA) scans. We examined indices of validity comparing BMI-defined obesity (≥30kg/m) with obesity defined by percent body fat. We then used probabilistic bias analysis models stratified by age and race to explore the effect of exposure misclassification on the obesity-mortality relationship. Validation analyses highlight that using a BMI cutpoint of 30 kg/m to define obesity in postmenopausal women is associated with poor validity. There were notable differences in sensitivity by age and race. Results from the stratified bias analysis demonstrated that failing to adjust for exposure misclassification bias results in attenuated estimates of the obesity-mortality relationship. For example, in non-Hispanic white women age 50-59, the conventional risk difference was 0.017 (95% CI 0.01, 0.023) and the bias-adjusted risk difference was 0.035 (95% SI 0.028, 0.043). These results demonstrate the importance of using quantitative bias analysis techniques to account for non-differential exposure misclassification of BMI-defined obesity.

Airborne asbestos exposures associated with gasket and packing replacement: a simulation study and meta-analysis.

PubMed

Madl, Amy K; Hollins, Dana M; Devlin, Kathryn D; Donovan, Ellen P; Dopart, Pamela J; Scott, Paul K; Perez, Angela L

2014-08-01

Exposures to airborne asbestos during the removal and installation of internal gaskets and packing associated with a valve overhaul were characterized and compared to published data according to different variables (e.g., product, equipment, task, tool, setting, duration). Personal breathing zone and area samples were collected during twelve events simulating gasket and packing replacement, clean-up and clothing handling. These samples were analyzed using PCM and TEM methods and PCM-equivalent (PCME) airborne asbestos concentrations were calculated. A meta-analysis was performed to compare these data with airborne asbestos concentrations measured in other studies involving gaskets and packing. Short-term mechanic and assistant airborne asbestos concentrations during valve work averaged 0.013f/cc and 0.008f/cc (PCME), respectively. Area samples averaged 0.008f/cc, 0.005f/cc, and 0.003f/cc (PCME) for center, bystander, and remote background, respectively. Assuming a tradesman conservatively performs 1-3 gasket and/or packing replacements daily, an average 8-h TWA was estimated to be 0.002-0.010f/cc (PCME). Combining these results in a meta-analysis of the published exposure data showed that the majority of airborne asbestos exposures during work with gaskets and packing fall within a consistent and low range. Significant differences in airborne concentrations were observed between power versus manual tools and removal versus installation tasks. Airborne asbestos concentrations resulting from gasket and packing work during a valve overhaul are consistent with historical exposure data on replacement of asbestos-containing gasket and packing materials involving multiple variables and, in nearly all plausible scenarios, result in average airborne asbestos concentrations below contemporaneous occupational exposure limits for asbestos. Copyright © 2014 Elsevier Inc. All rights reserved.

Effect of Exposure Type and Timing of Injuries in Division I College Football: A 4-year Single Program Analysis.

PubMed

Krill, Michael K; Borchers, James R; Hoffman, Joshua T; Tatarski, Rachel L; Hewett, Timothy E

2017-02-01

Football players compete with a high risk of injury due to the sport. With the recent efforts to improve safety, the National Collegiate Athletic Association (NCAA) established new terminology to clearly define exposure types and reduce the number of high contact exposures. To compare football injury rates (IR) with a focus on game versus practice, time in season of injury, mechanism of injury and utilizing recent exposure types defined by the NCAA (live contact, full-pads and non-contact). Licensed medical professionals monitored a college football program regular season from 2012-2015. Each injury was classified by timing of the injury, mechanism of injury, and whether it occurred in game or practice. Player attendance and type of exposure (non-contact, full-pad or live contact, which involves live tackling to the ground and/or full-speed blocking and can occur in full-pad or half-pad ('shell') equipment) was documented. IR were calculated per 1000 athlete-exposures (AE). Mid-exact P tests compared rates between variables. The game IR was over three times as high as the practice IR (p < .001). Live contact exposures had the greatest IR of 5.702/1000 AE and were seven times more likely to produce an injury compared to non-contact exposures (p < .001); whereas, live contact exposures were about two times more likely to produce an injury compared to full-pad exposures (p = .004). The majority of injuries observed occurred from a contact mechanism (IR: 2.508/1000 AE). The highest IR during the fall football season occurred in the pre-season at 5.769/1000 AE. Overall IR observed in this cohort were lower than prior studies published before recent NCAA rule changes and guideline implementation to improve athlete safety. Athletes in this cohort were at significantly increased risk of injury from live contact exposures.

Lung Cancer Mortality (1950–1999) among Eldorado Uranium Workers: A Comparison of Models of Carcinogenesis and Empirical Excess Risk Models

PubMed Central

Eidemüller, Markus; Jacob, Peter; Lane, Rachel S. D.; Frost, Stanley E.; Zablotska, Lydia B.

2012-01-01

Lung cancer mortality after exposure to radon decay products (RDP) among 16,236 male Eldorado uranium workers was analyzed. Male workers from the Beaverlodge and Port Radium uranium mines and the Port Hope radium and uranium refinery and processing facility who were first employed between 1932 and 1980 were followed up from 1950 to 1999. A total of 618 lung cancer deaths were observed. The analysis compared the results of the biologically-based two-stage clonal expansion (TSCE) model to the empirical excess risk model. The spontaneous clonal expansion rate of pre-malignant cells was reduced at older ages under the assumptions of the TSCE model. Exposure to RDP was associated with increase in the clonal expansion rate during exposure but not afterwards. The increase was stronger for lower exposure rates. A radiation-induced bystander effect could be a possible explanation for such an exposure response. Results on excess risks were compared to a linear dose-response parametric excess risk model with attained age, time since exposure and dose rate as effect modifiers. In all models the excess relative risk decreased with increasing attained age, increasing time since exposure and increasing exposure rate. Large model uncertainties were found in particular for small exposure rates. PMID:22936975

Accounting for differing exposure patterns between laboratory tests and the field in the assessment of long-term risks of pesticides to terrestrial vertebrates.

PubMed

Fischer, David L

2005-11-01

Long-term risks of pesticides to birds and mammals are currently assessed by comparing effects thresholds determined in chronic laboratory studies to exposure levels expected to occur in the field. However, there is often a mismatch between exposure patterns tested in the laboratory tests (exposure levels held constant) and those experienced by animals in the field (exposure levels varying over time). Three methods for addressing this problem are presented and discussed. Time-weighted averaging (TWA) converts a variable field exposure regime to a single value that can be compared directly to the laboratory test results. Body-burden modeling (BBM) is applied to both laboratory and field exposure regimes allowing a straightforward comparison of body residue levels expected for each situation. Temporal analysis (TA) uses expert judgment to decide if the length of time exposure exceeds a toxicity threshold is long enough to cause biologically significant effects. To reduce uncertainty in long-term assessments, the conduct of specialized laboratory tests in which test subjects are administered a time-varying exposure that mimics what occurs in the field should be considered. Such tests may also be useful testing the validity of each of these assessment methods.

Comparison of premortem and postmortem estimates of plutonium deposited in the skeleton and liver of six individuals

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

Sula, M.J.; Bihl, D.E.; Carbaugh, E.H.

1988-04-01

Assessment of organ burdens after internal exposures to radionuclides is often necessary to evaluate the health and regulatory implications of the exposure. The assessment of plutonium activity in skeleton and liver is usually estimated from measurements of plutonium excreted via urine. As part of the overall evaluation of internal dose assessment techniques, it is useful to compare the results of organ burden estimates made from evaluation of urinary excretion data with those made at death from tissue samples collected posthumously from the individual. Estimates of plutonium in the skeleton and liver, based on postmortem analysis of tissue samples for sixmore » individuals, were obtained from the US Transuranium Registry (USTR). Bioassay data and other radiation exposure information obtained from the individuals' files were used to estimate their skeleton and liver burdens at the times of their deaths, and these estimates were compared to those obtained through tissue analysis. 6 refs., 2 tabs.« less

Internal exposure from building materials exhaling (222)Rn and (220)Rn as compared to external exposure due to their natural radioactivity content.

PubMed

Ujić, Predrag; Celiković, Igor; Kandić, Aleksandar; Vukanac, Ivana; Durasević, Mirjana; Dragosavac, Dusan; Zunić, Zora S

2010-01-01

The main scope of this paper is to point out the importance of introducing radon and thoron exhalation measurements from building materials in the regulating frame. Currently (2009), such a regulation of this kind of exposure is not explicitly included in the Serbian regulating network. To this end, this work reports concentration measurements of (226)Ra, (232)Th and (40)K and radon and thoron exhalation rates from building materials used in Serbia. Following detailed analysis, it was noticed that both internal exposures to radon and/or thoron exhaling from building materials may exceed external exposures to their precursors contained therein.

Assigning exposure to pesticides and solvents from self-reports collected by a computer assisted personal interview and expert assessment of job codes: the UK Adult Brain Tumour Study.

PubMed

Hepworth, S J; Bolton, A; Parslow, R C; van Tongeren, M; Muir, K R; McKinney, P A

2006-04-01

To compare assignment of occupational pesticide and solvent exposure using self-reported data collected by a computer assisted personal interview (CAPI) with exposure based on expert assessment of job codes. To discuss the advantages and disadvantages of using a CAPI to collect individual occupational exposure data. Between 2001 and 2004, 1495 participants were interviewed using a CAPI for a case-control study of adult brain tumours and acoustic neuromas. Two types of occupational data were collected: (1) a full history, including job title from which a job code was assigned from the Standard Occupational Classification; and (2) specific details on pesticide and solvent exposure reported by participants. Study members' experiences of using the CAPI were recorded and advantages and disadvantages summarised. Of 7192 jobs recorded, the prevalence of self-reported exposure was 1.3% for pesticides and 11.5% for solvents. Comparing this with exposure expertly assessed from job titles showed 53.6% and 45.8% concordance for pesticides and solvents respectively. Advantages of the CAPI include no data entry stage, automatic input validation, and a reduction in interviewer bias. Disadvantages include an adverse effect on study implementation as a consequence of resources required for programming and difficulties encountered with data management prior to analysis. Different methods of exposure assessment derive different exposure levels for pesticide and solvent exposure at work. Agreement between self-reported and expert assessment of exposure was greater for pesticides compared to solvents. The advantages of using a CAPI for the collection of complex data outweigh the disadvantages for interviewers and data quality but using such a method requires extra resources at the study outset.

Assigning exposure to pesticides and solvents from self‐reports collected by a computer assisted personal interview and expert assessment of job codes: the UK Adult Brain Tumour Study

PubMed Central

Hepworth, S J; Bolton, A; Parslow, R C; van Tongeren, M; Muir, K R; McKinney, P A

2006-01-01

Objectives To compare assignment of occupational pesticide and solvent exposure using self‐reported data collected by a computer assisted personal interview (CAPI) with exposure based on expert assessment of job codes. To discuss the advantages and disadvantages of using a CAPI to collect individual occupational exposure data. Methods Between 2001 and 2004, 1495 participants were interviewed using a CAPI for a case‐control study of adult brain tumours and acoustic neuromas. Two types of occupational data were collected: (1) a full history, including job title from which a job code was assigned from the Standard Occupational Classification; and (2) specific details on pesticide and solvent exposure reported by participants. Study members' experiences of using the CAPI were recorded and advantages and disadvantages summarised. Results Of 7192 jobs recorded, the prevalence of self‐reported exposure was 1.3% for pesticides and 11.5% for solvents. Comparing this with exposure expertly assessed from job titles showed 53.6% and 45.8% concordance for pesticides and solvents respectively. Advantages of the CAPI include no data entry stage, automatic input validation, and a reduction in interviewer bias. Disadvantages include an adverse effect on study implementation as a consequence of resources required for programming and difficulties encountered with data management prior to analysis. Conclusions Different methods of exposure assessment derive different exposure levels for pesticide and solvent exposure at work. Agreement between self‐reported and expert assessment of exposure was greater for pesticides compared to solvents. The advantages of using a CAPI for the collection of complex data outweigh the disadvantages for interviewers and data quality but using such a method requires extra resources at the study outset. PMID:16556747

Risk factors for tube exposure as a late complication of glaucoma drainage implant surgery.

PubMed

Chaku, Meenakshi; Netland, Peter A; Ishida, Kyoko; Rhee, Douglas J

2016-01-01

The purpose of this study was to evaluate the risk factors for tube exposure after glaucoma drainage implant surgery. This was a retrospective case-controlled observational study of 64 eyes from 64 patients. Thirty-two eyes of 32 patients with tube erosion requiring surgical revision were compared with 32 matched control eyes of 32 patients. Univariate and multivariate risk factor analyses were performed. Mean age was significantly younger in the tube exposure group compared with the control group (48.2±28.1 years versus 67.3±18.0 years, respectively; P=0.003). The proportion of diabetic patients (12.5%) in the tube exposure group was significantly less (P=0.041) compared with the control group (37.5%). Comparisons of the type and position of the drainage implant were not significantly different between the two groups. The average time to tube exposure was 17.2±18.0 months after implantation of the drainage device. In both univariate and multivariate analyses, younger age (P=0.005 and P=0.027) and inflammation prior to tube exposure (P≤0.001 and P=0.004) were significant risk factors. Diabetes was a significant risk factor only in the univariate analysis (P=0.027). Younger age and inflammation were significant risk factors for tube exposure after drainage implant surgery.

Antidepressant exposure may protect against decrement in frontal gray matter volumes in geriatric depression.

PubMed

Lavretsky, Helen; Roybal, Donna J; Ballmaier, Martina; Toga, Arthur W; Kumar, Anand

2005-08-01

Depressed elderly patients with and without antidepressant exposure were compared to normal controls to examine the effects of prior antidepressant exposure on regional brain gray matter volumes using magnetic resonance imaging (MRI). The study was conducted from October 1999 to January 2003. Patients and controls were closely matched by age and education. They underwent comprehensive neuropsychiatric and physical examinations. Measures of the total frontal lobe and the frontal gray and white matter volumes corrected by the intracranial volume were obtained using MRI, together with clinical measures of medical burden. Historical information about prior exposure to antidepressant drugs was collected using multiple information sources. The groups were compared using multivariate analyses of covariance, controlling for age, sex, and medical burden. The study sample comprised 41 patients who met the DSM-IV criteria for major depressive disorder (32 women; 11 antidepressant exposure and 30 drug-naive; mean age 70.5 years) and 41 controls (20 women; mean age 72.2 years). In the multivariate analysis, the depressed group had smaller corrected orbitofrontal cortex (OFC) total and gray matter volumes compared to the controls (p < .01). However, depressed patients with prior antidepressant exposure had larger OFC gray matter volumes compared to drug-naive depressed patients, but smaller than those in normal controls (p = .005). This effect was not explained by the group differences in sex ratio, age at onset of depression, or the number or duration of depressive episodes. We observed larger OFC regional volumes in depressed patients exposed to antidepressants compared to the drug-naive depressed subjects, but smaller than those in age-matched controls. Antidepressant exposure may protect against gray matter loss in geriatric depression.

Brief Counseling on Secondhand Smoke Exposure in Pregnant Women in Argentina and Uruguay.

PubMed

Alemán, Alicia; Morello, Paola; Colomar, Mercedes; Llambi, Laura; Berrueta, Mabel; Gibbons, Luz; Buekens, Pierre; Althabe, Fernando

2016-12-29

Argentina and Uruguay have a high prevalence of smoking during pregnancy, as well as of secondhand smoke (SHS) exposure. In this secondary analysis of a trial to implement brief smoking cessation counseling during antenatal care in Argentina and Uruguay, we aim to evaluate the effects of the intervention on the rates of self-reported SHS exposure at home and at work, and on attitudes recalled by non-smoker women enrolled in the intervention group compared with the control group. We randomly assigned (1:1) 20 antenatal care clusters in Argentina and Uruguay to receive a multifaceted intervention to implement brief smoking cessation counseling, which also included questions and counseling regarding SHS exposure, or to receive the standard of care. There was not a statistically significant difference between groups of the intervention's effect (reduction of exposure to SHS) on any of the three exposure outcome measures (exposure at home, work or other indoor areas) or on the attitudes of women regarding exposure (avoiding breathing SHS and having rooms where smoking is forbidden). This analysis shows that we should not expect reductions in SHS exposure with this modest intervention alone. To achieve such reductions, strategies engaging partners and other household members may be more effective.

Direct stenting versus balloon predilation: Jury is still out.

PubMed

Belardi, Jorge A; Albertal, Mariano

2017-08-01

Compared to balloon predilation, direct stenting (DS) shortens procedural time and reduces radiation and contrast exposure. A meta-analysis that included 7 studies comparing these 2 strategies revealed lower adverse event rate with DS. Studies included in the present meta-analysis were mostly observational and utilized first generation drug-eluting stent. Patient and lesion selection may explain these positive results. © 2017 Wiley Periodicals, Inc.

Changes in exposure to ‘life stressors’ in the Aboriginal and Torres Strait Islander population, 2002 to 2008

PubMed Central

2014-01-01

Background The Negative Life Events Scale (NLES) has been included in nationally representative surveys of the Indigenous and Australian population since 2002 as a measure of exposure to a range of ‘life stressors’. There has been limited reporting or analysis of estimates of the NLES from these surveys. This paper reports changes in exposure to stressors from 2002 to 2008 for the Indigenous population, and examines inter-relationships between eleven NLES items. Data for the 2006 Australian population is also included for comparative purposes. Methods Data from the 2002 and 2008 National Aboriginal and Torres Strait Islander Social Surveys (NATSISS) and the 2006 General Social Survey (GSS) were accessed from the Australia Bureau of Statistics in order to determine significant changes in exposure to stressors for the 2002 and 2008 Indigenous population by remoteness and to compare this with the 2006 Australian population. Factor analysis was used to assess the inter-relationships between stressors for the Indigenous and Australian population by remoteness. Results In remote locations, between 2002 and 2008, exposure to life stressors decreased significantly for the Indigenous population across seven of the eleven stressors. In non-remote locations, exposure to four of the stressors increased significantly. Exposure to stressors in the 2002 and 2008 non-remote Indigenous population were significantly higher than those for the 2006 Australian population for all items, except ‘alcohol and/or drug problems’ and ‘trouble with the police’, which showed no evidence of a difference. The factor analysis of the NLES for the 2002 and 2008 remote and non-remote Indigenous populations and the 2006 Australian population showed a consistent clustering of items into three groups: social transgressions; grief and trauma; and labour market stressors. Conclusions The reduction in exposure to life stressors for the remote Indigenous population may be related to policy and practice changes (e.g. more police, income quarantining, housing construction). The differential change in exposure to life stressors between remote and non-remote locations highlights the importance of presenting data for these geographic locations separately. PMID:24512200

Establishing Long-Term Efficacy in Chronic Disease: Use of Recursive Partitioning and Propensity Score Adjustment to Estimate Outcome in MS

PubMed Central

Goodin, Douglas S.; Jones, Jason; Li, David; Traboulsee, Anthony; Reder, Anthony T.; Beckmann, Karola; Konieczny, Andreas; Knappertz, Volker

2011-01-01

Context Establishing the long-term benefit of therapy in chronic diseases has been challenging. Long-term studies require non-randomized designs and, thus, are often confounded by biases. For example, although disease-modifying therapy in MS has a convincing benefit on several short-term outcome-measures in randomized trials, its impact on long-term function remains uncertain. Objective Data from the 16-year Long-Term Follow-up study of interferon-beta-1b is used to assess the relationship between drug-exposure and long-term disability in MS patients. Design/Setting To mitigate the bias of outcome-dependent exposure variation in non-randomized long-term studies, drug-exposure was measured as the medication-possession-ratio, adjusted up or down according to multiple different weighting-schemes based on MS severity and MS duration at treatment initiation. A recursive-partitioning algorithm assessed whether exposure (using any weighing scheme) affected long-term outcome. The optimal cut-point that was used to define “high” or “low” exposure-groups was chosen by the algorithm. Subsequent to verification of an exposure-impact that included all predictor variables, the two groups were compared using a weighted propensity-stratified analysis in order to mitigate any treatment-selection bias that may have been present. Finally, multiple sensitivity-analyses were undertaken using different definitions of long-term outcome and different assumptions about the data. Main Outcome Measure Long-Term Disability. Results In these analyses, the same weighting-scheme was consistently selected by the recursive-partitioning algorithm. This scheme reduced (down-weighted) the effectiveness of drug exposure as either disease duration or disability at treatment-onset increased. Applying this scheme and using propensity-stratification to further mitigate bias, high-exposure had a consistently better clinical outcome compared to low-exposure (Cox proportional hazard ratio = 0.30–0.42; p<0.0001). Conclusions Early initiation and sustained use of interferon-beta-1b has a beneficial impact on long-term outcome in MS. Our analysis strategy provides a methodological framework for bias-mitigation in the analysis of non-randomized clinical data. Trial Registration Clinicaltrials.gov NCT00206635 PMID:22140424

MR signal-fat-fraction analysis and T2* weighted imaging measure BAT reliably on humans without cold exposure.

PubMed

Holstila, Milja; Pesola, Marko; Saari, Teemu; Koskensalo, Kalle; Raiko, Juho; Borra, Ronald J H; Nuutila, Pirjo; Parkkola, Riitta; Virtanen, Kirsi A

2017-05-01

Brown adipose tissue (BAT) is compositionally distinct from white adipose tissue (WAT) in terms of triglyceride and water content. In adult humans, the most significant BAT depot is localized in the supraclavicular area. Our aim is to differentiate brown adipose tissue from white adipose tissue using fat T2* relaxation time mapping and signal-fat-fraction (SFF) analysis based on a commercially available modified 2-point-Dixon (mDixon) water-fat separation method. We hypothesize that magnetic resonance (MR) imaging can reliably measure BAT regardless of the cold-induced metabolic activation, with BAT having a significantly higher water and iron content compared to WAT. The supraclavicular area of 13 volunteers was studied on 3T PET-MRI scanner using T2* relaxation time and SFF mapping both during cold exposure and at ambient temperature; and 18 F-FDG PET during cold exposure. Volumes of interest (VOIs) were defined semiautomatically in the supraclavicular fat depot, subcutaneous WAT and muscle. The supraclavicular fat depot (assumed to contain BAT) had a significantly lower SFF and fat T2* relaxation time compared to subcutaneous WAT. Cold exposure did not significantly affect MR-based measurements. SFF and T2* values measured during cold exposure and at ambient temperature correlated inversely with the glucose uptake measured by 18 F-FDG PET. Human BAT can be reliably and safely assessed using MRI without cold activation and PET-related radiation exposure. Copyright © 2017 Elsevier Inc. All rights reserved.

Analysis of Intervention Strategies for Inhalation Exposure to Polycyclic Aromatic Hydrocarbons and Associated Lung Cancer Risk Based on a Monte Carlo Population Exposure Assessment Model

PubMed Central

Zhou, Bin; Zhao, Bin

2014-01-01

It is difficult to evaluate and compare interventions for reducing exposure to air pollutants, including polycyclic aromatic hydrocarbons (PAHs), a widely found air pollutant in both indoor and outdoor air. This study presents the first application of the Monte Carlo population exposure assessment model to quantify the effects of different intervention strategies on inhalation exposure to PAHs and the associated lung cancer risk. The method was applied to the population in Beijing, China, in the year 2006. Several intervention strategies were designed and studied, including atmospheric cleaning, smoking prohibition indoors, use of clean fuel for cooking, enhancing ventilation while cooking and use of indoor cleaners. Their performances were quantified by population attributable fraction (PAF) and potential impact fraction (PIF) of lung cancer risk, and the changes in indoor PAH concentrations and annual inhalation doses were also calculated and compared. The results showed that atmospheric cleaning and use of indoor cleaners were the two most effective interventions. The sensitivity analysis showed that several input parameters had major influence on the modeled PAH inhalation exposure and the rankings of different interventions. The ranking was reasonably robust for the remaining majority of parameters. The method itself can be extended to other pollutants and in different places. It enables the quantitative comparison of different intervention strategies and would benefit intervention design and relevant policy making. PMID:24416436

A case-control study of diesel exhaust exposure and bladder cancer.

PubMed

Wynder, E L; Dieck, G S; Hall, N E; Lahti, H

1985-08-01

The relationship between bladder cancer and employment in occupations involving exposure to diesel exhaust was examined using data from a hospital-based case-control study of men aged 20 to 80 years in 18 hospitals in six U.S. cities, from January 1981 to May 1983. In this analysis, 194 cases and 582 controls were compared according to occupation, smoking history, alcohol and coffee consumption, and various demographic variables. No difference was found in the proportion of bladder cancer cases employed in occupations with exposure to diesel exhaust compared to controls. This relationship did not change after taking smoking habits into account. Bladder cancer cases were significantly more likely to be current smokers of cigarettes than were controls.

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.

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.

Chromosome aberration analysis in peripheral lymphocytes of Gulf War and Balkans War veterans.

PubMed

Schröder, H; Heimers, A; Frentzel-Beyme, R; Schott, A; Hoffmann, W

2003-01-01

Chromosome aberrations and sister chromatid exchanges (SCEs) were determined in standard peripheral lymphocyte metaphase preparations of 13 British Gulf War veterans, two veterans of the recent war in the Balkans and one veteran of both wars. All 16 volunteers suspect exposures to depleted uranium (DU) while deployed at the two different theatres of war in 1990 and later on. The Bremen laboratory control served as a reference in this study. Compared with this control there was a statistically significant increase in the frequency of dicentric chromosomes (dic) and centric ring chromosomes (cR) in the veterans' group. indicating a previous exposure to ionising radiation. The statistically significant overdispersion of die and cR indicates non-uniform irradiation as would be expected after non-uniform exposure and/or exposure to radiation with a high linear energy transfer (LET). The frequency of SCEs was decreased when compared with the laboratory control.

Repeated aerosol-vapor JP-8 jet fuel exposure affects neurobehavior and neurotransmitter levels in a rat model.

PubMed

Baldwin, Carol M; Figueredo, Aurelio J; Wright, Lynda S; Wong, Simon S; Witten, Mark L

2007-07-01

Four groups of Fischer Brown Norway hybrid rats were exposed for 5, 10, 15, or 20 d to aerosolized-vapor jet propulsion fuel 8 (JP-8) compared to freely moving (5 and 10-d exposures) or sham-confined controls (15 and 20-d exposures). Behavioral testing utilized the U.S. Environmental Protection Agency Functional Observational Battery. Exploratory ethological factor analysis identified three salient factors (central nervous system [CNS] excitability, autonomic 1, and autonomic 2) for use in profiling JP-8 exposure in future studies. The factors were used as dependent variables in general linear modeling. Exposed animals were found to engage in more rearing and hyperaroused behavior compared to controls, replicating prior JP-8 exposure findings. Exposed animals also showed increasing but rapidly decelerating stool output (autonomic 1), and a significant increasing linear trend for urine output (autonomic 2). No significant trends were noted for either of the control groups for the autonomic factors. Rats from each of the groups for each of the time frames were randomly selected for tissue assay from seven brain regions for neurotransmitter levels. Hippocampal DOPAC was significantly elevated after 4-wk JP-8 exposure compared to both control groups, suggesting increased dopamine release and metabolism. Findings indicate that behavioral changes do not appear to manifest until wk 3 and 4 of exposure, suggesting the need for longitudinal studies to determine if these behaviors occur due to cumulative exposure, or due to behavioral sensitization related to repeated exposure to aerosolized-vapor JP-8.

The Toxicological Evaluation of Realistic Emissions of Source Aerosols Study: Statistical Methods

PubMed Central

Coull, Brent A.; Wellenius, Gregory A.; Gonzalez-Flecha, Beatriz; Diaz, Edgar; Koutrakis, Petros; Godleski, John J.

2013-01-01

The Toxicological Evaluation of Realistic Emissions of Source Aerosols (TERESA) study involved withdrawal, aging, and atmospheric transformation of emissions of three coal-fired power plants. Toxicological evaluations were carried out in rats exposed to different emission scenarios with extensive exposure characterization. Data generated had multiple levels of resolution: exposure, scenario and constituent chemical composition. Here, we outline a multilayered approach to analyze the associations between exposure and health effects beginning with standard ANOVA models that treat exposure as a categorical variable. The model assessed differences in exposure effects across scenarios (by plant). To assess unadjusted associations between pollutant concentrations and health, univariate analyses were conducted using the difference between the response means under exposed and control conditions and a single constituent concentration as the predictor. Then, a novel multivariate analysis of exposure composition and health was used based on random forests, a recent extension of classification and regression trees that were applied to the outcome differences. For each exposure constituent, this approach yielded a nonparametric measure of the importance of that constituent in predicting differences in response on a given day, controlling for the other measured constituent concentrations in the model. Finally, an R2 analysis compared the relative importance of exposure scenario, plant, and constituent concentrations on each outcome. Peak expiratory flow is used to demonstrate how the multiple levels of the analysis complement each other to assess constituents most strongly associated with health effects. PMID:21913820

The toxicological evaluation of realistic emissions of source aerosols study: statistical methods.

PubMed

Coull, Brent A; Wellenius, Gregory A; Gonzalez-Flecha, Beatriz; Diaz, Edgar; Koutrakis, Petros; Godleski, John J

2011-08-01

The Toxicological Evaluation of Realistic Emissions of Source Aerosols (TERESA) study involved withdrawal, aging, and atmospheric transformation of emissions of three coal-fired power plants. Toxicological evaluations were carried out in rats exposed to different emission scenarios with extensive exposure characterization. Data generated had multiple levels of resolution: exposure, scenario, and constituent chemical composition. Here, we outline a multilayered approach to analyze the associations between exposure and health effects beginning with standard ANOVA models that treat exposure as a categorical variable. The model assessed differences in exposure effects across scenarios (by plant). To assess unadjusted associations between pollutant concentrations and health, univariate analyses were conducted using the difference between the response means under exposed and control conditions and a single constituent concentration as the predictor. Then, a novel multivariate analysis of exposure composition and health was used based on Random Forests(™), a recent extension of classification and regression trees that were applied to the outcome differences. For each exposure constituent, this approach yielded a nonparametric measure of the importance of that constituent in predicting differences in response on a given day, controlling for the other measured constituent concentrations in the model. Finally, an R(2) analysis compared the relative importance of exposure scenario, plant, and constituent concentrations on each outcome. Peak expiratory flow (PEF) is used to demonstrate how the multiple levels of the analysis complement each other to assess constituents most strongly associated with health effects.

Lipid Adjustment for Chemical Exposures: Accounting for Concomitant Variables

PubMed Central

Li, Daniel; Longnecker, Matthew P.; Dunson, David B.

2013-01-01

Background Some environmental chemical exposures are lipophilic and need to be adjusted by serum lipid levels before data analyses. There are currently various strategies that attempt to account for this problem, but all have their drawbacks. To address such concerns, we propose a new method that uses Box-Cox transformations and a simple Bayesian hierarchical model to adjust for lipophilic chemical exposures. Methods We compared our Box-Cox method to existing methods. We ran simulation studies in which increasing levels of lipid-adjusted chemical exposure did and did not increase the odds of having a disease, and we looked at both single-exposure and multiple-exposures cases. We also analyzed an epidemiology dataset that examined the effects of various chemical exposures on the risk of birth defects. Results Compared with existing methods, our Box-Cox method produced unbiased estimates, good coverage, similar power, and lower type-I error rates. This was the case in both single- and multiple-exposure simulation studies. Results from analysis of the birth-defect data differed from results using existing methods. Conclusion Our Box-Cox method is a novel and intuitive way to account for the lipophilic nature of certain chemical exposures. It addresses some of the problems with existing methods, is easily extendable to multiple exposures, and can be used in any analyses that involve concomitant variables. PMID:24051893

Liraglutide 3.0 mg for Weight Management: A Population Pharmacokinetic Analysis.

PubMed

Overgaard, Rune V; Petri, Kristin C; Jacobsen, Lisbeth V; Jensen, Christine B

2016-11-01

This analysis used a population pharmacokinetic approach to identify covariates that influence plasma exposure of liraglutide 3.0 mg, a glucagon-like peptide-1 (GLP-1) receptor agonist approved for weight management in overweight and obese individuals. Samples for pharmacokinetic analysis were drawn at weeks 2, 12 and 28 of the phase IIIa SCALE Obesity and Prediabetes (N = 2339) and SCALE Diabetes (N = 584) trials. Dose proportionality of liraglutide in obese subjects was investigated using data from a phase II dose-finding study (N = 331). Dose-proportional exposure of liraglutide up to and including 3.0 mg was confirmed. Body weight and sex influenced exposure of liraglutide 3.0 mg, while age ≥70 years, race, ethnicity and baseline glycaemic status did not. Compared with a reference subject weighing 100 kg, exposure of liraglutide 3.0 mg was 44 % lower for a subject weighing 234 kg (90 % CI 41-47), 41 % higher for a subject weighing 60 kg (90 % CI 37-46), and 32 % higher (90 % CI 28-35) in females than males with the same body weight. Neither injection site nor renal function significantly influenced exposure of liraglutide 3.0 mg (post hoc analysis). Population pharmacokinetics of liraglutide up to and including 3.0 mg daily in overweight and obese adults demonstrated dose-proportional exposure, and limited effect of covariates other than sex and body weight. These findings were similar to those previously observed with liraglutide up to 1.8 mg in subjects with type 2 diabetes mellitus. Further analysis of exposure-response relationship and its effect on dose requirements is addressed in a separate publication.

Gamma-H2AX-based dose estimation for whole and partial body radiation exposure.

PubMed

Horn, Simon; Barnard, Stephen; Rothkamm, Kai

2011-01-01

Most human exposures to ionising radiation are partial body exposures. However, to date only limited tools are available for rapid and accurate estimation of the dose distribution and the extent of the body spared from the exposure. These parameters are of great importance for emergency triage and clinical management of exposed individuals. Here, measurements of γ-H2AX immunofluorescence by microscopy and flow cytometry were compared as rapid biodosimetric tools for whole and partial body exposures. Ex vivo uniformly X-irradiated blood lymphocytes from one donor were used to generate a universal biexponential calibration function for γ-H2AX foci/intensity yields per unit dose for time points up to 96 hours post exposure. Foci--but not intensity--levels remained significantly above background for 96 hours for doses of 0.5 Gy or more. Foci-based dose estimates for ex vivo X-irradiated blood samples from 13 volunteers were in excellent agreement with the actual dose delivered to the targeted samples. Flow cytometric dose estimates for X-irradiated blood samples from 8 volunteers were in excellent agreement with the actual dose delivered at 1 hour post exposure but less so at 24 hours post exposure. In partial body exposures, simulated by mixing ex vivo irradiated and unirradiated lymphocytes, foci/intensity distributions were significantly over-dispersed compared to uniformly irradiated lymphocytes. For both methods and in all cases the estimated fraction of irradiated lymphocytes and dose to that fraction, calculated using the zero contaminated Poisson test and γ-H2AX calibration function, were in good agreement with the actual mixing ratios and doses delivered to the samples. In conclusion, γ-H2AX analysis of irradiated lymphocytes enables rapid and accurate assessment of whole body doses while dispersion analysis of foci or intensity distributions helps determine partial body doses and the irradiated fraction size in cases of partial body exposures.

Relationship between mediation analysis and the structured life course approach

PubMed Central

Howe, Laura D; Smith, Andrew D; Macdonald-Wallis, Corrie; Anderson, Emma L; Galobardes, Bruna; Lawlor, Debbie A; Ben-Shlomo, Yoav; Hardy, Rebecca; Cooper, Rachel; Tilling, Kate; Fraser, Abigail

2016-01-01

Abstract Many questions in life course epidemiology involve mediation and/or interaction because of the long latency period between exposures and outcomes. In this paper, we explore how mediation analysis (based on counterfactual theory and implemented using conventional regression approaches) links with a structured approach to selecting life course hypotheses. Using theory and simulated data, we show how the alternative life course hypotheses assessed in the structured life course approach correspond to different combinations of mediation and interaction parameters. For example, an early life critical period model corresponds to a direct effect of the early life exposure, but no indirect effect via the mediator and no interaction between the early life exposure and the mediator. We also compare these methods using an illustrative real-data example using data on parental occupational social class (early life exposure), own adult occupational social class (mediator) and physical capability (outcome). PMID:27681097

Prescription-drug-related risk in driving: comparing conventional and lasso shrinkage logistic regressions.

PubMed

Avalos, Marta; Adroher, Nuria Duran; Lagarde, Emmanuel; Thiessard, Frantz; Grandvalet, Yves; Contrand, Benjamin; Orriols, Ludivine

2012-09-01

Large data sets with many variables provide particular challenges when constructing analytic models. Lasso-related methods provide a useful tool, although one that remains unfamiliar to most epidemiologists. We illustrate the application of lasso methods in an analysis of the impact of prescribed drugs on the risk of a road traffic crash, using a large French nationwide database (PLoS Med 2010;7:e1000366). In the original case-control study, the authors analyzed each exposure separately. We use the lasso method, which can simultaneously perform estimation and variable selection in a single model. We compare point estimates and confidence intervals using (1) a separate logistic regression model for each drug with a Bonferroni correction and (2) lasso shrinkage logistic regression analysis. Shrinkage regression had little effect on (bias corrected) point estimates, but led to less conservative results, noticeably for drugs with moderate levels of exposure. Carbamates, carboxamide derivative and fatty acid derivative antiepileptics, drugs used in opioid dependence, and mineral supplements of potassium showed stronger associations. Lasso is a relevant method in the analysis of databases with large number of exposures and can be recommended as an alternative to conventional strategies.

A modular Human Exposure Model (HEM) framework to ...

EPA Pesticide Factsheets

Life Cycle Impact Analysis (LCIA) has proven to be a valuable tool for systematically comparing processes and products, and has been proposed for use in Chemical Alternatives Analysis (CAA). The exposure assessment portion of the human health impact scores of LCIA has historically focused on far-field sources (environmentally mediated exposures) while research has shown that use related exposures, (near-field exposures) typically dominate population exposure. Characterizing the human health impacts of chemicals in consumer products over the life cycle of these products requires an evaluation of both near-field as well far-field sources. Assessing the impacts of the near-field exposures requires bridging the scientific and technical gaps that currently prevent the harmonious use of the best available methods and tools from the fields of LCIA and human health exposure and risk assessment. The U.S. EPA’s Chemical Safety and Sustainability LC-HEM project is developing the Human Exposure Model (HEM) to assess near-field exposures to chemicals that occur to various populations over the life cycle of a commercial product. The HEM will be a publically available, web-based, modular system which will allow for the evaluation of chemical/product impacts in a LCIA framework to support CAA. We present here an overview of the framework for the modular HEM system. The framework includes a data flow diagram of in-progress and future planned modules, the definition of each mod

Comparison of the near field/far field model and the advanced reach tool (ART) model V1.5: exposure estimates to benzene during parts washing with mineral spirits.

PubMed

LeBlanc, Mallory; Allen, Joseph G; Herrick, Robert F; Stewart, James H

2018-03-01

The Advanced Reach Tool V1.5 (ART) is a mathematical model for occupational exposures conceptually based on, but implemented differently than, the "classic" Near Field/Far Field (NF/FF) exposure model. The NF/FF model conceptualizes two distinct exposure "zones"; the near field, within approximately 1m of the breathing zone, and the far field, consisting of the rest of the room in which the exposure occurs. ART has been reported to provide "realistic and reasonable worst case" estimates of the exposure distribution. In this study, benzene exposure during the use of a metal parts washer was modeled using ART V1.5, and compared to actual measured workers samples and to NF/FF model results from three previous studies. Next, the exposure concentrations expected to be exceeded 25%, 10% and 5% of the time for the exposure scenario were calculated using ART. Lastly, ART exposure estimates were compared with and without Bayesian adjustment. The modeled parts washing benzene exposure scenario included distinct tasks, e.g. spraying, brushing, rinsing and soaking/drying. Because ART can directly incorporate specific types of tasks that are part of the exposure scenario, the present analysis identified each task's determinants of exposure and performance time, thus extending the work of the previous three studies where the process of parts washing was modeled as one event. The ART 50th percentile exposure estimate for benzene (0.425ppm) more closely approximated the reported measured mean value of 0.50ppm than the NF/FF model estimates of 0.33ppm, 0.070ppm or 0.2ppm obtained from other modeling studies of this exposure scenario. The ART model with the Bayesian analysis provided the closest estimate to the measured value (0.50ppm). ART (with Bayesian adjustment) was then used to assess the 75th, the 90th and 95th percentile exposures, predicting that on randomly selected days during this parts washing exposure scenario, 25% of the benzene exposures would be above 0.70ppm; 10% above 0.95ppm; and 5% above 1.15ppm. These exposure estimates at the three different percentiles of the ART exposure distribution refer to the modeled exposure scenario not a specific workplace or worker. This study provides a detailed comparison of modeling tools currently available to occupational hygienists and other exposure assessors. Possible applications are considered. Copyright © 2017 Elsevier GmbH. All rights reserved.

Prenatal stress alters amygdala functional connectivity in preterm neonates.

PubMed

Scheinost, Dustin; Kwon, Soo Hyun; Lacadie, Cheryl; Sze, Gordon; Sinha, Rajita; Constable, R Todd; Ment, Laura R

2016-01-01

Exposure to prenatal and early-life stress results in alterations in neural connectivity and an increased risk for neuropsychiatric disorders. In particular, alterations in amygdala connectivity have emerged as a common effect across several recent studies. However, the impact of prenatal stress exposure on the functional organization of the amygdala has yet to be explored in the prematurely-born, a population at high risk for neuropsychiatric disorders. We test the hypothesis that preterm birth and prenatal exposure to maternal stress alter functional connectivity of the amygdala using two independent cohorts. The first cohort is used to establish the effects of preterm birth and consists of 12 very preterm neonates and 25 term controls, all without prenatal stress exposure. The second is analyzed to establish the effects of prenatal stress exposure and consists of 16 extremely preterm neonates with prenatal stress exposure and 10 extremely preterm neonates with no known prenatal stress exposure. Standard resting-state functional magnetic resonance imaging and seed connectivity methods are used. When compared to term controls, very preterm neonates show significantly reduced connectivity between the amygdala and the thalamus, the hypothalamus, the brainstem, and the insula (p < 0.05). Similarly, when compared to extremely preterm neonates without exposure to prenatal stress, extremely preterm neonates with exposure to prenatal stress show significantly less connectivity between the left amygdala and the thalamus, the hypothalamus, and the peristriate cortex (p < 0.05). Exploratory analysis of the combined cohorts suggests additive effects of prenatal stress on alterations in amygdala connectivity associated with preterm birth. Functional connectivity from the amygdala to other subcortical regions is decreased in preterm neonates compared to term controls. In addition, these data, for the first time, suggest that prenatal stress exposure amplifies these decreases.

Randomized comparison of group versus individual educational interventions for pregnant women to reduce their secondhand smoke exposure.

PubMed

Chi, Ying-Chen; Sha, Feng; Yip, Paul S F; Chen, Jiunn-Liang; Chen, Ying-Yeh

2016-10-01

Secondhand smoke (SHS) exposure is deleterious to pregnant women and their unborn children. The prevalence of SHS exposure among pregnant women is particularly high in many Asian countries where approximately half of the male population smokes. We aim to investigate the efficacy of an intervention based on an expanded Health Belief Model (HBM) incorporating self-efficacy to educate and empower pregnant women to reduce their SHS exposure. We conducted a 3-arm randomized controlled trial (N = 50 in each arm) comparing the effectiveness of group-based and individual-based interventions with a treatment-as-usual group. A questionnaire tapping into constructs of the expanded HBM was administered at baseline and 1- and 2-month follow-ups. Exhaled carbon monoxide was used to determine SHS exposure (>=6 ppm). ANOVA was used to compare HBM construct scores, self-efficacy for rejecting SHS exposure, and SHS rejection behavior among the 3 groups at baseline and the 1- and 2-month follow-ups, while logistic regression analysis was used to compare the risk of exposure to SHS at each follow-up. The group-based intervention significantly improved health beliefs, self-efficacy, and self-reported rejection behaviors. The individual-based intervention effect was limited to some health belief constructs and SHS rejection behaviors. Both group- and individual-based interventions showed significant reductions in SHS exposure 2 months after the intervention (P < 0.0001). Group-based educational interventions based on the HBM are particularly effective in training pregnant women to avoid and refuse exposure to SHS. Policy makers should consider offering group-delivered programs to educate and empower pregnant women to reduce their SHS exposure.

Cadmium exposure and risk of lung cancer: a meta-analysis of cohort and case-control studies among general and occupational populations.

PubMed

Chen, Cheng; Xun, Pengcheng; Nishijo, Muneko; He, Ka

2016-09-01

The association between cadmium exposure and risk of lung cancer is still unclear. We quantitatively reviewed the observational studies that investigated the association between cadmium exposure and lung cancer risk in both general and occupational populations published through April 2015. The final data set is comprised of three cohort studies in the general population totaling 22,551 participants (354 events) with a mean follow-up of 15 years, five occupational cohort studies including 4205 individuals (180 events) with an average follow-up of 31 years, and three occupational case-control studies including 4740 cases and 6268 controls. Comparing the highest to the lowest category of cadmium exposure, the weighted relative risk and 95% confidence interval of lung cancer in the general population was 1.42 (95% CI (0.91, 2.23)); the weighted risk estimates (95% CIs) of lung cancer in three occupational cohort studies and three case-control studies were 0.68 (95% CI (0.33, 1.41)) and 1.61 (95% CI (0.94, 2.75)), respectively. No linear association was found. When comparing participants exposed to cadmium with non-exposed based on available data, the association became statistically significant. According to findings from this meta-analysis, the possibility that cadmium exposure may increase risk of lung cancer cannot be completely ruled out in either general or occupational population.

Aggression from Patients or Next of Kin and Exposure to Bullying Behaviors: A Conglomerate Experience?

PubMed Central

Notelaers, Guy; Bjorvatn, Bjørn; Moen, Bente Elisabeth; Einarsen, Ståle

2017-01-01

Although workplace violence and aggression have been identified as important stressors in the nursing profession, studies simultaneously comparing patient-initiated aggression and exposure to bullying behaviors at work are rather scarce. The aim of this study was to compare aggression from patients or next of kin and exposure to bullying behaviors in terms of prevalence, health-related quality of life outcomes, and potential overlap in those targeted. In the period of 2008-2009, data were collected among 2059 members of the Norwegian Nurses Organization. Latent class (LC) analysis and a multivariate analysis of variance (MANOVA) were used to investigate the proposed relationships. The results showed that aggression from patients or next of kin and exposure to bullying behaviors were perceived as separate and independent stressors. Although aggression from patients or next of kin was more frequent than workplace bullying, the latter was the only significant stressor related to health-related quality of life in terms of reduced mental health functioning. Although being a rather infrequent experience, exposure to bullying behaviors seems to have more severe health-related outcomes for nurses than aggression from patients or next of kin. Hence, the results of the study strengthen previous findings and suggest that managers must aim to maintain a positive psychosocial work environment with zero-tolerance for bullying. PMID:28270936

Lead and ethanol co-exposure lead to blood oxidative stress and subsequent neuronal apoptosis in rats.

PubMed

Flora, Swaran J S; Gautam, Pratibha; Kushwaha, Pramod

2012-01-01

The present study was aimed at investigating chronic exposure to lead and ethanol, individually and in combination with blood oxidative stress leading to possible brain apoptosis in rats. Rats were exposed to lead (0.1% w/v in drinking water) or ethanol (1 and 10%) either individually or in combination for four months. Biochemical variables indicative of oxidative stress (blood and brain) and brain apoptosis were examined. Native polyacrylamide agarose gel electrophoresis was carried out in brain homogenates for glucose-6-phosphate dehydrogenase (G6PD) analysis, whereas western blot analysis was done for the determination of apoptotic markers like Bax, Bcl-2, caspase-3, cytochrome c and p53. The results suggest that most pronounced increase in oxidative stress in red blood cells and brain of animals co-exposed to lead and 10% ethanol compared all the other groups. Decrease in G6PD activity followed the same trend. Upregulation of Bax, cytochrome c, caspase-3, p53 and down-regulation of Bcl-2 suggested apoptosis in the rat brain co-exposed to lead and ethanol (10%) compared with their individual exposures. Significantly high lead accumulation in blood and brain during co-exposure further support synergistic toxicity. The present study thus suggests that higher consumption of ethanol during lead exposure may lead to brain apoptosis, which may be mediated through oxidative stress.

The effectiveness of breath carbon monoxide analyzer in screening for environmental tobacco smoke exposure in Saudi pregnant women.

PubMed

Alzeidan, Rasmieh Ayed; Mandil, Ahmed Amin; Fayed, Amel Ahmed; Wahabi, Hayfaa Abdulmajeed

2013-10-01

Exposure to environmental tobacco smoke (ETS) has harmful effects on the pregnancy outcomes similar to those observed in actively smoking pregnant women. The aim of this study was to estimate the sensitivity and specificity of the breath carbon monoxide (BCO) analysis in the assessment of smoking status among Saudi pregnant women, including ETS exposure compared to self-reported tobacco smoke exposure. A cross-sectional design was used during January 2012, 560 pregnant women, irrespective of their gestational age, agreed to undergo BCO testing and completed the data collection sheet for the study. Sensitivity, specificity, positive and negative predictive values were calculated to compare the BCO test with self-reported exposure to ETS. Of the study population 151 (27%) women self-reported ETS exposure during the index pregnancy, 409 (73%) self-reported non-exposure. Sensitivity of the test was 32.5% (95% CI; 25.2-40.3%), the Specificity was much higher at 69.2% (95% CI; 64.4-73.5%), the positive predictive value was 28% (95% CI, 21.9-35.1%), and the negative predictive value was 73.5% (95% CI; 68.9-77.7%). The BCO test is an ineffective tool to detect the level of ETS exposure among Saudi pregnant women.

Combining evidence from multiple electronic health care databases: performances of one-stage and two-stage meta-analysis in matched case-control studies.

PubMed

La Gamba, Fabiola; Corrao, Giovanni; Romio, Silvana; Sturkenboom, Miriam; Trifirò, Gianluca; Schink, Tania; de Ridder, Maria

2017-10-01

Clustering of patients in databases is usually ignored in one-stage meta-analysis of multi-database studies using matched case-control data. The aim of this study was to compare bias and efficiency of such a one-stage meta-analysis with a two-stage meta-analysis. First, we compared the approaches by generating matched case-control data under 5 simulated scenarios, built by varying: (1) the exposure-outcome association; (2) its variability among databases; (3) the confounding strength of one covariate on this association; (4) its variability; and (5) the (heterogeneous) confounding strength of two covariates. Second, we made the same comparison using empirical data from the ARITMO project, a multiple database study investigating the risk of ventricular arrhythmia following the use of medications with arrhythmogenic potential. In our study, we specifically investigated the effect of current use of promethazine. Bias increased for one-stage meta-analysis with increasing (1) between-database variance of exposure effect and (2) heterogeneous confounding generated by two covariates. The efficiency of one-stage meta-analysis was slightly lower than that of two-stage meta-analysis for the majority of investigated scenarios. Based on ARITMO data, there were no evident differences between one-stage (OR = 1.50, CI = [1.08; 2.08]) and two-stage (OR = 1.55, CI = [1.12; 2.16]) approaches. When the effect of interest is heterogeneous, a one-stage meta-analysis ignoring clustering gives biased estimates. Two-stage meta-analysis generates estimates at least as accurate and precise as one-stage meta-analysis. However, in a study using small databases and rare exposures and/or outcomes, a correct one-stage meta-analysis becomes essential. Copyright © 2017 John Wiley & Sons, Ltd.

High-Throughput Models for Exposure-Based Chemical ...

EPA Pesticide Factsheets

The United States Environmental Protection Agency (U.S. EPA) must characterize potential risks to human health and the environment associated with manufacture and use of thousands of chemicals. High-throughput screening (HTS) for biological activity allows the ToxCast research program to prioritize chemical inventories for potential hazard. Similar capabilities for estimating exposure potential would support rapid risk-based prioritization for chemicals with limited information; here, we propose a framework for high-throughput exposure assessment. To demonstrate application, an analysis was conducted that predicts human exposure potential for chemicals and estimates uncertainty in these predictions by comparison to biomonitoring data. We evaluated 1936 chemicals using far-field mass balance human exposure models (USEtox and RAIDAR) and an indicator for indoor and/or consumer use. These predictions were compared to exposures inferred by Bayesian analysis from urine concentrations for 82 chemicals reported in the National Health and Nutrition Examination Survey (NHANES). Joint regression on all factors provided a calibrated consensus prediction, the variance of which serves as an empirical determination of uncertainty for prioritization on absolute exposure potential. Information on use was found to be most predictive; generally, chemicals above the limit of detection in NHANES had consumer/indoor use. Coupled with hazard HTS, exposure HTS can place risk earlie

Digital repeat analysis; setup and operation.

PubMed

Nol, J; Isouard, G; Mirecki, J

2006-06-01

Since the emergence of digital imaging, there have been questions about the necessity of continuing reject analysis programs in imaging departments to evaluate performance and quality. As a marketing strategy, most suppliers of digital technology focus on the supremacy of the technology and its ability to reduce the number of repeats, resulting in less radiation doses given to patients and increased productivity in the department. On the other hand, quality assurance radiographers and radiologists believe that repeats are mainly related to positioning skills, and repeat analysis is the main tool to plan training needs to up-skill radiographers. A comparative study between conventional and digital imaging was undertaken to compare outcomes and evaluate the need for reject analysis. However, digital technology still being at its early development stages, setting a credible reject analysis program became the major task of the study. It took the department, with the help of the suppliers of the computed radiography reader and the picture archiving and communication system, over 2 years of software enhancement to build a reliable digital repeat analysis system. The results were supportive of both philosophies; the number of repeats as a result of exposure factors was reduced dramatically; however, the percentage of repeats as a result of positioning skills was slightly on the increase for the simple reason that some rejects in the conventional system qualifying for both exposure and positioning errors were classified as exposure error. The ability of digitally adjusting dark or light images reclassified some of those images as positioning errors.

COVARIATE-ADAPTIVE CLUSTERING OF EXPOSURES FOR AIR POLLUTION EPIDEMIOLOGY COHORTS*

PubMed Central

Keller, Joshua P.; Drton, Mathias; Larson, Timothy; Kaufman, Joel D.; Sandler, Dale P.; Szpiro, Adam A.

2017-01-01

Cohort studies in air pollution epidemiology aim to establish associations between health outcomes and air pollution exposures. Statistical analysis of such associations is complicated by the multivariate nature of the pollutant exposure data as well as the spatial misalignment that arises from the fact that exposure data are collected at regulatory monitoring network locations distinct from cohort locations. We present a novel clustering approach for addressing this challenge. Specifically, we present a method that uses geographic covariate information to cluster multi-pollutant observations and predict cluster membership at cohort locations. Our predictive k-means procedure identifies centers using a mixture model and is followed by multi-class spatial prediction. In simulations, we demonstrate that predictive k-means can reduce misclassification error by over 50% compared to ordinary k-means, with minimal loss in cluster representativeness. The improved prediction accuracy results in large gains of 30% or more in power for detecting effect modification by cluster in a simulated health analysis. In an analysis of the NIEHS Sister Study cohort using predictive k-means, we find that the association between systolic blood pressure (SBP) and long-term fine particulate matter (PM2.5) exposure varies significantly between different clusters of PM2.5 component profiles. Our cluster-based analysis shows that for subjects assigned to a cluster located in the Midwestern U.S., a 10 μg/m3 difference in exposure is associated with 4.37 mmHg (95% CI, 2.38, 6.35) higher SBP. PMID:28572869

Instrumental variables vs. grouping approach for reducing bias due to measurement error.

PubMed

Batistatou, Evridiki; McNamee, Roseanne

2008-01-01

Attenuation of the exposure-response relationship due to exposure measurement error is often encountered in epidemiology. Given that error cannot be totally eliminated, bias correction methods of analysis are needed. Many methods require more than one exposure measurement per person to be made, but the `group mean OLS method,' in which subjects are grouped into several a priori defined groups followed by ordinary least squares (OLS) regression on the group means, can be applied with one measurement. An alternative approach is to use an instrumental variable (IV) method in which both the single error-prone measure and an IV are used in IV analysis. In this paper we show that the `group mean OLS' estimator is equal to an IV estimator with the group mean used as IV, but that the variance estimators for the two methods are different. We derive a simple expression for the bias in the common estimator which is a simple function of group size, reliability and contrast of exposure between groups, and show that the bias can be very small when group size is large. We compare this method with a new proposal (group mean ranking method), also applicable with a single exposure measurement, in which the IV is the rank of the group means. When there are two independent exposure measurements per subject, we propose a new IV method (EVROS IV) and compare it with Carroll and Stefanski's (CS IV) proposal in which the second measure is used as an IV; the new IV estimator combines aspects of the `group mean' and `CS' strategies. All methods are evaluated in terms of bias, precision and root mean square error via simulations and a dataset from occupational epidemiology. The `group mean ranking method' does not offer much improvement over the `group mean method.' Compared with the `CS' method, the `EVROS' method is less affected by low reliability of exposure. We conclude that the group IV methods we propose may provide a useful way to handle mismeasured exposures in epidemiology with or without replicate measurements. Our finding may also have implications for the use of aggregate variables in epidemiology to control for unmeasured confounding.

Exposure-response analysis and risk assessment for lung cancer in relationship to silica exposure: a 44-year cohort study of 34,018 workers.

PubMed

Liu, Yuewei; Steenland, Kyle; Rong, Yi; Hnizdo, Eva; Huang, Xiji; Zhang, Hai; Shi, Tingming; Sun, Yi; Wu, Tangchun; Chen, Weihong

2013-11-01

Crystalline silica has been classified as a human carcinogen by the International Agency for Research on Cancer (Lyon, France); however, few previous studies have provided quantitative data on silica exposure, silicosis, and/or smoking. We investigated a cohort in China (in 1960-2003) of 34,018 workers without exposure to carcinogenic confounders. Cumulative silica exposure was estimated by linking a job-exposure matrix to work history. Cox proportional hazards model was used to conduct exposure-response analysis and risk assessment. During a mean 34.5-year follow-up, 546 lung cancer deaths were identified. Categorical analyses by quartiles of cumulative silica exposure (using a 25-year lag) yielded hazard ratios of 1.26, 1.54, 1.68, and 1.70, respectively, compared with the unexposed group. Monotonic exposure-response trends were observed among nonsilicotics (P for trend < 0.001). Analyses using splines showed similar trends. The joint effect of silica and smoking was more than additive and close to multiplicative. For workers exposed from ages 20 to 65 years at 0.1 mg/m(3) of silica exposure, the estimated excess lifetime risk (through age 75 years) was 0.51%. These findings confirm silica as a human carcinogen and suggest that current exposure limits in many countries might be insufficient to protect workers from lung cancer. They also indicate that smoking cessation could help reduce lung cancer risk for silica-exposed individuals.

Environmental epigenomics: Current approaches to assess epigenetic effects of endocrine disrupting compounds (EDC's) on human health.

PubMed

Tapia-Orozco, Natalia; Santiago-Toledo, Gerardo; Barrón, Valeria; Espinosa-García, Ana María; García-García, José Antonio; García-Arrazola, Roeb

2017-04-01

Environmental Epigenomics is a developing field to study the epigenetic effect on human health from exposure to environmental factors. Endocrine disrupting chemicals have been detected primarily in pharmaceutical drugs, personal care products, food additives, and food containers. Exposure to endocrine-disrupting chemicals (EDCs) has been associated with a high incidence and prevalence of many endocrine-related disorders in humans. Nevertheless, further evidence is needed to establish a correlation between exposure to EDC and human disorders. Conventional detection of EDCs is based on chemical structure and concentration sample analysis. However, substantial evidence has emerged, suggesting that cell exposure to EDCs leads to epigenetic changes, independently of its chemical structure with non-monotonic low-dose responses. Consequently, a paradigm shift in toxicology assessment of EDCs is proposed based on a comprehensive review of analytical techniques used to evaluate the epigenetic effects. Fundamental insights reported elsewhere are compared in order to establish DNA methylation analysis as a viable method for assessing endocrine disruptors beyond the conventional study approach of chemical structure and concentration analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

Medical students' exposure to pharmaceutical industry marketing: a survey at one U.S. medical school.

PubMed

Bellin, Melena; McCarthy, Susan; Drevlow, Laurel; Pierach, Claus

2004-11-01

While much is known about the interactions between the pharmaceutical industry and physicians, very little is known about pharmaceutical marketing directed toward medical students. This study sought to characterize the extent and forms of medical students' exposure to pharmaceutical industry marketing. In 2001-02, an anonymous, 17-item questionnaire was distributed to 165 preclinical and 116 clinical students at the University of Minnesota Medical School-Twin Cities. The main outcome measures were the number and forms of exposures to pharmaceutical industry marketing reported by medical students and whether students had discussed these exposures with teachers or advisors. Preclinical and clinical students were compared using chi(2) analysis (p < .05). One hundred fourteen (69.1%) preclinical students and 107 (92.2%) clinical students responded. Nearly all students reported at least one exposure to pharmaceutical industry marketing. Seventy-six (71.7%) clinical students compared to 38 (33.3%) preclinical students recalled over 20 exposures (p < .005). Clinical students were more likely to have received a free meal (p < .01), textbook (p < .005), pocket text (p < .005), or trinket (p < .005) than were their preclinical colleagues. Most students (68.2%) had not discussed pharmaceutical marketing with an instructor or advisor; 59 (55.7%) clinical students as compared to 87 (80.6%) preclinical students recalled no such discussion (p < .005). Medical students have extensive exposure to pharmaceutical industry marketing during their early years of training. Given existing evidence that such exposure influences physicians' practice and prescribing patterns, the authors propose that medical school curricula include formal instruction to prepare students to critically assess these contacts.

No evidence for an increase in circulatory disease mortality in astronauts following space radiation exposures

NASA Astrophysics Data System (ADS)

Cucinotta, Francis A.; Hamada, Nobuyuki; Little, Mark P.

2016-08-01

Previous analysis has shown that astronauts have a significantly lower standardized mortality ratio for circulatory disease mortality compared to the U.S. population, which is consistent with the rigorous selection process and healthy lifestyles of astronauts, and modest space radiation exposures from past space missions. However, a recent report by Delp et al. estimated the proportional mortality ratio for ages of 55-64 y of Apollo lunar mission astronauts to claim a high risk of cardiovascular disease due to space radiation compared to the U.S. population or to non-flight astronauts. In this Commentary we discuss important deficiencies in the methods and assumptions on radiation exposures used by Delp et al. that we judge cast serious doubt on their conclusions.

Cluster-based exposure variation analysis

PubMed Central

2013-01-01

Background Static posture, repetitive movements and lack of physical variation are known risk factors for work-related musculoskeletal disorders, and thus needs to be properly assessed in occupational studies. The aims of this study were (i) to investigate the effectiveness of a conventional exposure variation analysis (EVA) in discriminating exposure time lines and (ii) to compare it with a new cluster-based method for analysis of exposure variation. Methods For this purpose, we simulated a repeated cyclic exposure varying within each cycle between “low” and “high” exposure levels in a “near” or “far” range, and with “low” or “high” velocities (exposure change rates). The duration of each cycle was also manipulated by selecting a “small” or “large” standard deviation of the cycle time. Theses parameters reflected three dimensions of exposure variation, i.e. range, frequency and temporal similarity. Each simulation trace included two realizations of 100 concatenated cycles with either low (ρ = 0.1), medium (ρ = 0.5) or high (ρ = 0.9) correlation between the realizations. These traces were analyzed by conventional EVA, and a novel cluster-based EVA (C-EVA). Principal component analysis (PCA) was applied on the marginal distributions of 1) the EVA of each of the realizations (univariate approach), 2) a combination of the EVA of both realizations (multivariate approach) and 3) C-EVA. The least number of principal components describing more than 90% of variability in each case was selected and the projection of marginal distributions along the selected principal component was calculated. A linear classifier was then applied to these projections to discriminate between the simulated exposure patterns, and the accuracy of classified realizations was determined. Results C-EVA classified exposures more correctly than univariate and multivariate EVA approaches; classification accuracy was 49%, 47% and 52% for EVA (univariate and multivariate), and C-EVA, respectively (p < 0.001). All three methods performed poorly in discriminating exposure patterns differing with respect to the variability in cycle time duration. Conclusion While C-EVA had a higher accuracy than conventional EVA, both failed to detect differences in temporal similarity. The data-driven optimality of data reduction and the capability of handling multiple exposure time lines in a single analysis are the advantages of the C-EVA. PMID:23557439

Decompression sickness during simulated extravehicular activity: ambulation vs. non-ambulation.

PubMed

Webb, James T; Beckstrand, Devin P; Pilmanis, Andrew A; Balldin, Ulf I

2005-08-01

Extravehicular activity (EVA) is required from the International Space Station on a regular basis. Because of the weightless environment during EVA, physical activity is performed using mostly upper-body movements since the lower body is anchored for stability. The adynamic model (restricted lower-body activity; non-ambulation) was designed to simulate this environment during earthbound studies of decompression sickness (DCS) risk. DCS symptoms during ambulatory (walking) and non-ambulatory high altitude exposure activity were compared. The objective was to determine if symptom incidences during ambulatory and non-ambulatory exposures are comparable and provide analogous estimates of risk under otherwise identical conditions. A retrospective analysis was accomplished on DCS symptoms from 2010 ambulatory and 330 non-ambulatory exposures. There was no significant difference between the overall incidence of DCS or joint-pain DCS in the ambulatory (49% and 40%) vs. the non-ambulatory exposures (53% and 36%; p > 0.1). DCS involving joint pain only in the lower body was higher during ambulatory exposures (28%) than non-ambulatory exposures (18%; p < 0.01). Non-ambulatory exposures terminated more frequently with non-joint-pain DCS (17%) or upper-body-only joint pain (18%) as compared with ambulatory exposures, 9% and 11% (p < 0.01), respectively. These findings show that lower-body, weight-bearing activity shifts the incidence of joint-pain DCS from the upper body to the lower body without altering the total incidence of DCS or joint-pain DCS. Use of data from previous and future subject exposures involving ambulatory activity while decompressed appears to be a valid analogue of non-ambulatory activity in determining DCS risk during simulated EVA studies.

Temporal observations of bright soil exposures at Gusev crater, Mars

USGS Publications Warehouse

Rice, M.S.; Bell, J.F.; Cloutis, E.A.; Wray, J.J.; Herkenhoff, K. E.; Sullivan, R.; Johnson, J. R.; Anderson, R.B.

2011-01-01

The Mars Exploration Rover Spirit has discovered bright soil deposits in its wheel tracks that previously have been confirmed to contain ferric sulfates and/or opaline silica. Repeated Pancam multispectral observations have been acquired at four of these deposits to monitor spectral and textural changes over time during exposure to Martian surface conditions. Previous studies suggested that temporal spectral changes occur because of mineralogic changes (e.g., phase transitions accompanying dehydration). In this study, we present a multispectral and temporal analysis of eight Pancam image sequences at the Tyrone exposure, three at the Gertrude Weise exposure, two at the Kit Carson exposure, and ten at the Ulysses exposure that have been acquired as of sol 2132 (1 January 2010). We compare observed variations in Pancam data to spectral changes predicted by laboratory experiments for the dehydration of ferric sulfates. We also present a spectral analysis of repeated Mars Reconnaissance Orbiter HiRISE observations spanning 32 sols and a textural analysis of Spirit Microscopic Imager observations of Ulysses spanning 102 sols. At all bright soil exposures, we observe no statistically significant spectral changes with time that are uniquely diagnostic of dehydration and/or mineralogic phase changes. However, at Kit Carson and Ulysses, we observe significant textural changes, including slumping within the wheel trench, movement of individual grains, disappearance of fines, and dispersal of soil clods. All observed textural changes are consistent with aeolian sorting and/or minor amounts of air fall dust deposition.

Temporal observations of bright soil exposures at Gusev crater, Mars

USGS Publications Warehouse

Rice, M.S.; Bell, J.F.; Cloutis, E.A.; Wray, J.J.; Herkenhoff, K. E.; Sullivan, R.; Johnson, J. R.; Anderson, R.B.

2011-01-01

The Mars Exploration Rover Spirit has discovered bright soil deposits in its wheel tracks that previously have been confirmed to contain ferric sulfates and/or opaline silica. Repeated Pancam multispectral observations have been acquired at four of these deposits to monitor spectral and textural changes over time during exposure to Martian surface conditions. Previous studies suggested that temporal spectral changes occur because of mineralogic changes (e.g., phase transitions accompanying dehydration). In this study, we present a multispectral and temporal analysis of eight Pancam image sequences at the Tyrone exposure, three at the Gertrude Weise exposure, two at the Kit Carson exposure, and ten at the Ulysses exposure that have been acquired as of sol 2132 (1 January 2010). We compare observed variations in Pancam data to spectral changes predicted by laboratory experiments for the dehydration of ferric sulfates. We also present a spectral analysis of repeated Mars Reconnaissance Orbiter HiRISE observations spanning 32 sols and a textural analysis of Spirit Microscopic Imager observations of Ulysses spanning 102 sols. At all bright soil exposures, we observe no statistically significant spectral changes with time that are uniquely diagnostic of dehydration and/or mineralogic phase changes. However, at Kit Carson and Ulysses, we observe significant textural changes, including slumping within the wheel trench, movement of individual grains, disappearance of fines, and dispersal of soil clods. All observed textural changes are consistent with aeolian sorting and/or minor amounts of air fall dust deposition. Copyright 2011 by the American Geophysical Union.

Spaceflight-relevant types of ionizing radiation and cortical bone: Potential LET effect?

NASA Astrophysics Data System (ADS)

Lloyd, Shane A. J.; Bandstra, Eric R.; Travis, Neil D.; Nelson, Gregory A.; Bourland, J. Daniel; Pecaut, Michael J.; Gridley, Daila S.; Willey, Jeffrey S.; Bateman, Ted A.

2008-12-01

Extended exposure to microgravity conditions results in significant bone loss. Coupled with radiation exposure, this phenomenon may place astronauts at a greater risk for mission-critical fractures. In a previous study, we identified a profound and prolonged loss of trabecular bone (29-39%) in mice following exposure to an acute, 2 Gy dose of radiation simulating both solar and cosmic sources. However, because skeletal strength depends on trabecular and cortical bone, accurate assessment of strength requires analysis of both bone compartments. The objective of the present study was to examine various properties of cortical bone in mice following exposure to multiple types of spaceflight-relevant radiation. Nine-week old, female C57BL/6 mice were sacrificed 110 days after exposure to a single, whole body, 2 Gy dose of gamma, proton, carbon, or iron radiation. Femora were evaluated with biomechanical testing, microcomputed tomography, quantitative histomorphometry, percent mineral content, and micro-hardness analysis. Compared to non-irradiated controls, there were significant differences compared to carbon or iron radiation for only fracture force, medullary area and mineral content. A greater differential effect based on linear energy transfer (LET) level may be present: high-LET (carbon or iron) particle irradiation was associated with a decline in structural properties (maximum force, fracture force, medullary area, and cortical porosity) and mineral composition compared to low-LET radiation (gamma and proton). Bone loss following irradiation appears to be largely specific to trabecular bone and may indicate unique biological microenvironments and microdosimetry conditions. However, the limited time points examined and non-haversian skeletal structure of the mice employed highlight the need for further investigation.

Questionable sound exposure outside of the womb: frequency analysis of environmental noise in the neonatal intensive care unit.

PubMed

Lahav, Amir

2015-01-01

Recent research raises concerns about the adverse effects of noise exposure on the developing preterm infant. However, current guidelines for NICU noise remain focused on loudness levels, leaving the problem of exposure to potentially harmful sound frequencies largely overlooked. This study examined the frequency spectra present in a level-II NICU. Noise measurements were taken in two level-II open-bay nurseries. Measurements were taken over 5 days for a period of 24 h each. Spectral analysis was focused on comparing sound frequencies in the range of human speech during daytime (7 AM-7 PM) vs. night-time (7 PM-7 AM). On average, daytime noise levels (Leq = 60.05 dBA) were higher than night-time (Leq = 58.67 dBA). Spectral analysis of frequency bands (>50 dB) revealed that infants were exposed to frequencies <500 Hz 100% of the time and to frequencies >500 Hz 57% of the time. During daytime, infants were exposed to nearly 20% more sounds within the speech frequency range compared with night-time (p = 0.018). Measuring the frequency spectra of NICU sounds is necessary to attain a thorough understanding of both the noise levels and the type of sounds that preterm infants are exposed to throughout their hospital stay. The risk of high-frequency noise exposure in the preterm population is still unclear and warrants further investigation. © 2014 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

Effects of exposure in single and multiple contexts on fear renewal: The moderating role of threat-specific and nonspecific emotionality.

PubMed

Olatunji, Bunmi O; Tomarken, Andrew; Wentworth, Brian; Fritzsche, Laura

2017-03-01

The current study examines effects of exposure in multiple contexts on fear reduction and renewal and the moderating effect of baseline threat-specific and nonspecific emotionality. Snake-fearful participants received a negative or neutral emotion induction and were randomized to video exposure to a snake in a single context, multiple context, or a no exposure control group. Anxiety in response to video presentations of a snake was significantly reduced in the two exposure groups compared to the control group, especially among those with heightened baseline threat-specific emotionality as indicated by snake anxiety ratings at baseline. Although the two exposure groups did not differ in responding when confronted with a novel snake, both exposure groups reported significantly lower snake anxiety and arousal than the control group. Subsequent analysis did show that compared to controls, the single context group demonstrated greater increase in anxiety and arousal from post-exposure to exposure to the novel snake among those with heightened snake anxiety at baseline. Furthermore, the multiple context group was less avoidant and less fearful than the single context group on a post-exposure behavioral test. The study used an analogue exposure paradigm with an analogue sample and findings may not be generalizable to a clinical population. These findings suggest that baseline threat-specific emotionality influences fear reduction and renewal. The benefits of exposure in multiple contexts are discussed in relation to a distinct pattern of symptom change that is in line with an inhibitory learning approach. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Regression on order statistics and its application in estimating nondetects for food exposure assessment].

PubMed

Yu, Xiaojin; Liu, Pei; Min, Jie; Chen, Qiguang

2009-01-01

To explore the application of regression on order statistics (ROS) in estimating nondetects for food exposure assessment. Regression on order statistics was adopted in analysis of cadmium residual data set from global food contaminant monitoring, the mean residual was estimated basing SAS programming and compared with the results from substitution methods. The results show that ROS method performs better obviously than substitution methods for being robust and convenient for posterior analysis. Regression on order statistics is worth to adopt,but more efforts should be make for details of application of this method.

Proteomic analysis of tree peony (Paeonia ostii 'Feng Dan') seed germination affected by low temperature.

PubMed

Ren, Xiu-Xia; Xue, Jing-Qi; Wang, Shun-Li; Xue, Yu-Qian; Zhang, Ping; Jiang, Hai-Dong; Zhang, Xiu-Xin

Seed germination is a critical process that is influenced by various factors. In the present study, the effect of low temperature (4 °C) on tree peony seed germination was investigated. Compared to seeds maintained at 25 °C, germination was inhibited when seeds were kept at 4 °C. Furthermore, low-temperature exposure of seeds resulted in a delay in water uptake, starch degradation, and soluble sugar consumption and a subsequent increase in soluble protein levels. Two-dimensional gel electrophoresis (2-DE) proteomic analysis identified 100 protein spots. Comparative analysis indicated that low-temperature exposure apparently mainly affected glycolysis and the tricarboxylic acid (TCA) cycle, while also significantly affecting proteometabolism-related factors. Moreover, low-temperature exposure led to the induction of abscisic acid, whereas the gibberellin pathway was not affected. Further comparison of the two temperature conditions showed that low-temperature exposure delays carbohydrate metabolism, adenosine triphosphate (ATP) production, respiration, and proteolysis and increases defense response factors. To further examine the obtained proteomic findings, four genes were evaluated by quantitative polymerase chain reaction (qPCR). The obtained transcriptional results for the GAPC gene coincided with the translational results, thus further suggesting that the delay in glycolysis may play a key role in low-temperature-induced inhibition of seed germination. However, the other three genes examined, which included FPP synthase, PCNT115, and endochitinase, showed non-correlative transcriptional and translational profiles. Our results suggest that the exposure of tree peony seeds to low temperature results in a delay in the degradation of starch and other metabolites, which in turn affects glycolysis and some other processes, thereby ultimately inhibiting seed germination. Copyright © 2017. Published by Elsevier GmbH.

Analysis of Longitudinal Studies With Repeated Outcome Measures: Adjusting for Time-Dependent Confounding Using Conventional Methods.

PubMed

Keogh, Ruth H; Daniel, Rhian M; VanderWeele, Tyler J; Vansteelandt, Stijn

2018-05-01

Estimation of causal effects of time-varying exposures using longitudinal data is a common problem in epidemiology. When there are time-varying confounders, which may include past outcomes, affected by prior exposure, standard regression methods can lead to bias. Methods such as inverse probability weighted estimation of marginal structural models have been developed to address this problem. However, in this paper we show how standard regression methods can be used, even in the presence of time-dependent confounding, to estimate the total effect of an exposure on a subsequent outcome by controlling appropriately for prior exposures, outcomes, and time-varying covariates. We refer to the resulting estimation approach as sequential conditional mean models (SCMMs), which can be fitted using generalized estimating equations. We outline this approach and describe how including propensity score adjustment is advantageous. We compare the causal effects being estimated using SCMMs and marginal structural models, and we compare the two approaches using simulations. SCMMs enable more precise inferences, with greater robustness against model misspecification via propensity score adjustment, and easily accommodate continuous exposures and interactions. A new test for direct effects of past exposures on a subsequent outcome is described.

2,4-dichlorophenoxyacetic acid (2,4-D) and risk of non-Hodgkin lymphoma: a meta-analysis accounting for exposure levels.

PubMed

Smith, Adam M; Smith, Martyn T; La Merrill, Michele A; Liaw, Jane; Steinmaus, Craig

2017-04-01

2,4-Dichlorophenoxyacetic acid (2,4-D) is one of the most commonly used selective herbicides in the world. A number of epidemiology studies have found an association between 2,4-D exposure and non-Hodgkin lymphoma (NHL) but these results are inconsistent and controversial. A previous meta-analysis found no clear association overall but did not specifically examine high-exposure groups. We conducted a systematic review and meta-analysis of the peer-reviewed epidemiologic studies of the associations between 2,4-D and NHL, with a particular focus on high-exposure groups, and evaluations of heterogeneity, dose-response, and bias. A total of 12 observational studies, 11 case-control studies, and one cohort study, were included. The summary relative risk for NHL using study results comparing subjects who were ever versus never exposed to 2,4-D was 1.38 (95% confidence interval (CI), 1.07-1.77). However, in analyses focusing on results from highly exposed groups, the summary relative risk for NHL was 1.73 (95% CI, 1.10-2.72). No clear bias based on study design, exposure assessment methodology, or outcome misclassification was seen. Overall, these findings provide new evidence for an association between NHL and exposure to the herbicide 2,4-D. Copyright © 2017 Elsevier Inc. All rights reserved.

Effectiveness of permethrin-treated clothing to prevent tick exposure in foresters in the central Appalachian region of the USA.

PubMed

L Richards, Stephanie; G Balanay, Jo Anne; W Harris, Jonathan

2015-01-01

Outdoor workers are at risk from mosquito and tick bites and the extent to which exposures are linked to vector-borne disease is not understood. This pilot study characterizes for ester exposure to mosquitoes and ticks, and assesses effectiveness of permethrin-treated clothing for prevention of tick bites. Foresters (N = 34) from Kentucky, North Carolina, Ohio, Tennessee, Virginia, and West Virginia were placed into treatment (permethrin-treated clothing) or control (untreated clothing) groups. Foresters completed questionnaires about work-related tick/mosquito exposure and 454 ticks were collected/identified from May to June 2013. A time-weighted analysis based on information submitted by foresters about time working outdoors showed that control participants received a lower rate of tick exposure (0.15 tick bites/hour; 13 bites/person) compared to treatment participants (0.27 bites/hour; 21 bites/person). However, more control participants (85 %) received at least one tick bite compared to treatment participants (52 %). Outdoor workers should be aware of available protective measures, such as permethrin-treated clothing, that may mitigate occupational risks.

Working memory function is linked to trauma exposure, independently of post-traumatic stress disorder symptoms.

PubMed

Blanchette, Isabelle; Caparos, Serge

2016-11-01

The purpose of the study was to examine how working memory (WM) may be related to exposure to potentially traumatic events and symptoms of post-traumatic stress disorder (PTSD). In four studies, we measured WM function using adaptations of the running span and the reading span tasks. We compared the performance of women reporting experiences of sexual abuse to control participants (total n = 144 controls and 84 victims). We measured severity of the sexual abuse experiences as well as exposure to general life stress. In all studies, trauma-exposed participants showed significantly lower WM function compared to control participants. In addition to traditional null hypothesis testing, we used a mini-meta analysis to estimate the combined estimated effect size of this difference, which was in the moderate range (d = 0.43 with 0.15-0.70 95% confidence interval). Regression equations showed that PTSD symptoms did not mediate the relationship between trauma exposure and WM function. Our results show that trauma exposure per se can be associated with important cognitive correlates even in individuals who do not develop psychopathological reactions.

Avoidance of sun exposure as a risk factor for major causes of death: a competing risk analysis of the Melanoma in Southern Sweden cohort.

PubMed

Lindqvist, P G; Epstein, E; Nielsen, K; Landin-Olsson, M; Ingvar, C; Olsson, H

2016-10-01

Women with active sunlight exposure habits experience a lower mortality rate than women who avoid sun exposure; however, they are at an increased risk of skin cancer. We aimed to explore the differences in main causes of death according to sun exposure. We assessed the differences in sun exposure as a risk factor for all-cause mortality in a competing risk scenario for 29 518 Swedish women in a prospective 20-year follow-up of the Melanoma in Southern Sweden (MISS) cohort. Women were recruited from 1990 to 1992 (aged 25-64 years at the start of the study). We obtained detailed information at baseline on sun exposure habits and potential confounders. The data were analysed using modern survival statistics. Women with active sun exposure habits were mainly at a lower risk of cardiovascular disease (CVD) and noncancer/non-CVD death as compared to those who avoided sun exposure. As a result of their increased survival, the relative contribution of cancer death increased in these women. Nonsmokers who avoided sun exposure had a life expectancy similar to smokers in the highest sun exposure group, indicating that avoidance of sun exposure is a risk factor for death of a similar magnitude as smoking. Compared to the highest sun exposure group, life expectancy of avoiders of sun exposure was reduced by 0.6-2.1 years. The longer life expectancy amongst women with active sun exposure habits was related to a decrease in CVD and noncancer/non-CVD mortality, causing the relative contribution of death due to cancer to increase. © 2016 The Association for the Publication of the Journal of Internal Medicine.

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

PubMed

Zradziński, Patryk

2013-06-01

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

Comparative proteomic analysis reveals heart toxicity induced by chronic arsenic exposure in rats.

PubMed

Huang, Qingyu; Xi, Guochen; Alamdar, Ambreen; Zhang, Jie; Shen, Heqing

2017-10-01

Arsenic is a widespread metalloid in the environment, which poses a broad spectrum of adverse effects on human health. However, a global view of arsenic-induced heart toxicity is still lacking, and the underlying molecular mechanisms remain unclear. By performing a comparative quantitative proteomic analysis, the present study aims to investigate the alterations of proteome profile in rat heart after long-term exposure to arsenic. As a result, we found that the abundance of 81 proteins were significantly altered by arsenic treatment (35 up-regulated and 46 down-regulated). Among these, 33 proteins were specifically associated with cardiovascular system development and function, including heart development, heart morphology, cardiac contraction and dilation, and other cardiovascular functions. It is further proposed that the aberrant regulation of 14 proteins induced by arsenic would disturb cardiac contraction and relaxation, impair heart morphogenesis and development, and induce thrombosis in rats, which is mediated by the Akt/p38 MAPK signaling pathway. Overall, these findings will augment our knowledge of the involved mechanisms and develop useful biomarkers for cardiotoxicity induced by environmental arsenic exposure. Copyright © 2017 Elsevier Ltd. All rights reserved.

Risk of breast cancer following exposure to tetrachloroethylene-contaminated drinking water in Cape Cod, Massachusetts: reanalysis of a case-control study using a modified exposure assessment

PubMed Central

2011-01-01

Background Tetrachloroethylene (PCE) is an important occupational chemical used in metal degreasing and drycleaning and a prevalent drinking water contaminant. Exposure often occurs with other chemicals but it occurred alone in a pattern that reduced the likelihood of confounding in a unique scenario on Cape Cod, Massachusetts. We previously found a small to moderate increased risk of breast cancer among women with the highest exposures using a simple exposure model. We have taken advantage of technical improvements in publically available software to incorporate a more sophisticated determination of water flow and direction to see if previous results were robust to more accurate exposure assessment. Methods The current analysis used PCE exposure estimates generated with the addition of water distribution modeling software (EPANET 2.0) to test model assumptions, compare exposure distributions to prior methods, and re-examine the risk of breast cancer. In addition, we applied data smoothing to examine nonlinear relationships between breast cancer and exposure. We also compared a set of measured PCE concentrations in water samples collected in 1980 to modeled estimates. Results Thirty-nine percent of individuals considered unexposed in prior epidemiological analyses were considered exposed using the current method, but mostly at low exposure levels. As a result, the exposure distribution was shifted downward resulting in a lower value for the 90th percentile, the definition of "high exposure" in prior analyses. The current analyses confirmed a modest increase in the risk of breast cancer for women with high PCE exposure levels defined by either the 90th percentile (adjusted ORs 1.0-1.5 for 0-19 year latency assumptions) or smoothing analysis cut point (adjusted ORs 1.3-2.0 for 0-15 year latency assumptions). Current exposure estimates had a higher correlation with PCE concentrations in water samples (Spearman correlation coefficient = 0.65, p < 0.0001) than estimates generated using the prior method (0.54, p < 0.0001). Conclusions The incorporation of sophisticated flow estimates in the exposure assessment method shifted the PCE exposure distribution downward, but did not meaningfully affect the exposure ranking of subjects or the strength of the association with the risk of breast cancer found in earlier analyses. Thus, the current analyses show a slightly elevated breast cancer risk for highly exposed women, with strengthened exposure assessment and minimization of misclassification by using the latest technology. PMID:21600013

In Vitro Exposures in Diesel Exhaust Atmospheres: Resuspension of PM from Filters Verses Direct Deposition of PM from Air

PubMed Central

Lichtveld, Kim M.; Ebersviller, Seth M.; Sexton, Kenneth G.; Vizuete, William; Jaspers, Ilona; Jeffries, Harvey E.

2012-01-01

One of the most widely used in vitro particulate matter (PM) exposures methods is the collection of PM on filters, followed by resuspension in a liquid medium, with subsequent addition onto a cell culture. To avoid disruption of equilibria between gases and PM, we have developed a direct in vitro sampling and exposure method (DSEM) capable of PM-only exposures. We hypothesize that the separation of phases and post-treatment of filter-collected PM significantly modifies the toxicity of the PM compared to direct deposition, resulting in a distorted view of the potential PM health effects. Controlled test environments were created in a chamber that combined diesel exhaust with an urban-like mixture. The complex mixture was analyzed using both the DSEM and concurrently-collected filter samples. The DSEM showed that PM from test atmospheres produced significant inflammatory response, while the resuspension exposures at the same exposure concentration did not. Increasing the concentration of resuspended PM sixteen times was required to yield measurable IL-8 expression. Chemical analysis of the resuspended PM indicated a total absence of carbonyl compounds compared to the test atmosphere during the direct-exposures. Therefore, collection and resuspension of PM into liquid modifies its toxicity and likely leads to underestimating toxicity. PMID:22834915

Comparison of screening-level and Monte Carlo approaches for wildlife food web exposure modeling

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

Pastorok, R.; Butcher, M.; LaTier, A.

1995-12-31

The implications of using quantitative uncertainty analysis (e.g., Monte Carlo) and site-specific tissue residue data for wildlife exposure modeling were examined with data on trace elements at the Clark Fork River Superfund Site. Exposure of white-tailed deer, red fox, and American kestrel was evaluated using three approaches. First, a screening-level exposure model was based on conservative estimates of exposure parameters, including estimates of dietary residues derived from bioconcentration factors (BCFs) and soil chemistry. A second model without Monte Carlo was based on site-specific data for tissue residues of trace elements (As, Cd, Cu, Pb, Zn) in key dietary species andmore » plausible assumptions for habitat spatial segmentation and other exposure parameters. Dietary species sampled included dominant grasses (tufted hairgrass and redtop), willows, alfalfa, barley, invertebrates (grasshoppers, spiders, and beetles), and deer mice. Third, the Monte Carlo analysis was based on the site-specific residue data and assumed or estimated distributions for exposure parameters. Substantial uncertainties are associated with several exposure parameters, especially BCFS, such that exposure and risk may be greatly overestimated in screening-level approaches. The results of the three approaches are compared with respect to realism, practicality, and data gaps. Collection of site-specific data on trace elements concentrations in plants and animals eaten by the target wildlife receptors is a cost-effective way to obtain realistic estimates of exposure. Implications of the results for exposure and risk estimates are discussed relative to use of wildlife exposure modeling and evaluation of remedial actions at Superfund sites.« less

Symbolic Analysis of Heart Rate Variability During Exposure to Musical Auditory Stimulation.

PubMed

Vanderlei, Franciele Marques; de Abreu, Luiz Carlos; Garner, David Matthew; Valenti, Vitor Engrácia

2016-01-01

In recent years, the application of nonlinear methods for analysis of heart rate variability (HRV) has increased. However, studies on the influence of music on cardiac autonomic modulation in those circumstances are rare. The research team aimed to evaluate the acute effects on HRV of selected auditory stimulation by 2 musical styles, measuring the results using nonlinear methods of analysis: Shannon entropy, symbolic analysis, and correlation-dimension analysis. Prospective control study in which the volunteers were exposed to music and variables were compared between control (no auditory stimulation) and during exposure to music. All procedures were performed in a sound-proofed room at the Faculty of Science and Technology at São Paulo State University (UNESP), São Paulo, Brazil. Participants were 22 healthy female students, aged between 18 and 30 y. Prior to the actual intervention, the participants remained at rest for 20 min, and then they were exposed to one of the selected types of music, either classical baroque (64-84 dB) or heavy-metal (75-84 dB). Each musical session lasted a total of 5 min and 15 s. At a point occurring up to 1 wk after that day, the participants listened to the second type of music. The 2 types of music were delivered in a random sequence that depended on the group to which the participant was assigned. The study analyzed the following HRV indices through Shannon entropy; symbolic analysis-0V%, 1V%, 2LV%, and 2ULV%; and correlation-dimension analysis. During exposure to auditory stimulation by heavy-metal or classical baroque music, the study established no statistically significant variations regarding the indices for the Shannon entropy; the symbolic analysis-0V%, 1V%, and 2ULV%; and the correlation-dimension analysis. However, during heavy-metal music, the 2LV% index in the symbolic analysis was reduced compared with the controls. Auditory stimulation with the heavy-metal music reduced the parasympathetic modulation of HRV, whereas no significant changes occurred in cardiac autonomic modulation during exposure to the classical music.

Occupational and Biomass Exposure in Chronic Obstructive Pulmonary Disease: Results of a Cross-Sectional Analysis of the On-Sint Study.

PubMed

López-Campos, José Luis; Fernández-Villar, Alberto; Calero-Acuña, Carmen; Represas-Represas, Cristina; López-Ramírez, Cecilia; Fernández, Virginia Leiro; Casamor, Ricard

2017-01-01

Although tobacco smoke is the main risk factor for chronic obstructive pulmonary disease (COPD), other inhaled toxics have also been associated with the disease. The present study analyzes data from exposure to these substances in a cohort of patients with COPD and assesses their impact on the clinical presentation of the disease. This is a cross-sectional analysis of the Clinical presentation, diagnosis and course of chronic obstructive pulmonary disease (On-Sint) study. All patients were smokers or ex-smokers as per protocol. In addition, during the inclusion visit patients were enquired about their occupational and biomass exposure history. The clinical features of patients with and without an added risk factor to tobacco were compared and those significant were entered in a multivariate logistic regression analysis, expressed as odds ratio (OR). The sample size was 1214 patients with COPD, of which 1012 (83.4%) had tobacco as the only risk factor and 202 (16.6%) had additional ones, mainly 174 (14.3%) with occupational gases and 32 (2.6%) with biomass exposure. The geographical distribution of this exposure showed a preference for the northern parts of the country and the East coast. The biomass exposure was rather low. Male gender (OR: 2.180), CAT score (OR: 1.036) and the use of long-term oxygen therapy (OR: 1.642) were associated with having an additional risk factor in the multivariate analysis. Occupational exposures are more common than biomass in Spain. COPD caused by tobacco plus other inhalants has some differential features and a more impaired quality of life. Copyright © 2016 SEPAR. Publicado por Elsevier España, S.L.U. All rights reserved.

[Hospitality workers' exposure to environmental tobacco smoke before and after implementation of smoking ban in public places: a review of epidemiological studies].

PubMed

Polańska, Kinga; Hanke, Wojciech; Konieczko, Katarzyna

2011-01-01

Environmental tobacco smoke (ETS) exposure induces serious negative health consequences, of which the increased risk of cardiovascular diseases, cancer, respiratory symptoms and poor pregnancy outcomes appear to be most important. Taking into account those health consequences of ETS exposure most countries have introduced legislation to ban or restrict smoking in public places. In this paper the effectiveness of the introduced legislation was analyzed with regard to the protection of hospitality workers from ETS exposure in the workplace. The analysis of 12 papers published after 2000 covered the year of publication, type of legislation, study population, hospitality venue (pub, bar, restaurant, disco) and type of markers or self-reported perception of exposure to ETS. The analysis indicates that the legislation to ban smoking in hospitality venues protects workers from ETS exposure when the venues are 100% tobacco smoke free. The reduction of the cotinine level in biological samples after the implementation of smoke free law was 57-89%, comparing to the biomarker level in the samples taken before the new law was introduced. About 90% of reduction in nicotine and PM levels was also noted. In addition, the positive self perception reported by workers proved the effectiveness of new legislation protecting them from ETS exposure.

Population Pharmacokinetics and Exposure Response Assessment of CC-292, a Potent BTK Inhibitor, in Patients With Chronic Lymphocytic Leukemia.

PubMed

Li, Yan; Ramírez-Valle, Francisco; Xue, Yongjun; Ventura, Judith I; Gouedard, Olivier; Mei, Jay; Takeshita, Kenichi; Palmisano, Maria; Zhou, Simon

2017-10-01

CC-292, a potent Bruton tyrosine kinase inhibitor, is under development for the treatment of B-cell malignancies. An analysis was performed to develop a population pharmacokinetic model of CC-292 and assess the influence of demographics and disease-related covariates on CC-292 exposure and to assess the exposure-response (overall response rate) relationship in patients with chronic lymphocytic leukemia. Population pharmacokinetic analysis was based on a 2-compartment base model conducted in NONMEM. Categorical exposure-response analysis was performed using logistic regression in SAS. The population pharmacokinetic analysis results indicated that CC-292 pharmacokinetic disposition is similar between healthy subjects and patients. CC-292 showed a larger central compartment volume of distribution than the peripheral compartment volume of distribution (158 L and 72 L, respectively) and a faster clearance than intercompartmental clearance (134 L/h and 18.7 L/h, respectively), indicating that for CC-292, clearance from blood occurs faster than distribution into deep tissues and organs. CC-292 clearance is not affected by demographics or baseline clinical lab factors, except for sex. Although sex significantly reduced variation of apparent clearance, the sex effect on apparent clearance is unlikely to be clinically relevant. The exposure-response analysis suggested that higher drug exposure is linearly correlated with higher overall response rate. A twice-daily dose regimen showed higher overall response rate as compared to once-daily dosing, consistent with a threshold concentration of approximately 300 ng/mL, above which the probability of overall response rate significantly increases. © 2017, The Authors. The Journal of Clinical Pharmacology Published by Wiley Periodicals, Inc. on behalf of American College of Clinical Pharmacology.

Early Indication of Noise-induced Hearing Loss from PMP Use in Adolescents: A Cross-Sectional Analysis

PubMed Central

Colon, Diana C.; Verdugo-Raab, Ulla; Alvarez, Carmelo P.; Steffens, Thomas; Marcrum, Steven C.; Kolb, Stefanie; Herr, Caroline; Twardella, Dorothee

2016-01-01

Context: Distortion product otoacoustic emissions (DPOAEs) may indicate preclinical noise-induced hearing loss (NIHL) in adolescents from unsafe personal music player (PMP) use. Aims: The objective, therefore, was to observe preclinical signs of NIHL in 9th grade adolescents with clinically normal hearing by comparing DPOAE signals between different levels of A-weighted equivalent PMP exposure. Settings and Design: Subjects were recruited from all secondary-level schools located in the city of Regensburg, Germany during two academic years 2009/2010 and 2010/2011. Subjects and Methods: A-weighted equivalent sound pressure levels (SPLs) for a 40-hour work week (LAeq,40h) were estimated from questionnaire responses on output and duration of PMP use of the previous week. Subjects were then categorized into four levels of exposure: <80, 80–85, >85 to <90, and ≥90 A-weighted Decibel [dB(A)]. DPOAE signals were collected by trained audiological staff, applying a standard optimized protocol, at the Department of Otorhinolaryngology of the University Hospital Regensburg. Statistical Analysis Used: Mean DPOAE signals were compared between levels by unpaired t test. Novel linear regression models adjusting for other leisure noise exposures and with outcome variables DPoutcome and 4 kilo Hertz (kHz) DPOAEs estimated effects between levels. Results: A total of 1468 subjects (56% female, mostly aged 15 or 16 years) were available for analysis. Comparison of DPOAE means by PMP exposure typically showed no greater than 1 dB difference between groups. In fact, comparisons between ≥90 dB(A) and <80 dB(A) presented the least differences in magnitude. Both DPoutcome and 4 kHz linear regression models presented a weak association with the 4-level PMP exposure variable. An expected dose-response to PMP exposure was not observed in any analyses. Conclusions: DPOAE signal strength alone cannot indicate preclinical NIHL in adolescents. PMID:27991459

Phenotypic malignant changes and untargeted lipidomic analysis of long-term exposed prostate cancer cells to endocrine disruptors

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

Bedia, Carmen, E-mail: carmen.bedia@idaea.csic.es; Dalmau, Núria, E-mail: nuria.dalmau@idaea.csic.es; Jaumot, Joaquim, E-mail: joaquim.jaumot@idaea.csic.es

2015-07-15

Endocrine disruptors (EDs) are a class of environmental toxic molecules able to interfere with the normal hormone metabolism. Numerous studies involve EDs exposure to initiation and development of cancers, including prostate cancer. In this work, three different EDs (aldrin, aroclor 1254 and chlorpyrifos (CPF)) were investigated as potential inducers of a malignant phenotype in DU145 prostate cancer cells after a chronic exposure. Epithelial to mesenchymal transition (EMT) induction, proliferation, migration, colony formation and release of metalloproteinase 2 (MMP-2) were analyzed in 50-day exposed cells to the selected EDs. As a result, aldrin and CPF exposure led to an EMT inductionmore » (loss of 16% and 14% of E-cadherin levels, respectively, compared to the unexposed cells). Aroclor and CPF presented an increased migration (134% and 126%, respectively), colony formation (204% and 144%, respectively) and MMP-2 release (137% in both cases) compared to the unexposed cells. An untargeted lipidomic analysis was performed to decipher the lipids involved in the observed transformations. As general results, aldrin exposure showed a global decrease in phospholipids and sphingolipids, and aroclor and CPF showed an increase of certain phospholipids, glycosphingolipids as well as a remarkable increase of some cardiolipin species. Furthermore, the three exposures resulted in an increase of some triglyceride species. In conclusion, some significant changes in lipids were identified and thus we postulate that some lipid compounds and lipid metabolic pathways could be involved in the acquisition of the malignant phenotype in exposed prostate cancer cells to the selected EDs. - Highlights: • Aldrin, aroclor and chlorpyrifos induced an aggressive phenotype in DU145 cells. • An untargeted lipidomic analysis has been performed on chronic exposed cells. • Lipidomic results showed changes in specific lipid species under chronic exposure. • These lipids may have a role in the acquisition of a malignant phenotype.« less

Ethnic Diversity, Inter-group Attitudes and Countervailing Pathways of Positive and Negative Inter-group Contact: An Analysis Across Workplaces and Neighbourhoods.

PubMed

Laurence, James; Schmid, Katharina; Hewstone, Miles

2018-01-01

This study advances the current literature investigating the relationship between contextual out-group exposure, inter-group attitudes and the role of inter-group contact. Firstly, it introduces the concept of contact-valence into this relationship; that is, whether contact is experienced positively or negatively. Secondly, it presents a comparative analysis of how processes of out-group exposure and frequency of (valenced) contact affect prejudice across both neighbourhoods and workplaces. Applying path analysis modelling to a nationally-representative sample of white British individuals in England, we demonstrate, across both contexts, that increasing out-group exposure is associated with higher rates of both positively- and negatively-valenced contact. This results in exposure exhibiting both positive and negative indirect associations with prejudice via more frequent inter-group mixing. These countervailing contact-pathways help explain how out-group exposure is associated with inter-group attitudes. In neighbourhoods, increasing numbers of individuals experiencing positive-contact suppress an otherwise negative effect of neighbourhood diversity (driven partly by increasing numbers of individuals reporting negative contact). Across workplaces the effect differs such that increasing numbers of individuals experiencing negative-contact suppress an otherwise positive effect of workplace diversity (driven largely by increasing numbers of individuals experiencing positive contact).

On the equivalence of case-crossover and time series methods in environmental epidemiology.

PubMed

Lu, Yun; Zeger, Scott L

2007-04-01

The case-crossover design was introduced in epidemiology 15 years ago as a method for studying the effects of a risk factor on a health event using only cases. The idea is to compare a case's exposure immediately prior to or during the case-defining event with that same person's exposure at otherwise similar "reference" times. An alternative approach to the analysis of daily exposure and case-only data is time series analysis. Here, log-linear regression models express the expected total number of events on each day as a function of the exposure level and potential confounding variables. In time series analyses of air pollution, smooth functions of time and weather are the main confounders. Time series and case-crossover methods are often viewed as competing methods. In this paper, we show that case-crossover using conditional logistic regression is a special case of time series analysis when there is a common exposure such as in air pollution studies. This equivalence provides computational convenience for case-crossover analyses and a better understanding of time series models. Time series log-linear regression accounts for overdispersion of the Poisson variance, while case-crossover analyses typically do not. This equivalence also permits model checking for case-crossover data using standard log-linear model diagnostics.

Weathering effects on tensile and stress rupture strength of glass fiber reinforced vinylester and epoxy thermoset pipes

NASA Astrophysics Data System (ADS)

Nizamuddin, Syed

Glass fiber reinforced vinylester (GFRE) and epoxy (GFRE) pipes have been used for more than three decades to mitigate corrosion problems in oil fields, chemical and industrial plants. In these services, both GFRV and GFRE pipes are exposed to various environmental conditions. Long-term mechanical durability of these pipes after exposure to environmental conditions, which include natural weathering exposure to seasonal temperature variation, sea water, humidity and other corrosive fluids like crude oil, should be well known. Although extensive research has been undertaken, several major issues pertaining to the performance of these pipes under a number of environmental conditions still remain unresolved. The main objective of this study is to investigate the effects of natural weathering, combined natural weathering with seawater and crude oil exposure, for time periods ranging from 3 to 36 months respectively, on the tensile and stress rupture behavior of GFRV and GFRE pipes. Ring specimens are machined from GFRV and GFRE pipes and tested before and after exposure to different weathering conditions prevalent in the eastern region (Dhahran) of Saudi Arabia and present under service conditions. The natural weathering and combined natural weathering with crude oil exposure of GFRV specimens revealed increased tensile strength even after 36 months of exposure when compared with that of the as received samples. However, the combined natural weathering with seawater exposure of GFRV samples revealed better tensile behavior till 24 months of exposure, and after 36 months their tensile strength was seen to be below that of the as received GFRV samples. The stress rupture behavior of natural weather exposed GFRV samples showed an improvement after 12 months of exposure and it decreased after 24 and 36 months of exposure when compared with the as received GFRV samples. The combined natural weathering with crude oil and seawater exposure of GFRV sample revealed improved stress rupture behavior after 12 months of exposure. The as received GFRE pipe specimens revealed higher average tensile strength when compared to the as received GFRV sample, whereas the stress rupture behavior was comparatively low. The seawater exposure of the GFRE specimens resulted in drastic reduction in both tensile and stress rupture properties. Fractographic analysis was performed using an optical microscope and SEM in order to explain the possible controlling mechanisms of failure.

Comparative Genome Analysis of Ciprofloxacin-Resistant Pseudomonas aeruginosa Reveals Genes Within Newly Identified High Variability Regions Associated With Drug Resistance Development

PubMed Central

Su, Hsun-Cheng; Khatun, Jainab; Kanavy, Dona M.

2013-01-01

The alarming rise of ciprofloxacin-resistant Pseudomonas aeruginosa has been reported in several clinical studies. Though the mutation of resistance genes and their role in drug resistance has been researched, the process by which the bacterium acquires high-level resistance is still not well understood. How does the genomic evolution of P. aeruginosa affect resistance development? Could the exposure of antibiotics to the bacteria enrich genomic variants that lead to the development of resistance, and if so, how are these variants distributed through the genome? To answer these questions, we performed 454 pyrosequencing and a whole genome analysis both before and after exposure to ciprofloxacin. The comparative sequence data revealed 93 unique resistance strain variation sites, which included a mutation in the DNA gyrase subunit A gene. We generated variation-distribution maps comparing the wild and resistant types, and isolated 19 candidates from three discrete resistance-associated high variability regions that had available transposon mutants, to perform a ciprofloxacin exposure assay. Of these region candidates with transposon disruptions, 79% (15/19) showed a reduction in the ability to gain high-level resistance, suggesting that genes within these high variability regions might enrich for certain functions associated with resistance development. PMID:23808957

Comparing children's GPS tracks with geospatial proxies for exposure to junk food.

PubMed

Sadler, Richard C; Gilliland, Jason A

2015-01-01

Various geospatial techniques have been employed to estimate children's exposure to environmental cardiometabolic risk factors, including junk food. But many studies uncritically rely on exposure proxies which differ greatly from actual exposure. Misrepresentation of exposure by researchers could lead to poor decisions and ineffective policymaking. This study conducts a GIS-based analysis of GPS tracks--'activity spaces'--and 21 proxies for activity spaces (e.g. buffers, container approaches) for a sample of 526 children (ages 9-14) in London, Ontario, Canada. These measures are combined with a validated food environment database (including fast food and convenience stores) to create a series of junk food exposure estimates and quantify the errors resulting from use of different proxy methods. Results indicate that exposure proxies consistently underestimate exposure to junk foods by as much as 68%. This underestimation is important to policy development because children are exposed to more junk food than estimated using typical methods. Copyright © 2015 Elsevier Ltd. All rights reserved.

Preoperative biological therapy and short-term outcomes of abdominal surgery in patients with inflammatory bowel disease.

PubMed

Waterman, Matti; Xu, Wei; Dinani, Amreen; Steinhart, A Hillary; Croitoru, Kenneth; Nguyen, Geoffrey C; McLeod, Robin S; Greenberg, Gordon R; Cohen, Zane; Silverberg, Mark S

2013-03-01

Previous investigations of short-term outcomes after preoperative exposure to biological therapy in inflammatory bowel disease (IBD) were conflicting. The authors aimed to assess postoperative outcomes in patients who underwent abdominal surgery with recent exposure to anti-tumour necrosis factor therapy. A retrospective case-control study with detailed matching was performed for subjects with IBD with and without exposure to biologics within 180 days of abdominal surgery. Postoperative outcomes were compared between the groups. 473 procedures were reviewed consisting of 195 patients with exposure to biologics and 278 matched controls. There were no significant differences in most postoperative outcomes such as: length of stay, fever (≥ 38.5°C), urinary tract infection, pneumonia, bacteraemia, readmission, reoperations and mortality. On univariate analysis, procedures on biologics had more wound infections compared with controls (19% vs 11%; p=0.008), but this was not significant in multivariate analysis. Concomitant therapy with biologics and thiopurines was associated with increased frequencies of urinary tract infections (p=0.0007) and wound infections (p=0.0045). Operations performed ≤ 14 days from last biologic dose had similar rates of infections and other outcomes when compared with those performed within 15-30 days or 31-180 days. Patients with detectable preoperative infliximab levels had similar rates of wound infection compared with those with undetectable levels (3/10 vs 0/9; p=0.21). Preoperative treatment with TNF-α antagonists in patients with IBD is not associated with most early postoperative complications. A shorter time interval from last biological dose is not associated with increased postoperative complications. In most cases, surgery should not be delayed, and appropriate biological therapy may be continued perioperatively.

Comparative analysis of the transcriptome responses of zebrafish embryos after exposure to low concentrations of cadmium, cobalt and copper.

PubMed

Sonnack, Laura; Klawonn, Thorsten; Kriehuber, Ralf; Hollert, Henner; Schäfers, Christoph; Fenske, Martina

2018-03-01

Metal toxicity is a global environmental challenge. Fish are particularly prone to metal exposure, which can be lethal or cause sublethal physiological impairments. The objective of this study was to investigate how adverse effects of chronic exposure to non-toxic levels of essential and non-essential metals in early life stage zebrafish may be explained by changes in the transcriptome. We therefore studied the effects of three different metals at low concentrations in zebrafish embryos by transcriptomics analysis. The study design compared exposure effects caused by different metals at different developmental stages (pre-hatch and post-hatch). Wild-type embryos were exposed to solutions of low concentrations of copper (CuSO 4 ), cadmium (CdCl 2 ) and cobalt (CoSO 4 ) until 96h post-fertilization (hpf) and microarray experiments were carried out to determine transcriptome profiles at 48 and 96hpf. We found that the toxic metal cadmium affected the expression of more genes at 96hpf than 48hpf. The opposite effect was observed for the essential metals cobalt and copper, which also showed enrichment of different GO terms. Genes involved in neuromast and motor neuron development were significantly enriched, agreeing with our previous results showing motor neuron and neuromast damage in the embryos. Our data provide evidence that the response of the transcriptome of fish embryos to metal exposure differs for essential and non-essential metals. Copyright © 2017 Elsevier Inc. All rights reserved.

Assessing child time-activity patterns in relation to indoor cooking fires in developing countries: a methodological comparison.

PubMed

Barnes, Brendon; Mathee, Angela; Moiloa, Kebitsamang

2005-01-01

Indoor air pollution, caused by the indoor burning of biomass fuels, has been associated with an increased risk of child acute respiratory infections in developing countries. The amount of time that children spend in proximity to fires is a crucial determinant of the health impact of indoor air pollution. Researchers are reliant on social scientific methods to assess exposure based on child location patterns in relation to indoor fires. The inappropriate use of methods could lead to misclassification of exposure. The aim of this paper is to compare two methods (observations and questionnaire interview) with video analysis (which is thought to offer a more accurate assessment of exposure) in rural South African villages. Compared to video analysis, results show that observations may underestimate the amount of time that children spend very close (within 1.5 m) to fires. This is possibly due to reactivity caused by the presence of an observer. The questionnaire interview offers a more accurate assessment of the amounts of time that children spend within 1.5 m of fires at the expense of a detailed behavioural analysis. By drawing on the strengths and weaknesses of each, this paper discusses the appropriateness of methods to different research contexts.

Chlorine dioxide water disinfection: a prospective epidemiology study

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

Michael, G.E.; Miday, R.K.; Bercz, J.P.

An epidemiologic study of 198 persons exposed for 3 months to drinking water disinfected with chlorine dioxide was conducted in a rural village. A control population of 118 nonexposed persons was also studied. Pre-exposure hematologic and serum chemical parameters were compared with test results after 115 days of exposure. Chlorite ion levels in the water averaged approximately 5 ppM during the study period. Statistical analysis (ANOVA) of the data failed to identify any significant exposure-related effects. This study suggests that future evaluations of chlorine dioxide disinfection should be directed toward populations with potentially increased sensitivity to hemolytic agents.

Eye-Specific Gene Expression following Embryonic Ethanol Exposure in Zebrafish: Roles for Heat Shock Factor 1

PubMed Central

Kashyap, Bhavani; Pegorsch, Laurel; Frey, Ruth A.; Sun, Chi; Shelden, Eric A.; Stenkamp, Deborah L.

2014-01-01

The mechanisms through which ethanol exposure results in developmental defects remain unclear. We used the zebrafish model to elucidate eye-specific mechanisms that underlie ethanol-mediated microphthalmia (reduced eye size), through time-series microarray analysis of gene expression within eyes of embryos exposed to 1.5% ethanol. 62 genes were differentially expressed (DE) in ethanol-treated as compared to control eyes sampled during retinal neurogenesis (24-48 hours post-fertilization). The EDGE (extraction of differential gene expression) algorithm identified >3000 genes DE over developmental time in ethanol-exposed eyes as compared to controls. The DE lists included several genes indicating a mis-regulated cellular stress response due to ethanol exposure. Combined treatment with sub-threshold levels of ethanol and a morpholino targeting heat shock factor 1 mRNA resulted in microphthalmia, suggesting convergent molecular pathways. Thermal preconditioning partially prevented ethanol-mediated microphthalmia while maintaining Hsf-1 expression. These data suggest roles for reduced Hsf-1 in mediating microphthalmic effects of embryonic ethanol exposure. PMID:24355176

In Utero Exposure to Low-Dose Alcohol Induces Reprogramming of Mammary Development and Tumor Risk in MMTV-erbB-2 Transgenic Mice

PubMed Central

Ma, Zhikun; Blackwelder, Amanda J.; Lee, Harry; Zhao, Ming; Yang, Xiaohe

2015-01-01

There is increasing evidence that prenatal exposure to environmental factors may modify breast cancer risk later in life. This study aimed to investigate the effects of in utero exposure to low-dose alcohol on mammary development and tumor risk. Pregnant MMTV-erbB-2 mice were exposed to alcohol (6 g/kg/day) between day 13 and day 19 of gestation, and the female offspring were examined for tumor risk. Whole mount analysis indicated that in utero exposure to low-dose alcohol induced significant increases in ductal extension at 10 weeks of age. Molecular analysis showed that in utero alcohol exposure induced upregulation of ERα signaling and activation of Akt and Erk1/2 in pubertal mammary glands. However, enhanced signaling in the EGFR/erbB-2 pathway appeared to be more prominent in 10-week-old glands than did signaling in the other pathways. Interestingly, tumor development in mice with in utero exposure to low-dose alcohol was slightly delayed compared to control mice, but tumor multiplicity was increased. The results indicate that in utero exposure to low-dose alcohol induces the reprogramming of mammary development by mechanisms that include altered signaling in the estrogen receptor (ER) and erbB-2 pathways. The intriguing tumor development pattern might be related to alcohol dose and exposure conditions, and warrants further investigation. PMID:25853264

Are metals emitted from electronic cigarettes a reason for health concern? A risk-assessment analysis of currently available literature.

PubMed

Farsalinos, Konstantinos E; Voudris, Vassilis; Poulas, Konstantinos

2015-05-15

Studies have found that metals are emitted to the electronic cigarette (EC) aerosol. However, the potential health impact of exposure to such metals has not been adequately defined. The purpose of this study was to perform a risk assessment analysis, evaluating the exposure of electronic cigarette (EC) users to metal emissions based on findings from the published literature. Two studies were found in the literature, measuring metals emitted to the aerosol from 13 EC products. We estimated that users take on average 600 EC puffs per day, but we evaluated the daily exposure from 1200 puffs. Estimates of exposure were compared with the chronic Permissible Daily Exposure (PDE) from inhalational medications defined by the U.S. Pharmacopeia (cadmium, chromium, copper, lead and nickel), the Minimal Risk Level (MRL) defined by the Agency for Toxic Substances and Disease Registry (manganese) and the Recommended Exposure Limit (REL) defined by the National Institute of Occupational Safety and Health (aluminum, barium, iron, tin, titanium, zinc and zirconium). The average daily exposure from 13 EC products was 2.6 to 387 times lower than the safety cut-off point of PDEs, 325 times lower than the safety limit of MRL and 665 to 77,514 times lower than the safety cut-off point of RELs. Only one of the 13 products was found to result in exposure 10% higher than PDE for one metal (cadmium) at the extreme daily use of 1200 puffs. Significant differences in emissions between products were observed. Based on currently available data, overall exposure to metals from EC use is not expected to be of significant health concern for smokers switching to EC use, but is an unnecessary source of exposure for never-smokers. Metal analysis should be expanded to more products and exposure can be further reduced through improvements in product quality and appropriate choice of materials.

Porous and nonporous orbital implants for treating the anophthalmic socket: A meta-analysis of case series studies.

PubMed

Schellini, Silvana; Jorge, Eliane; Sousa, Roberta; Burroughs, John; El-Dib, Regina

2016-01-01

To assess the efficacy and safety of porous and nonporous implants for management of the anophthalmic socket. Case series meta-analysis was conducted with no language restriction, including studies from: PUBMED, EMBASE and LILACS. Study eligibility criteria were case series design with more than 20 cases reported, use of porous and/or nonporous orbital implants, anophthalmic socket and, treatment success defined as no implant exposure or extrusion. Complications rates from each included study were quantified. Proportional meta-analysis was performed on both outcomes with a random-effects model and the 95% confidential intervals were calculated. A total of 35 case series studies with a total of 3,805 patients were included in the meta-analysis. There are no studies comparing porous and nonporous implants in the anophthalmic socket treatment. There was no statistically significant difference between porous polyethylene (PP) and hydroxyapatite (HA) on implant exposure: 0.026 (0.012-0.045) vs 0.054 (0.041-0.070), respectively and, neither on implant extrusion: 0.0042 (0.0008-0.010) vs. 0.018 (0.004-0.042), respectively. However, there was a significant difference supporting the use of PP when compared to bioceramic implant: 0.026 (0.012 -0.045) vs. 0.12 (0.06-0.20), respectively, on implant exposure. PP implants showed lower chance of exposure than bioceramic implant for anophthalmic socket reconstruction, although we cannot rule out the possibility of heterogeneity bias due to the nature and level of evidence of the included studies. Clinical trials are necessary to expand the knowledge of porous and nonporous orbital implants in the anophthalmic socket management.

Brain region-specific gene expression changes after chronic intermittent ethanol exposure and early withdrawal in C57BL/6J mice

PubMed Central

Melendez, Roberto I.; McGinty, Jacqueline F.; Kalivas, Peter W.; Becker, Howard C.

2014-01-01

Neuroadaptations that participate in the ontogeny of alcohol dependence are likely a result of altered gene expression in various brain regions. The present study investigated brain region-specific changes in the pattern and magnitude of gene expression immediately following chronic intermittent ethanol (CIE) exposure and 8 hours following final ethanol exposure [i.e. early withdrawal (EWD)]. High-density oligonucleotide microarrays (Affymetrix 430A 2.0, Affymetrix, Santa Clara, CA, USA) and bioinformatics analysis were used to characterize gene expression and function in the prefrontal cortex (PFC), hippocampus (HPC) and nucleus accumbens (NAc) of C57BL/6J mice (Jackson Laboratories, Bar Harbor, ME, USA). Gene expression levels were determined using gene chip robust multi-array average followed by statistical analysis of microarrays and validated by quantitative real-time reverse transcription polymerase chain reaction and Western blot analysis. Results indicated that immediately following CIE exposure, changes in gene expression were strikingly greater in the PFC (284 genes) compared with the HPC (16 genes) and NAc (32 genes). Bioinformatics analysis revealed that most of the transcriptionally responsive genes in the PFC were involved in Ras/MAPK signaling, notch signaling or ubiquitination. In contrast, during EWD, changes in gene expression were greatest in the HPC (139 genes) compared with the PFC (four genes) and NAc (eight genes). The most transcriptionally responsive genes in the HPC were involved in mRNA processing or actin dynamics. Of the few genes detected in the NAc, the most representatives were involved in circadian rhythms. Overall, these findings indicate that brain region-specific and time-dependent neuroadaptive alterations in gene expression play an integral role in the development of alcohol dependence and withdrawal. PMID:21812870

Variability in quartz exposure in the construction industry: implications for assessing exposure-response relations.

PubMed

Tjoe Nij, Evelyn; Höhr, Doris; Borm, Paul; Burstyn, Igor; Spierings, Judith; Steffens, Friso; Lumens, Mieke; Spee, Ton; Heederik, Dick

2004-03-01

The aims of this study were to determine implications of inter- and intraindividual variation in exposure to respirable (quartz) dust and of heterogeneity in dust characteristics for epidemiologic research in construction workers. Full-shift personal measurements (n = 67) from 34 construction workers were collected. The between-worker and day-to-day variances of quartz and respirable dust exposure were estimated using mixed models. Heterogeneity in dust characteristics was evaluated by electron microscopic analysis and electron spin resonance. A grouping strategy based on job title resulted in a 2- and 3.5-fold reduction in expected attenuation of a hypothetical exposure-response relation for respirable dust and quartz exposure, respectively, compared to an individual based approach. Material worked on explained most of the between-worker variance in respirable dust and quartz exposure. However, for risk assessment in epidemiology, grouping workers based on the materials they work on is not practical. Microscopic characterization of dust samples showed large quantities of aluminum silicates and large quantities of smaller particles, resulting in a D(50) between 1 and 2 microm. For risk analysis, job title can be used to create exposure groups, although error is introduced by the heterogeneity of dust produced by different construction workers activities and by the nonuniformity of exposure groups. A grouping scheme based on materials worked on would be superior, for both exposure and risk assessment, but is not practical when assessing past exposure. In dust from construction sites, factors are present that are capable of influencing the toxicological potency.

Estimating pesticide exposure from dietary intake and organic food choices: the Multi-Ethnic Study of Atherosclerosis (MESA).

PubMed

Curl, Cynthia L; Beresford, Shirley A A; Fenske, Richard A; Fitzpatrick, Annette L; Lu, Chensheng; Nettleton, Jennifer A; Kaufman, Joel D

2015-05-01

Organophosphate pesticide (OP) exposure to the U.S. population is dominated by dietary intake. The magnitude of exposure from diet depends partly on personal decisions such as which foods to eat and whether to choose organic food. Most studies of OP exposure rely on urinary biomarkers, which are limited by short half-lives and often lack specificity to parent compounds. A reliable means of estimating long-term dietary exposure to individual OPs is needed to assess the potential relationship with adverse health effects. We assessed long-term dietary exposure to 14 OPs among 4,466 participants in the Multi-Ethnic Study of Atherosclerosis, and examined the influence of organic produce consumption on this exposure. Individual-level exposure was estimated by combining information on typical intake of specific food items with average OP residue levels on those items. In an analysis restricted to a subset of participants who reported rarely or never eating organic produce ("conventional consumers"), we assessed urinary dialkylphosphate (DAP) levels across tertiles of estimated exposure (n = 480). In a second analysis, we compared DAP levels across subgroups with differing self-reported organic produce consumption habits (n = 240). Among conventional consumers, increasing tertile of estimated dietary OP exposure was associated with higher DAP concentrations (p < 0.05). DAP concentrations were also significantly lower in groups reporting more frequent consumption of organic produce (p < 0.02). Long-term dietary exposure to OPs was estimated from dietary intake data, and estimates were consistent with DAP measurements. More frequent consumption of organic produce was associated with lower DAPs.

A prospective cohort study investigating an exposure-response relationship among vibration-exposed male workers with numbness of the hands.

PubMed

Edlund, Maria; Burström, Lage; Gerhardsson, Lars; Lundström, Ronnie; Nilsson, Tohr; Sandén, Helena; Hagberg, Mats

2014-03-01

The aim of this study was to investigate the exposure-response relationship of hand-arm vibration exposure to neurological symptoms (numbness) of the hand in a cohort of vibration-exposed workers. The baseline cohort comprised 241 office and manual workers with and without exposure to hand-arm vibration. Numbness (the symptom or event) in the hand was assessed for all subjects at baseline and follow-ups after 5, 10, and 16 years. The workers were stratified into quartiles with no exposure in the first quartile and increasing intensity of exposure in quartiles 2-4 (groups 1-3). Data analysis was performed using survival analysis (time to event). Information on cumulative exposure and years of exposure to event was collected via questionnaires. Measurements were performed in accordance with the International Organization for Standardization (ISO) 5349-1. The hazard ratio (HR) of risk of event (numbness) differed statistically significantly between the non-exposed group (group 0) and the two higher exposure groups (groups 2 and 3). There was also a significant ratio difference between the lowest exposure group (group 1) and the two higher groups. The ratio for group 1 was 1.77 [95% confidence interval (95% CI) 0.96-3.26] compared with 3.78 (95% CI 2.15-6.62) and 5.31 (95% CI 3.06-9.20) for groups 2 and 3, respectively. The results suggest a dose-response relationship between vibration exposure and numbness of the hands. This underlines the importance of keeping vibration levels low to prevent neurological injury to the hands.

Occupational exposure to magnetic fields in relation to mortality from brain cancer among electricity generation and transmission workers.

PubMed Central

Harrington, J M; McBride, D I; Sorahan, T; Paddle, G M; van Tongeren, M

1997-01-01

OBJECTIVE: To investigate whether the risks of mortality from brain cancer are related to occupational exposure to magnetic fields. METHODS: A total of 112 cases of primary brain cancer (1972-91) were identified from a cohort of 84,018 male and female employees of the (then) Central Electricity Generating Board and its privatised successor companies. Individual cumulative occupational exposures to magnetic fields were estimated by linking available computerised job history data with magnetic field measurements collected over 675 person-workshifts. Estimated exposure histories of the case workers were compared with those of 654 control workers drawn from the cohort (nested case-control study), by means of conditional logistic regression. RESULTS: For exposure assessments based on arithmetic means, the risk of mortality from brain cancer for subjects with an estimated cumulative exposure to magnetic fields of 5.4-13.4 microT.y v subjects with lower exposures (0.0-5.3 microT.y) was 1.04 (95% confidence interval (95% CI) 0.60 to 1.80). The corresponding relative risk in subjects with higher exposures (> or = 13.5 microT.y) was 0.95 (95% CI 0.54 to 1.69). There was no indication of a positive trend for cumulative exposure and risk of mortality from brain cancer either when the analysis used exposure assessments based on geometric means or when the analysis was restricted to exposures received within five years of the case diagnosis (or corresponding period for controls). CONCLUSIONS: Although the exposure categorisation was based solely on recent observations, the study findings do not support the hypothesis that the risk of brain cancer is associated with occupational exposure to magnetic fields. PMID:9072027

Cancer and non-cancer health effects from food contaminant exposures for children and adults in California: a risk assessment

PubMed Central

2012-01-01

Background In the absence of current cumulative dietary exposure assessments, this analysis was conducted to estimate exposure to multiple dietary contaminants for children, who are more vulnerable to toxic exposure than adults. Methods We estimated exposure to multiple food contaminants based on dietary data from preschool-age children (2–4 years, n=207), school-age children (5–7 years, n=157), parents of young children (n=446), and older adults (n=149). We compared exposure estimates for eleven toxic compounds (acrylamide, arsenic, lead, mercury, chlorpyrifos, permethrin, endosulfan, dieldrin, chlordane, DDE, and dioxin) based on self-reported food frequency data by age group. To determine if cancer and non-cancer benchmark levels were exceeded, chemical levels in food were derived from publicly available databases including the Total Diet Study. Results Cancer benchmark levels were exceeded by all children (100%) for arsenic, dieldrin, DDE, and dioxins. Non-cancer benchmarks were exceeded by >95% of preschool-age children for acrylamide and by 10% of preschool-age children for mercury. Preschool-age children had significantly higher estimated intakes of 6 of 11 compounds compared to school-age children (p<0.0001 to p=0.02). Based on self-reported dietary data, the greatest exposure to pesticides from foods included in this analysis were tomatoes, peaches, apples, peppers, grapes, lettuce, broccoli, strawberries, spinach, dairy, pears, green beans, and celery. Conclusions Dietary strategies to reduce exposure to toxic compounds for which cancer and non-cancer benchmarks are exceeded by children vary by compound. These strategies include consuming organically produced dairy and selected fruits and vegetables to reduce pesticide intake, consuming less animal foods (meat, dairy, and fish) to reduce intake of persistent organic pollutants and metals, and consuming lower quantities of chips, cereal, crackers, and other processed carbohydrate foods to reduce acrylamide intake. PMID:23140444

Relationship between mediation analysis and the structured life course approach.

PubMed

Howe, Laura D; Smith, Andrew D; Macdonald-Wallis, Corrie; Anderson, Emma L; Galobardes, Bruna; Lawlor, Debbie A; Ben-Shlomo, Yoav; Hardy, Rebecca; Cooper, Rachel; Tilling, Kate; Fraser, Abigail

2016-08-01

Many questions in life course epidemiology involve mediation and/or interaction because of the long latency period between exposures and outcomes. In this paper, we explore how mediation analysis (based on counterfactual theory and implemented using conventional regression approaches) links with a structured approach to selecting life course hypotheses. Using theory and simulated data, we show how the alternative life course hypotheses assessed in the structured life course approach correspond to different combinations of mediation and interaction parameters. For example, an early life critical period model corresponds to a direct effect of the early life exposure, but no indirect effect via the mediator and no interaction between the early life exposure and the mediator. We also compare these methods using an illustrative real-data example using data on parental occupational social class (early life exposure), own adult occupational social class (mediator) and physical capability (outcome). © The Author 2016. Published by Oxford University Press on behalf of the International Epidemiological Association.

The Impact of UV-dose, Body Surface Area Exposed and Other Factors on Cutaneous Vitamin D Synthesis Measured as Serum 25(OH)D Concentration: Systematic Review and Meta-analysis.

PubMed

Jager, Nadine; Schöpe, Jakob; Wagenpfeil, Stefan; Bocionek, Peter; Saternus, Roman; Vogt, Thomas; Reichrath, Jörg

2018-02-01

To optimize public health campaigns concerning UV exposure, it is important to characterize factors that influence UV-induced cutaneous vitamin D production. This systematic review and meta-analysis investigated the impact of different individual and environmental factors including exposed body surface area (BSA), UVB dose and vitamin D status, on serum 25(OH)D concentration. In accordance with Preferred Reporting Items for Systematic Reviews and Meta-analyses, and Meta-analysis of Observational studies in Epidemiology guidelines, a systematic literature search was conducted (MEDLINE; 01/1960-07/2016) investigating the impact of these factors on vitamin D status after artificial UV exposure as main outcome measure. Summary mean differences [and 95% confidence interval (CI)] were derived from random-effects meta-analysis to account for possible heterogeneity across studies. Meta-regression was conducted to account for impact of UVB dose, baseline 25(OH)D level and BSA. We identified 15 studies, with an estimated mean 25(OH)D rise per standard erythema dose (SED) of 0.19 nmol/l (95% CI 0.11-0.26 nmol/l). Results from meta-regression suggest a significant impact of UV dose and baseline 25(OH)D concentration on serum 25(OH)D level (p<0.01). Single UVB doses between 0.75 and 3 SED resulted in the highest rise of serum 25(OH)D per dose unit. BSA exposed had a smaller, non-proportional, not significant impact. Partial BSA exposure resulted in relatively higher rise compared to whole-body exposure (e.g. exposure of face and hands caused an 8-fold higher rise of serum 25(OH)D concentration/SED/1% BSA compared to whole-body exposure). Our findings support previous reports, estimating that the half-life of serum 25(OH)D varies depending on different factors. Our results indicate that partial BSA exposure (e.g. 10%) with moderate UV doses (e.g. 1 SED) is effective in generating or maintaining a healthy vitamin D status. However, due to limitations that include possible confounding factors such as skin type, which could not be considered, these findings should be interpreted with caution. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

No evidence for an increase in circulatory disease mortality in astronauts following space radiation exposures.

PubMed

Cucinotta, Francis A; Hamada, Nobuyuki; Little, Mark P

2016-08-01

Previous analysis has shown that astronauts have a significantly lower standardized mortality ratio for circulatory disease mortality compared to the U.S. population, which is consistent with the rigorous selection process and healthy lifestyles of astronauts, and modest space radiation exposures from past space missions. However, a recent report by Delp et al. estimated the proportional mortality ratio for ages of 55-64 y of Apollo lunar mission astronauts to claim a high risk of cardiovascular disease due to space radiation compared to the U.S. population or to non-flight astronauts. In this Commentary we discuss important deficiencies in the methods and assumptions on radiation exposures used by Delp et al. that we judge cast serious doubt on their conclusions. Copyright © 2016 The Committee on Space Research (COSPAR). All rights reserved.

Comparative analysis of COPD associated with tobacco smoking, biomass smoke exposure or both.

PubMed

Olloquequi, Jordi; Jaime, Sergio; Parra, Viviana; Cornejo-Córdova, Elizabeth; Valdivia, Gonzalo; Agustí, Àlvar; Silva O, Rafael

2018-01-18

Exposure to noxious gases and particles contained in both tobacco smoking (TS) and biomass smoke (BS) are well recognized environmental risk factors for chronic obstructive pulmonary disease (COPD). COPD is characterized by an abnormal inflammatory response, both in the pulmonary and systemic compartments. The differential effects of TS, BS or their combined exposure have not been well characterized yet. This study sought to compare the lung function characteristics and systemic inflammatory response in COPD patients exposed to TS, BS or their combination. Sociodemographic, clinical and lung functional parameters were compared across 49 COPD patients with a history of smoking and no BS exposure (TS COPD), 31 never-smoker COPD patients with BS exposure (BS COPD), 46 COPD patients with a combined exposure (TS + BS COPD) and 52 healthy controls (HC) who have never been exposed neither to TS or BS. Blood cell counts, C-reactive protein (CRP), fibrinogen and immunoglobulin E (IgE) levels were quantified in all four groups. TS + BS COPD patients exhibited significantly lower oxygen saturation than the rest of groups (p < 0.01). Spirometry and diffusing capacity were significantly higher in BS than in TS or TS + BS patients. CRP levels were significantly higher in TS COPD patients than in BS COPD group (p < 0.05), whereas fibrinogen was raised in COPD patients with a history of smoking (TS and TS + BS) when compared to control subjects (p < 0.01). Finally, COPD patients with BS exposure (BS and BS + TS groups) showed higher IgE levels than TS and HC (p < 0.05). There are significant physiological and inflammatory differences between COPD patients with TS, BS and TS + BS exposures. The latter had worse blood oxygenation, whereas the raised levels of IgE in BS exposed patients suggests a differential Th2 systemic inflammatory pattern triggered by this pollutant.

Providing a Theoretical Basis for Nanotoxicity Risk Analysis Departing from Traditional Physiologically-Based Pharmacokinetic (PBPK) Modeling

DTIC Science & Technology

2010-09-01

estimation of total exposure at any toxicological endpoint in the body. This effort is a significant contribution as it highlights future research needs...rigorous modeling of the nanoparticle transport by including physico-chemical properties of engineered particles. Similarly, toxicological dose-response...exposure risks as compared to larger sized particles of the same material. Although the toxicology of a base material may be thoroughly defined, the

Comparative occupational radiation exposure between fixed and mobile imaging systems.

PubMed

Kendrick, Daniel E; Miller, Claire P; Moorehead, Pamela A; Kim, Ann H; Baele, Henry R; Wong, Virginia L; Jordan, David W; Kashyap, Vikram S

2016-01-01

Endovascular intervention exposes surgical staff to scattered radiation, which varies according to procedure and imaging equipment. The purpose of this study was to determine differences in occupational exposure between procedures performed with fixed imaging (FI) in an endovascular suite compared with conventional mobile imaging (MI) in a standard operating room. A series of 116 endovascular cases were performed over a 4-month interval in a dedicated endovascular suite with FI and conventional operating room with MI. All cases were performed at a single institution and radiation dose was recorded using real-time dosimetry badges from Unfors RaySafe (Hopkinton, Mass). A dosimeter was mounted in each room to establish a radiation baseline. Staff dose was recorded using individual badges worn on the torso lead. Total mean air kerma (Kar; mGy, patient dose) and mean case dose (mSv, scattered radiation) were compared between rooms and across all staff positions for cases of varying complexity. Statistical analyses for all continuous variables were performed using t test and analysis of variance where appropriate. A total of 43 cases with MI and 73 cases with FI were performed by four vascular surgeons. Total mean Kar, and case dose were significantly higher with FI compared with MI. (mean ± standard error of the mean, 523 ± 49 mGy vs 98 ± 19 mGy; P < .00001; 0.77 ± 0.03 mSv vs 0.16 ± 0.08 mSv, P < .00001). Exposure for the primary surgeon and assistant was significantly higher with FI compared with MI. Mean exposure for all cases using either imaging modality, was significantly higher for the primary surgeon and assistant than for support staff (ie, nurse, radiology technologist) beyond 6 feet from the X-ray source, indicated according to one-way analysis of variance (MI: P < .00001; FI: P < .00001). Support staff exposure was negligible and did not differ between FI and MI. Room dose stratified according to case complexity (Kar) showed statistically significantly higher scattered radiation in FI vs MI across all quartiles. The scattered radiation is several-fold higher with FI than MI across all levels of case complexity. Radiation exposure decreases with distance from the radiation source, and is negligible outside of a 6-foot radius. Modern endovascular suites allow high-fidelity imaging, yet additional strategies to minimize exposure and occupational risk are needed. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Prolactin is a peripheral marker of manganese neurotoxicity

PubMed Central

Marreilha dos Santos, AP; Lopes Santos, M; BatorÉu, Maria C; Aschner, M

2011-01-01

Excessive exposure to Mn induces neurotoxicity, referred to as manganism. Exposure assessment relies on Mn blood and urine analyses, both of which show poor correlation to exposure. Accordingly, there is a critical need for better surrogate biomarkers of Mn exposure. The aim of this study was to examine the relationship between Mn exposure and early indicators of neurotoxicity, with particular emphasis on peripheral biomarkers. Male Wistar rats (180–200 g) were injected intraperitoneally with 4 or 8 doses of Mn (10 mg/kg). Mn exposure was evaluated by analysis of Mn levels in brain and blood along with biochemical end-points (see below). Results Brain Mn levels were significantly increased both after 4 and 8 doses of Mn compared with controls (p<0.001). Blood levels failed to reflect a dose-dependent increase in brain Mn, with only the 8-dose treated group showing significant differences (p<0.001). Brain glutathione (GSH) levels were significantly decreased in the 8-dose-treated animals (p<0.001). A significant and dose-dependent increase in prolactin levels was found for both treated groups (p<0.001) compared to controls. In addition, a decrease in motor activity was observed in the 8-dose-treated group compared to controls. Conclusions 1) The present study demonstrates that peripheral blood level is a poor indicator of Mn brain accumulation and exposure; 2) Mn reduces GSH brain levels, likely reflecting oxidative stress; 3) Mn increases blood prolactin levels, indicating changes in the integrity of the dopaminergic system. Taken together these results suggest that peripheral prolactin levels may serve as reliable predictive biomarkers of Mn neurotoxicity. PMID:21262206

Sexual behaviour of heterosexual men and women receiving antiretroviral pre-exposure prophylaxis for HIV prevention: a longitudinal analysis.

PubMed

Mugwanya, Kenneth K; Donnell, Deborah; Celum, Connie; Thomas, Katherine K; Ndase, Patrick; Mugo, Nelly; Katabira, Elly; Ngure, Kenneth; Baeten, Jared M

2013-12-01

Scarce data are available to assess sexual behaviour of individuals using antiretroviral pre-exposure prophylaxis for HIV prevention. Increased sexual risk taking by individuals using effective HIV prevention strategies, like pre-exposure prophylaxis, could offset the benefits of HIV prevention. We studied whether the use of pre-exposure prophylaxis in HIV-uninfected men and women in HIV-serodiscordant couples was associated with increased sexual risk behaviour. We undertook a longitudinal analysis of data from the Partners PrEP Study, a double-blind, randomised, placebo-controlled trial of daily oral pre-exposure prophylaxis among HIV-uninfected partners of heterosexual HIV-serodiscordant couples (n=3163, ≥18 years of age). Efficacy for HIV prevention was publicly reported in July 2011, and participants continued monthly follow-up thereafter. We used regression analyses to compare the frequency of sex-unprotected by a condom-during the 12 months after compared with the 12 months before July 2011, to assess whether knowledge of pre-exposure prophylaxis efficacy for HIV prevention caused increased sexual risk behaviour. We analysed 56 132 person-months from 3024 HIV-uninfected individuals (64% male). The average frequency of unprotected sex with the HIV-infected study partner was 59 per 100 person-months before unmasking versus 53 after unmasking; we recorded no immediate change (p=0·66) or change over time (p=0·25) after July, 2011. We identified a significant increase in unprotected sex with outside partners after July, 2011, but the effect was small (average of 6·8 unprotected sex acts per year vs 6·2 acts in a predicted counterfactual scenario had patients remained masked, p=0·04). Compared with before July, 2011, we noted no significant increase in incident sexually transmitted infections or pregnancy after July, 2011. Pre-exposure prophylaxis, provided as part of a comprehensive prevention package, might not result in substantial changes in risk-taking sexual behaviour by heterosexual couples. The Bill & Melinda Gates Foundation and the US National Institute of Mental Health. Copyright © 2013 Elsevier Ltd. All rights reserved.

On the Formation and Seasonal Properties of Topical Cirrus Clouds over Amazon Basin (2.89ºS, 59.97ºW): Observations from Lidar, Radiosonde and Satellite instruments.

NASA Astrophysics Data System (ADS)

Blagev, D. P.; Mendoza, D. L.; Rea, S.; Sorensen, J.

2014-12-01

Adverse health effects have been associated with urban pollutant exposure arising from close proximity to highly-emitting sources and atmospheric mixing. The relative air pollution exposure dose and time effects on various diseases remains unknown. This study compares the increased risk of health complications when patients are exposed to short term high-levels of air pollution vs. longer term exposure to lower levels of air pollution. We used the electronic medical record of an integrated hospital system based in Utah, Intermountain Healthcare, to identify a cohort of patients with Chronic Obstructive Pulmonary Disease (COPD) who were seen between 2009-2014. We determined patient demographics as well as comorbidity data and healthcare utilization. To determine the approximate air pollution dose and time exposure, we used the Hestia highly-resolved emissions inventory for Salt Lake County, Utah in conjunction with emissions based on the National Emissions Inventory (NEI). Hourly emissions of CO2 and criteria air pollutants were gridded at a 0.002o x 0.002o resolution for the study years. The resulting emissions were transported using the CALPUFF and AERMOD dispersion models to estimate air pollutant concentrations at an hourly 0.002o x 0.002oresolution. Additionally, pollutant concentrations were estimated at each patient's home and work address to estimate exposure. Multivariate analysis adjusting for patient demographics, comorbidities and severity of COPD was performed to determine association between air pollution exposure and the risk of hospitalization or emergency department (ED) visit for COPD exacerbation and an equivalency estimate for air pollution exposure was developed. We noted associations with air pollution levels for each pollutant and hospitalizations and ED visits for COPD and other patient comorbidities. We also present an equivalency estimate for dose of air pollution exposure and health outcomes. This analysis compares the increased risk of health complications when patients are exposed to short term high-levels of air pollution vs. longer term exposure to lower levels of air pollution. These findings highlight pollutant emissions and exposures spatial and temporal heterogeneity and associated health effects.

Interaction between Chronic Obstructive Pulmonary Disease (COPD) and other important health conditions and measurable air pollution

NASA Astrophysics Data System (ADS)

Blagev, D. P.; Mendoza, D. L.; Rea, S.; Sorensen, J.

2015-12-01

Adverse health effects have been associated with urban pollutant exposure arising from close proximity to highly-emitting sources and atmospheric mixing. The relative air pollution exposure dose and time effects on various diseases remains unknown. This study compares the increased risk of health complications when patients are exposed to short term high-levels of air pollution vs. longer term exposure to lower levels of air pollution. We used the electronic medical record of an integrated hospital system based in Utah, Intermountain Healthcare, to identify a cohort of patients with Chronic Obstructive Pulmonary Disease (COPD) who were seen between 2009-2014. We determined patient demographics as well as comorbidity data and healthcare utilization. To determine the approximate air pollution dose and time exposure, we used the Hestia highly-resolved emissions inventory for Salt Lake County, Utah in conjunction with emissions based on the National Emissions Inventory (NEI). Hourly emissions of CO2 and criteria air pollutants were gridded at a 0.002o x 0.002o resolution for the study years. The resulting emissions were transported using the CALPUFF and AERMOD dispersion models to estimate air pollutant concentrations at an hourly 0.002o x 0.002oresolution. Additionally, pollutant concentrations were estimated at each patient's home and work address to estimate exposure. Multivariate analysis adjusting for patient demographics, comorbidities and severity of COPD was performed to determine association between air pollution exposure and the risk of hospitalization or emergency department (ED) visit for COPD exacerbation and an equivalency estimate for air pollution exposure was developed. We noted associations with air pollution levels for each pollutant and hospitalizations and ED visits for COPD and other patient comorbidities. We also present an equivalency estimate for dose of air pollution exposure and health outcomes. This analysis compares the increased risk of health complications when patients are exposed to short term high-levels of air pollution vs. longer term exposure to lower levels of air pollution. These findings highlight pollutant emissions and exposures spatial and temporal heterogeneity and associated health effects.

Allergen Sensitization Pattern by Sex: A Cluster Analysis in Korea.

PubMed

Ohn, Jungyoon; Paik, Seung Hwan; Doh, Eun Jin; Park, Hyun-Sun; Yoon, Hyun-Sun; Cho, Soyun

2017-12-01

Allergens tend to sensitize simultaneously. Etiology of this phenomenon has been suggested to be allergen cross-reactivity or concurrent exposure. However, little is known about specific allergen sensitization patterns. To investigate the allergen sensitization characteristics according to gender. Multiple allergen simultaneous test (MAST) is widely used as a screening tool for detecting allergen sensitization in dermatologic clinics. We retrospectively reviewed the medical records of patients with MAST results between 2008 and 2014 in our Department of Dermatology. A cluster analysis was performed to elucidate the allergen-specific immunoglobulin (Ig)E cluster pattern. The results of MAST (39 allergen-specific IgEs) from 4,360 cases were analyzed. By cluster analysis, 39items were grouped into 8 clusters. Each cluster had characteristic features. When compared with female, the male group tended to be sensitized more frequently to all tested allergens, except for fungus allergens cluster. The cluster and comparative analysis results demonstrate that the allergen sensitization is clustered, manifesting allergen similarity or co-exposure. Only the fungus cluster allergens tend to sensitize female group more frequently than male group.

Identification of the key molecules involved in chronic copper exposure-aggravated memory impairment in transgenic mice of Alzheimer's disease using proteomic analysis.

PubMed

Yu, Jun; Luo, Xiaobin; Xu, Hua; Ma, Quan; Yuan, Jianhui; Li, Xuling; Chang, Raymond Chuen-Chung; Qu, Zhongsen; Huang, Xinfeng; Zhuang, Zhixiong; Liu, Jianjun; Yang, Xifei

2015-01-01

Alzheimer's disease (AD) is the most common neurodegenerative disease characterized by a progressive impairment of cognitive functions including spatial learning and memory. Excess copper exposure accelerates the development of AD; however, the potential mechanisms by which copper exacerbates the symptoms of AD remain unknown. In this study, we explored the effects of chronic copper exposure on cognitive function by treating 6 month-old triple AD transgenic (3xTg-AD) mice with 250 ppm copper sulfate in drinking water for 6 months, and identified several potential key molecules involved in the effects of chronic copper exposure on memory by proteomic analysis. The behavioral test showed that chronic copper exposure aggravated memory impairment of 3xTg-AD mice. Two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) coupled with mass spectrometry revealed a total of 44 differentially expressed proteins (18 upregulated and 26 down-regulated) in hippocampus between the wild-type (WT) mice and non-exposed 3xTg-AD mice. A total of 40 differentially expressed proteins were revealed (20 upregulated and 20 down-regulated) in hippocampus between copper exposed and non-exposed 3xTg-AD mice. Among these differentially expressed proteins, complexin-1 and complexin-2, two memory associated proteins, were significantly decreased in hippocampus of 3xTg-AD mice compared with the WT mice. Furthermore, the expression of these two proteins was further down-regulated in 3xTg-AD mice when exposed to copper. The abnormal expression of complexin-1 and complexin-2 identified by proteomic analysis was verified by western blot analysis. Taken together, our data showed that chronic copper exposure accelerated memory impairment and altered the expression of proteins in hippocampus in 3xTg-AD mice. The functional analysis on the differentially expressed proteins suggested that complexin-1 and complexin-2 may be the key molecules involved in chronic copper exposure-aggravated memory impairment in AD.

Measuring exposure in Hurricane Katrina: a meta-analysis and an integrative data analysis.

PubMed

Chan, Christian S; Rhodes, Jean E

2014-01-01

To date there is no consensus on the operationalization of exposure severity in the study of the impact of natural disasters. This is problematic because incomplete and inconsistent measurement of exposure limits the internal and external validity of disaster studies. The current paper examined the predictive validity of severity measures in two interrelated studies of Hurricane Katrina survivors. First, in a meta-analysis of eight studies that measured both exposure severity and posttraumatic stress, the effect size was estimated to be r = .266. The moderating effects of sample and study characteristics were examined and we found that minority status and number of stressors assessed were significant moderators. Second, in an integrative data analysis of five independent samples of Hurricane Katrina survivors, the impact of specific disaster-related stressors on mental health was compared. Threat to physical integrity of self and others were found to have the strongest association with posttraumatic stress (PTS) and general psychological distress (GPD). The lack of basic necessities, such as food, water, and medical care, and loss of pet were also found to be strongly associated with both PTS and GPD. The results from the two studies are integrated and their implication for disaster research and relief are discussed.

Measuring Exposure in Hurricane Katrina: A Meta-Analysis and an Integrative Data Analysis

PubMed Central

Chan, Christian S.; Rhodes, Jean E.

2014-01-01

To date there is no consensus on the operationalization of exposure severity in the study of the impact of natural disasters. This is problematic because incomplete and inconsistent measurement of exposure limits the internal and external validity of disaster studies. The current paper examined the predictive validity of severity measures in two interrelated studies of Hurricane Katrina survivors. First, in a meta-analysis of eight studies that measured both exposure severity and posttraumatic stress, the effect size was estimated to be r = .266. The moderating effects of sample and study characteristics were examined and we found that minority status and number of stressors assessed were significant moderators. Second, in an integrative data analysis of five independent samples of Hurricane Katrina survivors, the impact of specific disaster-related stressors on mental health was compared. Threat to physical integrity of self and others were found to have the strongest association with posttraumatic stress (PTS) and general psychological distress (GPD). The lack of basic necessities, such as food, water, and medical care, and loss of pet were also found to be strongly associated with both PTS and GPD. The results from the two studies are integrated and their implication for disaster research and relief are discussed. PMID:24713851

Occupational Exposure to Nano-Objects and Their Agglomerates and Aggregates Across Various Life Cycle Stages; A Broad-Scale Exposure Study.

PubMed

Bekker, Cindy; Kuijpers, Eelco; Brouwer, Derk H; Vermeulen, Roel; Fransman, Wouter

2015-07-01

Occupational exposure to manufactured nano-objects and their agglomerates, and aggregates (NOAA) has been described in several workplace air monitoring studies. However, data pooling for general conclusions and exposure estimates are hampered by limited exposure data across the occupational life cycle of NOAA and a lack in comparability between the methods of collecting and analysing the data. By applying a consistent method of collecting and analysing the workplace exposure data, this study aimed to provide information about the occupational NOAA exposure levels across various life cycle stages of NOAA in the Netherlands which can also be used for multi-purpose use. Personal/near field task-based exposure data was collected using a multi-source exposure assessment method collecting real time particle number concentration, particle size distribution (PSD), filter-based samples for morphological, and elemental analysis and detailed contextual information. A decision logic was followed allowing a consistent and objective way of analysing the exposure data. In total, 46 measurement surveys were conducted at 15 companies covering 18 different exposure situations across various occupational life cycle stages of NOAA. Highest activity-effect levels were found during replacement of big bags (<1000-76000 # cm(-3)), mixing/dumping of powders manually (<1000-52000 # cm(-3)) and mechanically (<1000-100000 # cm(-3)), and spraying of liquid (2000-800000 # cm(-3)) showing a high variability between and within the various exposure situations. In general, a limited change in PSD was found during the activity compared to the background. This broad-scale exposure study gives a comprehensive overview of the NOAA exposure situations in the Netherlands and an indication of the levels of occupational exposure to NOAA across various life cycle of NOAA. The collected workplace exposure data and contextual information will serve as basis for future pooling of data and modelling of worker exposure. © The Author 2015. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Needlestick and other potential blood and body fluid exposures among health care workers in British Columbia, Canada.

PubMed

Alamgir, Hasanat; Cvitkovich, Yuri; Astrakianakis, George; Yu, Shicheng; Yassi, Annalee

2008-02-01

Health care workers have high risk of exposure to human blood and body fluids (BBF) from patients in acute care and residents in nursing homes or personal homes. This analysis examined the epidemiology for BBF exposure across health care settings (acute care, nursing homes, and community care). Detailed analysis of BBF exposure among the health care workforce in 3 British Columbian health regions was conducted by Poisson regression modeling, with generalized estimating equations to determine the relative risk associated with various occupations. Acute care had the majority of needlestick, sharps, and splash events with the BBF exposure rate in acute care 2 to 3 times higher compared with nursing home and community care settings. Registered nurses had the highest frequency of needlestick, sharps, and splash events. Laboratory assistants had the highest exposure rates from needlestick injuries and splashes, whereas licensed practical nurses had the highest exposure rate from sharps. Most needlestick injuries (51.3%) occurred at the patient's bedside. Sharps incidents occurred primarily in operating rooms (26.9%) and at the patient's bedside (20.9%). Splashes occurred most frequently at the patient's bedside (46.1%) and predominantly affected the eyes or face/mouth. The majority of needlestick/sharps injuries occurred during use for registered nurses, during disposal for licensed practical nurses, and after disposal for care aides. The high risk of BBF exposure for some occupations indicates there is room for improvement to reduce BBF exposure by targeting high-risk groups for prevention strategies.

MOLECULAR MARKER ANALYSIS OF DEARS SAMPLES

EPA Science Inventory

Source apportionment based on organic molecular markers provides a promising approach for meeting the Detroit Exposure and Aerosol Research Study (DEARS) objective of comparing source contributions between community air monitoring stations and various neighborhoods. Source appor...

(ISEA) MOLECULAR MARKER ANALYSIS OF DEARS SAMPLES

EPA Science Inventory

Source apportionment based on organic molecular markers provides a promising approach for meeting the Detroit Exposure and Aerosol Research Study (DEARS) objective of comparing source contributions between community air monitoring stations and various neighborhoods. Source appor...

Analysis of systems hardware flown on LDEF: New findings and comparison to other retrieved spacecraft hardware

NASA Technical Reports Server (NTRS)

Dursch, Harry; Bohnhoff-Hlavacek, Gail; Blue, Donald; Hansen, Patricia

1995-01-01

The Long Duration Exposure Facility (LDEF) was retrieved in 1990 after spending 69 months in low-earth-orbit (LEO). A wide variety of mechanical, electrical, thermal, and optical systems, subsystems, and components were flown on LDEF. The Systems Special Investigation Group (Systems SIG) was formed by NASA to investigate the effects of the 69 month exposure on systems related hardware and to coordinate and collate all systems analysis of LDEF hardware. This report is the Systems SIG final report which updates earlier findings and compares LDEF systems findings to results from other retrieved spacecraft hardware such as Hubble Space Telescope. Also included are sections titled (1) Effects of Long Duration Space Exposure on Optical Scatter, (2) Contamination Survey of LDEF, and (3) Degradation of Optical Materials in Space.

Quantitative analysis of carbides and the sigma phase in thermally exposed GTD-111

NASA Astrophysics Data System (ADS)

Lee, Han-sang; Kim, Doo-soo; Yoo, Keun-bong; Song, Kyu-so

2012-04-01

The effects of thermal exposure on γ', carbides and TCP-type phases, such as the sigma and eta phases, in the nickel-based superalloy GTD-111 were investigated in this study. The thermal exposure was performed at 871 °C and 982 °C for 1,000, 5,000 and 10,000 h, after which the thermally exposed specimens were compared in terms of their microstructure, weight fraction and growth rate of each precipitate. Electrolytic extraction and Rietveld refinement were successfully applied for a quantitative analysis of the carbides and the sigma phase in the thermally exposed GTD-111. The weight fractions of MC, Cr-rich M23C6 and the sigma phase for various thermal exposure times and temperatures were obtained to understand the formation and decomposition rate of each phase.

Analysis of systems hardware flown on LDEF: New findings and comparison to other retrieved spacecraft hardware

NASA Astrophysics Data System (ADS)

Dursch, Harry; Bohnhoff-Hlavacek, Gail; Blue, Donald; Hansen, Patricia

1995-09-01

The Long Duration Exposure Facility (LDEF) was retrieved in 1990 after spending 69 months in low-earth-orbit (LEO). A wide variety of mechanical, electrical, thermal, and optical systems, subsystems, and components were flown on LDEF. The Systems Special Investigation Group (Systems SIG) was formed by NASA to investigate the effects of the 69 month exposure on systems related hardware and to coordinate and collate all systems analysis of LDEF hardware. This report is the Systems SIG final report which updates earlier findings and compares LDEF systems findings to results from other retrieved spacecraft hardware such as Hubble Space Telescope. Also included are sections titled (1) Effects of Long Duration Space Exposure on Optical Scatter, (2) Contamination Survey of LDEF, and (3) Degradation of Optical Materials in Space.

Lifetime fluoridation exposure and dental caries experience in a military population.

PubMed

Mahoney, Gregory; Slade, Gary D; Kitchener, Scott; Barnett, Adrian

2008-12-01

While there is good evidence of caries-preventive benefits of fluoride in drinking water among children and adolescents, there is little information about effectiveness of water fluoridation among adults. To determine whether exposure to fluoride in drinking water is associated with caries experience in Australian Defence Force (ADF) personnel. Cross-sectional study of 876 deployable ADF personnel aged 17-56 years. At each person's mandatory annual dental examination, military dentists recorded the number of decayed, missing and filled teeth (DMFT) using visual, tactile and radiographic criteria. Participants also completed a questionnaire, listing residential locations in each year from 1964 to 2003. People were classified into four categories according to the percentage of their lifetime living in places with fluoridated water: <10%, 10% to <50%, 50% to <90% and > or =90%. Mean DMFT was compared among those categories of fluoridation exposure and the association was evaluated statistically using analysis of variance to adjust for age, sex, years of service and rank. Without adjustment for confounders, the mean DMFT (+/-95% confidence interval) was 6.3 +/- 0.8 for <10% fluoridation exposure, 7.8 +/- 0.8 for 10% to <50% exposure, 7.5 +/- 0.7 for 50% to <90% exposure and 4.6 +/- 0.6 for > or =90% exposure (P < 0.01). However, age was inversely associated with mean DMFT and in the <10% exposure group, 91% of people were aged <35 years. Service rank was also significantly associated with both fluoridation exposure and DMFT. After adjustment for all covariates, mean DMFT was 24% lower among people in the two groups with > or =50% exposure compared with the <10% exposure group. Degree of lifetime exposure to fluoridated drinking water was inversely associated with DMFT in a dose-response manner among this adult military population.

The effects of different intensities, frequencies and exposure times of extremely low-frequency electromagnetic fields on the growth of Staphylococcus aureus and Escherichia coli O157:H7.

PubMed

Bayır, Ece; Bilgi, Eyüp; Şendemir-Ürkmez, Aylin; Hameş-Kocabaş, E Esin

2015-03-01

The impact of different types of extremely low-frequency electromagnetic fields (ELF-EMF) on the growth of Staphylococcus aureus and Escherichia coli O157:H7 was investigated. The cultures of bacteria in broth media were exposed to sinusoidal homogenous ELF-EMF with 2 and 4 mT magnetic intensities. Each intensity for each bacteria was combined with three different frequencies (20, 40 and 50 Hz), and four different exposure times (1, 2, 4 and 6 h). A cell suspension of each experiment was diluted for the appropriate range and inoculated to Mueller-Hinton Agar (MHA) plates after exposure to ELF-EMF. The number of colony forming units (CFU) of both strains was obtained after incubation at 37 °C for 24 h. Data were statistically evaluated by one-way analysis of variance (ANOVA), statistical significance was described at p < 0.05 and data were compared with their non-exposed controls. Magnetic intensity, frequency and exposure time of ELF-EMFs changed the characteristic responses for both microorganisms. Samples exposed to ELF-EMF showed a statistically significant decrease compared to their controls in colony forming capability, especially at long exposure times. An exposure to 4 mT-20 Hz ELF-EMF of 6 h produced maximum inhibition of CFU compared to their controls for both microorganisms (95.2% for S. aureus and 85% for E. coli).

Occupational exposure to solar ultraviolet radiation and the risk of prostate cancer.

PubMed

Peters, Cheryl E; Demers, Paul A; Kalia, Sunil; Hystad, Perry; Villeneuve, Paul J; Nicol, Anne-Marie; Kreiger, Nancy; Koehoorn, Mieke W

2016-11-01

Preventable risk factors for prostate cancer are poorly understood; sun exposure is a possible protective factor. The goal of this study was to investigate prostate cancer risk in outdoor workers, a population with high sun exposure. Prostate cancer cases and controls from a large study (conducted between 1994 and 1997) were used for this analysis. A job exposure matrix (JEM) was used to assign solar ultraviolet radiation (UVR) at work as moderate (2 to <6 hours outside/day) or high (≥6 hours). Average daily satellite UV-B measures were linked to the latitude/longitude of the residences of each participant. Several other exposure metrics were also examined, including ever/never exposed and standard erythemal dose by years (SED×years). Logistic regression was used to evaluate the association between solar UVR exposure and the odds of prostate cancer. A total of 1638 cases and 1697 controls were included. Men of Indian and Asian descent had reduced odds of prostate cancer (ORs 0.17 (0.08 to 0.35) and 0.25 (0.15 to 0.41), respectively) compared with Caucasian men, as did single men (OR 0.76 (0.58 to 0.98)) compared with married men. Overall, no statistically significant associations were observed between sun exposure and prostate cancer with 1 exception. In the satellite-enhanced JEM that considered exposure in high category jobs only, prostate cancer odds in the highest quartile of cumulative exposure was decreased compared with unexposed men (OR 0.68 (0.51 to 0.92)). This study found limited evidence for an association with prostate cancer, with the exception of 1 statistically significant finding of a decreased risk among workers with the longest term and highest sun exposure. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Assessment of urinary metals following exposure to a large vegetative fire, New Mexico, 2000.

PubMed

Wolfe, Mitchell I; Mott, Joshua A; Voorhees, Ronald E; Sewell, C Mack; Paschal, Dan; Wood, Charles M; McKinney, Patrick E; Redd, Stephen

2004-03-01

In May 2000, a vegetative fire burned 47,000 acres in northern New Mexico, including 7500 acres of land administered by the Los Alamos National Laboratory. We evaluated potential human exposures from the fire. We surveyed two populations (firefighters and the general population) in four cities for urine heavy metal concentrations. Reference concentrations were based on the Third National Health and Nutrition Examination Survey (NHANES III). Multivariate linear regression assessed the association of urinary metal concentrations with smoke exposure. We also performed isotopic analysis of uranium and cesium on a subset of specimens. A total of 92 firefighters and 135 nonfirefighters participated. In both populations, urinary nickel, cesium, chromium, and uranium concentrations were greater than expected compared with NHANES III reference values. No values required immediate medical follow-up. Regression analysis demonstrated that for National Guard members, arsenic and cadmium levels were significantly related to smoke exposure, and for firefighters, cesium and arsenic levels were significantly related to exposure; however, only for cesium in National Guard members was this association in the positive direction. Isotopic analysis demonstrated that the cesium and uranium were naturally occurring. Some people had spot urine metal concentrations above nationally derived reference values, and values for some metals were associated with smoke exposure. These associations had little public health or clinical importance. Studies of exposures resulting from vegetative fires are difficult, and careful consideration should be given to the technical and communication processes at the outset of a fire exposure investigation. Recommendations for future investigations include testing as soon as possible during or after a fire, and early clinical consultation with a medical toxicologist.

Biopersistent Granular Dust and Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis

PubMed Central

Brüske, Irene; Thiering, Elisabeth; Heinrich, Joachim; Huster, Katharina; Nowak, Dennis

2013-01-01

Objective Applying a systematic review to identify studies eligible for meta-analysis of the association between occupational exposure to inorganic dust and the development of chronic obstructive pulmonary disease (COPD), and conducting a meta-analysis. Data Sources Searches of PubMed and Embase for the time period 1970–2010 yielded 257 cross-sectional and longitudinal studies on people exposed to inorganic dust at the workplace with data on lung function. These studies were independently abstracted and evaluated by two authors; any disagreement was resolved by a third reviewer. Of 55 publications accepted for meta-analysis, 27 investigated the effects of occupational exposure to biopersistent granular dust (bg-dust). Methods A random effects meta-analysis allowed us to provide an estimate of the average exposure effect on spirometric parameters presented in forest plots. Between-study heterogeneity was assessed by using I2 statistics, with I2>25% indicating significant heterogeneity. Publication bias was investigated by visual inspection of funnel plots. The influence of individual studies was assessed by dropping the respective study before pooling study-specific estimates. Results The mean FEV1 of workers exposed to bg-dust was 160 ml lower or 5.7% less than predicted compared to workers with no/low exposure. The risk of an obstructive airway disease—defined as FEV1/FVC < 70%—increased by 7% per 1 mg· m-3 respirable bg-dust. Conclusion Occupational inhalative exposure to bg-dust was associated with a statistically significant decreased FEV1 and FEV1/FVC revealing airway obstruction consistent with COPD. PMID:24278358

Occupational COPD and job exposure matrices: a systematic review and meta-analysis

PubMed Central

Sadhra, Steven; Kurmi, Om P; Sadhra, Sandeep S; Lam, Kin Bong Hubert; Ayres, Jon G

2017-01-01

Background The association between occupational exposure and COPD reported previously has mostly been derived from studies relying on self-reported exposure to vapors, gases, dust, or fumes (VGDF), which could be subjective and prone to biases. The aim of this study was to assess the strength of association between exposure and COPD from studies that derived exposure by job exposure matrices (JEMs). Methods A systematic search of JEM-based occupational COPD studies published between 1980 and 2015 was conducted in PubMed and EMBASE, followed by meta-analysis. Meta-analysis was performed using a random-effects model, with results presented as a pooled effect estimate with 95% confidence intervals (CIs). The quality of study (risk of bias and confounding) was assessed by 13 RTI questionnaires. Heterogeneity between studies and its possible sources were assessed by Egger test and meta-regression, respectively. Results In all, 61 studies were identified and 29 were included in the meta-analysis. Based on JEM-based studies, there was 22% (pooled odds ratio =1.22; 95% CI 1.18–1.27) increased risk of COPD among those exposed to airborne pollutants arising from occupation. Comparatively, higher risk estimates were obtained for general populations JEMs (based on expert consensus) than workplace-based JEM were derived using measured exposure data (1.26; 1.20–1.33 vs 1.14; 1.10–1.19). Higher risk estimates were also obtained for self-reported exposure to VGDF than JEMs-based exposure to VGDF (1.91; 1.72–2.13 vs 1.10; 1.06–1.24). Dusts, particularly biological dusts (1.33; 1.17–1.51), had the highest risk estimates for COPD. Although the majority of occupational COPD studies focus on dusty environments, no difference in risk estimates was found for the common forms of occupational airborne pollutants. Conclusion Our findings highlight the need to interpret previous studies with caution as self-reported exposure to VGDF may have overestimated the risk of occupational COPD. PMID:28260879

The relationship between occupational noise and vibration exposure and headache/eyestrain, based on the fourth Korean Working Condition Survey (KWCS).

PubMed

Kim, Jihyun; Lee, Wanhyung; Won, Jong-Uk; Yoon, Jin-Ha; Seok, Hongdeok; Kim, Yeong-Kwang; Lee, Seunghyun; Roh, Jaehoon

2017-01-01

The individual and combined effect of occupational noise and vibration exposures, on workers' health has not been thoroughly investigated. In order to find better ways to prevent and manage workers' headache, this study aimed to investigate the effects of occupational noise and vibration exposure on headache/eyestrain. We used data from the fourth Korean Working Condition Survey (2014). After applying inclusion and exclusion criteria, 25,751 workers were included. Occupational noise and vibration exposure and the prevalence of headache/eyestrain were investigated by self-reported survey. Chi-square tests were used to compare differences in baseline characteristics between the group with headache/eyestrain and the group without. Odds ratios and 95% confidence intervals were estimated using a logistic regression model adjusted for several covariates. Area under the receiver operating characteristics curve (AUROC) analysis was used to evaluate the effect of occupational noise and/or vibration exposure. Among the 25,751 study subjects, 4,903 had experienced headache/eyestrain in the preceding year. There were significant differences in age, education level, household income, occupational classification, shift work, occupational vibration exposure, and occupational noise exposure between the two groups (all p<0.05). The odds ratios between each exposure and headache/eyestrain increased proportionally with the level of exposure, increasing from 1.08 to 1.26 with increasing vibration exposure, and from 1.25 to 1.41 with increasing noise exposure. According to the AUROC analysis, the predictive power of each exposure was significant, and increased when the two exposures were considered in combination. The findings of this study show that both occupational noise and vibration exposures are associated with headache/eyestrain; noise exposure more strongly so. However, when the two exposures are considered in combination, the explanatory power for headache/eyestrain is increased. Therefore, efforts aimed at reducing and managing occupational noise and vibration exposure are crucial to maintaining workers' health.

The relationship between occupational noise and vibration exposure and headache/eyestrain, based on the fourth Korean Working Condition Survey (KWCS)

PubMed Central

Kim, Jihyun; Lee, Wanhyung; Won, Jong-Uk; Yoon, Jin-Ha; Seok, Hongdeok; Kim, Yeong-Kwang; Lee, Seunghyun

2017-01-01

Introduction The individual and combined effect of occupational noise and vibration exposures, on workers’ health has not been thoroughly investigated. In order to find better ways to prevent and manage workers’ headache, this study aimed to investigate the effects of occupational noise and vibration exposure on headache/eyestrain. Methods We used data from the fourth Korean Working Condition Survey (2014). After applying inclusion and exclusion criteria, 25,751 workers were included. Occupational noise and vibration exposure and the prevalence of headache/eyestrain were investigated by self-reported survey. Chi-square tests were used to compare differences in baseline characteristics between the group with headache/eyestrain and the group without. Odds ratios and 95% confidence intervals were estimated using a logistic regression model adjusted for several covariates. Area under the receiver operating characteristics curve (AUROC) analysis was used to evaluate the effect of occupational noise and/or vibration exposure. Results Among the 25,751 study subjects, 4,903 had experienced headache/eyestrain in the preceding year. There were significant differences in age, education level, household income, occupational classification, shift work, occupational vibration exposure, and occupational noise exposure between the two groups (all p<0.05). The odds ratios between each exposure and headache/eyestrain increased proportionally with the level of exposure, increasing from 1.08 to 1.26 with increasing vibration exposure, and from 1.25 to 1.41 with increasing noise exposure. According to the AUROC analysis, the predictive power of each exposure was significant, and increased when the two exposures were considered in combination. Discussion The findings of this study show that both occupational noise and vibration exposures are associated with headache/eyestrain; noise exposure more strongly so. However, when the two exposures are considered in combination, the explanatory power for headache/eyestrain is increased. Therefore, efforts aimed at reducing and managing occupational noise and vibration exposure are crucial to maintaining workers’ health. PMID:28542287

Intravenous bisphosphonate-related osteonecrosis of the jaws: Influence of coadjuvant antineoplastic treatment and study of buccodental condition

PubMed Central

Bagán, José; Poveda-Roda, Rafael

2013-01-01

Objectives: To determine whether coadjuvant antineoplastic treatment can influence the number and size of bone exposures among patients with intravenous bisphosphonate-related osteonecrosis of the jaws (iBRONJ), and to analyze the buccodental condition of these patients. Material and methods: The study sample comprised 67 patients with iBRONJ, 53 patients without iBRONJ receiving treatment with intravenous bisphosphonates, and 36 healthy subjects. In all three groups, measurements were made of the CAO index and of resting whole saliva and stimulated whole saliva. In the patients with iBRONJ, the size (cm) and number of bone exposures were recorded. The data obtained were subjected to analysis of variance (ANOVA), the Mann-Whitney U-test, and multivariate logistic regression analysis. Results: A total of 57.6% of the patients presented single bone exposure, 25.4% presented two, and 17% more than two exposures. The mean exposure size was 2.3±1.9 cm. Neither the bivariate analysis nor the multivariate multiple regression analysis found coadjuvant antineoplastic treatment to exert a statistically significant effect upon the number and size of bone exposures. On the other hand, there were statistically significant differences among the three study groups in relation to the CAO index (p=0.02) and the number of missing teeth (p=0.00). The resting whole saliva and stimulated whole saliva levels were similar in the three groups, though the patients with osteonecrosis of the jaws showed comparatively lower SWS levels. Conclusions: Coadjuvant antineoplastic treatment alone appears to exert no influence upon the size and number of bone exposures in iBRONJ. The patients with this disease show a higher CAO index and a larger number of missing teeth. Key words:Osteonecrosis of the jaws, bisphosphonates, bone exposure, CAO index, resting whole saliva, stimulated whole saliva. PMID:23229272

Influence of exposure assessment and parameterization on exposure response. Aspects of epidemiologic cohort analysis using the Libby Amphibole asbestos worker cohort.

PubMed

Bateson, Thomas F; Kopylev, Leonid

2015-01-01

Recent meta-analyses of occupational epidemiology studies identified two important exposure data quality factors in predicting summary effect measures for asbestos-associated lung cancer mortality risk: sufficiency of job history data and percent coverage of work history by measured exposures. The objective was to evaluate different exposure parameterizations suggested in the asbestos literature using the Libby, MT asbestos worker cohort and to evaluate influences of exposure measurement error caused by historically estimated exposure data on lung cancer risks. Focusing on workers hired after 1959, when job histories were well-known and occupational exposures were predominantly based on measured exposures (85% coverage), we found that cumulative exposure alone, and with allowance of exponential decay, fit lung cancer mortality data similarly. Residence-time-weighted metrics did not fit well. Compared with previous analyses based on the whole cohort of Libby workers hired after 1935, when job histories were less well-known and exposures less frequently measured (47% coverage), our analyses based on higher quality exposure data yielded an effect size as much as 3.6 times higher. Future occupational cohort studies should continue to refine retrospective exposure assessment methods, consider multiple exposure metrics, and explore new methods of maintaining statistical power while minimizing exposure measurement error.

Evaluation of economic effects and the health and performance of the general cattle population after exposure to cattle persistently infected with bovine viral diarrhea virus in a starter feedlot.

PubMed

Hessman, Bill E; Fulton, Robert W; Sjeklocha, David B; Murphy, Timothy A; Ridpath, Julia F; Payton, Mark E

2009-01-01

To evaluate economic effects and health and performance of the general cattle population after exposure to cattle persistently infected (PI) with bovine viral diarrhea virus (BVDV) in a feedlot. 21,743 high-risk calves from the southeastern United States. PI status was determined by use of an antigen-capture ELISA (ACE) and confirmed by use of a second ACE, reverse transcriptase-PCR assay of sera, immunohistochemical analysis, and virus isolation from sera. Groups with various amounts of exposure to BVDV PI cattle were used. After being placed in the feedlot, identified PI cattle were removed from 1 section, but PI cattle remained in another section of the feedlot. Exposure groups for cattle lots arriving without PI animals were determined by spatial association to cattle lots, with PI animals remaining or removed from the lot. 15,348 cattle maintained their exposure group. Performance outcomes improved slightly among the 5 exposure groups as the risk for exposure to BVDV PI cattle decreased. Health outcomes had an association with exposure risk that depended on the exposure group. Comparing cattle lots with direct exposure with those without direct exposure revealed significant improvements in all performance outcomes and in first relapse percentage and mortality percentage in the health outcomes. Economic analysis revealed that fatalities accounted for losses of $5.26/animal and performance losses were $88.26/animal. This study provided evidence that exposure of the general population of feedlot cattle to BVDV PI animals resulted in substantial costs attributable to negative effects on performance and increased fatalities.

Performance characteristics of a Kodak computed radiography system.

PubMed

Bradford, C D; Peppler, W W; Dobbins, J T

1999-01-01

The performance characteristics of a photostimulable phosphor based computed radiographic (CR) system were studied. The modulation transfer function (MTF), noise power spectra (NPS), and detective quantum efficiency (DQE) of the Kodak Digital Science computed radiography (CR) system (Eastman Kodak Co.-model 400) were measured and compared to previously published results of a Fuji based CR system (Philips Medical Systems-PCR model 7000). To maximize comparability, the same measurement techniques and analysis methods were used. The DQE at four exposure levels (30, 3, 0.3, 0.03 mR) and two plate types (standard and high resolution) were calculated from the NPS and MTF measurements. The NPS was determined from two-dimensional Fourier analysis of uniformly exposed plates. The presampling MTF was determined from the Fourier transform (FT) of the system's finely sampled line spread function (LSF) as produced by a narrow slit. A comparison of the slit type ("beveled edge" versus "straight edge") and its effect on the resulting MTF measurements was also performed. The results show that both systems are comparable in resolution performance. The noise power studies indicated a higher level of noise for the Kodak images (approximately 20% at the low exposure levels and 40%-70% at higher exposure levels). Within the clinically relevant exposure range (0.3-3 mR), the resulting DQE for the Kodak plates ranged between 20%-50% lower than for the corresponding Fuji plates. Measurements of the presampling MTF with the two slit types have shown that a correction factor can be applied to compensate for transmission through the relief edges.

Workplace air measurements and likelihood of exposure to manufactured nano-objects, agglomerates, and aggregates

NASA Astrophysics Data System (ADS)

Brouwer, Derk H.; van Duuren-Stuurman, Birgit; Berges, Markus; Bard, Delphine; Jankowska, Elzbieta; Moehlmann, Carsten; Pelzer, Johannes; Mark, Dave

2013-11-01

Manufactured nano-objects, agglomerates, and aggregates (NOAA) may have adverse effect on human health, but little is known about occupational risks since actual estimates of exposure are lacking. In a large-scale workplace air-monitoring campaign, 19 enterprises were visited and 120 potential exposure scenarios were measured. A multi-metric exposure assessment approach was followed and a decision logic was developed to afford analysis of all results in concert. The overall evaluation was classified by categories of likelihood of exposure. At task level about 53 % showed increased particle number or surface area concentration compared to "background" level, whereas 72 % of the TEM samples revealed an indication that NOAA were present in the workplace. For 54 out of the 120 task-based exposure scenarios, an overall evaluation could be made based on all parameters of the decision logic. For only 1 exposure scenario (approximately 2 %), the highest level of potential likelihood was assigned, whereas in total in 56 % of the exposure scenarios the overall evaluation revealed the lowest level of likelihood. However, for the remaining 42 % exposure to NOAA could not be excluded.

Isocyanate exposure and occupational asthma: a case-referent study

PubMed Central

Meredith, S; Bugler, J; Clark, R

2000-01-01

OBJECTIVE—To examine the quantitative relation between exposure to isocyanates and occupational asthma, and to explore the role of atopy and smoking in occurrence of the disease.
METHOD—A case-referent study was undertaken of cases from two manufacturing companies (A and B) from which referents without disease could be selected and reliable exposure measurements were available. In company A, 27 cases mainly attributed to toluene diisocyanate (TDI) were matched to 51 referents on work area, start and duration of employment, sex, and age. Exposures were estimated from existing measurements by job category. In company B there were seven cases attributed to 4,4'-diphenylmethane diisocyanate (MDI) in two areas of the plant; 12 non-cases from the same areas were used as referents. Personal exposure measurements were available for all cases and 11 referents.
RESULTS—No difference in peak exposures between cases and referents was found in either plant; but in both, time weighted average (TWA) exposures at the time of onset of asthma were higher for cases. In A, the mean TWA exposure for cases was 1.5 (95% confidence interval (95% CI) 1.2 to 1.8) ppb compared with 1.2 (1.0 to 1.4) ppb for referents. From a matched analysis, the odds ratio (OR) associated with 8 hour TWA exposure to isocyanates greater than 1.125 ppb (the median concentration for the referent group) was 3.2 (95% CI 0.96 to 10.6; p=0.06). Occupational asthma was associated with a pre-employment history of atopic illness (OR 3.5, p=0.04) and, less strongly, with smoking (OR 2.1, p=0.14). In B, small numbers limited analysis, but three of seven cases had at least one TWA exposure measurement greater than 5 ppb compared with one of 11 referents (OR 7.5, p=0.09).
CONCLUSION—Asthma can occur at low concentrations of isocyanates, but even at low concentrations, the higher the exposure the greater the risk. By contrast with other studies, smoking and atopy seemed to increase the odds of occupational asthma due to isocyanates, but did not affect the estimate of risk associated with exposure.


Keywords: occupational asthma; isocyanates PMID:11077012

Silicosis surveillance in New Jersey: targeting workplaces using occupational disease and exposure surveillance data.

PubMed

Valiante, D J; Richards, T B; Kinsley, K B

1992-01-01

To identify workplaces in New Jersey with potential for silica exposure, the New Jersey Department of Health compared four-digit Standard Industrial Classifications (SICs) identified by three different data sources: the National Occupational Exposure Survey (NOES), a new Jersey silicosis case registry, and regulatory agency compliance inspections in New Jersey. In total, the three data sources identified 204 SICs in New Jersey with potential for silica exposure. Forty-five percent of these SICs were identified by NOES only, 16% by registry cases only, 6% by compliance inspections only, and 33% by two or more sources. Since different surveillance sources implicate different SICs, this type of analysis is a useful first step in planning programs for prevention of silicosis.

Skin analysis following dermal exposure to kerosene in rats: the effects of postmortem exposure and fire.

PubMed

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

2004-02-01

To evaluate the usefulness of skin analysis for the forensic examination of cases involving postmortem dermal exposure to kerosene and/or fire, an experimental study using rats was performed. Rats received dermal exposure to kerosene before or after death, and the effect of fire was determined by burning an area of exposed skin after death. Kerosene concentrations in skin and blood were determined by gas chromatography-mass spectrometry and microscopic observation was performed for skin samples. No differences were observed in skin kerosene levels between antemortem and postmortem exposure. Kerosene concentrations in mildly burned skin where the stratum corneum (SC) was retained were approximately 84% compared to those in non-burned exposed skin, whereas concentrations in severely burned skin where the SC was almost completely burned off were 28% of non-burned skin. Even in non-exposed control skin 14% of the original kerosene concentrations could be detected, which was considered to be caused by contamination during the experimental protocol combined with kerosene's property of a high affinity for the SC. These results suggest that (1) skin analysis is useful in estimating the type of petroleum product involved in crimes or accidents even for postmortem exposure, (2) whether the SC is retained or not primarily determined the kerosene levels in burned skin, and (3) attention must be paid to evaluate the results obtained from skin samples in the light of the circumstances surrounding the case.

Exposure enriched outcome dependent designs for longitudinal studies of gene-environment interaction.

PubMed

Sun, Zhichao; Mukherjee, Bhramar; Estes, Jason P; Vokonas, Pantel S; Park, Sung Kyun

2017-08-15

Joint effects of genetic and environmental factors have been increasingly recognized in the development of many complex human diseases. Despite the popularity of case-control and case-only designs, longitudinal cohort studies that can capture time-varying outcome and exposure information have long been recommended for gene-environment (G × E) interactions. To date, literature on sampling designs for longitudinal studies of G × E interaction is quite limited. We therefore consider designs that can prioritize a subsample of the existing cohort for retrospective genotyping on the basis of currently available outcome, exposure, and covariate data. In this work, we propose stratified sampling based on summaries of individual exposures and outcome trajectories and develop a full conditional likelihood approach for estimation that adjusts for the biased sample. We compare the performance of our proposed design and analysis with combinations of different sampling designs and estimation approaches via simulation. We observe that the full conditional likelihood provides improved estimates for the G × E interaction and joint exposure effects over uncorrected complete-case analysis, and the exposure enriched outcome trajectory dependent design outperforms other designs in terms of estimation efficiency and power for detection of the G × E interaction. We also illustrate our design and analysis using data from the Normative Aging Study, an ongoing longitudinal cohort study initiated by the Veterans Administration in 1963. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Effectiveness of N95 respirators versus surgical masks in protecting health care workers from acute respiratory infection: a systematic review and meta-analysis

PubMed Central

Smith, Jeffrey D.; MacDougall, Colin C.; Johnstone, Jennie; Copes, Ray A.; Schwartz, Brian; Garber, Gary E.

2016-01-01

Background: Conflicting recommendations exist related to which facial protection should be used by health care workers to prevent transmission of acute respiratory infections, including pandemic influenza. We performed a systematic review of both clinical and surrogate exposure data comparing N95 respirators and surgical masks for the prevention of transmissible acute respiratory infections. Methods: We searched various electronic databases and the grey literature for relevant studies published from January 1990 to December 2014. Randomized controlled trials (RCTs), cohort studies and case–control studies that included data on health care workers wearing N95 respirators and surgical masks to prevent acute respiratory infections were included in the meta-analysis. Surrogate exposure studies comparing N95 respirators and surgical masks using manikins or adult volunteers under simulated conditions were summarized separately. Outcomes from clinical studies were laboratory-confirmed respiratory infection, influenza-like illness and workplace absenteeism. Outcomes from surrogate exposure studies were filter penetration, face-seal leakage and total inward leakage. Results: We identified 6 clinical studies (3 RCTs, 1 cohort study and 2 case–control studies) and 23 surrogate exposure studies. In the meta-analysis of the clinical studies, we found no significant difference between N95 respirators and surgical masks in associated risk of (a) laboratory-confirmed respiratory infection (RCTs: odds ratio [OR] 0.89, 95% confidence interval [CI] 0.64–1.24; cohort study: OR 0.43, 95% CI 0.03–6.41; case–control studies: OR 0.91, 95% CI 0.25–3.36); (b) influenza-like illness (RCTs: OR 0.51, 95% CI 0.19–1.41); or (c) reported workplace absenteeism (RCT: OR 0.92, 95% CI 0.57–1.50). In the surrogate exposure studies, N95 respirators were associated with less filter penetration, less face-seal leakage and less total inward leakage under laboratory experimental conditions, compared with surgical masks. Interpretation: Although N95 respirators appeared to have a protective advantage over surgical masks in laboratory settings, our meta-analysis showed that there were insufficient data to determine definitively whether N95 respirators are superior to surgical masks in protecting health care workers against transmissible acute respiratory infections in clinical settings. PMID:26952529

Effectiveness of N95 respirators versus surgical masks in protecting health care workers from acute respiratory infection: a systematic review and meta-analysis.

PubMed

Smith, Jeffrey D; MacDougall, Colin C; Johnstone, Jennie; Copes, Ray A; Schwartz, Brian; Garber, Gary E

2016-05-17

Conflicting recommendations exist related to which facial protection should be used by health care workers to prevent transmission of acute respiratory infections, including pandemic influenza. We performed a systematic review of both clinical and surrogate exposure data comparing N95 respirators and surgical masks for the prevention of transmissible acute respiratory infections. We searched various electronic databases and the grey literature for relevant studies published from January 1990 to December 2014. Randomized controlled trials (RCTs), cohort studies and case-control studies that included data on health care workers wearing N95 respirators and surgical masks to prevent acute respiratory infections were included in the meta-analysis. Surrogate exposure studies comparing N95 respirators and surgical masks using manikins or adult volunteers under simulated conditions were summarized separately. Outcomes from clinical studies were laboratory-confirmed respiratory infection, influenza-like illness and workplace absenteeism. Outcomes from surrogate exposure studies were filter penetration, face-seal leakage and total inward leakage. We identified 6 clinical studies (3 RCTs, 1 cohort study and 2 case-control studies) and 23 surrogate exposure studies. In the meta-analysis of the clinical studies, we found no significant difference between N95 respirators and surgical masks in associated risk of (a) laboratory-confirmed respiratory infection (RCTs: odds ratio [OR] 0.89, 95% confidence interval [CI] 0.64-1.24; cohort study: OR 0.43, 95% CI 0.03-6.41; case-control studies: OR 0.91, 95% CI 0.25-3.36); (b) influenza-like illness (RCTs: OR 0.51, 95% CI 0.19-1.41); or (c) reported workplace absenteeism (RCT: OR 0.92, 95% CI 0.57-1.50). In the surrogate exposure studies, N95 respirators were associated with less filter penetration, less face-seal leakage and less total inward leakage under laboratory experimental conditions, compared with surgical masks. Although N95 respirators appeared to have a protective advantage over surgical masks in laboratory settings, our meta-analysis showed that there were insufficient data to determine definitively whether N95 respirators are superior to surgical masks in protecting health care workers against transmissible acute respiratory infections in clinical settings. © 2016 Canadian Medical Association or its licensors.

Exposure to secondhand smoke and associated factors among non-smoking pregnant women with smoking husbands in Sichuan province, China.

PubMed

Yang, Lian; Tong, Elisa K; Mao, Zhengzhong; Hu, Teh-wei

2010-01-01

Secondhand smoke (SHS) exposure harms pregnant women and the fetus. China has the world's largest number of smokers and a high male smoking prevalence rate. To compare exposure to SHS among rural and urban Chinese non-smoking pregnant women with smoking husbands, and analyze factors associated with the level of SHS exposure and hair nicotine concentration. Sichuan province, China. In all 1,181 non-smoking pregnant women with smoking husbands recruited from eight district/county Women and Children's hospitals. The women completed a questionnaire in April and May 2008. Based on systematic sampling, 186 pregnant women were selected for sampling the nicotine concentration in their hair. Ordinal logistic regression analysis was conducted to examine correlates with self-reported SHS exposure (total and at home); linear regression was conducted for the sub-sample of hair nicotine concentrations. Secondhand smoking exposure rates, hair nicotine levels. About 75.1% of the non-smoking pregnant women with smoking husbands reported regular SHS exposure. The major source of exposure was through their husband. In the multivariate analysis, the risk of greater SHS exposure (total and at home) and hair nicotine concentration was increased for women who were rural, had a husband with greater cigarette consumption, less knowledge about SHS, less negative attitudes about SHS, and no smoke-free home rules. The high prevalence rate of SHS exposure suggests that it is important for non-smoking pregnant women, especially rural women, to establish smoke-free home rules and increase knowledge and negative attitudes towards SHS.

Elevated Plasma Norepinephrine After In Utero Exposure to Cocaine and Marijuana

PubMed Central

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

2008-01-01

Objective To compare plasma catecholamine concentrations between cocaine-exposed and unexposed term newborns and to determine the relationship between plasma catecholamines and newborn behavior. Methods Forty-six newborn infants participating in a prospective study of the neonatal and long-term effects of prenatal cocaine exposure were studied. Based on maternal self-report, maternal urine screening, and infant meconium analysis, 24 infants were classified as cocaine-exposed and 22 as unexposed. Between 24 and 72 hours postpartum, plasma samples for norepinephrine (NE), epinephrine, dopamine, and dihydroxyphenylalanine analysis were obtained. The Neonatal Behavioral Assessment Scale was administered at 1 to 3 days of age and at 2 weeks of age by examiners masked to the drug exposure status of the newborns. Results The cocaine-exposed newborns had increased plasma NE concentrations when compared to the unexposed infants (geometric mean, 923 pg/mL vs 667 pg/mL). There were no significant differences in plasma epinephrine, dopamine, or dihydroxyphenylalanine concentrations. Analysis for the effect of potential confounding variables revealed that maternal marijuana use was also associated with increased plasma NE, although birth weight, gender, and maternal use of alcohol or cigarettes were not. Geometric mean plasma NE was 1164 pg/mL in those infants with in utero exposure to both cocaine and marijuana compared to 812 pg/mL in those exposed to only cocaine and 667 pg/mL in those exposed to neither. Among the cocaine-exposed infants, plasma NE concentration correlated with an increased score for the depressed cluster (r = .53) and a decreased score for the orientation cluster (r = −.43) of the Neonatal Behavioral Assessment Scale administered at 1 to 3 days of age. Adjusting for marijuana exposure had no effect on these relationships between plasma NE and the depressed and orientation clusters. Conclusion Plasma NE is increased in newborns exposed to cocaine and marijuana. Increased plasma NE is associated with selected neurobehavioral disturbances among cocaine exposed infants at 1 to 3 days of life but not at 2 weeks. PMID:9093298

More than 2500 years of oil exposure shape sediment microbiomes with the potential for syntrophic degradation of hydrocarbons linked to methanogenesis.

PubMed

Michas, Antonios; Vestergaard, Gisle; Trautwein, Kathleen; Avramidis, Pavlos; Hatzinikolaou, Dimitris G; Vorgias, Constantinos E; Wilkes, Heinz; Rabus, Ralf; Schloter, Michael; Schöler, Anne

2017-09-11

Natural oil seeps offer the opportunity to study the adaptation of ecosystems and the associated microbiota to long-term oil exposure. In the current study, we investigated a land-to-sea transition ecosystem called "Keri Lake" in Zakynthos Island, Greece. This ecosystem is unique due to asphalt oil springs found at several sites, a phenomenon already reported 2500 years ago. Sediment microbiomes at Keri Lake were studied, and their structure and functional potential were compared to other ecosystems with oil exposure histories of various time periods. Replicate sediment cores (up to 3-m depth) were retrieved from one site exposed to oil as well as a non-exposed control site. Samples from three different depths were subjected to chemical analysis and metagenomic shotgun sequencing. At the oil-exposed site, we observed high amounts of asphalt oil compounds and a depletion of sulfate compared to the non-exposed control site. The numbers of reads assigned to genes involved in the anaerobic degradation of hydrocarbons were similar between the two sites. The numbers of denitrifiers and sulfate reducers were clearly lower in the samples from the oil-exposed site, while a higher abundance of methanogens was detected compared to the non-exposed site. Higher abundances of the genes of methanogenesis were also observed in the metagenomes from other ecosystems with a long history of oil exposure, compared to short-term exposed environments. The analysis of Keri Lake metagenomes revealed that microbiomes in the oil-exposed sediment have a higher potential for methanogenesis over denitrification/sulfate reduction, compared to those in the non-exposed site. Comparison with metagenomes from various oil-impacted environments suggests that syntrophic interactions of hydrocarbon degraders with methanogens are favored in the ecosystems with a long-term presence of oil.

A comparison of infant hair, cord blood and meconium analysis to detect fetal exposure to environmental pesticides

PubMed Central

Ostrea, Enrique M.; Bielawski, Dawn M.; Posecion, Norberto C.; Corrion, Melissa; Villanueva-Uy, Esterlita; Jin, Yan; Janisse, James J.; Ager, Joel W.

2008-01-01

OBJECTIVE The detection of fetal exposure to environmental pesticides is important because many of the pesticides are neurotoxicants and fetal exposure to these compounds can adversely affect prenatal and subsequent neurodevelopment. The aim of this study was to determine, by the comparative analysis of infant hair, cord blood and meconium, the most sensitive matrix to detect fetal exposure to pesticides. PATIENTS AND METHODS Pregnant women were prospectively recruited from an agricultural site in the Philippines where a preliminary survey indicated a substantial use at home and in the farm of the following pesticides: propoxur, cyfluthrin, chlorpyrifos, cypermethrin, pretilachlor, bioallethrin, malathion, diazinon and transfluthrin. Infant hair, cord blood and meconium were obtained after birth and were analyzed by gas chromatography/mass spectrometry for the above compounds, including lindane and DDT (1,1,1-trichloro-2,2-bis, p-chlorophenylethane) and some of their known metabolites. RESULTS A total of 638 infants were included in the study. The highest exposure rate to pesticides was detected in meconium (23.8% to propoxur, 1.9% to pretilachlor, 1.9% to cypermethrin, 0.8% to cyfluthrin, 0.6% to DDT and 0.3% to malathion and bioallethrin). Cord blood was only positive for propoxur (1.9%) whereas infant hair was only positive for chlorpyrifos (0.2%). The highest exposure was to household pesticide (propoxur). The frequency and concentration of pesticides were compared in the three matrices and there was a significantly higher frequency and concentration of propoxur, pretilachlor, DDT, cyfluthrin and cypermethrin in meconium compared to cord blood and infant hair. Pesticide metabolites were not found in any of the matrices analyzed, except in one meconium sample which was positive for DDE (4,4′ dichlorodiphenyldichloro ethylene), a DDT metabolite. CONCLUSIONS There is significant exposure of the pregnant woman and her fetus to pesticides, particularly to the home pesticide, propoxur. Our study has demonstrated that among cord blood, meconium or infant hair, meconium is the most sensitive matrix to analyze for fetal exposure to pesticides. The accumulation of pesticides in meconium, the ease of meconium collection and the large amount of meconium that could be collected are factors that contribute to the increased sensitivity of this matrix. PMID:17949707

Occupational exposure to chrome VI compounds in French companies: results of a national campaign to measure exposure (2010-2013).

PubMed

Vincent, Raymond; Gillet, Martine; Goutet, Pierre; Guichard, Christine; Hédouin-Langlet, Catherine; Frocaut, Anne Marie; Lambert, Pierre; Leray, Fabrice; Mardelle, Patricia; Dorotte, Michel; Rousset, Davy

2015-01-01

A campaign to measure exposure to hexavalent chromium compounds was carried out in France by the seven CARSAT chemistry laboratories, CRAMIF laboratory, and INRS over the 2010-2013 period. The survey included 99 companies involved in various activity sectors. The inhalable fraction of airborne particles was sampled, and exposure levels were determined using ion chromatography analysis combined with post-column derivatization and UV detection. The quality of the measurement results was guaranteed by an inter-laboratory comparison system involving all the laboratories participating in this study. Exposure levels frequently exceeded the French occupational exposure limit value (OELV) of 1 µg m(-3), in activities such as thermal metallization and manufacturing and application of paint in the aeronautics sector. The results also reveal a general trend for a greater proportion of soluble Chromium VI (Cr VI) compounds compared with insoluble compounds. Qualitative and quantitative information relating to the presence of other metallic compounds in the air of workplaces is also provided, for example for Cr III, Ni, Fe, etc. The sampling strategy used and the measurement method are easy to implement, making it possible to check occupational exposure with a view to comparing it to an 8 h-OELV of 1 µg m(-3). © The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Comparative and Predictive Multimedia Assessments Using Monte Carlo Uncertainty Analyses

NASA Astrophysics Data System (ADS)

Whelan, G.

2002-05-01

Multiple-pathway frameworks (sometimes referred to as multimedia models) provide a platform for combining medium-specific environmental models and databases, such that they can be utilized in a more holistic assessment of contaminant fate and transport in the environment. These frameworks provide a relatively seamless transfer of information from one model to the next and from databases to models. Within these frameworks, multiple models are linked, resulting in models that consume information from upstream models and produce information to be consumed by downstream models. The Framework for Risk Analysis in Multimedia Environmental Systems (FRAMES) is an example, which allows users to link their models to other models and databases. FRAMES is an icon-driven, site-layout platform that is an open-architecture, object-oriented system that interacts with environmental databases; helps the user construct a Conceptual Site Model that is real-world based; allows the user to choose the most appropriate models to solve simulation requirements; solves the standard risk paradigm of release transport and fate; and exposure/risk assessments to people and ecology; and presents graphical packages for analyzing results. FRAMES is specifically designed allow users to link their own models into a system, which contains models developed by others. This paper will present the use of FRAMES to evaluate potential human health exposures using real site data and realistic assumptions from sources, through the vadose and saturated zones, to exposure and risk assessment at three real-world sites, using the Multimedia Environmental Pollutant Assessment System (MEPAS), which is a multimedia model contained within FRAMES. These real-world examples use predictive and comparative approaches coupled with a Monte Carlo analysis. A predictive analysis is where models are calibrated to monitored site data, prior to the assessment, and a comparative analysis is where models are not calibrated but based solely on literature or judgement and is usually used to compare alternatives. In many cases, a combination is employed where the model is calibrated to a portion of the data (e.g., to determine hydrodynamics), then used to compare alternatives. Three subsurface-based multimedia examples are presented, increasing in complexity. The first presents the application of a predictive, deterministic assessment; the second presents a predictive and comparative, Monte Carlo analysis; and the third presents a comparative, multi-dimensional Monte Carlo analysis. Endpoints are typically presented in terms of concentration, hazard, risk, and dose, and because the vadose zone model typically represents a connection between a source and the aquifer, it does not generally represent the final medium in a multimedia risk assessment.

Web-Based Survey Application to Collect Contextually Relevant Geographic Data With Exposure Times: Application Development and Feasibility Testing

PubMed Central

Tobin, Karin; Rudolph, Jonathan; Latkin, Carl

2018-01-01

Background Although studies that characterize the risk environment by linking contextual factors with individual-level data have advanced infectious disease and substance use research, there are opportunities to refine how we define relevant neighborhood exposures; this can in turn reduce the potential for exposure misclassification. For example, for those who do not inject at home, injection risk behaviors may be more influenced by the environment where they inject than where they live. Similarly, among those who spend more time away from home, a measure that accounts for different neighborhood exposures by weighting each unique location proportional to the percentage of time spent there may be more correlated with health behaviors than one’s residential environment. Objective This study aimed to develop a Web-based application that interacts with Google Maps application program interfaces (APIs) to collect contextually relevant locations and the amount of time spent in each. Our analysis examined the extent of overlap across different location types and compared different approaches for classifying neighborhood exposure. Methods Between May 2014 and March 2017, 547 participants enrolled in a Baltimore HIV care and prevention study completed an interviewer-administered Web-based survey that collected information about where participants were recruited, worked, lived, socialized, injected drugs, and spent most of their time. For each location, participants gave an address or intersection which they confirmed using Google Map and Street views. Geographic coordinates (and hours spent in each location) were joined to neighborhood indicators by Community Statistical Area (CSA). We computed a weighted exposure based on the proportion of time spent in each unique location. We compared neighborhood exposures based on each of the different location types with one another and the weighted exposure using analysis of variance with Bonferroni corrections to account for multiple comparisons. Results Participants reported spending the most time at home, followed by the location where they injected drugs. Injection locations overlapped most frequently with locations where people reported socializing and living or sleeping. The least time was spent in the locations where participants reported earning money and being recruited for the study; these locations were also the least likely to overlap with other location types. We observed statistically significant differences in neighborhood exposures according to the approach used. Overall, people reported earning money in higher-income neighborhoods and being recruited for the study and injecting in neighborhoods with more violent crime, abandoned houses, and poverty. Conclusions This analysis revealed statistically significant differences in neighborhood exposures when defined by different locations or weighted based on exposure time. Future analyses are needed to determine which exposure measures are most strongly associated with health and risk behaviors and to explore whether associations between individual-level behaviors and neighborhood exposures are modified by exposure times. PMID:29351899

Toxicological responses in SW mice exposed to inhaled pyrolysates of polymer/tobacco mixtures and blended tobacco.

PubMed

Werley, Michael S; Lee, K Monika; Lemus-Olalde, Ranulfo

2009-12-01

Modern cigarette manufacturing is highly automated and produces millions of cigarettes per day. The potential for small inclusions of non-cigarette materials such as wood, cardboard packaging, plastic, and other materials exists as a result of bulk handling and high-speed processing of tobacco. Many non-tobacco inclusions such as wood, paper, and cardboard would be expected to yield similar pyrolysis products as a burning cigarette. The aircraft industry has developed an extensive literature on the pyrolysis products of plastics, however, that have been reported to yield toxic by-products upon burning, by-products that have been lethal in animals and humans upon acute exposure under some exposure conditions. Some of these smoke constituents have also been reported in cigarette smoke. Five synthetic polymers, nylon 6, acrylonitrile-butadiene-styrene (ABS), nylon 12, nylon 6,6, and acrylonitrile-butadiene (AB), and the natural polymer wool were evaluated by adding them to tobacco at a 3, 10, and 30% inclusion level and then pyrolyzing the mixture. The validated smoke generation and exposure system have been described previously. We used the DIN 53-436 tube furnace and nose-only exposure chamber in combination to conduct exposures in Swiss-Webster mice. Potentially useful biological endpoints for predicting hazards in humans included sensory irritation and pulmonary irritation, respiratory function, clinical signs, body weights, bronchoalveolar lavage (BAL) fluid analysis, carboxyhemoglogin, blood cyanide concentrations, and histopathology of the respiratory tract. Chemical analysis of selected smoke constituents in the test atmosphere was also performed in order to compare the toxicological responses with exposure to the test atmospheres. Under the conditions of these studies, biological responses considered relevant and useful for prediction of effects in humans were found for sensory irritation, body weights, BAL fluid analysis, and histopathology of the nose. There was a marked sensory irritation response that recovered slowly for some polymers. Sustained body weight depression, lesions of the respiratory epithelium of the nose, and morphological changes in pulmonary alveolar macrophages (PAM) were observed after exposure to some polymer/tobacco pyrolysates. These responses were increased compared to exposure to tobacco pyrolysate alone. No moribundity or mortality occurred during the study. The data suggest that polymeric inclusions pose a minimal additional toxicologic hazard in humans.

Relative Importance and Additive Effects of Maternal and Infant Risk Factors on Childhood Asthma

PubMed Central

Rosas-Salazar, Christian; James, Kristina; Escobar, Gabriel; Gebretsadik, Tebeb; Li, Sherian Xu; Carroll, Kecia N.; Walsh, Eileen; Mitchel, Edward; Das, Suman; Kumar, Rajesh; Yu, Chang; Dupont, William D.; Hartert, Tina V.

2016-01-01

Background Environmental exposures that occur in utero and during early life may contribute to the development of childhood asthma through alteration of the human microbiome. The objectives of this study were to estimate the cumulative effect and relative importance of environmental exposures on the risk of childhood asthma. Methods We conducted a population-based birth cohort study of mother-child dyads who were born between 1995 and 2003 and were continuously enrolled in the PRIMA (Prevention of RSV: Impact on Morbidity and Asthma) cohort. The individual and cumulative impact of maternal urinary tract infections (UTI) during pregnancy, maternal colonization with group B streptococcus (GBS), mode of delivery, infant antibiotic use, and older siblings at home, on the risk of childhood asthma were estimated using logistic regression. Dose-response effect on childhood asthma risk was assessed for continuous risk factors: number of maternal UTIs during pregnancy, courses of infant antibiotics, and number of older siblings at home. We further assessed and compared the relative importance of these exposures on the asthma risk. In a subgroup of children for whom maternal antibiotic use during pregnancy information was available, the effect of maternal antibiotic use on the risk of childhood asthma was estimated. Results Among 136,098 singleton birth infants, 13.29% developed asthma. In both univariate and adjusted analyses, maternal UTI during pregnancy (odds ratio [OR] 1.2, 95% confidence interval [CI] 1.18, 1.25; adjusted OR [AOR] 1.04, 95%CI 1.02, 1.07 for every additional UTI) and infant antibiotic use (OR 1.21, 95%CI 1.20, 1.22; AOR 1.16, 95%CI 1.15, 1.17 for every additional course) were associated with an increased risk of childhood asthma, while having older siblings at home (OR 0.92, 95%CI 0.91, 0.93; AOR 0.85, 95%CI 0.84, 0.87 for each additional sibling) was associated with a decreased risk of childhood asthma, in a dose-dependent manner. Compared with vaginal delivery, C-section delivery increased odds of childhood asthma by 34% (OR 1.34, 95%CI 1.29, 1.39) in the univariate analysis and 11% after adjusting for other environmental exposures and covariates (AOR 1.11, 95%CI 1.06, 1.15). Maternal GBS was associated with a significant increased risk of childhood asthma in the univariate analysis (OR 1.27, 95%CI 1.19, 1.35), but not in the adjusted analysis (AOR 1.03, 95%CI 0.96, 1.10). In the subgroup analysis of children whose maternal antibiotic use information was available, maternal antibiotic use was associated with an increased risk of childhood asthma in a similar dose-dependent manner in the univariate and adjusted analyses (OR 1.13, 95%CI 1.12, 1.15; AOR 1.06, 95%CI 1.05, 1.08 for every additional course). Compared with infants with the lowest number of exposures (no UTI during pregnancy, vaginal delivery, at least five older siblings at home, no antibiotics during infancy), infants with the highest number of exposures (at least three UTIs during pregnancy, C-section delivery, no older siblings, eight or more courses of antibiotics during infancy) had a 7.77 fold increased odds of developing asthma (AOR: 7.77, 95%CI: 6.25, 9.65). Lastly, infant antibiotic use had the greatest impact on asthma risk compared with maternal UTI during pregnancy, mode of delivery and having older siblings at home. Conclusion Early-life exposures, maternal UTI during pregnancy (maternal antibiotic use), mode of delivery, infant antibiotic use, and having older siblings at home, are associated with an increased risk of childhood asthma in a cumulative manner, and for those continuous variables, a dose-dependent relationship. Compared with in utero exposures, exposures occurring during infancy have a greater impact on the risk of developing childhood asthma. PMID:27002979

Relative Importance and Additive Effects of Maternal and Infant Risk Factors on Childhood Asthma.

PubMed

Wu, Pingsheng; Feldman, Amy S; Rosas-Salazar, Christian; James, Kristina; Escobar, Gabriel; Gebretsadik, Tebeb; Li, Sherian Xu; Carroll, Kecia N; Walsh, Eileen; Mitchel, Edward; Das, Suman; Kumar, Rajesh; Yu, Chang; Dupont, William D; Hartert, Tina V

2016-01-01

Environmental exposures that occur in utero and during early life may contribute to the development of childhood asthma through alteration of the human microbiome. The objectives of this study were to estimate the cumulative effect and relative importance of environmental exposures on the risk of childhood asthma. We conducted a population-based birth cohort study of mother-child dyads who were born between 1995 and 2003 and were continuously enrolled in the PRIMA (Prevention of RSV: Impact on Morbidity and Asthma) cohort. The individual and cumulative impact of maternal urinary tract infections (UTI) during pregnancy, maternal colonization with group B streptococcus (GBS), mode of delivery, infant antibiotic use, and older siblings at home, on the risk of childhood asthma were estimated using logistic regression. Dose-response effect on childhood asthma risk was assessed for continuous risk factors: number of maternal UTIs during pregnancy, courses of infant antibiotics, and number of older siblings at home. We further assessed and compared the relative importance of these exposures on the asthma risk. In a subgroup of children for whom maternal antibiotic use during pregnancy information was available, the effect of maternal antibiotic use on the risk of childhood asthma was estimated. Among 136,098 singleton birth infants, 13.29% developed asthma. In both univariate and adjusted analyses, maternal UTI during pregnancy (odds ratio [OR] 1.2, 95% confidence interval [CI] 1.18, 1.25; adjusted OR [AOR] 1.04, 95%CI 1.02, 1.07 for every additional UTI) and infant antibiotic use (OR 1.21, 95%CI 1.20, 1.22; AOR 1.16, 95%CI 1.15, 1.17 for every additional course) were associated with an increased risk of childhood asthma, while having older siblings at home (OR 0.92, 95%CI 0.91, 0.93; AOR 0.85, 95%CI 0.84, 0.87 for each additional sibling) was associated with a decreased risk of childhood asthma, in a dose-dependent manner. Compared with vaginal delivery, C-section delivery increased odds of childhood asthma by 34% (OR 1.34, 95%CI 1.29, 1.39) in the univariate analysis and 11% after adjusting for other environmental exposures and covariates (AOR 1.11, 95%CI 1.06, 1.15). Maternal GBS was associated with a significant increased risk of childhood asthma in the univariate analysis (OR 1.27, 95%CI 1.19, 1.35), but not in the adjusted analysis (AOR 1.03, 95%CI 0.96, 1.10). In the subgroup analysis of children whose maternal antibiotic use information was available, maternal antibiotic use was associated with an increased risk of childhood asthma in a similar dose-dependent manner in the univariate and adjusted analyses (OR 1.13, 95%CI 1.12, 1.15; AOR 1.06, 95%CI 1.05, 1.08 for every additional course). Compared with infants with the lowest number of exposures (no UTI during pregnancy, vaginal delivery, at least five older siblings at home, no antibiotics during infancy), infants with the highest number of exposures (at least three UTIs during pregnancy, C-section delivery, no older siblings, eight or more courses of antibiotics during infancy) had a 7.77 fold increased odds of developing asthma (AOR: 7.77, 95%CI: 6.25, 9.65). Lastly, infant antibiotic use had the greatest impact on asthma risk compared with maternal UTI during pregnancy, mode of delivery and having older siblings at home. Early-life exposures, maternal UTI during pregnancy (maternal antibiotic use), mode of delivery, infant antibiotic use, and having older siblings at home, are associated with an increased risk of childhood asthma in a cumulative manner, and for those continuous variables, a dose-dependent relationship. Compared with in utero exposures, exposures occurring during infancy have a greater impact on the risk of developing childhood asthma.

Long-term effect of early-life stress from earthquake exposure on working memory in adulthood.

PubMed

Li, Na; Wang, Yumei; Zhao, Xiaochuan; Gao, Yuanyuan; Song, Mei; Yu, Lulu; Wang, Lan; Li, Ning; Chen, Qianqian; Li, Yunpeng; Cai, Jiajia; Wang, Xueyi

2015-01-01

The present study aimed to investigate the long-term effect of 1976 Tangshan earthquake exposure in early life on performance of working memory in adulthood. A total of 907 study subjects born and raised in Tangshan were enrolled in this study. They were divided into three groups according to the dates of birth: infant exposure (3-12 months, n=274), prenatal exposure (n=269), and no exposure (born at least 1 year after the earthquake, n=364). The prenatal group was further divided into first, second, and third trimester subgroups based on the timing of exposure during pregnancy. Hopkins Verbal Learning Test-Revised and Brief Visuospatial Memory Test-Revised (BVMT-R) were used to measure the performance of working memory. Unconditional logistic regression analysis was used to analyze the influential factors for impaired working memory. The Hopkins Verbal Learning Test-Revised scores did not show significant difference across the three groups. Compared with no exposure group, the BVMT-R scores were slightly lower in the prenatal exposure group and markedly decreased in the infant exposure group. When the BVMT-R scores were analyzed in three subgroups, the results showed that the subjects whose mothers were exposed to earthquake in the second and third trimesters of pregnancy had significantly lower BVMT-R scores compared with those in the first trimester. Education level and early-life earthquake exposure were identified as independent risk factors for reduced performance of visuospatial memory indicated by lower BVMT-R scores. Infant exposure to earthquake-related stress impairs visuospatial memory in adulthood. Fetuses in the middle and late stages of development are more vulnerable to stress-induced damage that consequently results in impaired visuospatial memory. Education and early-life trauma can also influence the performance of working memory in adulthood.

Tobacco smoke exposure in public places and workplaces after smoke-free policy implementation: a longitudinal analysis of smoker cohorts in Mexico and Uruguay.

PubMed

Thrasher, James F; Nayeli Abad-Vivero, Erika; Sebrié, Ernesto M; Barrientos-Gutierrez, Tonatiuh; Boado, Marcelo; Yong, Hua Hie; Arillo-Santillán, Edna; Bianco, Eduardo

2013-12-01

To determine the prevalence, correlates and changes in secondhand smoke (SHS) exposure over the period after comprehensive smoke-free policy implementation in two Latin American countries. Data were analysed from population-based representative samples of adult smokers and recent quitters from the 2008 and 2010 waves of the International Tobacco Control Policy Evaluation Survey in Mexico (n = 1766 and 1840, respectively) and Uruguay (n = 1379 and 1411, respectively). Prevalence of SHS exposure was estimated for regulated venues, and generalized estimating equations were used to determine correlates of SHS exposure. Workplace SHS exposure in the last month was similar within and across countries (range: Mexico 20-25%; Uruguay 14-29%). At the most recent restaurant visit, SHS exposure was lower where comprehensive smoke-free policies were implemented (range: Uruguay 6-9%; Mexico City 5-7%) compared with Mexican cities with weaker policies, where exposure remained higher but decreased over time (32-17%). At the most recent bar visit, SHS exposure was common (range: Uruguay 8-36%; Mexico City 23-31%), although highest in jurisdictions with weaker policies (range in other Mexican cities: 74-86%). In Uruguay, males were more likely than females to be exposed to SHS across venues, as were younger compared with older smokers in Mexico. Comprehensive smoke-free policies are more effective than weaker policies, although compliance in Mexico and Uruguay is not as high as desired.

Image Noise, CNR, and Detectability of Low-Contrast, Low-Attenuation Liver Lesions in a Phantom: Effects of Radiation Exposure, Phantom Size, Integrated Circuit Detector, and Iterative Reconstruction.

PubMed

Goenka, Ajit H; Herts, Brian R; Dong, Frank; Obuchowski, Nancy A; Primak, Andrew N; Karim, Wadih; Baker, Mark E

2016-08-01

Purpose To assess image noise, contrast-to-noise ratio (CNR) and detectability of low-contrast, low-attenuation liver lesions in a semianthropomorphic phantom by using either a discrete circuit (DC) detector and filtered back projection (FBP) or an integrated circuit (IC) detector and iterative reconstruction (IR) with changes in radiation exposure and phantom size. Materials and Methods An anthropomorphic phantom without or with a 5-cm-thick fat-mimicking ring (widths, 30 and 40 cm) containing liver inserts with four spherical lesions was scanned with five exposure settings on each of two computed tomography scanners, one equipped with a DC detector and the other with an IC detector. Images from the DC and IC detector scanners were reconstructed with FBP and IR, respectively. Image noise and lesion CNR were measured. Four radiologists evaluated lesion presence on a five-point diagnostic confidence scale. Data analyses included receiver operating characteristic (ROC) curve analysis and noninferiority analysis. Results The combination of IC and IR significantly reduced image noise (P < .001) (with the greatest reduction in the 40-cm phantom and at lower exposures) and improved lesion CNR (P < .001). There was no significant difference in area under the ROC curve between detector-reconstruction combinations at fixed exposure for either phantom. Reader accuracy with IC-IR was noninferior at 50% (100 mAs [effective]) and 25% (300 mAs [effective]) exposure reduction for the 30- and 40-cm phantoms, respectively (adjusted P < .001 and .04 respectively). IC-IR improved readers' confidence in the presence of a lesion (P = .029) independent of phantom size or exposure level. Conclusion IC-IR improved objective image quality and lesion detection confidence but did not result in superior diagnostic accuracy when compared with DC-FBP. Moderate exposure reductions maintained comparable diagnostic accuracy for both detector-reconstruction combinations. Lesion detection in the 40-cm phantom was inferior at smaller exposure reduction than in the 30-cm phantom. (©) RSNA, 2016 Online supplemental material is available for this article.

A Bayesian Model and Stochastic Exposure (Dose) Estimation for Relative Exposure Risk Comparison Involving Asbestos-Containing Dropped Ceiling Panel Installation and Maintenance Tasks.

PubMed

Boelter, Fred W; Xia, Yulin; Persky, Jacob D

2017-09-01

Assessing exposures to hazards in order to characterize risk is at the core of occupational hygiene. Our study examined dropped ceiling systems commonly used in schools and commercial buildings and lay-in ceiling panels that may have contained asbestos prior to the mid to late 1970s. However, most ceiling panels and tiles do not contain asbestos. Since asbestos risk relates to dose, we estimated the distribution of eight-hour TWA concentrations and one-year exposures (a one-year dose equivalent) to asbestos fibers (asbestos f/cc-years) for five groups of workers who may encounter dropped ceilings: specialists, generalists, maintenance workers, nonprofessional do-it-yourself (DIY) persons, and other tradespersons who are bystanders to ceiling work. Concentration data (asbestos f/cc) were obtained through two exposure assessment studies in the field and one chamber study. Bayesian and stochastic models were applied to estimate distributions of eight-hour TWAs and annual exposures (dose). The eight-hour TWAs for all work categories were below current and historic occupational exposure limits (OELs). Exposures to asbestos fibers from dropped ceiling work would be categorized as "highly controlled" for maintenance workers and "well controlled" for remaining work categories, according to the American Industrial Hygiene Association exposure control rating system. Annual exposures (dose) were found to be greatest for specialists, followed by maintenance workers, generalists, bystanders, and DIY. On a comparative basis, modeled dose and thus risk from dropped ceilings for all work categories were orders of magnitude lower than published exposures for other sources of banned friable asbestos-containing building material commonly encountered in construction trades. © 2016 The Authors Risk Analysis published by Wiley Periodicals, Inc. on behalf of Society for Risk Analysis.

Influence of salinity and temperature on acute toxicity of cadmium to Mysidopsis bahia molenock

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

Voyer, R.A.; Modica, G.

1990-01-01

Acute toxicity tests were conducted to compare estimates of toxicity, as modified by salinity and temperature, based on response surface techniques with those derived using conventional test methods, and to compare effect of a single episodic exposure to cadmium as a function of salinity with that of continuous exposure. Regression analysis indicated that mortality following continuous 96-hr exposure is related to linear and quadratic effects of salinity and cadmium at 20 C, and to the linear and quadratic effects of cadmium only at 25C. LC50s decreased with increases in temperature and decreases in salinity. Based on the regression model developed,more » 96-hr LC50s ranged from 15.5 to 28.0 micro Cd/L at 10 and 30% salinities, respectively, at 25C; and from 47 to 85 microgram Cd/L at these salinities at 20C.« less

Berkson error adjustment and other exposure surrogates in occupational case-control studies, with application to the Canadian INTEROCC study.

PubMed

Oraby, Tamer; Sivaganesan, Siva; Bowman, Joseph D; Kincl, Laurel; Richardson, Lesley; McBride, Mary; Siemiatycki, Jack; Cardis, Elisabeth; Krewski, Daniel

2018-05-01

Many epidemiological studies assessing the relationship between exposure and disease are carried out without data on individual exposures. When this barrier is encountered in occupational studies, the subject exposures are often evaluated with a job-exposure matrix (JEM), which consists of mean exposure for occupational categories measured on a comparable group of workers. One of the objectives of the seven-country case-control study of occupational exposure and brain cancer risk, INTEROCC, was to investigate the relationship of occupational exposure to electromagnetic fields (EMF) in different frequency ranges and brain cancer risk. In this paper, we use the Canadian data from INTEROCC to estimate the odds of developing brain tumours due to occupational exposure to EMF. The first step was to find the best EMF exposure surrogate among the arithmetic mean, the geometric mean, and the mean of log-normal exposure distribution for each occupation in the JEM, in comparison to Berkson error adjustments via numerical approximation of the likelihood function. Contrary to previous studies of Berkson errors in JEMs, we found that the geometric mean was the best exposure surrogate. This analysis provided no evidence that cumulative lifetime exposure to extremely low frequency magnetic fields increases brain cancer risk, a finding consistent with other recent epidemiological studies.

Exposure to psychosocial work factors in 31 European countries.

PubMed

Niedhammer, I; Sultan-Taïeb, H; Chastang, J-F; Vermeylen, G; Parent-Thirion, A

2012-04-01

Although psychosocial work factors are recognized as major occupational risk factors, little information is available regarding the prevalence of exposure to these factors and the differences in exposure between countries. To explore the differences in various psychosocial work exposures between 31 European countries. The study was based on a sample of 14,881 male and 14,799 female workers from the 2005 European Working Conditions Survey. Eighteen psychosocial work factors were studied: low decision latitude (skill discretion and decision authority), high psychological demands, job strain, low social support, iso-strain, physical violence, sexual harassment, bullying, discrimination, work-family imbalance, long working hours, high effort, job insecurity, low job promotion, low reward and effort-reward imbalance. Covariates were age, number of workers in household, occupation, economic activity, self-employed/employee, public/private sector and part/full time work. Statistical analysis was performed using multilevel logistic regression analysis. Significant differences in all psychosocial work factors were observed between countries. The rank of the countries varied according to the exposure considered. However, some countries, especially Denmark, Netherlands and Norway, displayed a significantly lower prevalence of exposure to four factors or more, while some Southern and Eastern countries, especially Czech Republic, Greece, Lithuania and Turkey, had a higher prevalence. Differences in psychosocial work exposures were found between countries. This study is the first to compare a large set of psychosocial work exposures between 31 European countries. These findings may be useful to guide prevention policies at European level.

Comparing milled fiber, Quebec ore, and textile factory dust: has another piece of the asbestos puzzle fallen into place?

PubMed

Berman, D Wayne

2010-01-01

Results of a meta-analysis indicate that the variation in potency factors observed across published epidemiology studies can be substantially reconciled (especially for mesothelioma) by considering the effects of fiber size and mineral type, but that better characterization of historical exposures is needed before improved exposure metrics potentially capable of fully reconciling the disparate potency factors can be evaluated. Therefore, an approach for better characterizing historical exposures, the Modified Elutriator Method (MEM), was evaluated to determine the degree that dusts elutriated using this method adequately mimic dusts generated by processing in a factory. To evaluate this approach, elutriated dusts from Grade 3 milled fiber (the predominant feedstock used at a South Carolina [SC] textile factory) were compared to factory dust collected at the same facility. Elutriated dusts from chrysotile ore were also compared to dusts collected in Quebec mines and mills. Results indicate that despite the substantial variation within each sample set, elutriated dusts from Grade 3 fiber compare favorably to textile dusts and elutriated ore dusts compare to dusts from mines and mills. Given this performance, the MEM was also applied to address the disparity in lung cancer mortality per unit of exposure observed, respectively, among chrysotile miners/millers in Quebec and SC textile workers. Thus, dusts generated by elutriation of stockpiled chrysotile ore (representing mine exposures) and Grade 3 milled fiber (representing textile exposures) were compared. Results indicate that dusts from each sample differ from one another. Despite such variation, however, the dusts are distinct and fibers in Grade 3 dusts are significantly longer than fibers in ore dusts. Moreover, phase-contrast microscopy (PCM) structures in Grade 3 dusts are 100% asbestos and counts of PCM-sized structures are identical, whether viewed by PCM or transmission electron microscope (TEM). In contrast, a third of PCM structures in ore dusts are not asbestos and only a third that are counted by PCM are also counted by TEM. These distinctions also mirror the characteristics of the bulk materials themselves. Perhaps most important, when the differences in size distributions and PCM/TEM distinctions in these dusts are combined, the combined difference is sufficient to completely explain the difference in exposure/response observed between the textile worker and miner/miller cohorts. Importantly, however, evidence that such an explanation is valid can only be derived from a meta-analysis (risk assessment) covering a diverse range of epidemiology study environments, which is beyond the scope of the current study. The above findings suggest that elutriator-generated dusts mimic factory dusts with sufficient reliability to support comparisons between historical exposures experienced by the various cohorts studied by epidemiologists. A simulation was also conducted to evaluate the relative degree that the characteristics of dust are driven by the properties of the bulk material processed versus the nature of the mechanical forces applied. That results indicate it is the properties of bulk materials reinforces the theoretical basis justifying use of the elutriator to reconstruct historical exposures. Thus, the elutriator may be a valuable tool for reconstructing historical exposures suitable for supporting continued refinements of the risk models being developed to predict asbestos-related cancer risk.

Efficacy of exposure versus cognitive therapy in anxiety disorders: systematic review and meta-analysis

PubMed Central

2011-01-01

Background There is growing evidence of the effectiveness of Cognitive Behavioural Therapy (CBT) for a wide range of psychological disorders. There is a continued controversy about whether challenging maladaptive thoughts rather than use of behavioural interventions alone is associated with the greatest efficacy. However little is known about the relative efficacy of various components of CBT. This review aims to compare the relative efficacy of Cognitive Therapy (CT) versus Exposure (E) for a range of anxiety disorders using the most clinically relevant outcome measures and estimating the summary relative efficacy by combining the studies in a meta-analysis. Methods Psych INFO, MEDLINE and EMBASE were searched from the first available year to May 2010. All randomised controlled studies comparing the efficacy of exposure with cognitive therapy were included. Odds ratios (OR) or standardised means' differences (Hedges' g) for the most clinically relevant primary outcomes were calculated. Outcomes of the studies were grouped according to specific disorders and were combined in meta-analyses exploring short-term and long-term outcomes. Results 20 Randomised Controlled Trials with (n = 1,308) directly comparing the efficacy of CT and E in anxiety disorders were included in the meta-analysis. No statistically significant difference in the relative efficacy of CT and E was revealed in Post Traumatic Stress Disorder (PTSD), in Obsessive Compulsive Disorder (OCD) and in Panic Disorder (PD). There was a statistically significant difference favouring CT versus E in Social Phobia both in the short-term (Z = 3.72, p = 0.0002) and the long-term (Z = 3.28, p = 0.001) outcomes. Conclusions On the basis of extant literature, there appears to be no evidence of differential efficacy between cognitive therapy and exposure in PD, PTSD and OCD and strong evidence of superior efficacy of cognitive therapy in social phobia PMID:22185596

BME Estimation of Residential Exposure to Ambient PM10 and Ozone at Multiple Time Scales

PubMed Central

Yu, Hwa-Lung; Chen, Jiu-Chiuan; Christakos, George; Jerrett, Michael

2009-01-01

Background Long-term human exposure to ambient pollutants can be an important contributing or etiologic factor of many chronic diseases. Spatiotemporal estimation (mapping) of long-term exposure at residential areas based on field observations recorded in the U.S. Environmental Protection Agency’s Air Quality System often suffer from missing data issues due to the scarce monitoring network across space and the inconsistent recording periods at different monitors. Objective We developed and compared two upscaling methods: UM1 (data aggregation followed by exposure estimation) and UM2 (exposure estimation followed by data aggregation) for the long-term PM10 (particulate matter with aerodynamic diameter ≤ 10 μm) and ozone exposure estimations and applied them in multiple time scales to estimate PM and ozone exposures for the residential areas of the Health Effects of Air Pollution on Lupus (HEAPL) study. Method We used Bayesian maximum entropy (BME) analysis for the two upscaling methods. We performed spatiotemporal cross-validations at multiple time scales by UM1 and UM2 to assess the estimation accuracy across space and time. Results Compared with the kriging method, the integration of soft information by the BME method can effectively increase the estimation accuracy for both pollutants. The spatiotemporal distributions of estimation errors from UM1 and UM2 were similar. The cross-validation results indicated that UM2 is generally better than UM1 in exposure estimations at multiple time scales in terms of predictive accuracy and lack of bias. For yearly PM10 estimations, both approaches have comparable performance, but the implementation of UM1 is associated with much lower computation burden. Conclusion BME-based upscaling methods UM1 and UM2 can assimilate core and site-specific knowledge bases of different formats for long-term exposure estimation. This study shows that UM1 can perform reasonably well when the aggregation process does not alter the spatiotemporal structure of the original data set; otherwise, UM2 is preferable. PMID:19440491

Occupational and environmental lead exposure in Port Harcourt, Nigeria: analysis of its association with renal function indices.

PubMed

Alasia, D D; Emem-Chioma, P C; Wokoma, F S

2010-01-01

In spite of the high risk of lead exposure in Nigeria, there is a paucity of data on the occupational and environmental burden of lead exposure and its impact on human health especially its nephrotoxic effects. This study aims to assess the degree of occupational and environmental lead exposure in Port Harcourt Nigeria and the relationship between lead exposure and indices of renal function. A cross sectional comparative study of 190 aduIt subjects with occupational lead exposure and 80 matched controls. Blood lead was used as the biomarker of lead exposure. Serum urea, creatinine, uric acid, urine albumin and glomerular filtration rate were the renal function indices measured. Occupationally lead exposed subjects had higher mean blood lead 50.37 +/- 24.58 ug/dI, than controls 41.40 +/- 26.85 ug/dl (p = 0.008). The mean values of serum urea, creatinine and uric acid were significantly higher in study subjects compared to controls 3.06 +/- 0.81 mmol/L vs. 2.7 +/- 0.84 mmol/L (p = 0.002), 87.2 +/- 14.30 umol/L vs. 80.68 +/- 14.70 umol/L (p = 0.001) and 271.93 +/- 71.18 umol/L vs. 231.1 +/- 62.70 umol/L (p = 0.000) respectively. Creatinine clearance was significantly lower in subjects compared to controls 98.86 +/- 21.26 mI/min/1.72m2 vs. 108.18 +/- 25.16 mI/min/1.72m2 (p = 0.002). Blood lead correlated positively only with blood urea [r = .031, r2 = .017, p = .031] and negatively [r = -.144, r2 = .02 1, p = .018] with serum phosphate. The level of environmental and occupational lead exposure in Port Harcourt, Nigeria is high, with occupational lead exposure increasing the risk of lead toxicity and renal function impairment.

[Prenatal lead exposure related to cord blood brain derived neurotrophic factor (BDNF) levels and impaired neonatal neurobehavioral development].

PubMed

Ren, L H; Mu, X Y; Chen, H Y; Yang, H L; Qi, W

2016-06-01

To explore the relationship between umbilical cord blood brain-derived neurotrophic factor (BDNF) and neonatal neurobehavioral development in lead exposure infants. All infants and their mother were randomly selected during 2011 to 2012, subjects were selected according to the umbilical cord blood lead concentrations, which contcentration of lead was higher than 0.48 μmol/L were taken into high lead exposure group, about 60 subjects included. Comparing to the high lead exposure group, according to gender, weight, pregnant week, length and head circumferenece, the level of cord blood lead concentration under 0.48 μmol/L were taken into control group, 60 cases included. Lead content was determined by graphite furnace atomic absorption spectrometry. Neonatal behavioral neurological assessment (NBNA) was used to determine the development of neonatal neuronal behavior. The content of BDNF was detected by ELISA. Comparing the BDNF and the NBNA score between two groups, and linear correlation was given on analysis the correlation between lead concentration in cord blood and BDNF, BDNF and the NBNA score. Lead content in high exposure group was (0.613±0.139) μmol/L, and higher than (0.336±0.142) μmol/L in low exposure group (t=3.21, P<0.001) . NBNA summary score (36.35±1.86), active muscle tension score (6.90±0.27) and general assessment score (5.93±0.32) in high exposure group were lower than those (38.13±0.96, 7.79±0.35, 6.00±0.00) in low exposure group (t values were 8.21, 10.23, 2.32, respectively, P values were <0.001, <0.001 and 0.037) . BDNF content in high exposure group which was (3.538±1.203) ng/ml was higher than low exposure group (2.464±0.918) ng/ml (t=7.60, P<0.001). The correlation analysis found that the cord blood BDNF content was negatively correlated with NBNA summary score, passive muscle tension and active muscle tone score (r was -0.27, -0.29, -0.30, respectively, P values were <0.001, respectively) . Prenatal lead exposure results poor neonatal neurobehavioral development and cord blood BDNF was negatively correlated with neonatal neurodevelopment, may serve as a useful biomarker.

A review of job-exposure matrix methodology for application to workers exposed to radiation from internally deposited plutonium or other radioactive materials.

PubMed

Liu, Hanhua; Wakeford, Richard; Riddell, Anthony; O'Hagan, Jacqueline; MacGregor, David; Agius, Raymond; Wilson, Christine; Peace, Mark; de Vocht, Frank

2016-03-01

Any potential health effects of radiation emitted from radionuclides deposited in the bodies of workers exposed to radioactive materials can be directly investigated through epidemiological studies. However, estimates of radionuclide exposure and consequent tissue-specific doses, particularly for early workers for whom monitoring was relatively crude but exposures tended to be highest, can be uncertain, limiting the accuracy of risk estimates. We review the use of job-exposure matrices (JEMs) in peer-reviewed epidemiological and exposure assessment studies of nuclear industry workers exposed to radioactive materials as a method for addressing gaps in exposure data, and discuss methodology and comparability between studies. We identified nine studies of nuclear worker cohorts in France, Russia, the USA and the UK that had incorporated JEMs in their exposure assessments. All these JEMs were study or cohort-specific, and although broadly comparable methodologies were used in their construction, this is insufficient to enable the transfer of any one JEM to another study. Moreover there was often inadequate detail on whether, or how, JEMs were validated. JEMs have become more detailed and more quantitative, and this trend may eventually enable better comparison across, and the pooling of, studies. We conclude that JEMs have been shown to be a valuable exposure assessment methodology for imputation of missing exposure data for nuclear worker cohorts with data not missing at random. The next step forward for direct comparison or pooled analysis of complete cohorts would be the use of transparent and transferable methods.

A study of the effect of relaxing music on heart rate recovery after exercise among healthy students.

PubMed

Tan, Fuitze; Tengah, Asrin; Nee, Lo Yah; Fredericks, Salim

2014-05-01

Music has been employed in various clinical settings to reduce anxiety. However, meta-analysis has shown music to have little influence on haemodynamic parameters. This study aimed at investigating the effect of relaxing music on heart rate recovery after exercise. Twenty-three student volunteers underwent treadmill exercise and were assessed for heart rate recovery and saliva analysis; comparing exposure to sedative music with exposure to silence during the recovery period immediately following exercise. No differences were found between music and non-music exposure regarding: heart rate recovery, resting pulse rate, and salivary cortisol. Music was no different to silence in affecting these physiological measures, which are all associated with anxiety. Relaxing music unaccompanied by meditation techniques or other such interventions may not have a major role in reducing anxiety in certain experimental settings. Copyright © 2014 Elsevier Ltd. All rights reserved.

Exposure to Hypoxia at High Altitude (5380 m) for 1 Year Induces Reversible Effects on Semen Quality and Serum Reproductive Hormone Levels in Young Male Adults.

PubMed

He, Jiang; Cui, Jianhua; Wang, Rui; Gao, Liang; Gao, Xiaokang; Yang, Liu; Zhang, Qiong; Cao, Jinjun; Yu, Wuzhong

2015-09-01

This study investigated the effect of hypoxia at high altitude on the semen quality and the serum reproductive hormone levels in male adults. A total of 52 male soldiers were enrolled in this cohort study. They were exposed to hypoxia at high altitude (5380 m) for 12 months when undergoing a service. After exposure, they were followed up for 6 months. The samples of semen and peripheral blood were collected at 1 month before exposure (M0), 6 months of exposure (M6), 12 months of exposure (M12), and 6 months after exposure (M18). The semen quality was assessed with computer-assisted analysis system, and the serum levels of reproductive hormones, including prolactin (PRL), luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone were analyzed by ELISA. Compared with those at M0, total sperm count, sperm density, motility, survival rate, and serum levels of LH, PRL and testosterone were significantly decreased, whereas the liquefaction time was significantly prolonged and serum FSH level was significantly increased at M6 (p<0.05). At M12, total sperm count and sperm density increased, whereas sperm motility, survival rate, and the liquefaction time further decreased. Sperm velocities, progression ratios, and lateral head displacements were also decreased. Serum FSH level decreased while serum LH, PRL, and testosterone levels increased. Compared with those at M6, the changes in these detected parameters of semen and hormone at M12 were significant (p<0.05). At M18, all these detected parameters except testosterone level returned to levels comparable to those before exposure. In conclusion, hypoxia at high altitude causes adverse effects on semen quality and reproductive hormones, and these effects are reversible.

Associations of lifetime active and passive smoking with spontaneous abortion, stillbirth and tubal ectopic pregnancy: a cross-sectional analysis of historical data from the Women's Health Initiative.

PubMed

Hyland, Andrew; Piazza, Kenneth M; Hovey, Kathleen M; Ockene, Judith K; Andrews, Christopher A; Rivard, Cheryl; Wactawski-Wende, Jean

2015-07-01

To examine the associations between tobacco exposure and adverse pregnancy outcomes using quantitative measures of lifetime active smoking and secondhand smoke (SHS) exposure. Historical reproductive data on 80 762 women who participated in the Women's Health Initiative Observational Study were examined with a cross-sectional analysis. We assessed self-reported lifetime active and passive tobacco smoke exposure, self-reported spontaneous abortions, stillbirths and ectopic pregnancies. When compared with never-smoking women, participants who were ever active smokers during their reproductive years had ORs (OR) of 1.16 (95% CI 1.08 to 1.26) for 1 or more spontaneous abortions, 1.44 (95% CI 1.20 to 1.73) for 1 or more stillbirths, and 1.43 (95% CI 1.10 to 1.86) for 1 or more ectopic pregnancies. Never-smoking women participants with the highest levels of lifetime SHS exposure, including childhood >10 years, adult home >20 years and adult work exposure >10 years, when compared with never-smoking women with no SHS exposure had adjusted ORs of 1.17 (95% CI 1.05 to 1.30) for spontaneous abortion, 1.55 (95% CI 1.21 to 1.97) for stillbirth, and 1.61 (95% CI 1.16 to 2.24) for ectopic pregnancy. Women who were ever-smokers during their reproductive years had significantly greater estimates of risk for spontaneous abortion, stillbirth and tubal ectopic pregnancy. Never-smoking women with the highest levels of lifetime exposure to SHS had significantly increased estimates of risk for spontaneous abortion, stillbirth and tubal ectopic pregnancy. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Child development following in utero exposure

PubMed Central

Shallcross, R.; Bromley, R.L.; Irwin, B.; Bonnett, L.J.; Morrow, J.

2011-01-01

Objective: Children born to women with epilepsy (WWE), exposed in utero to levetiracetam (LEV, n = 51), were assessed for early cognitive development and compared to children exposed to sodium valproate in utero (VPA, n = 44) and a group of children representative of the general population (n = 97). Methods: Children were recruited prospectively from 2 cohorts in the United Kingdom and assessed using the Griffiths Mental Development Scale (1996), aged <24 months. Information regarding maternal demographics were collected and controlled for. This is an observational study with researchers not involved in the clinical management of the WWE. Results: On overall developmental ability, children exposed to LEV obtained higher developmental scores when compared to children exposed to VPA (p < 0.001). When compared, children exposed to LEV did not differ from control children (p = 0.62) on overall development. Eight percent of children exposed to LEV in utero fell within the below average range (DQ score of <84), compared with 40% of children exposed to VPA. After controlling for maternal epilepsy and demographic factors using linear regression analysis, exposure to LEV in utero was not associated with outcome (p = 0.67). Conversely, when compared with VPA exposure, LEV exposure was associated with higher scores for the overall developmental quotient (p < 0.001). Conclusion: Children exposed to LEV in utero are not at an increased risk of delayed early cognitive development under the age of 24 months. LEV may therefore be a preferable drug choice, where appropriate, for WWE prior to and of childbearing age. PMID:21263139

The influence of occupational exposure to pesticides, polycyclic aromatic hydrocarbons, diesel exhaust, metal dust, metal fumes, and mineral oil on prostate cancer: a prospective cohort study.

PubMed

Boers, D; Zeegers, M P A; Swaen, G M; Kant, Ij; van den Brandt, P A

2005-08-01

To investigate the relation between exposure to pesticides, polycyclic aromatic hydrocarbons (PAHs), diesel exhaust, metal dust, metal fumes, and mineral oil in relation to prostate cancer incidence in a large prospective study. This cohort study was conducted among 58,279 men in the Netherlands. In September 1986, cohort members (55-69 years) completed a self-administered questionnaire on potential cancer risk factors, including job history. Follow up for prostate cancer incidence was established by linkage to cancer registries until December 1995 (9.3 years of follow up). The analyses included 1386 cases of prostate cancer and 2335 subcohort members. A blinded case-by-case expert exposure assessment was carried out to assign cases and subcohort members a cumulative probability of exposure for each potential carcinogenic exposure. In multivariate analyses there was a significant negative association for pesticides (RR 0.60; 95% CI 0.37 to 0.95) when comparing the highest tertile of exposure to pesticides with no exposure. No association was found for occupational exposure to PAHs (RR 0.75; 95% CI 0.42 to 1.31), diesel exhaust (RR 0.81; 95% CI 0.62 to 1.06), metal dust (RR 1.01; 95% CI 0.72 to 1.40), metal fumes (RR 1.11; 95% CI 0.80 to 1.54), or mineral oil (RR 0.99; 95% CI 0.66 to 1.48) when comparing the highest tertile of exposure with no exposure. In subgroup analysis, with respect to tumour invasiveness and morphology, null results were found for occupational exposure to pesticides, PAH, diesel exhaust, metal dust, metal fumes, and mineral oil. These results suggest a negative association between occupational exposure to pesticides and prostate cancer. For other carcinogenic exposures results suggest no association between occupational exposure to PAHs, diesel exhaust, metal dust, metal fumes, or mineral oil and prostate cancer.

Whole-body vibration and the risk of low back pain and sciatica: a systematic review and meta-analysis.

PubMed

Burström, Lage; Nilsson, Tohr; Wahlström, Jens

2015-05-01

The aim of this systematic literature review was to evaluate the association between whole-body vibration (WBV) and low back pain (LBP) and sciatica with special attention given to exposure estimates. Moreover, the aim was to estimate the magnitude of such an association using meta-analysis and to compare our findings with previous reviews. The authors systematically searched the PubMed (National Library of Medicine, Bethesda), Nioshtic2 (National Institute for Occupational Safety and Health (NIOSH, Morgantown), and ScienceDirect (Elsevier, Amsterdam) databases for records up to December 31, 2013. Two of the authors independently assessed studies to determine their eligibility, validity, and possible risk of bias. The literature search gave a total of 306 references out of which 28 studies were reviewed and 20 were included in the meta-analysis. Exposure to WBV was associated with increased prevalence of LBP and sciatica [pooled odds ratio (OR) = 2.17, 95% confidence interval (CI) 1.61-2.91 and OR 1.92, 95% CI 1.38-2.67, respectively]. Workers exposed to high vibration levels had a pooled risk estimate of 1.5 for both outcomes when compared with workers exposed to low levels of vibration. The results also indicate that some publication bias could have occurred especially for sciatica. This review shows that there is scientific evidence that exposure to WBV increases the risk of LBP and sciatica.

The Prevalence of Exposure to Workplace Secondhand Smoke in the United States: 2010 to 2015.

PubMed

Dai, Hongying; Hao, Jianqiang

2017-11-01

To compare changes in exposure to workplace secondhand smoke (SHS) by industry of employment and occupation from 2010 to 2015. Data were collected from 2010 and 2015 National Health Interview Survey. Weighted estimates of the prevalence of exposure to workplace SHS among currently working nonsmokers in 2010 (n = 12 627) and 2015 (n = 16 399) were compared. The prevalence of exposure to workplace SHS among currently working nonsmokers was 10.0% in 2015 and 9.5% in 2010. Exposure to workplace SHS is disproportionally high among male workers, young workers, non-Hispanic blacks, Hispanics, workers with low education and low income, and workers residing in the Southern United States. Tobacco control policies have effectively reduced exposure to workplace SHS in a few white-collar and service job categories but blue-collar workers remain to have a high prevalence of exposure to workplace SHS. From 2010 to 2015, "transportation and warehousing industries" had the largest increase in SHS exposure (13.3%-21.5%, p value = .004) and "arts, entertainment, and recreation industries" had the largest decline in prevalence of exposure to SHS (20.1%-11.5%, p value = .01). In the multivariate analysis, workers with service (aOR = 1.4, p < .0001) and blue-collar occupations (aOR = 2.5, p < .0001) had a significantly higher prevalence of exposure to workplace SHS than those with white-collar occupations. Disparities of SHS exposure by industry, occupation, and social demographic class continue to exist. Blue-collar workers, especially those working in "transportation and construction industries," along with young workers and workers in high risk social classes are priority groups for future workplace SHS prevention. An estimated 12.6 million working nonsmokers were regularly exposed to SHS at work in 2015. We compared the changes in prevalence of exposure to workplace SHS from 2010 to 2015 by social demographic class, industry of employment and occupation. Our findings could help inform the policymakers and health practitioners to establish stronger smoke-free air laws and conduct education campaigns to reduce the exposure to workplace SHS, especially among certain industries and occupations with a disproportionally high prevalence of exposure to workplace SHS. © The Author 2016. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Exposure to pesticides and diabetes: A systematic review and meta-analysis.

PubMed

Evangelou, Evangelos; Ntritsos, Georgios; Chondrogiorgi, Maria; Kavvoura, Fotini K; Hernández, Antonio F; Ntzani, Evangelia E; Tzoulaki, Ioanna

2016-05-01

Diabetes mellitus has a multifactorial pathogenesis with a strong genetic component as well as many environmental and lifestyle influences. Emerging evidence suggests that environmental contaminants, including pesticides, might play an important role in the pathogenesis of diabetes. We performed a systematic review and meta-analysis of observational studies that assessed the association between exposure to pesticides and diabetes and we examined the presence of heterogeneity and biases across available studies. A comprehensive literature search of peer-reviewed original research pertaining to pesticide exposure and diabetes, published until 30st May 2015, with no language restriction, was conducted. Eligible studies were those that investigated potential associations between pesticides and diabetes without restrictions on diabetes type. We included cohort studies, case-control studies and cross-sectional studies. We extracted information on study characteristics, type of pesticide assessed, exposure assessment, outcome definition, effect estimate and sample size. We identified 22 studies assessing the association between pesticides and diabetes. The summary OR for the association of top vs. bottom tertile of exposure to any type of pesticide and diabetes was 1.58 (95% CI: 1.32-1.90, p=1.21×10(-6)), with large heterogeneity (I(2)=66.8%). Studies evaluating Type 2 diabetes in particular (n=13 studies), showed a similar summary effect comparing top vs. bottom tertiles of exposure: 1.61 (95% CI 1.37-1.88, p=3.51×10(-9)) with no heterogeneity (I(2)=0%). Analysis by type of pesticide yielded an increased risk of diabetes for DDE, heptachlor, HCB, DDT, and trans-nonachlor or chlordane. The epidemiological evidence, supported by mechanistic studies, suggests an association between exposure to organochlorine pesticides and Type 2 diabetes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Civil construction work: The unseen contributor to the occupational and global disease burden

PubMed Central

Sitalakshmi, R.; Saikumar, P.; Jeyachandran, P.; Manoharan; Thangavel; Thomas, Jayakar

2016-01-01

Background: Construction industry is the second largest employment giving industry in India with many semi-skilled or unskilled workers taking up the occupation for livelihood without any training and proper guidance. Aim: To evaluate the pathogenic association of cement exposure to occupational contact dermatoses as evidenced by immune markers and to correlate their pulmonary functions with years of exposure to cement. Setting and Design: This was a cross-sectional study conducted among randomly selected cement workers. Methods and material: Evaluation of socioeconomic status (SES) and years of exposure of cement workers was done using a questionnaire. Clinical examination of skin lesions and strip patch test with application of potassium dichromate on unexposed skin was performed. Results were interpreted after 48 hours. Absolute eosinophil count (AEC) and IgE levels measured, and spirometric evaluation was performed. Statistical Analysis: Analysis of variance and Pearson's correlation test were used for data analysis. P < 0.05 was considered to be statistically significant. Results: Clinically, skin lesions were noticed in 51%, elevated AEC in 47%, and raised Anti IgE in 73%. Two participants developed positive reactions to the skin strip patch test. Duration of exposure to cement and SES were compared with clinical skin lesions. Spirometry result was normal in 81%, obstruction in 8%, restriction in 10%, and mixed pattern in 1%. Forced expiratory volume at 1.0 second, forced expiratory flow (25–75%), and  (PEFR) Peak Expiratory Flow Rate were markedly reduced with years of exposure. Workers who had greater skin lesions and with increase in exposure had increased AEC and IgE levels, although statistically not significant. Conclusions: Exposure to cement and poor SES is strongly correlated to increased prevalence of skin lesions and reduced pulmonary functions. PMID:28194084

Dream recall and dream content in obsessive-compulsive patients: is there a change during exposure treatment?

PubMed

Kuelz, Anne K; Stotz, Ulrike; Riemann, Dieter; Schredl, Michael; Voderholzer, Ulrich

2010-08-01

Very little is known about dreams in patients with obsessive compulsive disorder, especially regarding changes over the course of treatment with stimulus exposure and response prevention. By use of dream content analysis, 40 dreams of 9 obsessive compulsive (OC) inpatients were compared with 84 dreams of 10 matched OC outpatients and 63 dreams of 11 healthy control participants. Dream protocols of inpatients were collected at the beginning of treatment and after the first exposure exercises. Controls filled in dream protocols in respective intervals. Before treatment, dreams of patients showed significantly less positive contents than dreams of healthy controls. Under treatment with exposure, a significant reduction of OC themes was observed. The findings support the continuity hypothesis of dreaming by showing a link between day-time symptoms and OC symptoms in dreams. Contrary to expectations, however, exposure treatment does not intensify dreams.

Control technology for crystalline silica exposures in construction: wet abrasive blasting.

PubMed

Golla, Vijay; Heitbrink, William

2004-03-01

This study was designed to document the effect that wet abrasive blasting has on reducing worker exposure to crystalline silica, which has been associated with silicosis and premature death. In this study, worker exposure to respirable crystalline silica was monitored during wet abrasive blasting on the exterior walls of a parking garage to remove surface concrete and expose the underlying aggregate. In this process a wet sand mix comprised of 80% dry sand and 20% water was used. Sampling and analysis revealed that the geometric mean respirable quartz concentration was 0.2 mg/m(3) for workers conducting abrasive blasting and 0.06 mg/m(3) for helpers. When abrasive blasting was conducted in areas that apparently had reduced natural ventilation, dust exposures appeared to increase. When compared with other published data, this case study suggests that wet abrasive blasting causes less exposure to crystalline silica than dry abrasive blasting.

Arsenic exposure and oral cavity lesions in Bangladesh.

PubMed

Syed, Emdadul H; Melkonian, Stephanie; Poudel, Krishna C; Yasuoka, Junko; Otsuka, Keiko; Ahmed, Alauddin; Islam, Tariqul; Parvez, Faruque; Slavkovich, Vesna; Graziano, Joseph H; Ahsan, Habibul; Jimba, Masamine

2013-01-01

To evaluate the relationship between arsenic exposure and oral cavity lesions among an arsenic-exposed population in Bangladesh. We carried out an analysis utilizing the baseline data of the Health Effects of Arsenic Exposure Longitudinal Study, which is an ongoing population-based cohort study to investigate health outcomes associated with arsenic exposure via drinking water in Araihazar, Bangladesh. We used multinomial regression models to estimate the risk of oral cavity lesions. Participants with high urinary arsenic levels (286.1 to 5000.0 μg/g) were more likely to develop arsenical lesions of the gums (multinomial odds ratio = 2.90; 95% confidence interval, 1.11 to 7.54), and tongue (multinomial odds ratio = 2.79; 95% confidence interval, 1.51 to 5.15), compared with those with urinary arsenic levels of 7.0 to 134.0 μg/g. Higher level of arsenic exposure was positively associated with increased arsenical lesions of the gums and tongue.

Effect of thermal exposure on the residual stress relaxation in a hardened cylindrical sample under creep conditions

NASA Astrophysics Data System (ADS)

Radchenko, V. P.; Saushkin, M. N.; Tsvetkov, V. V.

2016-05-01

This paper describes the effect of thermal exposure (high-temperature exposure) ( T = 675°C) on the residual creep stress relaxation in a surface hardened solid cylindrical sample made of ZhS6UVI alloy. The analysis is carried out with the use of experimental data for residual stresses after micro-shot peening and exposures to temperatures equal to T = 675°C during 50, 150, and 300 h. The paper presents the technique for solving the boundary-value creep problem for the hardened cylindrical sample with the initial stress-strain state under the condition of thermal exposure. The uniaxial experimental creep curves obtained under constant stresses of 500, 530, 570, and 600 MPa are used to construct the models describing the primary and secondary stages of creep. The calculated and experimental data for the longitudinal (axial) tensor components of residual stresses are compared, and their satisfactory agreement is determined.

Olfactory function in painters exposed to organic solvents.

PubMed

Sandmark, B; Broms, I; Löfgren, L; Ohlson, C G

1989-02-01

The olfactory receptor cells are in direct contact with the exterior environment, and some chemical agents can impair olfactory function. The olfactory function of 54 painters exposed to organic solvents was compared with that of 42 unexposed referents. A new clinical test validated for the sense of smell was used, the University of Pennsylvania Smell Identification Test. Age, smoking habits, exposure to organic solvents, and medical disorders of importance for the sense of smell were recorded. The painters had a somewhat lower test score than the referents. However, the influence of the exposure variable was not statistically significant in a multiple regression analysis including age and smoking habits. The exposure to organic solvents was low, and therefore an effect of high exposure on olfactory function cannot be ruled out. Since some of the painters had earlier been highly exposed, the effects of high exposure are likely to be reversible.

Quantitative plasma biomarker analysis in HDI exposure assessment.

PubMed

Flack, Sheila L; Fent, Kenneth W; Trelles Gaines, Linda G; Thomasen, Jennifer M; Whittaker, Steve; Ball, Louise M; Nylander-French, Leena A

2010-01-01

Quantification of amines in biological samples is important for evaluating occupational exposure to diisocyanates. In this study, we describe the quantification of 1,6-hexamethylene diamine (HDA) levels in hydrolyzed plasma of 46 spray painters applying 1,6-hexamethylene diisocyanate (HDI)-containing paint in vehicle repair shops collected during repeated visits to their workplace and their relationship with dermal and inhalation exposure to HDI monomer. HDA was detected in 76% of plasma samples, as heptafluorobutyryl derivatives, and the range of HDA concentrations was < or =0.02-0.92 microg l(-1). After log-transformation of the data, the correlation between plasma HDA levels and HDI inhalation exposure measured on the same workday was low (N = 108, r = 0.22, P = 0.026) compared with the correlation between plasma HDA levels and inhalation exposure occurring approximately 20 to 60 days before blood collection (N = 29, r = 0.57, P = 0.0014). The correlation between plasma HDA levels and HDI dermal exposure measured on the same workday, although statistically significant, was low (N = 108, r = 0.22, P = 0.040) while the correlation between HDA and dermal exposure occurring approximately 20 to 60 days before blood collection was slightly improved (N = 29, r = 0.36, P = 0.053). We evaluated various workplace factors and controls (i.e. location, personal protective equipment use and paint booth type) as modifiers of plasma HDA levels. Workers using a downdraft-ventilated booth had significantly lower plasma HDA levels relative to semi-downdraft and crossdraft booth types (P = 0.0108); this trend was comparable to HDI inhalation and dermal exposure levels stratified by booth type. These findings indicate that HDA concentration in hydrolyzed plasma may be used as a biomarker of cumulative inhalation and dermal exposure to HDI and for investigating the effectiveness of exposure controls in the workplace.

Time to revisit arsenic regulations: comparing drinking water and rice.

PubMed

Sauvé, Sébastien

2014-05-17

Current arsenic regulations focus on drinking water without due consideration for dietary uptake and thus seem incoherent with respect to the risks arising from rice consumption. Existing arsenic guidelines are a cost-benefit compromise and, as such, they should be periodically re-evaluated. Literature data was used to compare arsenic exposure from rice consumption relative to exposure arising from drinking water. Standard risk assessment paradigms show that arsenic regulations for drinking water should target a maximum concentration of nearly zero to prevent excessive lung and bladder cancer risks (among others). A feasibility threshold of 3 μg As l(-1) was determined, but a cost-benefit analysis concluded that it would be too expensive to target a threshold below 10 μg As l(-1). Data from the literature was used to compare exposure to arsenic from rice and rice product consumption relative to drinking water consumption. The exposure to arsenic from rice consumption can easily be equivalent to or greater than drinking water exposure that already exceeds standard risks and is based on feasibility and cost-benefit compromises. It must also be emphasized that many may disagree with the implications for their own health given the abnormally high cancer odds expected at the cost-benefit arsenic threshold. Tighter drinking water quality criteria should be implemented to properly protect people from excessive cancer risks. Food safety regulations must be put in place to prevent higher concentrations of arsenic in various drinks than those allowed in drinking water. Arsenic concentrations in rice should be regulated so as to roughly equate the risks and exposure levels observed from drinking water.

Urinary porphyrin excretion in neurotypical and autistic children.

PubMed

Woods, James S; Armel, Sarah E; Fulton, Denise I; Allen, Jason; Wessels, Kristine; Simmonds, P Lynne; Granpeesheh, Doreen; Mumper, Elizabeth; Bradstreet, J Jeffrey; Echeverria, Diana; Heyer, Nicholas J; Rooney, James P K

2010-10-01

Increased urinary concentrations of pentacarboxyl-, precopro- and copro-porphyrins have been associated with prolonged mercury (Hg) exposure in adults, and comparable increases have been attributed to Hg exposure in children with autism (AU). This study was designed to measure and compare urinary porphyrin concentrations in neurotypical (NT) children and same-age children with autism, and to examine the association between porphyrin levels and past or current Hg exposure in children with autism. This exploratory study enrolled 278 children 2-12 years of age. We evaluated three groups: AU, pervasive developmental disorder-not otherwise specified (PDD-NOS), and NT. Mothers/caregivers provided information at enrollment regarding medical, dental, and dietary exposures. Urine samples from all children were acquired for analyses of porphyrin, creatinine, and Hg. Differences between groups for mean porphyrin and Hg levels were evaluated. Logistic regression analysis was conducted to determine whether porphyrin levels were associated with increased risk of autism. Mean urinary porphyrin concentrations are naturally high in young children and decline by as much as 2.5-fold between 2 and 12 years of age. Elevated copro- (p < 0.009), hexacarboxyl- (p < 0.01) and pentacarboxyl- (p < 0.001) porphyrin concentrations were significantly associated with AU but not with PDD-NOS. No differences were found between NT and AU in urinary Hg levels or in past Hg exposure as determined by fish consumption, number of dental amalgam fillings, or vaccines received. These findings identify disordered porphyrin metabolism as a salient characteristic of autism. Hg exposures were comparable between diagnostic groups, and a porphyrin pattern consistent with that seen in Hg-exposed adults was not apparent.

[Pediatric exposures to laundry pods or capsules: more toxic than traditional laundry products?].

PubMed

Claudet, I; Honorat, R; Casasoprana, A; Grouteau, E; Franchitto, N

2014-06-01

New concentrated laundry pods, available on the European market for approximately 10 years, are associated with more severe intoxications compared to classic laundry detergents. To compare symptoms and severity after exposure to classic laundry detergents and new laundry pods in a pediatric population. Retrospective study conducted between 1st January 2002 and 30th June 2013 including all laundry detergent exposure patients admitted to our tertiary level pediatric emergency unit. Collected data were age, sex, date, time and location of exposure, type of product (powder, liquid, tablets, pods), estimated ingested quantity, time of admission, clinical symptoms, severity, complications, and progression. Descriptive analysis: eighty-nine children were included. The mean age was 2.1 ± 1.5 years (range, 36 days to 10 years), 65% of patients were aged less than 2 years. The male:female ratio was 1.5 (males, 60%). After exposure, 57% of children were symptomatic and most frequently developed digestive symptoms (75%). Comparative analysis: compared to classic laundry detergent, children exposed to laundry pods were more symptomatic (96% versus 51%, P<0.0001), had more digestive signs (P=0.003), more frequently had bronchospasm (P=0.02), had a higher risk of ocular lesions (P=0.04), and exposure was more severe (poisoning severity score grade 2, 92% versus 59%, P<0.0001). Laundry pod toxicity is more severe. The chemical composition of laundry pods has a higher concentration of surfactants and ethoxylated alcohols; they have a higher viscosity and hydrotropic power. The addition of water seems to modify the alkalinity, which explains the severity of ENT, gastric, and corneal lesions. The declaration to national poison centers of these intoxications should be pursued by emergency pediatricians, physicians, and pediatric intensivists. Family physicians can encourage parents to declare adverse effects to the National Consumer Product Safety Commission. Parents need to be better informed of the risk of laundry pods and strictly keep this type of product out of the reach of children. Given that it took 7 years after the first warning by the French poison centers to obtain safety recommendations for manufacturers, it is important to maintain pressure on companies to obtain the necessary modification of the physicochemical properties and child-resistant packaging. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Socioeconomic factors and home allergen exposure in children with asthma.

PubMed

Ungar, Wendy J; Cope, Shannon F; Kozyrskyj, Anita; Paterson, J Michael

2010-01-01

The objective of this study was to determine the association between sociodemographic factors and the elimination of allergen sources from homes of asthmatic children. In a cross-sectional analysis of data from 845 asthmatic children, multiple linear regression investigated the association between socioeconomic factors and failure to reduce allergen sources (i.e., stuffed toys, pets, carpeting, curtains, and cushions); failure to use linen covers; and not laundering linens weekly in hot water. Logistic regression assessed the relationship between socioeconomic status and exposure to environmental tobacco smoke. Mother's employment status was significantly associated with the quality of the home environment (P = .0002). Homemakers demonstrated fewer poor practices (3.1) compared with full-time or part-time employed mothers (3.6). Children whose mothers reported no post-secondary education were more likely to have environmental tobacco smoke exposure compared with those who had a post-secondary CE education or higher (OR 2.4, 95% CI 1.7, 3.5). Children whose mothers worked at home and were better educated were at reduced risk for exposure to sources of indoor allergens.

Parental dietary seleno-L-methionine exposure and resultant offspring developmental toxicity

PubMed Central

Chernick, Melissa; Ware, Megan; Albright, Elizabeth; Kwok, Kevin W.H.; Dong, Wu; Zheng, Na; Hinton, David E.

2015-01-01

Selenium (Se) leaches into water from agricultural soils and from storage sites for coal fly ash. Se toxicity causes population and community level effects in fishes and birds. We used the laboratory aquarium model fish, Japanese medaka (Oryzias latipes), an asynchronous breeder, to determine aspects of uptake in adults and resultant developmental toxicity in their offspring. The superior imaging properties of the model enabled detailed descriptions of phenotypic alterations not commonly reported in the existing Se literature. Adult males and females in treatment groups were exposed, separately and together, to a dry diet spiked with 0, 12.5, 25, or 50 µg/g (dry weight) seleno-L-methionine (SeMet) for 6 days, and their embryo progeny collected for 5 days, maintained under controlled conditions and observed daily for hatchability, mortality and/or developmental toxicity. Sites of alteration included: craniofacial, pericardium and abdomen (Pc/Ab), notochord, gall bladder, spleen, blood, and swim bladder. Next, adult tissue Se concentrations (liver, skeletal muscle, ovary and testis) were determined and compared in treatment groups of bred and unbred individuals. No significant difference was found across treatment groups at the various SeMet concentrations; and, subsequent analysis compared exposed vs. control in each of the treatment groups at 10 dpf. Increased embryo mortality was observed in all treatment groups, compared to controls, and embryos had a decreased hatching rate when both parents were exposed. Exposure resulted in significantly more total altered phenotypes than controls. When altered phenotypes following exposure of both parents were higher than maternal only exposure, a male role was suggested. The comparisons between treatment groups revealed that particular types of phenotypic change may be driven by the sex of the exposed parent. Additionally, breeding reduced Se concentrations in some adult tissues, specifically the liver of exposed females and skeletal muscle of exposed males. Detailed phenotypic analysis of progeny from SeMet exposed parents should inform investigations of later life stages in an effort to determine consequences of early life exposure. PMID:26655662

Understanding workers' exposure: Systematic review and data-analysis of emission potential for NOAA.

PubMed

Kuijpers, E; Bekker, C; Brouwer, D; le Feber, M; Fransman, W

2017-05-01

Exposure assessment for nano-objects, and their aggregates and agglomerates (NOAA), has evolved from explorative research toward more comprehensive exposure assessment, providing data to further develop currently used conservative control banding (CB) tools for risk assessment. This study aims to provide an overview of current knowledge on emission potential of NOAA across the occupational life cycle stages by a systematic review and subsequently use the results in a data analysis. Relevant parameters that influence emission were collected from peer-reviewed literature with a focus on the four source domains (SD) in the source-receptor conceptual framework for NOAA. To make the reviewed exposure data comparable, we applied an approach to normalize for workplace circumstances and measurement location, resulting in comparable "surrogate" emission levels. Finally, descriptive statistics were performed. During the synthesis of nanoparticles (SD1), mechanical reduction and gas phase synthesis resulted in the highest emission compared to wet chemistry and chemical vapor condensation. For the handling and transfer of bulk manufactured nanomaterial powders (SD2) the emission could be differentiated for five activity classes: (1) harvesting; (2) dumping; (3); mixing; (4) cleaning of a reactor; and (5) transferring. Additionally, SD2 was subdivided by the handled amount with cleaning further subdivided by energy level. Harvesting and dumping resulted in the highest emissions. Regarding processes with liquids (SD3b), it was possible to distinguish emissions for spraying (propellant gas, (high) pressure and pump), sonication and brushing/rolling. The highest emissions observed in SD3b were for propellant gas spraying and pressure spraying. The highest emissions for the handling of nano-articles (SD4) were found to nano-sized particles (including NOAA) for grinding. This study provides a valuable overview of emission assessments performed in the workplace during the occupational handling of NOAA. Analyses were made per source domain to derive emission levels which can be used for models to quantitatively predict the exposure.

Case study approach to modeling historical disinfection by-product exposure in Iowa drinking waters.

PubMed

Krasner, Stuart W; Cantor, Kenneth P; Weyer, Peter J; Hildesheim, Mariana; Amy, Gary

2017-08-01

In the 1980s, a case-control epidemiologic study was conducted in Iowa (USA) to analyze the association between exposure to disinfection by-products (DBPs) and bladder cancer risk. Trihalomethanes (THMs), the most commonly measured and dominant class of DBPs in drinking water, served as a primary metric and surrogate for the full DBP mixture. Average THM exposure was calculated, based on rough estimates of past levels in Iowa. To reduce misclassification, a follow-up study was undertaken to improve estimates of past THM levels and to re-evaluate their association with cancer risk. In addition, the risk associated with haloacetic acids, another class of DBPs, was examined. In the original analysis, surface water treatment plants were assigned one of two possible THM levels depending on the point of chlorination. The re-assessment considered each utility treating surface or groundwater on a case-by-case basis. Multiple treatment/disinfection scenarios and water quality parameters were considered with actual DBP measurements to develop estimates of past levels. The highest annual average THM level in the re-analysis was 156μg/L compared to 74μg/L for the original analysis. This allowed the analysis of subjects exposed at higher levels (>96μg/L). The re-analysis established a new approach, based on case studies and an understanding of the water quality and operational parameters that impact DBP formation, for determining historical exposure. Copyright © 2017. Published by Elsevier B.V.

Academic performance in adolescence after inguinal hernia repair in infancy: a nationwide cohort study.

PubMed

Hansen, Tom G; Pedersen, Jacob K; Henneberg, Steen W; Pedersen, Dorthe A; Murray, Jeffrey C; Morton, Neil S; Christensen, Kaare

2011-05-01

Although animal studies have indicated that general anesthetics may result in widespread apoptotic neurodegeneration and neurocognitive impairment in the developing brain, results from human studies are scarce. We investigated the association between exposure to surgery and anesthesia for inguinal hernia repair in infancy and subsequent academic performance. Using Danish birth cohorts from 1986-1990, we compared the academic performance of all children who had undergone inguinal hernia repair in infancy to a randomly selected, age-matched 5% population sample. Primary analysis compared average test scores at ninth grade adjusting for sex, birth weight, and paternal and maternal age and education. Secondary analysis compared the proportions of children not attaining test scores between the two groups. From 1986-1990 in Denmark, 2,689 children underwent inguinal hernia repair in infancy. A randomly selected, age-matched 5% population sample consists of 14,575 individuals. Although the exposure group performed worse than the control group (average score 0.26 lower; 95% CI, 0.21-0.31), after adjusting for known confounders, no statistically significant difference (-0.04; 95% CI, -0.09 to 0.01) between the exposure and control groups could be demonstrated. However, the odds ratio for test score nonattainment associated with inguinal hernia repair was 1.18 (95% CI, 1.04-1.35). Excluding from analyses children with other congenital malformations, the difference in mean test scores remained nearly unchanged (0.05; 95% CI, 0.00-0.11). In addition, the increased proportion of test score nonattainment within the exposure group was attenuated (odds ratio = 1.13; 95% CI, 0.98-1.31). In the ethnically and socioeconomically homogeneous Danish population, we found no evidence that a single, relatively brief anesthetic exposure in connection with hernia repair in infancy reduced academic performance at age 15 or 16 yr after adjusting for known confounding factors. However, the higher test score nonattainment rate among the hernia group could suggest that a subgroup of these children are developmentally disadvantaged compared with the background population.

Evaluating the 4-hour and 30-minute rules: effects of room temperature exposure on red blood cell quality and bacterial growth.

PubMed

Ramirez-Arcos, Sandra; Mastronardi, Cherie; Perkins, Heather; Kou, Yuntong; Turner, Tracey; Mastronardi, Emily; Hansen, Adele; Yi, Qi-Long; McLaughlin, Natasha; Kahwash, Eiad; Lin, Yulia; Acker, Jason

2013-04-01

A 30-minute rule was established to limit red blood cell (RBC) exposure to uncontrolled temperatures during storage and transportation. Also, RBC units issued for transfusion should not remain at room temperature (RT) for more than 4 hours (4-hour rule). This study was aimed at determining if single or multiple RT exposures affect RBC quality and/or promote bacterial growth. Growth and RT exposure experiments were performed in RBCs inoculated with Serratia liquefaciens and Serratia marcescens. RBCs were exposed once to RT for 5 hours (S. liquefaciens) or five times to RT for 30 minutes (S. marcescens) with periodic sampling for bacterial counts. Noncontaminated units were exposed to RT once (5 hr) or five times (30 min each) and sampled to measure in vitro quality variables. RBC core temperature was monitored using mock units with temperature loggers. Growth and RT exposure experiments were repeated three and at least six times, respectively. Statistical analysis was done using mixed-model analysis. RBC core temperature ranged from 7.3 to 11.6°C during 30-minute RT exposures and the time to reach 10°C varied from 22 to 55 minutes during 5-hour RT exposures. RBC quality was preserved after single or multiple RT exposures. Increased growth of S. liquefaciens was only observed after 2 hours of continuous RT exposure. S. marcescens concentration increased significantly in multiple-exposed units compared to the controls but did not reach clinically important levels. Single or multiple RT exposures did not affect RBC quality but slightly promoted bacterial growth in contaminated units. The clinical significance of these results remains unclear and needs further investigation. © 2012 American Association of Blood Banks.

Exposure to Secondhand Smoke and Associated Factors among Non-Smoking Pregnant Women with Smoking Husbands in Sichuan Province, China

PubMed Central

Yang, Lian; Tong, Elisa K.; Mao, Zhengzhong; Hu, Teh-wei

2013-01-01

Background Secondhand smoke (SHS) exposure harms pregnant women and the fetus. China has the world’s largest number of smokers and a high male smoking prevalence rate. Objective To compare exposure to SHS among rural and urban Chinese non-smoking pregnant women with smoking husbands, and analyze factors associated with the level of SHS exposure and hair nicotine concentration Setting Sichuan province, China. Population In all 1181 non-smoking pregnant women with smoking husbands recruited from eight district/county Women and Children’s hospitals. Methods The women completed a questionnaire in April and May 2008. Based on systematic sampling, 186 pregnant women were selected for sampling the nicotine concentration in their hair. Ordinal logistic regression analysis was conducted to examine correlates with self-reported SHS exposure (total and at home); linear regression was conducted for the sub-sample of hair nicotine concentrations. Main outcome measures Secondhand smoking exposure rates, hair nicotine levels. Results About 75.1% of the non-smoking pregnant women with smoking husbands reported regular SHS exposure. The major source of exposure was through their husband. In the multivariate analysis, the risk of greater SHS exposure (total and at home) and hair nicotine concentration was increased for women who were rural, had a husband with greater cigarette consumption, less knowledge about SHS, less negative attitudes about SHS, and no smoke-free home rules. Conclusions The high prevalence rate of SHS exposure suggests that it is important for non-smoking pregnant women, especially rural women, to establish smoke-free home rules and increase knowledge and negative attitudes towards SHS. PMID:20367430

Observations on the predictive value of short-term stake tests

Treesearch

Stan Lebow; Bessie Woodward; Patricia Lebow

2008-01-01

This paper compares average ratings of test stakes after 3, 4, 5, and 7 years exposure to their subsequent ratings after 11 years. Average ratings from over 200 treatment groups exposed in plots in southern Mississippi were compared to average ratings of a reference preservative. The analysis revealed that even perfect ratings after three years were not a reliable...

Quantifying and Adjusting for Disease Misclassification Due to Loss to Follow-Up in Historical Cohort Mortality Studies.

PubMed

Scott, Laura L F; Maldonado, George

2015-10-15

The purpose of this analysis was to quantify and adjust for disease misclassification from loss to follow-up in a historical cohort mortality study of workers where exposure was categorized as a multi-level variable. Disease classification parameters were defined using 2008 mortality data for the New Zealand population and the proportions of known deaths observed for the cohort. The probability distributions for each classification parameter were constructed to account for potential differences in mortality due to exposure status, gender, and ethnicity. Probabilistic uncertainty analysis (bias analysis), which uses Monte Carlo techniques, was then used to sample each parameter distribution 50,000 times, calculating adjusted odds ratios (ORDM-LTF) that compared the mortality of workers with the highest cumulative exposure to those that were considered never-exposed. The geometric mean ORDM-LTF ranged between 1.65 (certainty interval (CI): 0.50-3.88) and 3.33 (CI: 1.21-10.48), and the geometric mean of the disease-misclassification error factor (εDM-LTF), which is the ratio of the observed odds ratio to the adjusted odds ratio, had a range of 0.91 (CI: 0.29-2.52) to 1.85 (CI: 0.78-6.07). Only when workers in the highest exposure category were more likely than those never-exposed to be misclassified as non-cases did the ORDM-LTF frequency distributions shift further away from the null. The application of uncertainty analysis to historical cohort mortality studies with multi-level exposures can provide valuable insight into the magnitude and direction of study error resulting from losses to follow-up.

Prenatal folic acid and risk of asthma in children: a systematic review and meta-analysis

PubMed Central

Crider, Krista S; Cordero, Amy M; Qi, Yan Ping; Mulinare, Joseph; Dowling, Nicole F; Berry, Robert J

2016-01-01

Background Childhood asthma has become a critical public health problem because of its high morbidity and increasing prevalence. The impact of nutrition and other exposures during pregnancy on long-term health and development of children has been of increasing interest. Objective We performed a systematic review and meta-analysis of the association of folate and folic acid intake during pregnancy and risk of asthma and other allergic outcomes in children. Design We performed a systematic search of 8 electronic databases for articles that examined the association between prenatal folate or folic acid exposure and risk of asthma and other allergic outcomes (eg, allergy, eczema, and atopic dermatitis) in childhood. We performed a meta-analysis by using a random-effects model to derive a summary risk estimate of studies with similar exposure timing, exposure assessment, and outcomes. Results Our meta-analysis provided no evidence of an association between maternal folic acid supplement use (compared with no use) in the prepregnancy period through the first trimester and asthma in childhood (summary risk estimate: 1.01; 95% CI: 0.78, 1.30). Because of substantial heterogeneity in exposures and outcomes, it was not possible to generate summary measures for other folate indicators (eg, blood folate concentrations) and asthma or allergy-related outcomes; however, the preponderance of primary risk estimates was not elevated. Conclusions Our findings do not support an association between periconceptional folic acid supplementation and increased risk of asthma in children. However, because of the limited number and types of studies in the literature, additional research is needed. PMID:24004895

Using systematic reviews and meta-analyses to support regulatory decision making for neurotoxicants: lessons learned from a case study of PCBs.

PubMed

Goodman, Michael; Squibb, Katherine; Youngstrom, Eric; Anthony, Laura Gutermuth; Kenworthy, Lauren; Lipkin, Paul H; Mattison, Donald R; Lakind, Judy S

2010-06-01

Epidemiologic weight-of-evidence reviews to support regulatory decision making regarding the association between environmental chemical exposures and neurodevelopmental outcomes in children are often complicated by lack of consistency across studies. We examined prospective cohort studies evaluating the relation between prenatal and neonatal exposure to polychlorinated biphenyls (PCBs) and neurodevelopment in children to assess the feasibility of conducting a meta-analysis to support decision making. We described studies in terms of exposure and end point categorization, statistical analysis, and reporting of results. We used this evaluation to assess the feasibility of grouping studies into reasonably uniform categories. The current literature includes 11 cohorts of children for whom effects from prenatal or neonatal PCB exposures were assessed. The most consistently used tests included Brazelton's Neonatal Behavioral Assessment Scale, the neurologic optimality score in the neonatal period, the Bayley Scales of Infant Development at 5-8 months of age, and the McCarthy Scales of Children's Abilities in 5-year-olds. Despite administering the same tests at similar ages, the studies were too dissimilar to allow a meaningful quantitative examination of outcomes across cohorts. These analyses indicate that our ability to conduct weight-of-evidence assessments of the epidemiologic literature on neurotoxicants may be limited, even in the presence of multiple studies, if the available study methods, data analysis, and reporting lack comparability. Our findings add support to previous calls for establishing consensus standards for the conduct, analysis, and reporting of epidemiologic studies in general, and for those evaluating the effects of potential neurotoxic exposures in particular.

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

PubMed

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

2017-08-01

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

Risks for the development of outcomes related to occupational allergies: an application of the asthma-specific job exposure matrix compared with self-reports and investigator scores on job-training-related exposure.

PubMed

Suarthana, E; Heederik, D; Ghezzo, H; Malo, J-L; Kennedy, S M; Gautrin, D

2009-04-01

Risks for development of occupational sensitisation, bronchial hyper-responsiveness, rhinoconjunctival and chest symptoms at work associated with continued exposure to high molecular weight (HMW) allergens were estimated with three exposure assessment methods. A Cox regression analysis with adjustment for atopy and smoking habit was carried out in 408 apprentices in animal health technology, pastry making, and dental hygiene technology with an 8-year follow-up after training. The risk of continued exposure after training, estimated by the asthma-specific job exposure matrix (JEM), was compared with self-reports and investigator scores on job-training-related exposure. Associations between outcomes and work duration in job(s) related to training were also evaluated. Exposure to animal-derived HMW allergens, subsequent to the apprenticeship period, as estimated by the JEM, was associated with a significantly increased risk for occupational sensitisation (hazard ratio (HR) 6.4; 95% CI 2.3 to 18.2) and rhinoconjunctival symptoms at work (HR 2.6; 95% CI 1.1 to 6.2). Exposure to low molecular weight (LMW) agents significantly increased the risk of developing bronchial hyper-responsiveness (HR 2.3; 95% CI 1.1 to 5.4). Exposure verification appeared to be important to optimise the sensitivity and the specificity, as well as HRs produced by the JEM. Self-reports and investigator scores also indicated that further exposure to HMW allergens increased the risk of developing occupational allergies. The agreement between self-reports, investigator scores, and the JEM were moderate to good. There was no significant association between respiratory outcomes and work duration in jobs related to training. The asthma-specific JEM could estimate the risk of various outcomes of occupational allergies associated with exposure to HMW and LMW allergens, but it is relatively labour intensive. Exposure verification is an important integrated step in the JEM that optimised the performance of the matrix.

An empirical analysis of thermal protective performance of fabrics used in protective clothing.

PubMed

Mandal, Sumit; Song, Guowen

2014-10-01

Fabric-based protective clothing is widely used for occupational safety of firefighters/industrial workers. The aim of this paper is to study thermal protective performance provided by fabric systems and to propose an effective model for predicting the thermal protective performance under various thermal exposures. Different fabric systems that are commonly used to manufacture thermal protective clothing were selected. Laboratory simulations of the various thermal exposures were created to evaluate the protective performance of the selected fabric systems in terms of time required to generate second-degree burns. Through the characterization of selected fabric systems in a particular thermal exposure, various factors affecting the performances were statistically analyzed. The key factors for a particular thermal exposure were recognized based on the t-test analysis. Using these key factors, the performance predictive multiple linear regression and artificial neural network (ANN) models were developed and compared. The identified best-fit ANN models provide a basic tool to study thermal protective performance of a fabric. © The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Diffusion tensor imaging reveals changes in the adult rat brain following long-term and passive moderate acoustic exposure.

PubMed

Abdoli, Sherwin; Ho, Leon C; Zhang, Jevin W; Dong, Celia M; Lau, Condon; Wu, Ed X

2016-12-01

This study investigated neuroanatomical changes following long-term acoustic exposure at moderate sound pressure level (SPL) under passive conditions, without coupled behavioral training. The authors utilized diffusion tensor imaging (DTI) to detect morphological changes in white matter. DTIs from adult rats (n = 8) exposed to continuous acoustic exposure at moderate SPL for 2 months were compared with DTIs from rats (n = 8) reared under standard acoustic conditions. Two distinct forms of DTI analysis were applied in a sequential manner. First, DTI images were analyzed using voxel-based statistics which revealed greater fractional anisotropy (FA) of the pyramidal tract and decreased FA of the tectospinal tract and trigeminothalamic tract of the exposed rats. Region of interest analysis confirmed (p < 0.05) that FA had increased in the pyramidal tract but did not show a statistically significant difference in the FA of the tectospinal or trigeminothalamic tract. The results of the authors show that long-term and passive acoustic exposure at moderate SPL increases the organization of white matter in the pyramidal tract.

COMPARATIVE ANALYSIS OF REACTIVE OXYGEN SPECIES IN HUMAN PLASMA AND BLOOD

EPA Science Inventory

Reactive oxygen species (ROS) are commonly associated with diseased states (including asthma, cardiovascular disease, cancer) infections, and exposure to various toxicants in humans. It is of interest in epidemiology studies to characterize the association of oxidative stress in...

A comparative ecotoxicity analysis of α- and γ-phase aluminium oxide nanoparticles towards a freshwater bacterial isolate Bacillus licheniformis.

PubMed

Pakrashi, Sunandan; Kumar, Deepak; Iswarya, V; Bhuvaneshwari, M; Chandrasekaran, N; Mukherjee, Amitava

2014-12-01

Crystalline structure of nanoparticles may influence their physicochemical behaviour as well as their toxicological impact on biota. The differences in orientation of the atoms result in the variations in chemical stability. Thus, toxicological impacts of different crystalline phases of aluminium oxide nanoparticles are expected to vary. The present study brings out a comparative toxicity analysis of γ-phase and α-phase aluminium oxide nanoparticles of comparable hydrodynamic size range towards a freshwater bacterial isolate Bacillus licheniformis at low exposure concentrations (5, 1, 0.5 and 0.05 µg/mL). Upon 2-h exposure, the α-aluminium oxide particles showed lower toxicity than the γ-phase aluminium oxide. The lower level of oxidative stress generation and cell membrane damage in case of the α-phase aluminium oxide nanoparticles substantiated the toxicity results. The involvement of protein, lipopolysaccharides in nanoparticle-cell surface interaction, was noted in both the cases. To conclude, the crystallinity of aluminium oxide nanoparticles played an important role in the interaction and the toxicity response.

Statistical grand rounds: understanding the mechanism: mediation analysis in randomized and nonrandomized studies.

PubMed

Mascha, Edward J; Dalton, Jarrod E; Kurz, Andrea; Saager, Leif

2013-10-01

In comparative clinical studies, a common goal is to assess whether an exposure, or intervention, affects the outcome of interest. However, just as important is to understand the mechanism(s) for how the intervention affects outcome. For example, if preoperative anemia was shown to increase the risk of postoperative complications by 15%, it would be important to quantify how much of that effect was due to patients receiving intraoperative transfusions. Mediation analysis attempts to quantify how much, if any, of the effect of an intervention on outcome goes though prespecified mediator, or "mechanism" variable(s), that is, variables sitting on the causal pathway between exposure and outcome. Effects of an exposure on outcome can thus be divided into direct and indirect, or mediated, effects. Mediation is claimed when 2 conditions are true: the exposure affects the mediator and the mediator (adjusting for the exposure) affects the outcome. Understanding how an intervention affects outcome can validate or invalidate one's original hypothesis and also facilitate further research to modify the responsible factors, and thus improve patient outcome. We discuss the proper design and analysis of studies investigating mediation, including the importance of distinguishing mediator variables from confounding variables, the challenge of identifying potential mediators when the exposure is chronic versus acute, and the requirements for claiming mediation. Simple designs are considered, as well as those containing multiple mediators, multiple outcomes, and mixed data types. Methods are illustrated with data collected by the National Surgical Quality Improvement Project (NSQIP) and utilized in a companion paper which assessed the effects of preoperative anemic status on postoperative outcomes.

Results of bulk sediment analysis and bioassay testing on selected sediments from Oakland Inner Harbor and Alcatraz disposal site, San Francisco, California

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

Word, J Q; Ward, J A; Woodruff, D L

1990-09-01

The Battelle/Marine Sciences Laboratory (MSL) was contracted by the US Army Corps of Engineers, San Francisco District, to perform bulk sediment analysis and oyster larvae bioassays (elutriate) on sediments from Inner Oakland Harbor, California. Analysis of sediment characteristics by MSL indicated elevated priority pollutants, PAHs, pesticides, metals, organotins, and oil and grease concentrations, when compared to Alcatraz Island Dredged Material Disposal Site sediment concentrations. Larvae of the Pacific oyster, Crassostrea gigas, were exposed to seawater collected from the Alcatraz Island Site water, and a series of controls using water and sediments collected from Sequim Bay, Washington. Exposure of larvae tomore » the Alcatraz seawater and the 50% and 100% elutriate concentrations from each Oakland sediment resulted in low survival and a high proportion of abnormal larvae compared to Sequim Bay control exposures. MSL identified that field sample collection, preservation, and storage protocols used by Port of Oakland contractors were inconsistent with standard accepted practices. 23 refs., 10 figs., 40 tabs.« less

Surface remineralization potential of casein phosphopeptide-amorphous calcium phosphate on enamel eroded by cola-drinks: An in-situ model study.

PubMed

Grewal, Navneet; Kudupudi, Vinod; Grewal, Sukrit

2013-07-01

The aim of this study was to investigate the remineralization potential of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on enamel eroded by cola drinks. A total of 30 healthy subjects were selected from a random sample of 1200 children and divided into two groups of 15 each wherein calcium and phosphorus analyses and scanning electron microscope (SEM) analysis was carried out to investigate the remineralization of enamel surface. A total of 30 non-carious premolar teeth were selected from the human tooth bank (HTB) to prepare the in-situ appliance. Three enamel slabs were prepared from the same. One enamel slab was used to obtain baseline values and the other two were embedded into the upper palatal appliances prepared on the subjects' maxillary working model. The subjects wore the appliance after which 30 ml cola drink exposure was given. After 15 days, the slabs were removed and subjected to respective analysis. Means of all the readings of soluble calcium and phosphorous levels at baseline,post cola-drink exposure and post cpp-acp application were subjected to statistical analysis SPSS11.5 version. Comparison within groups and between groups was carried out using ANOVA and F-values at 1% level of significance. Decrease in calcium solubility of enamel in the CPP-ACP application group as compared to post-cola drink exposure group (P < 0.05) was seen. Distinctive change in surface topography of enamel in the post-CPP-ACP application group as compared to post-cola drink exposure group was observed. CPP-ACP significantly promoted remineralization of enamel eroded by cola drinks as revealed by significant morphological changes seen in SEM magnification and spectrophotometric analyses.

[Comparative immunogenicity of 2 antirabies vaccines in a 2-1-1 post-exposure vaccination schedule].

PubMed

Landry, P; Lazzaro, M; Darioli, R

1998-09-09

Few trials have compared the Purified Duck Embryo Vaccine (PDEV) and the Human Diploid Cell Vaccine (HDCV) in a post-exposure immunization schedule of 4 shots (2 on day 0 and 1 each on day 7 and 21, or 2-1-1 schedule). A retrospective analysis compared 10 patients with PEDV and 20 with HDCV, who had received the 2-1-1 schedule as well as 20 UI mg/kg of immune globulins on day 0. The median neutralizing antibody titers on day 21 (after 3 doses) and the median of maximum titers until day 90 were higher for HDCV than for PEDV (0.6 IU/ml versus 3.5 IU/ml [p < 0.04] and 2.5 IU/ml versus 5.8 IU/ml [p < 0.03] respectively). Seven patients had not reached the seroconversion titer of 0.5 IU/ml after 3 doses (day 21). These results differ from previous studies showing a 100% seroconversion rate on day 21, and suggest that more studies are required before these 2 vaccines can be used in the 2-1-1 schedule after severe exposure.

Evaluation of biodiesel’s impact on real-world occupational and environmental particulate matter exposures at a municipal facility in Keene, NH

PubMed Central

Thelen, Brett Amy; Ingalls, Jaime Kathryn; Treadwell, Melinda Dawn

2016-01-01

Many organizations are interested in biodiesel as a renewable, domestic energy source for use in transportation and heavy-duty equipment. Although numerous biodiesel emission studies exist, biodiesel exposure studies are nearly absent from the literature. This study compared the impact of petroleum diesel fuel and a B20 blend (20% soy-based biodiesel/80% petroleum diesel) on occupational and environmental exposures at a rural municipal facility in Keene, NH. For each fuel type, we measured concentrations of fine particulate matter (PM2.5), elemental carbon (EC), and organic carbon (OC) at multiple locations (in-cabin, work area, and near-field) at a materials recovery facility utilizing non-road equipment. B20 fuel use resulted in significant reductions in PM2.5 mass (56–76%), reductions in EC (5–29%), and increases in OC (294–467%). Concentrations of PM2.5 measured during petroleum diesel use were up to four times higher than PM2.5 concentrations during B20 use. Further analysis of the EC and OC fractions of total carbon also indicated substantial differences between fuels. Our results demonstrate that biodiesel blends significantly reduced PM2.5 exposure compared to petroleum diesel fuel in a workplace utilizing non-road construction-type equipment. While this suggests that biodiesel may reduce health risks associated with exposure to fine particulate matter mass, more exposure research is needed to better understand biodiesel-related changes in particulate matter composition and other exposure metrics.

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

Mathee, Angela

Introduction: Lead exposure in shooting ranges has been under scrutiny for decades, but no information in this regard is available in respect of African settings, and in South Africa specifically. The aim of this study was to determine the blood lead levels in the users of randomly selected private shooting ranges in South Africa's Gauteng province. Methods: An analytical cross sectional study was conducted, with participants recruited from four randomly selected shooting ranges and three archery ranges as a comparator group. Results: A total of 118 (87 shooters and 31 archers) were included in the analysis. Shooters had significantly highermore » blood lead levels (BLL) compared to archers with 36/85 (42.4%) of shooters versus 2/34 (5.9%) of archers found to have a BLL ≥10 μg/dl (p<0.001). Conclusion: Shooting ranges may constitute an import site of elevated exposure to lead. Improved ventilation, low levels of awareness of lead hazards, poor housekeeping, and inadequate personal hygiene facilities and practices at South African shooting ranges need urgent attention. - Highlights: • This is the first study, to our knowledge, of lead exposure in shooting ranges in an African setting. • This study indicates highly elevated lead exposure amongst the users of certain private shooting ranges in South Africa. • Lead exposure may be a serious, yet under-studied, source of adult lead exposure in South Africa, and possibly elsewhere on the African continent.« less

Increased Frequency of Rheumatoid Arthritis and Allergic Rhinitis among Pesticide Sprayers and Associations with Pesticide Use.

PubMed

Koureas, Michalis; Rachiotis, George; Tsakalof, Andreas; Hadjichristodoulou, Christos

2017-08-01

Objective : The aim of this study was to identify diseases linked with the pesticide sprayer occupation and explore possible associations with exposure history data. Methods : Α cross sectional study was conducted among pesticide sprayers ( n = 80) and the general population ( n = 90) in Thessaly (Greece). Medical history, demographic characteristics and detailed exposure history were recorded by conducting personal interviews. Lifetime exposure indicators were calculated for several pesticide chemical subclasses. Moreover, organophosphate metabolite levels were quantified in urine samples of all participants by using gas chromatography -mass spectrometry (GC-MS). Multinomial analysis was used to determine associations between occupational pesticide exposure and diseases or disorders. Results : In the pesticide sprayers group, significantly higher frequencies for rheumatoid arthritis (RA) and allergic rhinitis were observed compared with the control group ( p = 0.002 and p = 0.024 respectively). Within the pesticide sprayers group, high lifetime pesticide exposure was associated with increased risk for reporting RA (OR: 43.07 95% CI: 3.09-600.67) and allergic rhinitis (OR: 9.72 95% CI: 2.31-40.89), compared with low pesticide exposure. Exposure to organophsphate, guanidine and quinone pesticides were associated with RA while organophosphates, pyrethroids and paraquat were associated with allergic rhinitis. Despite the higher levels of certain pesticide metabolites observed among participants with rheumatoid arthritis, the differences were not statistically significant. One metabolite (diethylthiophosphate) was found to be significantly increased in allergic rhinitis cases ( p = 0.037). Conclusion s : The results from the current study suggest a possible association of occupational pesticide exposure with RA and allergic rhinitis that should be further investigated.

Tobacco smoke exposure in public places and workplaces after smoke-free policy implementation: a longitudinal analysis of smoker cohorts in Mexico and Uruguay

PubMed Central

Thrasher, James F.; Nayeli Abad-Vivero, Erika; Sebrié, Ernesto M.; Barrientos-Gutierrez, Tonatiuh; Boado, Marcelo; Yong, Hua Hie; Arillo-Santillán, Edna; Bianco, Eduardo

2013-01-01

Objective: To determine the prevalence, correlates and changes in secondhand smoke (SHS) exposure over the period after comprehensive smoke-free policy implementation in two Latin American countries. Methods: Data were analysed from population-based representative samples of adult smokers and recent quitters from the 2008 and 2010 waves of the International Tobacco Control Policy Evaluation Survey in Mexico (n = 1766 and 1840, respectively) and Uruguay (n = 1379 and 1411, respectively). Prevalence of SHS exposure was estimated for regulated venues, and generalized estimating equations were used to determine correlates of SHS exposure. Results: Workplace SHS exposure in the last month was similar within and across countries (range: Mexico 20–25%; Uruguay 14–29%). At the most recent restaurant visit, SHS exposure was lower where comprehensive smoke-free policies were implemented (range: Uruguay 6–9%; Mexico City 5–7%) compared with Mexican cities with weaker policies, where exposure remained higher but decreased over time (32–17%). At the most recent bar visit, SHS exposure was common (range: Uruguay 8–36%; Mexico City 23–31%), although highest in jurisdictions with weaker policies (range in other Mexican cities: 74–86%). In Uruguay, males were more likely than females to be exposed to SHS across venues, as were younger compared with older smokers in Mexico. Conclusions: Comprehensive smoke-free policies are more effective than weaker policies, although compliance in Mexico and Uruguay is not as high as desired. PMID:23172895

Mortality and cancer incidence in ammonium perfluorooctanoate production workers

PubMed Central

Raleigh, Katherine K; Alexander, Bruce H; Olsen, Geary W; Ramachandran, Gurumurthy; Morey, Sandy Z; Church, Timothy R; Logan, Perry W; Scott, Laura L F; Allen, Elizabeth M

2014-01-01

Objective To evaluate mortality and cancer incidence in a cohort of ammonium perfluorooctanoate (APFO) exposed workers. Methods We linked a combined cohort (n=9027) of employees from APFO and non-APFO production facilities in Minnesota to the National Death Index and to cancer registries of Minnesota and Wisconsin. Industrial hygiene data and expert evaluation were used to create a task-based job exposure matrix to estimate APFO exposure. Standardised mortality ratios were estimated using Minnesota population rates. HRs and 95% CIs for time-dependent cumulative APFO exposure were estimated with an extended Cox model. A priori outcomes of interest included cancers of the liver, pancreas, testes, kidney, prostate and breast, and mortality from cardiovascular, cerebrovascular and chronic renal diseases. Results Mortality rates in the APFO-exposed cohort were at or below the expected, compared with Minnesota. The HR for dying from the cancer and non-cancer outcomes of interest did not show an association with APFO exposure. Similarly, there was little evidence that the incident cancers were associated with APFO exposure. Compared to the non-exposed population, modestly elevated, but quite imprecise HRs were observed in the higher-exposure quartiles for bladder cancer (HR=1.66, 95% CI 0.86 to 3.18) and pancreatic cancer (HR=1.36, 95% CI 0.59 to 3.11). No association was observed between APFO exposure and kidney, prostate or breast cancers. Conclusions This analysis did not support an association between occupational APFO exposure and the evaluated health endpoints, however, the study had limited power to evaluate some conditions of interest. PMID:24832944

Are passive smoking, air pollution and obesity a greater mortality risk than major radiation incidents?

PubMed Central

Smith, Jim T

2007-01-01

Background Following a nuclear incident, the communication and perception of radiation risk becomes a (perhaps the) major public health issue. In response to such incidents it is therefore crucial to communicate radiation health risks in the context of other more common environmental and lifestyle risk factors. This study compares the risk of mortality from past radiation exposures (to people who survived the Hiroshima and Nagasaki atomic bombs and those exposed after the Chernobyl accident) with risks arising from air pollution, obesity and passive and active smoking. Methods A comparative assessment of mortality risks from ionising radiation was carried out by estimating radiation risks for realistic exposure scenarios and assessing those risks in comparison with risks from air pollution, obesity and passive and active smoking. Results The mortality risk to populations exposed to radiation from the Chernobyl accident may be no higher than that for other more common risk factors such as air pollution or passive smoking. Radiation exposures experienced by the most exposed group of survivors of Hiroshima and Nagasaki led to an average loss of life expectancy significantly lower than that caused by severe obesity or active smoking. Conclusion Population-averaged risks from exposures following major radiation incidents are clearly significant, but may be no greater than those from other much more common environmental and lifestyle factors. This comparative analysis, whilst highlighting inevitable uncertainties in risk quantification and comparison, helps place the potential consequences of radiation exposures in the context of other public health risks. PMID:17407581

Higher Initial DNA Damage and Persistent Cell Cycle Arrest after Carbon Ion Irradiation Compared to X-irradiation in Prostate and Colon Cancer Cells

PubMed Central

Suetens, Annelies; Konings, Katrien; Moreels, Marjan; Quintens, Roel; Verslegers, Mieke; Soors, Els; Tabury, Kevin; Grégoire, Vincent; Baatout, Sarah

2016-01-01

The use of charged-particle beams, such as carbon ions, is becoming a more and more attractive treatment option for cancer therapy. Given the precise absorbed dose-localization and an increased biological effectiveness, this form of therapy is much more advantageous compared to conventional radiotherapy, and is currently being used for treatment of specific cancer types. The high ballistic accuracy of particle beams deposits the maximal dose to the tumor, while damage to the surrounding healthy tissue is limited. In order to better understand the underlying mechanisms responsible for the increased biological effectiveness, we investigated the DNA damage and repair kinetics and cell cycle progression in two p53 mutant cell lines, more specifically a prostate (PC3) and colon (Caco-2) cancer cell line, after exposure to different radiation qualities. Cells were irradiated with various absorbed doses (0, 0.5, and 2 Gy) of accelerated 13C-ions at the Grand Accélérateur National d’Ions Lourds facility (Caen, France) or with X-rays (0, 0.1, 0.5, 1, 2, and 5 Gy). Microscopic analysis of DNA double-strand breaks showed dose-dependent increases in γ-H2AX foci numbers and foci occupancy after exposure to both types of irradiation, in both cell lines. However, 24 h after exposure, residual damage was more pronounced after lower doses of carbon ion irradiation compared to X-irradiation. Flow cytometric analysis showed that carbon ion irradiation induced a permanent G2/M arrest in PC3 cells at lower doses (2 Gy) compared to X-rays (5 Gy), while in Caco-2 cells the G2/M arrest was transient after irradiation with X-rays (2 and 5 Gy) but persistent after exposure to carbon ions (2 Gy). PMID:27148479

Secondhand smoke exposure of children at home and prevalence of parental smoking following implementation of the new tobacco control law in Macao.

PubMed

Zheng, Z L; Deng, H Y; Wu, C P; Lam, W L; Kuok, W S; Liang, W J; Wang, H L

2017-03-01

To investigate secondhand smoke exposure (SHS) of children at home and the prevalence of parental smoking after implementation of the new tobacco control law in Macao. This study explored whether the smoking ban in public places in Macao has decreased the prevalence of smoking or led to increased SHS exposure of children at home. As smokers cannot smoke in public places any more, they may smoke at home more frequently; a displacement effect of smoke-free legislation. Cross-sectional survey. This study surveyed 337 fathers and 538 mothers. Questions from a subset of key questions from the Global Adult Tobacco Survey (2nd edition) were applied to assess the SHS exposure of children and the prevalence of parental smoking since the smoking ban. A classification tree analysis was used to analyse the factors increasing SHS exposure of children. The prevalence of SHS exposure in children at home was 41.3%. The prevalence rates of paternal and maternal smoking were 43.7% and 3.8%, respectively. Compared with data reported by the Health Bureau of Macao SAR in 2011, the prevalence of parental smoking and the prevalence of SHS exposure of children at home have not decreased since the smoking ban. Analysis of the factors increasing the prevalence of SHS exposure of children indicated that fathers with an education level below high school were more likely to contribute to this increase, compared with fathers with a high school education or more (48.2% vs 32.4%, respectively). In addition, fathers represented the majority of smokers at home, accounting for 92.0% of 415 smoking parents. The prevalence of paternal smoking (82.0%) in the group of children with SHS exposure was much higher than that in the unexposed group (16.7%, Chi-squared test = 367.199, P = 0.000). The SHS exposure of children increased consistently with the decrease in paternal education level. This was consistent with the increasing prevalence of paternal smoking as paternal education level decreased. SHS exposure was most common among children whose fathers had an education level below high school and whose mothers were aged ≤29 years (75.0%). This study did not find any decline in the prevalence of parental smoking after the smoking ban. These parents were more likely to smoke at home after the ban, leading to more frequent SHS exposure for their children. Copyright © 2016 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

[Methylmethacrylate and organic dementia. A dose-response analysis among dental technicians and opticians].

PubMed

Steendahl, U; Prescott, E; Damsgaard, M T

1992-05-11

The substance methylmethacrylate (MMA) is an organic solvent which is employed inter alii for prostheses which is suspected of being neurotoxic. With the object of illustrating whether there is a connection between exposure to MMA and symptoms of organic dementia, a cross-sectional investigation was carried out on a population consisting of occupationally active dental technicians and opticians (n = 528) and a group of dental technicians who were no longer occupationally active (n = 173). No noteworthy difference in the background variables, apart from age, was observed. Age was taken into consideration in the analysis. The results show a statistically significant increase in the prevalence of the chronic symptoms on increasing exposure. Where the acute symptoms are concerned, the connection is not statistically significant, but a tendency is observed. A chronic symptom index constructed on the basis of 13 questions concerning chronic symptoms is compared with the life exposure and the age. A statistically significant increase in the index was found with exposure to MMA, although not for the oldest age group. The pattern symptoms, presence of bias and other forms of exposure are discussed. It is concluded that this investigation confirms the hypothesis that symptoms of organic dementia have a connection the exposure to MMA. The results support the presumption that MMA causes acute and chronic damage to the central nervous system even with exposure below the safety limits. It is recommended that the occupational environment of dental technicians, including the present safety limits, should be revised.

Physiologic effects of prolonged conducted electrical weapon discharge in ethanol-intoxicated adults.

PubMed

Moscati, Ronald; Ho, Jeffrey D; Dawes, Donald M; Miner, James R

2010-06-01

This study examines the physiologic effects of prolonged conducted electrical weapon (CEW) exposure on alcohol-intoxicated adult subjects. Adult volunteers were recruited at a TASER International training conference. All subjects ingested mixed drinks until clinical intoxication or until a minimum breath alcohol level of 0.08 mg/dL was achieved. Blood samples for venous pH, Pco(2), bicarbonate, and lactate were measured in all subjects at baseline, immediately after alcohol ingestion, immediately after exposure to a 15-second TASER X26 discharge (Taser International Inc, Scottsdale, AZ), and 24 hours post-alcohol ingestion. Laboratory values were compared at sampling times using repeated-measure analysis of variance. A focused analysis comparing time points within groups was then performed using paired t tests. Twenty-two subjects were enrolled into the study. There was a decrease in pH and bicarbonate and an increase in lactate after alcohol ingestion. There was a further increase in lactate and drop in pH after CEW exposure. No subject experienced a significant adverse event. All values had returned to baseline levels at 24 hours except lactate, which demonstrated a small but clinically insignificant increase. Prolonged continuous CEW exposure in the setting of acute alcohol intoxication has no clinically significant effect on subjects in terms of markers of metabolic acidosis. The acidosis seen is consistent with what occurs with ethanol intoxication or moderate exertion. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Are Pain-Related Fears Mediators for Reducing Disability and Pain in Patients with Complex Regional Pain Syndrome Type 1? An Explorative Analysis on Pain Exposure Physical Therapy

PubMed Central

Barnhoorn, Karlijn J.; Staal, J. Bart; van Dongen, Robert T. M.; Frölke, Jan Paul M.; Klomp, Frank P.; van de Meent, Henk; Samwel, Han; Nijhuis-van der Sanden, Maria W. G.

2015-01-01

Objective To investigate whether pain-related fears are mediators for reducing disability and pain in patients with Complex Regional Pain Syndrome type 1 when treating with Pain Exposure Physical Therapy. Design An explorative secondary analysis of a randomised controlled trial. Participants Fifty-six patients with Complex Regional Pain Syndrome type 1. Interventions The experimental group received Pain Exposure Physical Therapy in a maximum of five treatment sessions; the control group received conventional treatment following the Dutch multidisciplinary guideline. Outcome measures Levels of disability, pain, and pain-related fears (fear-avoidance beliefs, pain catastrophizing, and kinesiophobia) were measured at baseline and after 3, 6, and 9 months follow-up. Results The experimental group had a significantly larger decrease in disability of 7.77 points (95% CI 1.09 to 14.45) and in pain of 1.83 points (95% CI 0.44 to 3.23) over nine months than the control group. The potential mediators pain-related fears decreased significantly in both groups, but there were no significant differences between groups, which indicated that there was no mediation. Conclusion The reduction of pain-related fears was comparable in both groups. We found no indication that pain-related fears mediate the larger reduction of disability and pain in patients with Complex Regional Pain Syndrome type 1 treated with Pain Exposure Physical Therapy compared to conventional treatment. Trial registration International Clinical Trials Registry NCT00817128 PMID:25919011

Pharmacokinetics and exposure-effect relationships of capecitabine in elderly patients with breast or colorectal cancer

PubMed Central

Daher-Abdi, Zeinab; Lavau-Denes, Sandrine; Prémaud, Aurélie; Urien, Saik; Sauvage, François-Ludovic; MARTIN, Jean; Leobon, Sophie; Marquet, Pierre; Tubiana-Mathieu, Nicole; Rousseau, Annick

2014-01-01

Purpose The aims of the present study were (i) to investigate the impact of great age on pharmacokinetics of capecitabine and its metabolites and (ii) to evaluate the exposure/effect relationship of capecitabine in elderly patients. Methods Data collected from 20 elderly patients (75–92 years old) with breast or colorectal cancer, who received oral capecitabine were analyzed. In order to study the old age effect on pharmacokinetics, data collected from two phase I studies involving 40 younger adults (<75 years old) with metastatic cancer who received oral capecitabine, were added in the database. The population pharmacokinetic analysis was based on a four compartment model describing the sequence of capecitabine and three of its metabolites. Results The absorption rate constant was found lower in the oldest patient group (≥75 y) compared to the youngest group, and the constant rate elimination of the 5-fluorouracil metabolite was found decreased over time (i.e. after 2 consecutive weeks of capecitabine administration). This time effect was not found different between the two age groups. In elderly patients, the exposure-safety analysis showed, from the second cycle of chemotherapy, significantly higher median exposures of capecitabine and its metabolites (5′-deoxy-5-fluorocytidine,5′-deoxy-5-fluorouridine and 5-fluorouracil) in patients who experienced hand-foot syndrome compared to patients who did not. Conclusion This study puts forward new arguments for the treatment of elderly cancer patients who could benefit from capecitabine chemotherapy with acceptable toxicity. PMID:24801171

Comparative Study in Laboratory Rats to Validate Sperm Quality Methods and Endpoints

NASA Technical Reports Server (NTRS)

Price, W. A.; Briggs, G. B.; Alexander, W. K.; Still, K. R.; Grasman, K. A.

2000-01-01

Abstract The Naval Health Research Center, Detachment (Toxicology) performs toxicity studies in laboratory animals to characterize the risk of exposure to chemicals of Navy interest. Research was conducted at the Toxicology Detachment at WPAFB, OH in collaboration with Wright State University, Department of Biological Sciences for the validation of new bioassay methods for evaluating reproductive toxicity. The Hamilton Thorne sperm analyzer was used to evaluate sperm damage produced by exposure to a known testicular toxic agent, methoxyacetic acid and by inhalation exposure to JP-8 and JP-5 in laboratory rats. Sperm quality parameters were evaluated (sperm concentration, motility, and morphology) to provide evidence of sperm damage. The Hamilton Thorne sperm analyzer utilizes a DNA specific fluorescent stain (similar to flow cytometry) and digitized optical computer analysis to detect sperm cell damage. The computer assisted sperm analysis (CASA) is a more rapid, robust, predictive and sensitive method for characterizing reproductive toxicity. The results presented in this poster report validation information showing exposure to methoxyacetic acid causes reproductive toxicity and inhalation exposure to JP-8 and JP-5 had no significant effects. The CASA method detects early changes that result in reproductive deficits and these data will be used in a continuing program to characterize the toxicity of chemicals, and combinations of chemicals, of military interest to formulate permissible exposure limits.

Low-Level Blast Exposure Increases Transient Receptor Potential Vanilloid 1 (TRPV1) Expression in the Rat Cornea

PubMed Central

Por, Elaine D.; Choi, Jae-Hyek; Lund, Brian J.

2016-01-01

ABSTRACT Background: Blast-related ocular injuries sustained by military personnel have led to rigorous efforts to elucidate the effects of blast exposure on neurosensory function. Recent studies have provided some insight into cognitive and visual deficits sustained following blast exposure; however, limited data are available on the effects of blast on pain and inflammatory processes. Investigation of these secondary effects of blast exposure is necessary to fully comprehend the complex pathophysiology of blast-related injuries. The overall purpose of this study is to determine the effects of single and repeated blast exposure on pain and inflammatory mediators in ocular tissues. Methods: A compressed air shock tube was used to deliver a single or repeated blast (68.0 ± 2.7 kPa) to anesthetized rats daily for 5 days. Immunohistochemistry was performed on ocular tissues to determine the expression of the transient receptor potential vanilloid 1 (TRPV1) channel, calcitonin gene-related peptide (CGRP), substance P (SP), and endothelin-1 (ET-1) following single and repeated blast exposure. Neutrophil infiltration and myeloperoxidase (MPO) expression were also assessed in blast tissues via immunohistochemistry and enzyme-linked immunosorbent assay (ELISA) analysis, respectively. Results: TRPV1 expression was increased in rat corneas exposed to both single and repeated blast. Increased secretion of CGRP, SP, and ET-1 was also detected in rat corneas as compared to control. Moreover, repeated blast exposure resulted in neutrophil infiltration in the cornea and stromal layer as compared to control animals. Conclusion: Single and repeated blast exposure resulted in increased expression of TRPV1, CGRP, SP, and ET-1 as well as neutrophil infiltration. Collectively, these findings provide novel insight into the activation of pain and inflammation signaling mediators following blast exposure. PMID:27049881

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.

A Quasi-Experiment To Study the Impact of Vancomycin Area under the Concentration-Time Curve-Guided Dosing on Vancomycin-Associated Nephrotoxicity

PubMed Central

Finch, Natalie A.; Zasowski, Evan J.; Murray, Kyle P.; Mynatt, Ryan P.; Zhao, Jing J.; Yost, Raymond; Pogue, Jason M.

2017-01-01

ABSTRACT Evidence suggests that maintenance of vancomycin trough concentrations at between 15 and 20 mg/liter, as currently recommended, is frequently unnecessary to achieve the daily area under the concentration-time curve (AUC24) target of ≥400 mg · h/liter. Many patients with trough concentrations in this range have AUC24 values in excess of the therapeutic threshold and within the exposure range associated with nephrotoxicity. On the basis of this, the Detroit Medical Center switched from trough concentration-guided dosing to AUC-guided dosing to minimize potentially unnecessary vancomycin exposure. The primary objective of this analysis was to assess the impact of this intervention on vancomycin-associated nephrotoxicity in a single-center, retrospective quasi-experiment of hospitalized adult patients receiving intravenous vancomycin from 2014 to 2015. The primary analysis compared the incidence of nephrotoxicity between patients monitored by assessment of the AUC24 and those monitored by assessment of the trough concentration. Multivariable logistic and Cox proportional hazards regression examined the independent association between the monitoring strategy and nephrotoxicity. Secondary analysis compared vancomycin exposures (total daily dose, AUC, and trough concentrations) between monitoring strategies. Overall, 1,280 patients were included in the analysis. After adjusting for severity of illness, comorbidity, duration of vancomycin therapy, and concomitant receipt of nephrotoxins, AUC-guided dosing was independently associated with lower nephrotoxicity by both logistic regression (odds ratio, 0.52; 95% confidence interval [CI], 0.34 to 0.80; P = 0.003) and Cox proportional hazards regression (hazard ratio, 0.53; 95% CI, 0.35 to 0.78; P = 0.002). AUC-guided dosing was associated with lower total daily vancomycin doses, AUC values, and trough concentrations. Vancomycin AUC-guided dosing was associated with reduced nephrotoxicity, which appeared to be a result of reduced vancomycin exposure. PMID:28923869

A Quasi-Experiment To Study the Impact of Vancomycin Area under the Concentration-Time Curve-Guided Dosing on Vancomycin-Associated Nephrotoxicity.

PubMed

Finch, Natalie A; Zasowski, Evan J; Murray, Kyle P; Mynatt, Ryan P; Zhao, Jing J; Yost, Raymond; Pogue, Jason M; Rybak, Michael J

2017-12-01

Evidence suggests that maintenance of vancomycin trough concentrations at between 15 and 20 mg/liter, as currently recommended, is frequently unnecessary to achieve the daily area under the concentration-time curve (AUC 24 ) target of ≥400 mg · h/liter. Many patients with trough concentrations in this range have AUC 24 values in excess of the therapeutic threshold and within the exposure range associated with nephrotoxicity. On the basis of this, the Detroit Medical Center switched from trough concentration-guided dosing to AUC-guided dosing to minimize potentially unnecessary vancomycin exposure. The primary objective of this analysis was to assess the impact of this intervention on vancomycin-associated nephrotoxicity in a single-center, retrospective quasi-experiment of hospitalized adult patients receiving intravenous vancomycin from 2014 to 2015. The primary analysis compared the incidence of nephrotoxicity between patients monitored by assessment of the AUC 24 and those monitored by assessment of the trough concentration. Multivariable logistic and Cox proportional hazards regression examined the independent association between the monitoring strategy and nephrotoxicity. Secondary analysis compared vancomycin exposures (total daily dose, AUC, and trough concentrations) between monitoring strategies. Overall, 1,280 patients were included in the analysis. After adjusting for severity of illness, comorbidity, duration of vancomycin therapy, and concomitant receipt of nephrotoxins, AUC-guided dosing was independently associated with lower nephrotoxicity by both logistic regression (odds ratio, 0.52; 95% confidence interval [CI], 0.34 to 0.80; P = 0.003) and Cox proportional hazards regression (hazard ratio, 0.53; 95% CI, 0.35 to 0.78; P = 0.002). AUC-guided dosing was associated with lower total daily vancomycin doses, AUC values, and trough concentrations. Vancomycin AUC-guided dosing was associated with reduced nephrotoxicity, which appeared to be a result of reduced vancomycin exposure. Copyright © 2017 American Society for Microbiology.

Methylmercury-induced changes in gene transcription associated with neuroendocrine disruption in largemouth bass (Micropterus salmoides)

PubMed Central

Annis, Mandy L.; Brumbaugh, William G.; Chasar, Lia C.; Denslow, Nancy D.; Tillitt, Donald E.

2014-01-01

Methyl-mercury (MeHg) is a potent neuroendocrine disruptor that impairs reproductive processes in fish. The objectives of this study were to (1) characterize transcriptomic changes induced by MeHg exposure in the female largemouth bass (LMB) hypothalamus under controlled laboratory conditions, (2) investigate the health and reproductive impacts of MeHg exposure on male and female largemouth bass (LMB) in the natural environment, and (3) identify MeHg-associated gene expression patterns in whole brain of female LMB from MeHg-contaminated habitats. The laboratory experiment was a single injection of 2.5 μg MeHg/g body weight for 96 h exposure. The field survey compared river systems in Florida, USA with comparably lower concentrations of MeHg (Wekiva, Santa Fe, and St. Johns Rivers) in fish and one river system with LMB that contained elevated concentrations of MeHg (St. Marys River). Microarray analysis was used to quantify transcriptomic responses to MeHg exposure. Although fish at the high-MeHg site did not show overt health or reproductive impairment, there were MeHg-responsive genes and pathways identified in the laboratory study that were also altered in fish from the high-MeHg site relative to fish at the low-MeHg sites. Gene network analysis suggested that MeHg regulated the expression targets of neuropeptide receptor and steroid signaling, as well as structural components of the cell. Disease-associated gene networks related to MeHg exposure, based upon expression data, included cerebellum ataxia, movement disorders, and hypercalcemia. Gene responses in the CNS are consistent with the documented neurotoxicological and neuroendocrine disrupting effects of MeHg in vertebrates. PMID:24694518

Oxidative Stress Biomarkers in Exhaled Breath of Workers Exposed to Crystalline Silica Dust by SPME-GC-MS.

PubMed

Jalali, Mahdi; Zare Sakhvidi, Mohammad Javad; Bahrami, Abdulrahman; Berijani, Nima; Mahjub, Hussein

2016-01-01

Silicosis is considered an oxidative stress related disease that can lead to the development of lung cancer. In this study, our purpose was to analysis of volatile organic compounds (VOCs) in the exhaled breath of workers exposed to silica containing dust and compare peak area of these compounds with silicosis patients and healthy volunteers (smokers and nonsmokers) groups. In this cross sectional case-control study, the exhaled breath of 69 subjects including workers exposed to silica (n=20), silicosis patient (n=4), healthy non-smoker (n=20) and healthy smoker (n=25) were analyzed. We collected breath samples using 3-liter Tedlar bags. The VOCs were extracted with solid phase micro-extraction (SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS). Personal exposure intensity was measured according to NIOSH 7601 method. Respiratory parameters were measured using spirometry. Seventy percent and 100% of the exposures to crystalline silica dust exceeded from 8 h TWA ACGIH TLVs in case and positive control groups, respectively. A significant negative correlation was found between dust exposure intensity and FEV1/FVC when exposure and positive control groups were studied in a group (r2=-0.601, P<0.001). Totally, forty VOCs were found in all exhaled breath samples. Among the VOCs, the mean of peak area acetaldehyde, hexanal, nonanal, decane, pentad cane, 2-propanol and 3-hydroxy-2-butanone were higher in exhaled breath of the workers exposed to silica and silicosis patient compared to the healthy smoker and nonsmoker controls. In some cases the difference was significant (P<0.05). The analysis of some VOCs in exhaled breath of subjects is appropriate biomarker to determine of exposure to silica.

Methylmercury-induced changes in gene transcription associated with neuroendocrine disruption in largemouth bass (Micropterus salmoides).

PubMed

Richter, Catherine A; Martyniuk, Christopher J; Annis, Mandy L; Brumbaugh, William G; Chasar, Lia C; Denslow, Nancy D; Tillitt, Donald E

2014-07-01

Methyl-mercury (MeHg) is a potent neuroendocrine disruptor that impairs reproductive processes in fish. The objectives of this study were to (1) characterize transcriptomic changes induced by MeHg exposure in the female largemouth bass (LMB) hypothalamus under controlled laboratory conditions, (2) investigate the health and reproductive impacts of MeHg exposure on male and female largemouth bass (LMB) in the natural environment, and (3) identify MeHg-associated gene expression patterns in whole brain of female LMB from MeHg-contaminated habitats. The laboratory experiment was a single injection of 2.5 μg MeHg/g body weight for 96 h exposure. The field survey compared river systems in Florida, USA with comparably lower concentrations of MeHg (Wekiva, Santa Fe, and St. Johns Rivers) in fish and one river system with LMB that contained elevated concentrations of MeHg (St. Marys River). Microarray analysis was used to quantify transcriptomic responses to MeHg exposure. Although fish at the high-MeHg site did not show overt health or reproductive impairment, there were MeHg-responsive genes and pathways identified in the laboratory study that were also altered in fish from the high-MeHg site relative to fish at the low-MeHg sites. Gene network analysis suggested that MeHg regulated the expression targets of neuropeptide receptor and steroid signaling, as well as structural components of the cell. Disease-associated gene networks related to MeHg exposure, based upon expression data, included cerebellum ataxia, movement disorders, and hypercalcemia. Gene responses in the CNS are consistent with the documented neurotoxicological and neuroendocrine disrupting effects of MeHg in vertebrates. Published by Elsevier Inc.

Mortality among styrene-exposed workers in the reinforced plastic boatbuilding industry.

PubMed

Ruder, Avima M; Meyers, Alysha R; Bertke, Stephen J

2016-02-01

We updated mortality through 2011 for 5203 boat-building workers potentially exposed to styrene, and analysed mortality among 1678 employed a year or more between 1959 and 1978. The a priori hypotheses: excess leukaemia and lymphoma would be found. Standardised mortality ratios (SMRs) and 95% CIs and standardised rate ratios (SRRs) used Washington State rates and a person-years analysis programme, LTAS.NET. The SRR analysis compared outcomes among tertiles of estimated cumulative potential styrene exposure. Overall, 598 deaths (SMR=0.96, CI 0.89 to 1.04) included excess lung (SMR=1.23, CI 0.95 to 1.56) and ovarian cancer (SMR 3.08, CI 1.00 to 7.19), and chronic obstructive pulmonary disease (COPD) (SMR=1.15, CI 0.81 to 1.58). Among 580 workers with potential high-styrene exposure, COPD mortality increased 2-fold (SMR=2.02, CI 1.08 to 3.46). COPD was more pronounced among those with potential high-styrene exposure. However, no outcome was related to estimated cumulative styrene exposure, and there was no change when latency was taken into account. We found no excess leukaemia or lymphoma mortality. As in most occupational cohort studies, lack of information on lifestyle factors or other employment was a substantial limitation although we excluded from the analyses those (n=3525) who worked <1 year. Unanticipated excess ovarian cancer mortality could be a chance finding. Comparing subcohorts with potential high-styrene and low-styrene exposure, COPD mortality SRR was elevated while lung cancer SRR was not, suggesting that smoking was not the only cause for excess COPD mortality. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Methylmercury-induced changes in gene transcription associated with neuroendocrine disruption in largemouth bass (Micropterus salmoides)

USGS Publications Warehouse

Richter, Catherine A.; Martyniuk, Christopher J.; Annis, Mandy L.; Brumbaugh, William G.; Chasar, Lia C.; Denslow, Nancy D.; Tillitt, Donald E.

2014-01-01

Methyl-mercury (MeHg) is a potent neuroendocrine disruptor that impairs reproductive processes in fish. The objectives of this study were to (1) characterize transcriptomic changes induced by MeHg exposure in the female largemouth bass (LMB) hypothalamus under controlled laboratory conditions, (2) investigate the health and reproductive impacts of MeHg exposure on male and female largemouth bass (LMB) in the natural environment, and (3) identify MeHg-associated gene expression patterns in whole brain of female LMB from MeHg-contaminated habitats. The laboratory experiment was a single injection of 2.5 μg MeHg/g body weight for 96 h exposure. The field survey compared river systems in Florida, USA with comparably lower concentrations of MeHg (Wekiva, Santa Fe, and St. Johns Rivers) in fish and one river system with LMB that contained elevated concentrations of MeHg (St. Marys River). Microarray analysis was used to quantify transcriptomic responses to MeHg exposure. Although fish at the high-MeHg site did not show overt health or reproductive impairment, there were MeHg-responsive genes and pathways identified in the laboratory study that were also altered in fish from the high-MeHg site relative to fish at the low-MeHg sites. Gene network analysis suggested that MeHg regulated the expression targets of neuropeptide receptor and steroid signaling, as well as structural components of the cell. Disease-associated gene networks related to MeHg exposure, based upon expression data, included cerebellum ataxia, movement disorders, and hypercalcemia. Gene responses in the CNS are consistent with the documented neurotoxicological and neuroendocrine disrupting effects of MeHg in vertebrates.

Performance evaluation of power transmission coils for powering endoscopic wireless capsules.

PubMed

Basar, Md Rubel; Ahmad, Mohd Yazed; Cho, Jongman; Ibrahim, Fatimah

2015-01-01

This paper presents an analysis of H-field generated by a simple solenoid, pair of solenoids, pair of double-layer solenoids, segmented-solenoid, and Helmholtz power transmission coils (PTCs) to power an endoscopic wireless capsule (WC). The H-fields were computed using finite element analysis based on partial differential equations. Three parameters were considered in the analysis: i) the maximum level of H-field (Hmax) to which the patient's body would be exposed, ii) the minimum level of H-field (Hmin) effective for power transmission, and iii) uniformity of H-field. We validated our analysis by comparing the computed data with data measured from a fabricated Helmholtz PTC. This analysis disclosed that at the same excitation power, all the PTCs are able to transfer same amount of minimum usable power since they generated almost equal value of Hmin. The level of electromagnetic exposure and power transfer stability across all the PTCs would vary significantly which is mainly due to the different level of Hmax and H-field uniformity. The segmented solenoid PTC would cause the lowest exposure and this PTC can transfer the maximum amount of power. The Helmholtz PTC would be able to transfer the most stable power with a moderate level of exposure.

Impact of cytochrome P450 2C19 polymorphisms on citalopram/escitalopram exposure: a systematic review and meta-analysis.

PubMed

Chang, Ming; Tybring, Gunnel; Dahl, Marja-Liisa; Lindh, Jonatan D

2014-09-01

Citalopram and escitalopram, selective serotonin reuptake inhibitors, are primarily metabolized by cytochrome P450 (CYP) 2C19, which is a highly polymorphic enzyme known to cause inter-individual differences in pharmacokinetics. However, the impact of CYP2C19 polymorphisms on citalopram or escitalopram exposure has yet to be fully clarified, especially with regard to the quantitative impact of the CYP2C19*17 allele. The objective of this study was to quantify the effect of functional CYP2C19 allele variants on citalopram/escitalopram exposure. We performed a systematic review and meta-analysis with a structured search algorithm and eligibility criteria for including related studies, calculating the change of citalopram or escitalopram exposure associated with CYP2C19*2, *3, and *17 as compared with CYP2C19*1 using fixed-effect and random-effects models. Assessment of publication bias was performed by means of funnel plots and sensitivity analysis using meta-regressions. The pre-defined review protocol was registered at the PROSPERO international prospective register of systematic reviews, registration number CRD42013004106. Sixteen studies from 14 publications met the inclusion criteria. Eligible studies included 847 patients from psychiatric patient trials and 140 healthy subjects from pharmacokinetic studies. Compared to subjects with the EM/EM (CYP2C19*1/*1) genotype, the exposure to (es)citalopram increased by 95 % (95 % CI 40-149, p < 0.0001) in the poor metabolizer (PM)/PM (CYP2C19*2 or *3/*2 or *3), 30 % (95 % CI 4-55, p < 0.05) in the extensive metabolizer (EM)/PM (CYP2C19*1/*2 or *3), and 25 % (95 % CI 1-49, p < 0.05) in the ultrarapid metabolizer (UM)/PM (CYP2C19*17/*2 or *3) groups. In contrast, the exposure to (es)citalopram decreased by 36 % (95 % CI 27-46, p < 0.0001) in the UM/UM (CYP2C19*17/*17) and by 14 % (95 % CI 1-27, p < 0.05) in the UM/EM (CYP2C19*17/*1). This is the first meta-analysis based on a systematic review of accumulated information that addresses the relationship between CYP2C19 genotypes and the exposure to citalopram or escitalopram. All functional CYP2C19 genotype groups demonstrated significant effects on (es)citalopram exposure. The findings based on our pooled analysis are likely to help in understanding the inter-individual variability in the exposure to citalopram and escitalopram in psychiatric patients and to facilitate dose selection, particularly for the homozygous carriers of CYP2C19*2 or *3 (loss of function) and CYP2C19*17 (gain of function) alleles. The results could improve individualization of citalopram or escitalopram therapy and could also be used for physiologically based pharmacokinetic modeling as well as pharmacokinetic/pharmacodynamic modeling.

Estimating Pesticide Exposure from Dietary Intake and Organic Food Choices: The Multi-Ethnic Study of Atherosclerosis (MESA)

PubMed Central

Beresford, Shirley A.A.; Fenske, Richard A.; Fitzpatrick, Annette L.; Lu, Chensheng; Nettleton, Jennifer A.; Kaufman, Joel D.

2015-01-01

Background Organophosphate pesticide (OP) exposure to the U.S. population is dominated by dietary intake. The magnitude of exposure from diet depends partly on personal decisions such as which foods to eat and whether to choose organic food. Most studies of OP exposure rely on urinary biomarkers, which are limited by short half-lives and often lack specificity to parent compounds. A reliable means of estimating long-term dietary exposure to individual OPs is needed to assess the potential relationship with adverse health effects. Objectives We assessed long-term dietary exposure to 14 OPs among 4,466 participants in the Multi-Ethnic Study of Atherosclerosis, and examined the influence of organic produce consumption on this exposure. Methods Individual-level exposure was estimated by combining information on typical intake of specific food items with average OP residue levels on those items. In an analysis restricted to a subset of participants who reported rarely or never eating organic produce (“conventional consumers”), we assessed urinary dialkylphosphate (DAP) levels across tertiles of estimated exposure (n = 480). In a second analysis, we compared DAP levels across subgroups with differing self-reported organic produce consumption habits (n = 240). Results Among conventional consumers, increasing tertile of estimated dietary OP exposure was associated with higher DAP concentrations (p < 0.05). DAP concentrations were also significantly lower in groups reporting more frequent consumption of organic produce (p < 0.02). Conclusions Long-term dietary exposure to OPs was estimated from dietary intake data, and estimates were consistent with DAP measurements. More frequent consumption of organic produce was associated with lower DAPs. Citation Curl CL, Beresford SA, Fenske RA, Fitzpatrick AL, Lu C, Nettleton JA, Kaufman JD. 2015. Estimating pesticide exposure from dietary intake and organic food choices: the Multi-Ethnic Study of Atherosclerosis (MESA). Environ Health Perspect 123:475–483; http://dx.doi.org/10.1289/ehp.1408197 PMID:25650532

Bayesian adjustment for measurement error in continuous exposures in an individually matched case-control study.

PubMed

Espino-Hernandez, Gabriela; Gustafson, Paul; Burstyn, Igor

2011-05-14

In epidemiological studies explanatory variables are frequently subject to measurement error. The aim of this paper is to develop a Bayesian method to correct for measurement error in multiple continuous exposures in individually matched case-control studies. This is a topic that has not been widely investigated. The new method is illustrated using data from an individually matched case-control study of the association between thyroid hormone levels during pregnancy and exposure to perfluorinated acids. The objective of the motivating study was to examine the risk of maternal hypothyroxinemia due to exposure to three perfluorinated acids measured on a continuous scale. Results from the proposed method are compared with those obtained from a naive analysis. Using a Bayesian approach, the developed method considers a classical measurement error model for the exposures, as well as the conditional logistic regression likelihood as the disease model, together with a random-effect exposure model. Proper and diffuse prior distributions are assigned, and results from a quality control experiment are used to estimate the perfluorinated acids' measurement error variability. As a result, posterior distributions and 95% credible intervals of the odds ratios are computed. A sensitivity analysis of method's performance in this particular application with different measurement error variability was performed. The proposed Bayesian method to correct for measurement error is feasible and can be implemented using statistical software. For the study on perfluorinated acids, a comparison of the inferences which are corrected for measurement error to those which ignore it indicates that little adjustment is manifested for the level of measurement error actually exhibited in the exposures. Nevertheless, a sensitivity analysis shows that more substantial adjustments arise if larger measurement errors are assumed. In individually matched case-control studies, the use of conditional logistic regression likelihood as a disease model in the presence of measurement error in multiple continuous exposures can be justified by having a random-effect exposure model. The proposed method can be successfully implemented in WinBUGS to correct individually matched case-control studies for several mismeasured continuous exposures under a classical measurement error model.

Exposure to tobacco secondhand smoke and its associated factors among non-smoking adults in smoking-restricted and non-restricted areas: findings from a nationwide study in Malaysia

PubMed Central

Lim, Kuang Hock; Teh, Chien Huey; Nik Mohamed, Mohamad Haniki; Pan, Sayan; Ling, Miaw Yn; Mohd Yusoff, Muhammad Fadhli; Hassan, Noraryana; Baharom, Nizam; Dawam, Netty Darwina; Ismail, Norliana; Ghazali, Sumarni Mohd; Cheong, Kee Chee; Chong, Kar Hon; Lim, Hui Li

2018-01-01

Objectives Secondhand smoke (SHS) has been associated with increased morbidity and mortality. Therefore, the aims of the paper are to assess SHS exposure among non-smoking adults in Malaysia attending various smoking-restricted and non-restricted public areas according to the Control of Tobacco Product Regulations (CTPR) as well as its relationship with various sociodemographic variables. Design Data were extracted from a cross-sectional study, the Global Adults Tobacco Survey (GATS) 2011 which involved 3269 non-smokers in Malaysia. Data was obtained through face-to-face interviews using a validated pre-tested questionnaire. Factors associated with exposure to SHS were identified via multivariable analysis. Results The study revealed that almost two-thirds of respondents were exposed to SHS in at least one public area in the past 1 month, with a significantly higher exposure among males (70.6%), those with higher educational attainment (81.4%) and higher income (quintile 1%–73.9%). Besides, the exposure to SHS was almost four times higher in non-restricted areas compared with restricted areas under the CTPR (81.9% vs 22.9). Multivariable analysis revealed that males and younger adults at non-restricted areas were more likely to be exposed to SHS while no significant associated factors of SHS exposure was observed in restricted areas. Conclusions The study revealed the prevalence of SHS exposure was higher among Malaysian adults. Although smoke-free laws offer protection to non-smokers from exposure to SHS, enforcement activities in restricted areas should be enhanced to ensure strict public abidance. In addition, legislation of restricted areas should also be extended to greatly reduce the SHS exposure among non-smokers in Malaysia. PMID:29317411

Radio frequency electromagnetic field exposure in humans: Estimation of SAR distribution in the brain, effects on sleep and heart rate.

PubMed

Huber, Reto; Schuderer, Jürgen; Graf, Thomas; Jütz, Kathrin; Borbély, Alexander A; Kuster, Niels; Achermann, Peter

2003-05-01

In two previous studies we demonstrated that radiofrequency electromagnetic fields (RF EMF) similar to those emitted by digital radiotelephone handsets affect brain physiology of healthy young subjects exposed to RF EMF (900 MHz; spatial peak specific absorption rate [SAR] 1 W/kg) either during sleep or during the waking period preceding sleep. In the first experiment, subjects were exposed intermittently during an 8 h nighttime sleep episode and in the second experiment, unilaterally for 30 min prior to a 3 h daytime sleep episode. Here we report an extended analysis of the two studies as well as the detailed dosimetry of the brain areas, including the assessment of the exposure variability and uncertainties. The latter enabled a more in depth analysis and discussion of the findings. Compared to the control condition with sham exposure, spectral power of the non-rapid eye movement sleep electroencephalogram (EEG) was initially increased in the 9-14 Hz range in both experiments. No topographical differences with respect to the effect of RF EMF exposure were observed in the two experiments. Even unilateral exposure during waking induced a similar effect in both hemispheres. Exposure during sleep reduced waking after sleep onset and affected heart rate variability. Exposure prior to sleep reduced heart rate during waking and stage 1 sleep. The lack of asymmetries in the effects on sleep EEG, independent of bi- or unilateral exposure of the cortex, may indicate involvement of subcortical bilateral projections to the cortex in the generation of brain function changes, especially since the exposure of the thalamus was similar in both experiments (approx. 0.1 W/kg). Copyright 2003 Wiley-Liss, Inc.

Evaluation of air quality zone classification methods based on ambient air concentration exposure.

PubMed

Freeman, Brian; McBean, Ed; Gharabaghi, Bahram; Thé, Jesse

2017-05-01

Air quality zones are used by regulatory authorities to implement ambient air standards in order to protect human health. Air quality measurements at discrete air monitoring stations are critical tools to determine whether an air quality zone complies with local air quality standards or is noncompliant. This study presents a novel approach for evaluation of air quality zone classification methods by breaking the concentration distribution of a pollutant measured at an air monitoring station into compliance and exceedance probability density functions (PDFs) and then using Monte Carlo analysis with the Central Limit Theorem to estimate long-term exposure. The purpose of this paper is to compare the risk associated with selecting one ambient air classification approach over another by testing the possible exposure an individual living within a zone may face. The chronic daily intake (CDI) is utilized to compare different pollutant exposures over the classification duration of 3 years between two classification methods. Historical data collected from air monitoring stations in Kuwait are used to build representative models of 1-hr NO 2 and 8-hr O 3 within a zone that meets the compliance requirements of each method. The first method, the "3 Strike" method, is a conservative approach based on a winner-take-all approach common with most compliance classification methods, while the second, the 99% Rule method, allows for more robust analyses and incorporates long-term trends. A Monte Carlo analysis is used to model the CDI for each pollutant and each method with the zone at a single station and with multiple stations. The model assumes that the zone is already in compliance with air quality standards over the 3 years under the different classification methodologies. The model shows that while the CDI of the two methods differs by 2.7% over the exposure period for the single station case, the large number of samples taken over the duration period impacts the sensitivity of the statistical tests, causing the null hypothesis to fail. Local air quality managers can use either methodology to classify the compliance of an air zone, but must accept that the 99% Rule method may cause exposures that are statistically more significant than the 3 Strike method. A novel method using the Central Limit Theorem and Monte Carlo analysis is used to directly compare different air standard compliance classification methods by estimating the chronic daily intake of pollutants. This method allows air quality managers to rapidly see how individual classification methods may impact individual population groups, as well as to evaluate different pollutants based on dosage and exposure when complete health impacts are not known.

The effect of methylmercury exposure on behavior and cerebellar granule cell physiology in aged mice.

PubMed

Bellum, Sairam; Thuett, Kerry A; Bawa, Bhupinder; Abbott, Louise C

2013-09-01

Epidemiology studies have clearly documented that the central nervous system is highly susceptible to methylmercury toxicity, and exposure to this neurotoxicant in humans primarily results from consumption of contaminated fish. While the effects of methylmercury exposure have been studied in great detail, comparatively little is known about the effects of moderate to low dose methylmercury toxicity in the aging central nervous system. We examined the toxic effects of a moderate dose of methylmercury on the aging mouse cerebellum. Male and female C57BL/6 mice at 16-20 months of age were exposed to methylmercury by feeding a total dose of 5.0 mg kg(-1) body weight and assessed using four behavioral tests. Methylmercury-treated aged mice performed significantly worse in open field, footprint analysis and the vertical pole test compared with age-matched control mice. Isolated cerebellar granule cells from methylmercury-treated aged mice exhibited higher levels of reactive oxygen species and reduced mitochondrial membrane potentials, but no differences in basal intracellular calcium ion levels compared with age-matched control mice. When aged mice were exposed to a moderate dose of methylmercury, they exhibited a similar degree of impairment when compared with young adult mice exposed to the same moderate dose of methylmercury, as reported in earlier studies from this laboratory. Thus, at least in mice, exposure of the aged brain to moderate concentrations methylmercury does not pose greater risk compared with the young adult brain exposed to similar concentrations of methylmercury. Copyright © 2012 John Wiley & Sons, Ltd.

Effects of thermal and environmental exposure on the mechanical properties of graphite/polyimide composites

NASA Technical Reports Server (NTRS)

Hanson, M. P.; Serafini, T. T.

1971-01-01

Composites were exposed in circulating and static air environments up to 589 K for a maximum of 1000 hours. Composites of HT-S, HM-S, Thornel 50S, and Fortafil 5-Y fiber and a new addition type polyimide resin were laminated in a matched-die mold. Flexural strengths, flexural modulus, and interlaminar shear strengths were determined at 297, 533, and 598 K after various durations of exposure. Composite and fiber weight loss characteristics were determined by isothermal gravimetric analysis in air. Properties of composites exposed and tested at the environment temperatures were compared with those determined under short-term exposure. A new short beam interlaminar shear fixture is described. Environmental effects of long-term ambient temperature exposure on the elevated temperature mechanical properties of graphite/polyimide composites are presented.

Brief Embryonic Strychnine Exposure in Zebrafish Causes Long-Term Adult Behavioral Impairment with Indications of Embryonic Synaptic Changes

PubMed Central

Roy, Nicole M.; Arpie, Brianna; Lugo, Joseph; Linney, Elwood; Levin, Edward D.; Cerutti, Daniel

2015-01-01

Zebrafish provide a powerful model of the impacts of embryonic toxicant exposure on neural development that may result in long-term behavioral dysfunction. In this study, zebrafish embryos were treated with 1.5 mM strychnine for short embryonic time windows to induce transient changes in inhibitory neural signaling, and were subsequently raised in untreated water until adulthood. PCR analysis showed indications that strychnine exposure altered expression of some genes related to glycinergic, GABAergic and glutamatergic neuronal synapses during embryonic development. In adulthood, treated fish showed significant changes in swimming speed and tank diving behavior compared to controls. Taken together, these data show that a short embryonic exposure to a neurotoxicant can alter development of neural synapses and lead to changes in adult behavior. PMID:23022260

Brief embryonic strychnine exposure in zebrafish causes long-term adult behavioral impairment with indications of embryonic synaptic changes.

PubMed

Roy, Nicole M; Arpie, Brianna; Lugo, Joseph; Linney, Elwood; Levin, Edward D; Cerutti, Daniel

2012-01-01

Zebrafish provide a powerful model of the impacts of embryonic toxicant exposure on neural development that may result in long-term behavioral dysfunction. In this study, zebrafish embryos were treated with 1.5mM strychnine for short embryonic time windows to induce transient changes in inhibitory neural signaling, and were subsequently raised in untreated water until adulthood. PCR analysis showed indications that strychnine exposure altered expression of some genes related to glycinergic, GABAergic and glutamatergic neuronal synapses during embryonic development. In adulthood, treated fish showed significant changes in swimming speed and tank diving behavior compared to controls. Taken together, these data show that a short embryonic exposure to a neurotoxicant can alter development of neural synapses and lead to changes in adult behavior. Copyright © 2012 Elsevier Inc. All rights reserved.

Beyond the limits of present active matrix flat-panel imagers (AMFPIs) for diagnostic radiology

NASA Astrophysics Data System (ADS)

Antonuk, Larry E.; El-Mohri, Youcef; Jee, Kyung-Wook; Maolinbay, Manat; Nassif, Samer C.; Rong, Xiujiang; Siewerdsen, Jeffrey H.; Zhao, Qihua; Street, Robert A.

1999-05-01

A theoretical cascaded systems analysis of the performance limits of x-ray imagers based on thin-film, active matrix flat-panel technology is presented. This analysis specifically focuses upon an examination of the functional dependence of the detective quantum efficiency on exposure. While the DQE of AMFPI systems is relatively high at the large exposure levels associated with radiographic x-ray imaging, there is a significant decline in DQE with decreasing exposure over the medium and lower end of the exposure range associated with fluoroscopic imaging. This fall-off in DQE originates from the relatively large size of the additive noise of AMFPI systems compared to their overall system gain. Therefore, strategies to diminish additive noise and increase system gain should significantly improve performance. Potential strategies for noise reduction include the use of charge compensation lines while strategies for gain enhancement include continuous photodiodes, pixel amplification structures, or higher gain converters. The effect of the implementation of such strategies is examined for a variety for hypothetical imager configurations. Through the modeling of these configurations, such enhancements are shown to hold the potential of making low frequency DQE response large and essentially independent of exposure while greatly reducing the fall-off in DQE at higher spatial frequencies.

Inhalation exposure to isocyanates of car body repair shop workers and industrial spray painters.

PubMed

Pronk, Anjoeka; Tielemans, Erik; Skarping, Gunnar; Bobeldijk, Ivana; VAN Hemmen, Joop; Heederik, Dick; Preller, Liesbeth

2006-01-01

As part of a large-scale epidemiological study, occupational isocyanate exposure was assessed in spray-painting environments. The aim was to assess which compounds contribute to isocyanate exposure in car body repair shops and industrial painting companies, and to identify tasks with high risk of isocyanate exposure. Mainly personal task-based samples (n = 566) were collected from 24 car body repair shops and five industrial painting companies using impingers with DBA in toluene. Samples were analysed by LC-MS for isocyanate monomers, oligomers and products of thermal degradation. From the 23 analysed compounds, 20 were detected. Exploratory factor analysis resulted in a HDI, TDI and MDI factor with the thermal degradation products divided over the TDI and MDI factors. The HDI factor mainly consisted of HDI oligomers and was dominant in frequency and exposure levels in both industries. Spray painting of PU lacquers resulted in the highest exposures for the HDI factor (

Laboratory and exterior decay of wood plastic composite boards: voids analysis and computed tomography

Treesearch

Grace Sun; Rebecca E. Ibach; Meghan Faillace; Marek Gnatowski; Jessie A. Glaeser; John Haight

2016-01-01

After exposure in the field and laboratory soil block culture testing, the void content of wood–plastic composite (WPC) decking boards was compared to unexposed samples. A void volume analysis was conducted based on calculations of sample density and from micro-computed tomography (microCT) data. It was found that reference WPC contains voids of different sizes from...

Evaluation of Potential Exposure to Metals in Laundered Shop Towels

PubMed Central

Greenberg, Grace; Beck, Barbara D.

2013-01-01

We reported in 2003 that exposure to metals on laundered shop towels (LSTs) could exceed toxicity criteria. New data from LSTs used by workers in North America document the continued presence of metals in freshly laundered towels. We assessed potential exposure to metals based on concentrations of metals on the LSTs, estimates of LST usage by employees, and the transfer of metals from LST-to-hand, hand-to-mouth, and LST-to-lip, under average- or high-exposure scenarios. Exposure estimates were compared to toxicity criteria. Under an average-exposure scenario (excluding metals' data outliers), exceedances of the California Environmental Protection Agency, U.S. Environmental Protection Agency, and the Agency for Toxic Substances and Disease Registry toxicity criteria may occur for aluminum, cadmium, cobalt, copper, iron, and lead. Calculated intakes for these metals were up to more than 400-fold higher (lead) than their respective toxicity criterion. For the high-exposure scenario, additional exceedances may occur, and high-exposure intakes were up to 1,170-fold higher (lead) than their respective toxicity criterion. A sensitivity analysis indicated that alternate plausible assumptions could increase or decrease the magnitude of exceedances, but were unlikely to eliminate certain exceedances, particularly for lead. PMID:24453472

Investigation on circular asymmetry of geographical distribution in cancer mortality of Hiroshima atomic bomb survivors based on risk maps: analysis of spatial survival data.

PubMed

Tonda, Tetsuji; Satoh, Kenichi; Otani, Keiko; Sato, Yuya; Maruyama, Hirofumi; Kawakami, Hideshi; Tashiro, Satoshi; Hoshi, Masaharu; Ohtaki, Megu

2012-05-01

While there is a considerable number of studies on the relationship between the risk of disease or death and direct exposure from the atomic bomb in Hiroshima, the risk for indirect exposure caused by residual radioactivity has not yet been fully evaluated. One of the reasons is that risk assessments have utilized estimated radiation doses, but that it is difficult to estimate indirect exposure. To evaluate risks for other causes, including indirect radiation exposure, as well as direct exposure, a statistical method is described here that evaluates risk with respect to individual location at the time of atomic bomb exposure instead of radiation dose. In addition, it is also considered to split the risks into separate risks due to direct exposure and other causes using radiation dose. The proposed method is applied to a cohort study of Hiroshima atomic bomb survivors. The resultant contour map suggests that the region west to the hypocenter has a higher risk compared to other areas. This in turn suggests that there exists an impact on risk that cannot be explained by direct exposure.

Urinary Porphyrin Excretion in Neurotypical and Autistic Children

PubMed Central

Woods, James S.; Armel, Sarah E.; Fulton, Denise I.; Allen, Jason; Wessels, Kristine; Simmonds, P. Lynne; Granpeesheh, Doreen; Mumper, Elizabeth; Bradstreet, J. Jeffrey; Echeverria, Diana; Heyer, Nicholas J.; Rooney, James P.K.

2010-01-01

Background Increased urinary concentrations of pentacarboxyl-, precopro- and copro-porphyrins have been associated with prolonged mercury (Hg) exposure in adults, and comparable increases have been attributed to Hg exposure in children with autism (AU). Objectives This study was designed to measure and compare urinary porphyrin concentrations in neurotypical (NT) children and same-age children with autism, and to examine the association between porphyrin levels and past or current Hg exposure in children with autism. Methods This exploratory study enrolled 278 children 2–12 years of age. We evaluated three groups: AU, pervasive developmental disorder-not otherwise specified (PDD-NOS), and NT. Mothers/caregivers provided information at enrollment regarding medical, dental, and dietary exposures. Urine samples from all children were acquired for analyses of porphyrin, creatinine, and Hg. Differences between groups for mean porphyrin and Hg levels were evaluated. Logistic regression analysis was conducted to determine whether porphyrin levels were associated with increased risk of autism. Results Mean urinary porphyrin concentrations are naturally high in young children and decline by as much as 2.5-fold between 2 and 12 years of age. Elevated copro- (p < 0.009), hexacarboxyl- (p < 0.01) and pentacarboxyl- (p < 0.001) porphyrin concentrations were significantly associated with AU but not with PDD-NOS. No differences were found between NT and AU in urinary Hg levels or in past Hg exposure as determined by fish consumption, number of dental amalgam fillings, or vaccines received. Conclusions These findings identify disordered porphyrin metabolism as a salient characteristic of autism. Hg exposures were comparable between diagnostic groups, and a porphyrin pattern consistent with that seen in Hg-exposed adults was not apparent. PMID:20576582

Time to revisit arsenic regulations: comparing drinking water and rice

PubMed Central

2014-01-01

Background Current arsenic regulations focus on drinking water without due consideration for dietary uptake and thus seem incoherent with respect to the risks arising from rice consumption. Existing arsenic guidelines are a cost-benefit compromise and, as such, they should be periodically re-evaluated. Discussion Literature data was used to compare arsenic exposure from rice consumption relative to exposure arising from drinking water. Standard risk assessment paradigms show that arsenic regulations for drinking water should target a maximum concentration of nearly zero to prevent excessive lung and bladder cancer risks (among others). A feasibility threshold of 3 μg As l-1 was determined, but a cost-benefit analysis concluded that it would be too expensive to target a threshold below 10 μg As l-1. Data from the literature was used to compare exposure to arsenic from rice and rice product consumption relative to drinking water consumption. The exposure to arsenic from rice consumption can easily be equivalent to or greater than drinking water exposure that already exceeds standard risks and is based on feasibility and cost-benefit compromises. It must also be emphasized that many may disagree with the implications for their own health given the abnormally high cancer odds expected at the cost-benefit arsenic threshold. Summary Tighter drinking water quality criteria should be implemented to properly protect people from excessive cancer risks. Food safety regulations must be put in place to prevent higher concentrations of arsenic in various drinks than those allowed in drinking water. Arsenic concentrations in rice should be regulated so as to roughly equate the risks and exposure levels observed from drinking water. PMID:24884827

Omega 3 Fatty Acids Reduce Bone Resorption While Promoting Bone Generation in Rat Apical Periodontitis.

PubMed

Azuma, Mariane Maffei; Gomes-Filho, João Eduardo; Ervolino, Edilson; Pipa, Camila Barbosa; Cardoso, Carolina de Barros Morais; Andrada, Ana Cristina; Kawai, Toshihisa; Cintra, Luciano Tavares Angelo

2017-06-01

This study evaluated the effects of the dietary supplement omega 3 polyunsaturated fatty acids (ω-3 PUFAs) on pulp exposure-induced apical periodontitis (AP) in rats. Twenty-eight male rats were divided into groups: control untreated rats (C), control rats treated with ω-3 PUFAs alone (C-O), rats with pulp exposure-induced AP, and rats with pulp exposure-induced AP treated with ω-3 PUFAs (AP-O). The ω-3 PUFAs were administered orally, once a day, for 15 days before pulp exposure and, subsequently, 30 days after pulp exposure. Rats were killed 30 days after pulp exposure, and jaws were subjected to histologic and immunohistochemical analyses. Immunohistochemical analyses were performed to detect tartrate-resistant acid phosphatase-positive osteoclasts and osteocalcin-positive osteoblasts on the bone surface of periapical area. Results were statistically evaluated by using analysis of variance and Tukey honestly significant difference, and P < .05 was considered statistically significant. The bone resorption lesion was significantly larger in the AP group compared with AP-O, C, and C-O groups (P < .05). The level of inflammatory cell infiltration was significantly elevated, and the number of tartrate-resistant acid phosphatase-positive osteoclasts was significantly higher in the periapical lesions of the AP group compared with AP-O, C, and C-O groups (P < .05). The number of osteocalcin-positive osteoblasts was significantly increased in the AP-O group compared with the AP group (P > .05). Supplementation with ω-3 PUFAs not only suppresses bone resorption but also promotes new bone formation in the periapical area of rats with AP in conjunction with downregulation of inflammatory cell infiltration into the lesion. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Sub-chronic exposure to paraoxon neither induces nor exacerbates diabetes mellitus in Wistar rat.

PubMed

Nurulain, Syed M; Petroianu, Georg; Shafiullah, Mohamed; Kalász, Huba; Oz, Murat; Saeed, Tariq; Adem, Abdu; Adeghate, Ernest

2013-10-01

There is an increasing belief that organophosphorus compounds (OPCs) impair glucose homeostasis and cause hyperglycemia and diabetes mellitus. The present study was undertaken to investigate the putative diabetogenic effect of sub-lethal and sub-chronic exposure to paraoxon (POX), an extremely hazardous OPC used in pesticides. The effect of paraoxon on streptozotocin-induced diabetic rats was also examined. Each rat was injected with 100 nmol of POX 5 days per week for 6 weeks. Blood glucose levels and red blood cell acetylcholinesterase activity were measured weekly. Biochemical analysis and morphological studies were performed at the end of the experiment. The results revealed that POX neither induces nor exacerbates diabetes mellitus in experimental rats. Liver and kidney/body weight ratios revealed statistically insignificant differences when compared with controls. Biochemical analysis of urine samples showed a small but not significant increase in protein level in all groups. Urine bilirubin was significantly higher in the diabetes + POX group when compared with the control group. The number of blood cells in urine was significantly higher in the POX-treated group compared with the control group. Hyperglycemia was noted in the diabetes and diabetes + POX groups, but neither in the saline control nor in POX-treated normal rats. Electron microscopy of POX-treated pancreas did not show any morphological changes in beta cells. These results suggest that POX does not cause diabetes mellitus at sub-lethal sub-chronic exposure. Copyright © 2012 John Wiley & Sons, Ltd.

Analysis of Shear Bond Strength and Morphology of Er:YAG Laser-Recycled Ceramic Orthodontic Brackets.

PubMed

Han, Ruo-qiao; Yang, Kai; Ji, Ling-fei; Ling, Chen

2016-01-01

The aim of this study was to compare the recycling of deboned ceramic brackets via an Er:YAG laser or via the traditional chairside processing methods of flaming and sandblasting; shear bond strength and morphological changes were evaluated in recycled brackets versus new brackets. 3M Clarity Self-Ligating Ceramic Brackets with a microcrystalline base were divided into groups subjected to flaming, sandblasting, or exposure to an Er:YAG laser. New ceramic brackets served as a control group. Shear bond strengths were determined with an Electroforce test machine and tested for statistical significance through analysis of variance. Morphological examinations of the recycled ceramic bracket bases were conducted with scanning electron microscopy and confocal laser scanning microscopy. Residue on the bracket base was analyzed with Raman spectroscopy. Faded, dark adhesive was left on recycled bracket bases processed via flaming. Adhesive was thoroughly removed by both sandblasting and exposure to an Er:YAG laser. Compared with new brackets, shear bond strength was lower after sandblasting (p < 0.05), but not after exposure to an Er:YAG laser. The Er:YAG laser caused no damage to the bracket. Er:YAG lasers effectively remove adhesive from the bases of ceramic brackets without damaging them; thus, this method may be preferred over other recycling methods.

A Meta-Analysis of Treatments for Panic Disorder.

ERIC Educational Resources Information Center

Clum, George A.; And Others

1993-01-01

Used metanalysis to compare effectiveness of psychological and pharmacological treatments for panic disorder. Percentage of agoraphobic subjects in sample and duration of illness were unrelated to effect size (ES). Psychological coping strategies involving relaxation training, cognitive restructuring, and exposure yielded most consistent ESs;…

Magnetic Properties and the Giant Magnetoimpedance of Amorphous Co-Based Wires with a Carbon Coating

NASA Astrophysics Data System (ADS)

Golubeva, E. V.; Stepanova, E. A.; Balymov, K. G.; Volchkov, S. O.; Kurlyandskaya, G. V.

2018-04-01

A comparative analysis of the magnetic properties and specific features of the giant magnetoimpedance has been carried out for amorphous rapidly quenched wires with a composition of (Co0.94Fe0.06)72.5Si12.5B15 in the initial state and after the deposition of a carbon coating. The deposition of the defective graphene-like carbon layer was carried out under normal conditions during the exposure in toluene (methylbenzene). The method of the energy-dispersive X-ray spectroscopy made it possible to reliably show that after the modification in toluene, the carbon content on the surface significantly exceeds the natural amount of carbon. The deposition of the carbon coating induced changes in the distribution of the initial quenching stresses in the near-surface layer of amorphous wires. A comparative analysis of the magnetic and magnetoimpedance properties of the samples before and after exposure in the aromatic solvent confirms the occurrence of changes in the effective magnetic anisotropy as a result of this surface treatment.

Diet-induced obesity reprograms the inflammatory response of the murine lung to inhaled endotoxin

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

Tilton, Susan C., E-mail: susan.tilton@pnnl.gov; Waters, Katrina M.; Karin, Norman J.

The co-occurrence of environmental factors is common in complex human diseases and, as such, understanding the molecular responses involved is essential to determine risk and susceptibility to disease. We have investigated the key biological pathways that define susceptibility for pulmonary infection during obesity in diet-induced obese (DIO) and regular weight (RW) C57BL/6 mice exposed to inhaled lipopolysaccharide (LPS). LPS induced a strong inflammatory response in all mice as indicated by elevated cell counts of macrophages and neutrophils and levels of proinflammatory cytokines (MDC, MIP-1γ, IL-12, RANTES) in the bronchoalveolar lavage fluid. Additionally, DIO mice exhibited 50% greater macrophage cell counts,more » but decreased levels of the cytokines, IL-6, TARC, TNF-α, and VEGF relative to RW mice. Microarray analysis of lung tissue showed over half of the LPS-induced expression in DIO mice consisted of genes unique for obese mice, suggesting that obesity reprograms how the lung responds to subsequent insult. In particular, we found that obese animals exposed to LPS have gene signatures showing increased inflammatory and oxidative stress response and decreased antioxidant capacity compared with RW. Because signaling pathways for these responses can be common to various sources of environmentally induced lung damage, we further identified biomarkers that are indicative of specific toxicant exposure by comparing gene signatures after LPS exposure to those from a parallel study with cigarette smoke. These data show obesity may increase sensitivity to further insult and that co-occurrence of environmental stressors result in complex biosignatures that are not predicted from analysis of individual exposures. - Highlights: ► Obesity modulates inflammatory markers in BAL fluid after LPS exposure. ► Obese animals have a unique transcriptional signature in lung after LPS exposure. ► Obesity elevates inflammatory stress and reduces antioxidant capacity in the lung. ► Toxicant-specific biomarkers predict exposure independent of systemic inflammation.« less

Characterizing risk factors for pediatric lamp oil product exposures.

PubMed

Sheikh, S; Chang, A; Kieszak, S; Law, R; Bennett, H K W; Ernst, E; Bond, G R; Spiller, H A; Schurz-Rogers, H; Chu, A; Bronstein, A C; Schier, J G

2013-11-01

Poisonings from lamp oil ingestion continue to occur worldwide among the pediatric population despite preventive measures such as restricted sale of colored and scented lamp oils. This suggests that optimal prevention practices for unintentional pediatric exposures to lamp oil have yet to be identified and/or properly implemented. To characterize demographic, health data, and potential risk factors associated with reported exposures to lamp oil by callers to poison centers (PCs) in the US and discuss their public health implications. This was a two part study in which the first part included characterizing all exposures to a lamp oil product reported to the National Poison Data System (NPDS) with regard to demographics, exposure, health, and outcome data from 1/1/2000 to 12/31/2010. Regional penetrance was calculated using NPDS data by grouping states into four regions and dividing the number of exposure calls by pediatric population per region (from the 2000 US census). Temporal analyses were performed on NPDS data by comparing number of exposures by season and around the July 4th holiday. Poisson regression was used to model the count of exposures for these analyses. In the second part of this project, in order to identify risk factors we conducted a telephone-based survey to the parents of children from five PCs in five different states. The 10 most recent lamp oil product exposure calls for each poison center were systematically selected for inclusion. Calls in which a parent or guardian witnessed a pediatric lamp oil product ingestion were eligible for inclusion. Data on demographics, exposure information, behavioral traits, and health were collected. A descriptive analysis was performed and Fisher's exact test was used to evaluate associations between variables. All analyses were conducted using SAS v9.3. Among NPDS data, 2 years was the most common patient age reported and states in the Midwestern region had the highest numbers of exposure calls compared to other regions. Exposure calls differed by season (p < 0.0001) and were higher around the July 4th holiday compared to the rest of the days in July (2.09 vs. 1.89 calls/day, p < 0.002). Most exposures occurred inside a house, were managed on-site and also had a "no effect" medical outcome. Of the 50 PC-administered surveys to parents or guardians, 39 (78%) met inclusion criteria for analysis. The majority of ingestions occurred in children that were 2 years of age, that were not alone, involved tiki torch fuel products located on a table or shelf, and occurred inside the home. The amount of lamp oil ingested did not appear to be associated with either the smell (p = 0.19) or the color of the oil (p = 1.00) in this small sample. Approximately half were asymptomatic (n = 18; 46%), and of those that reported symptoms, cough was the most common (n = 20, 95%) complaint. Lamp oil product exposures are most common among young children (around 2 years of age) while at home, not alone and likely as a result of the product being in a child-accessible location. Increasing parental awareness about potential health risks to children from these products and teaching safe storage and handling practices may help prevent both exposures and associated illness. These activities may be of greater benefit in Midwestern states and during summer months (including the period around the July 4th holiday).

Holocaust exposure and subsequent suicide risk: a population-based study.

PubMed

Bursztein Lipsicas, Cendrine; Levav, Itzhak; Levine, Stephen Z

2017-03-01

To examine the association between the extent of genocide exposure and subsequent suicide risk among Holocaust survivors. Persons born in Holocaust-exposed European countries during the years 1922-1945 that immigrated to Israel by 1965 were identified in the Population Registry (N = 209,429), and followed up for suicide (1950-2014). They were divided into three groups based on likely exposure to Nazi persecution: those who immigrated before (indirect; n = 20,229; 10%), during (partial direct; n = 17,189; 8%), and after (full direct; n = 172,061; 82%) World War II. Groups were contrasted for suicide risk, accounting for the extent of genocide in their respective countries of origin, high (>70%) or lower levels (<50%). Cox model survival analyses were computed examining calendar year at suicide. Sensitivity analyses were recomputed for two additional suicide-associated variables (age and years since immigration) for each exposure group. All analyses were adjusted for confounders. Survival analysis showed that compared to the indirect exposure group, the partial direct exposure group from countries with high genocide level had a statistically significant (P < .05) increased suicide risk for the main outcome (calendar year: HR 1.78, 95% CI 1.09, 2.90). This effect significantly (P < .05) replicated in two sensitivity analyses for countries with higher relative levels of genocide (age: HR 1.77, 95% CI 1.09, 2.89; years since immigration: HR 1.85, 95% CI 1.14, 3.02). The full direct exposure group was not at significant suicide risk compared to the indirect exposure group. Suicide associations for groups from countries with relative lower level of genocide were not statistically significant. This study partly converges with findings identifying Holocaust survivors (full direct exposure) as a resilient group. A tentative mechanism for higher vulnerability to suicide risk of the partial direct exposure group from countries with higher genocide exposure includes protracted guilt feelings, having directly witnessed atrocities and escaped death.

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.

Infections and atopy: an exploratory study for a meta-analysis of the "hygiene hypothesis".

PubMed

Randi, G; Altieri, A; Chatenoud, L; Chiaffarino, F; La Vecchia, C

2004-12-01

According to the "hygiene hypothesis" selected allergic diseases could be prevented by exposure to infectious agents during early childhood. This study was performed to assess the feasibility of a future meta-analysis on the "hygiene hypothesis" and atopic diseases. Differences concerning the potential association with a history of infectious events, in terms of magnitude and homogeneity of global risk estimates between the three major atopic diseases (i.e. atopic dermatitis, asthma and allergic rhinitis) were examined. We conducted a preliminary analysis on a sample of articles published on this topic and cited in a recent and authoritative review. The ranges of relative risks estimates (between 0.6 and 0.8) were similar for atopic dermatitis, allergic rhinitis and asthma. Compared with asthma and allergic rhinitis, reported global risk estimates were more stable for atopic dermatitis (lowest heterogeneity). Our analysis suggests that three main categories of indirect markers of exposure to infection can be identified: 1) geographical gradient, 2) indices of potential contact with infectious agents (such as number of siblings) and 3) history of infectious events. In this exploratory study, we chose articles cited in a single review and obtained a preliminary quantification of the association between infections and atopic diseases. The association with indirect markers of infection corresponded to 20% protection for atopic dermatitis, 30% for allergic rhinitis and 40% for asthma. In a subsequent meta-analysis, diseases should be considered separately and differences between types of exposures should be taken into account as one of the major end-points, with attention to time since exposure and disease onset.

Characterization of Thin Film Polymers Through Dynamic Mechanical Analysis and Permeation

NASA Technical Reports Server (NTRS)

Herring, Helen

2003-01-01

Thin polymer films are being considered, as candidate materials to augment the permeation resistance of cryogenic hydrogen fuel tanks such as would be required for future reusable launch vehicles. To evaluate performance of candidate films after environmental exposure, an experimental study was performed to measure the thermal/mechanical and permeation performance of six, commercial-grade materials. Dynamic storage modulus, as measured by Dynamic Mechanical Analysis, was found over a range of temperatures. Permeability, as measured by helium gas diffusion, was found at room temperature. Test data was correlated with respect to film type and pre-test exposure to moisture, elevated temperature, and cryogenic temperature. Results indicated that the six films were comparable in performance and their resistance to environmental degradation.

Comparing Dimensional Accuracy Between a Polyvinyl Chloride Skull and Its Virtually Constructed Counterpart

DTIC Science & Technology

2015-06-01

exposure settings…………………...26 Table 4. Kodak 9500 Cone Beam 3D System exposure settings…………..….27 Table 5. Average and statistical analysis results...42 Figure 6 Image of Mounted PVC Skull Model on the Kodak 9500……….…......43 Figure 7 Screen image of Reconstructed CBCT Digital...replica was taken with the Kodak 9500 Cone Beam 3D System. To create the digital dental models fifteen type IV maxillary dental casts were made on the

Field evaluation of personal sampling methods for multiple bioaerosols.

PubMed

Wang, Chi-Hsun; Chen, Bean T; Han, Bor-Cheng; Liu, Andrew Chi-Yeu; Hung, Po-Chen; Chen, Chih-Yong; Chao, Hsing Jasmine

2015-01-01

Ambient bioaerosols are ubiquitous in the daily environment and can affect health in various ways. However, few studies have been conducted to comprehensively evaluate personal bioaerosol exposure in occupational and indoor environments because of the complex composition of bioaerosols and the lack of standardized sampling/analysis methods. We conducted a study to determine the most efficient collection/analysis method for the personal exposure assessment of multiple bioaerosols. The sampling efficiencies of three filters and four samplers were compared. According to our results, polycarbonate (PC) filters had the highest relative efficiency, particularly for bacteria. Side-by-side sampling was conducted to evaluate the three filter samplers (with PC filters) and the NIOSH Personal Bioaerosol Cyclone Sampler. According to the results, the Button Aerosol Sampler and the IOM Inhalable Dust Sampler had the highest relative efficiencies for fungi and bacteria, followed by the NIOSH sampler. Personal sampling was performed in a pig farm to assess occupational bioaerosol exposure and to evaluate the sampling/analysis methods. The Button and IOM samplers yielded a similar performance for personal bioaerosol sampling at the pig farm. However, the Button sampler is more likely to be clogged at high airborne dust concentrations because of its higher flow rate (4 L/min). Therefore, the IOM sampler is a more appropriate choice for performing personal sampling in environments with high dust levels. In summary, the Button and IOM samplers with PC filters are efficient sampling/analysis methods for the personal exposure assessment of multiple bioaerosols.

Tanning beds, sunlamps, and risk of cutaneous malignant melanoma.

PubMed

Gallagher, Richard P; Spinelli, John J; Lee, Tim K

2005-03-01

A number of studies have been conducted evaluating the risk of cutaneous malignant melanoma after exposure to sunlamps and/or sunbeds. The proportion of subjects in the individual studies who have reported exposure has, in general, been modest, and the resulting risk estimates for melanoma have been unstable with wide 95% confidence intervals (95% CI). The inconclusive results seen in individual studies have resulted in confusion as to the carcinogenicity of these devices. We conducted a systematic review and meta-analysis of these studies. A review of the literature from Jan 1, 1984 to April 2004 using MEDLINE identified 12 case-control studies and 1 cohort study which quantitatively evaluated the use of sunlamps and/or sunbeds and subsequent melanoma. After applying exclusion/inclusion criteria, 9 case-control and 1 cohort study provided data for the analysis. Summary odds ratios (OR) and 95% CIs for sunlamp/sunbed use and subsequent melanoma were calculated using a random-effect model. Ten studies provided data for assessment of melanoma risk among subjects who reported "ever" being exposed compared with those "never" exposed. A positive association was found between exposure and risk (summary OR, 1.25; 95% CI, 1.05-1.49). Significant heterogeneity between studies was present. Evaluation of the metrics "first exposure as a young adult" (5 studies) and "longest duration or highest frequency of exposure" (6 studies) also yielded significantly elevated risk estimates (summary OR, 1.69; 95% CI, 1.32-2.18, and 1.61; 95% CI, 1.21-2.12, respectively, with no heterogeneity in either analysis). Results indicate a significantly increased risk of cutaneous melanoma subsequent to sunbed/sunlamp exposure.

Endothelial Inflammatory Transcriptional Responses Induced by Plasma Following Inhalation of Diesel Emissions

PubMed Central

Schisler, Jonathan C.; Ronnebaum, Sarah M.; Madden, Michael; Channell, Meghan M.; Campen, Matthew J.; Willis, Monte S.

2016-01-01

Background Air pollution, especially emissions derived from traffic sources, is associated with adverse cardiovascular outcomes. However, it remains unclear how inhaled factors drive extrapulmonary pathology. Objectives Previously, we found that canonical inflammatory response transcripts were elevated in cultured endothelial cells treated with plasma obtained after exposure compared with pre-exposure samples or filtered air (sham) exposures. While the findings confirmed the presence of bioactive factor(s) in the plasma after diesel inhalation, we wanted to better examine the complete genomic response to investigate 1) major responsive transcripts and 2) collected response pathways and ontogeny that may help to refine this method and inform the pathogenesis. Methods We assayed endothelial RNA with gene expression microarrays, examining the responses of cultured endothelial cells to plasma obtained from 6 healthy human subjects exposed to 100 μg/m3 diesel exhaust or filtered air for 2 h on separate occasions. In addition to pre-exposure baseline samples, we investigated samples obtained immediately-post and 24h-post exposure. Results Microarray analysis of the coronary artery endothelial cells challenged with plasma identified 855 probes that changed over time following diesel exhaust exposure. Over-representation analysis identified inflammatory cytokine pathways were upregulated both at the 2 and 24 h condition. Novel pathways related to FOX transcription factors and secreted extracellular factors were also identified in the microarray analysis. Conclusions These outcomes are consistent with our recent findings that plasma contains bioactive and inflammatory factors following pollutant inhalation. The specific study design implicates a novel pathway related to inflammatory blood borne components that may drive the extrapulmonary toxicity of ambient air pollutants. PMID:25942053

Quantitative crystalline silica exposure assessment for a historical cohort epidemiologic study in the German porcelain industry.

PubMed

Birk, Thomas; Guldner, Karlheinz; Mundt, Kenneth A; Dahmann, Dirk; Adams, Robert C; Parsons, William

2010-09-01

A time-dependent quantitative exposure assessment of silica exposure among nearly 18,000 German porcelain workers was conducted. Results will be used to evaluate exposure-response disease risks. Over 8000 historical industrial hygiene (IH) measurements with original sampling and analysis protocols from 1954-2006 were obtained from the German Berufs- genossenschaft der keramischen-und Glas-Industrie (BGGK) and used to construct a job exposure matrix (JEM). Early measurements from different devices were converted to modern gravimetric equivalent values. Conversion factors were derived from parallel historical measurements and new side-by-side measurements using historical and modern devices in laboratory dust tunnels and active workplace locations. Exposure values were summarized and smoothed using LOESS regression; estimates for early years were derived using backward extrapolation techniques. Employee work histories were merged with JEM values to determine cumulative crystalline silica exposures for cohort members. Average silica concentrations were derived for six primary similar exposure groups (SEGs) for 1938-2006. Over 40% of the cohort accumulated <0.5 mg; just over one-third accumulated >1 mg/m(3)-years. Nearly 5000 workers had cumulative crystalline silica estimates >1.5 mg/m(3)-years. Similar numbers of men and women fell into each cumulative exposure category, except for 1113 women and 1567 men in the highest category. Over half of those hired before 1960 accumulated >3 mg/m(3)-years crystalline silica compared with 4.9% of those hired after 1960. Among those ever working in the materials preparation area, half accumulated >3 mg/m(3)-year compared with 12% of those never working in this area. Quantitative respirable silica exposures were estimated for each member of this cohort, including employment periods for which sampling used now obsolete technologies. Although individual cumulative exposure estimates ranged from background to about 40 mg/m(3)-years, many of these estimates reflect long-term exposures near modern exposure limit values, allowing direct evaluation of lung cancer and silicosis risks near these limits without extrapolation. This quantitative exposure assessment is the largest to date in the porcelain industry.

Proteomic analysis of the renal effects of simulated occupational jet fuel exposure.

PubMed

Witzmann, F A; Bauer, M D; Fieno, A M; Grant, R A; Keough, T W; Lacey, M P; Sun, Y; Witten, M L; Young, R S

2000-03-01

We analyzed protein expression in the cytosolic fraction prepared from whole kidneys in male Swiss-Webster mice exposed 1 h/day for five days to aerosolized JP-8 jet fuel at a concentration of 1000 mg/m3, simulating military occupational exposure. Kidney cytosol samples were solubilized and separated via large-scale, high-resolution two-dimensional electrophoresis (2-DE) and gel patterns scanned, digitized and processed for statistical analysis. Significant changes in soluble kidney proteins resulted from jet fuel exposure. Several of the altered proteins were identified by peptide mass finger-printing and related to ultrastructural abnormalities, altered protein processing, metabolic effects, and paradoxical stress protein/detoxification system responses. These results demonstrate a significant but comparatively moderate JP-8 effect on protein expression in the kidney and provide novel molecular evidence of JP-8 nephrotoxicity. Human risk is suggested by these data but conclusive assessment awaits a noninvasive search for biomarkers in JP-8 exposed humans.

Identification of differentially expressed proteins in Ostrinia furnacalis adults after exposure to ultraviolet A.

PubMed

Zhang, Changyu; Meng, Jianyu

2018-06-23

Ultraviolet A (UVA), the major component of solar UV irradiation, is an important environmental factor inducing damage to insects including cell death, photoreceptor damage, and oxidative stress. In order to improve understanding of the adaptation mechanisms of insect after UVA exposure, a comparative proteomic analysis was carried out to reveal differential protein expression in Ostrinia furnacalis. Three-day-old adults were treated with UVA for 1 h. Total proteins of control and UVA-treated insects were examined using two-dimensional electrophoresis (2-DE). 2-DE analysis demonstrated that 19 proteins were increased and 18 proteins were decreased significantly in O. furnacalis after UVA exposure, respectively. Thirty differentially expressed proteins were successfully identified by mass spectrometry. The identified proteins were involved in diverse biological processes, such as signal transduction, transport processing, cellular stress, metabolisms, and cytoskeleton organization. Our results reveal that the response patterns of O. furnacalis to UVA irradiation are complex and provide novel insights into the adaptation response to UVA irradiation stress.

Effectiveness of Non-nucleoside Reverse-Transcriptase Inhibitor-Based Antiretroviral Therapy in Women Previously Exposed to a Single Intrapartum Dose of Nevirapine: A Multi-country, Prospective Cohort Study

PubMed Central

Stringer, Jeffrey S. A.; McConnell, Michelle S.; Kiarie, James; Bolu, Omotayo; Anekthananon, Thanomsak; Jariyasethpong, Tavatchai; Potter, Dara; Mutsotso, Winnie; Borkowf, Craig B.; Mbori-Ngacha, Dorothy; Muiruri, Peter; Ong'ech, John Odero; Zulu, Isaac; Njobvu, Lungowe; Jetsawang, Bongkoch; Pathak, Sonal; Bulterys, Marc; Shaffer, Nathan; Weidle, Paul J.

2010-01-01

Background Intrapartum and neonatal single-dose nevirapine (NVP) reduces the risk of mother-to-child HIV transmission but also induces viral resistance to non-nucleoside reverse transcriptase inhibitor (NNRTI) drugs. This drug resistance largely fades over time. We hypothesized that women with a prior single-dose NVP exposure would have no more than a 10% higher cumulative prevalence of failure of their NNRTI-containing antiretroviral therapy (ART) over the first 48 wk of therapy than would women without a prior exposure. Methods and Findings We enrolled 355 NVP-exposed and 523 NVP-unexposed women at two sites in Zambia, one site in Kenya, and two sites in Thailand into a prospective, non-inferiority cohort study and followed them for 48 wk on ART. Those who died, discontinued NNRTI-containing ART, or had a plasma viral load ≥400 copies/ml at either the 24 wk or 48 wk study visits and confirmed on repeat testing were characterized as having failed therapy. Overall, 114 of 355 NVP-exposed women (32.1%) and 132 of 523 NVP-unexposed women (25.2%) met criteria for treatment failure. The difference in failure rates between the exposure groups was 6.9% (95% confidence interval [CI] 0.8%–13.0%). The failure rates of women stratified by our predefined exposure interval categories were as follows: 47 of 116 women in whom less than 6 mo elapsed between exposure and starting ART failed therapy (40%; p<0.001 compared to unexposed women); 25 of 67 women in whom 7–12 mo elapsed between exposure and starting ART failed therapy (37%; p = 0.04 compared to unexposed women); and 42 of 172 women in whom more than 12 mo elapsed between exposure and starting ART failed therapy (24%; p = 0.82 compared to unexposed women). Locally weighted regression analysis also indicated a clear inverse relationship between virologic failure and the exposure interval. Conclusions Prior exposure to single-dose NVP was associated with an increased risk of treatment failure; however, this risk seems largely confined to women with a more recent exposure. Women requiring ART within 12 mo of NVP exposure should not be prescribed an NNRTI-containing regimen as first-line therapy. Please see later in the article for the Editors' Summary PMID:20169113

Genotoxic effects following exposure to air pollution in street vendors from a high-traffic urban area.

PubMed

Domingues, Érica Prado; Silva, Guilherme Gomes; Oliveira, Andrei Barbassa; Mota, Lorrany Marins; Santos, Vanessa Santana Vieira; de Campos, Edimar Olegário; Pereira, Boscolli Barbosa

2018-03-14

Workers in several occupational environments are exposed to pollutants. Street vendors, for example, typically work in a high-traffic urban environment and are exposed to numerous air pollutants, including genotoxic substances emitted by motor vehicles. This study examined the genotoxic effects of exposure to air pollution. We conducted cytological analyses to assess frequencies of micronucleated (MN) and binucleated (BN) cells in a sample of exfoliated oral mucosa cells. We compared street vendors and control subjects in the city of Uberlândia, Minas Gerais, Brazil, and also collected quantitative information on exposure conditions of all test subjects, including concentrations of particulate matter. We found street vendors to exhibit higher frequencies of MN cells compared to the control group. We evaluated the effects of possible confounding variables on MN frequencies, namely the body mass index (BMI), age, as well as smoking and alcohol habits. Multiple linear regression analysis found no significant effects of any of those variables. Our results suggest that continued exposure to air pollution from traffic represents a major source of genotoxicity and raises concerns regarding disease prevention not only in street vendors but also other groups of people working in urban environments.

Auditory Effects of Exposure to Noise and Solvents: A Comparative Study

PubMed Central

Lobato, Diolen Conceição Barros; Lacerda, Adriana Bender Moreira De; Gonçalves, Cláudia Giglio De Oliveira; Coifman, Herton

2013-01-01

Introduction Industry workers are exposed to different environmental risk agents that, when combined, may potentiate risks to hearing. Objective To evaluate the effects of the combined exposure to noise and solvents on hearing in workers. Methods A transversal retrospective cohort study was performed through documentary analysis of an industry. The sample (n = 198) was divided into four groups: the noise group (NG), exposed only to noise; the noise and solvents group (NSG), exposed to noise and solvents; the noise control group and noise and solvents control group (CNS), no exposure. Results The NG showed 16.66% of cases suggestive of bilateral noise-induced hearing loss and NSG showed 5.26%. The NG and NSG had worse thresholds than their respective control groups. Females were less susceptible to noise than males; however, when simultaneously exposed to solvents, hearing was affected in a similar way, resulting in significant differences (p < 0.05). The 40- to 49-year-old age group was significantly worse (p < 0.05) in the auditory thresholds in the NSG compared with the CNS. Conclusion The results observed in this study indicate that simultaneous exposure to noise and solvents can damage the peripheral auditory system. PMID:25992079

Occupational safety considerations with hydrazine

NASA Technical Reports Server (NTRS)

Clewell, Harvey J., III; Mcdougal, James N.; George, Marilyn E.; Andersen, Melvin E.

1992-01-01

Hydrazine is a reducing agent that is most commonly used as a propellant and as an oxygen scavenger in boilers. Hydrazine is extremely irritating and has been demonstrated to produce both acute and chronic toxicity. As a result, the established permissible inhalation exposure limits are very low, and respiration protection is required whenever vapors are present. Liquid hydrazine penetrates the skin and produces a chemical burn; therefore, some protective measures must also be taken to protect the skin from liquid contact. Often, however, a cumbersome, whole-body protective suit is worn to protect against skin contact with vapor as well. To what extent it is actually necessary to protect skin from vapor penetration had not previously been demonstrated. In an attempt to answer this question, we conducted a study with rats to compare the dermal penetration of hydrazine vapor with inhalation. Pharmacokinetic modeling was used to compare body burdens resulting from these different routes of exposure. The analysis concluded that the vapor concentration during a skin-only exposure would have to be at least 200 times higher than that during inhalation to achieve the same body burden. This type of estimation illustrates the use of predictive toxicology in occupational exposures.

Exposures to jet fuel and benzene during aircraft fuel tank repair in the U.S. Air Force.

PubMed

Carlton, G N; Smith, L B

2000-06-01

Jet fuel and benzene vapor exposures were measured during aircraft fuel tank entry and repair at twelve U.S. Air Force bases. Breathing zone samples were collected on the fuel workers who performed the repair. In addition, instantaneous samples were taken at various points during the procedures with SUMMA canisters and subsequent analysis by mass spectrometry. The highest eight-hour time-weighted average (TWA) fuel exposure found was 1304 mg/m3; the highest 15-minute short-term exposure was 10,295 mg/m3. The results indicate workers who repair fuel tanks containing explosion suppression foam have a significantly higher exposure to jet fuel as compared to workers who repair tanks without foam (p < 0.001). It is assumed these elevations result from the tendency for fuel, absorbed by the foam, to volatilize during the foam removal process. Fuel tanks that allow flow-through ventilation during repair resulted in lower exposures compared to those tanks that have only one access port and, as a result, cannot be ventilated efficiently. The instantaneous sampling results confirm that benzene exposures occur during fuel tank repair; levels up to 49.1 mg/m3 were found inside the tanks during the repairs. As with jet fuel, these elevated benzene concentrations were more likely to occur in foamed tanks. The high temperatures associated with fuel tank repair, along with the requirement to wear vapor-permeable cotton coveralls for fire reasons, could result in an increase in the benzene body burden of tank entrants.

Exposure of luminous marine bacteria to low-dose gamma-radiation.

PubMed

Kudryasheva, N S; Petrova, A S; Dementyev, D V; Bondar, A A

2017-04-01

The study addresses biological effects of low-dose gamma-radiation. Radioactive 137 Cs-containing particles were used as model sources of gamma-radiation. Luminous marine bacterium Photobacterium phosphoreum was used as a bioassay with the bioluminescent intensity as the physiological parameter tested. To investigate the sensitivity of the bacteria to the low-dose gamma-radiation exposure (≤250 mGy), the irradiation conditions were varied as follows: bioluminescence intensity was measured at 5, 10, and 20°С for 175, 100, and 47 h, respectively, at different dose rates (up to 4100 μGy/h). There was no noticeable effect of gamma-radiation at 5 and 10°С, while the 20°С exposure revealed authentic bioluminescence inhibition. The 20°С results of gamma-radiation exposure were compared to those for low-dose alpha- and beta-radiation exposures studied previously under comparable experimental conditions. In contrast to ionizing radiation of alpha and beta types, gamma-emission did not initiate bacterial bioluminescence activation (adaptive response). As with alpha- and beta-radiation, gamma-emission did not demonstrate monotonic dose-effect dependencies; the bioluminescence inhibition efficiency was found to be related to the exposure time, while no dose rate dependence was found. The sequence analysis of 16S ribosomal RNA gene did not reveal a mutagenic effect of low-dose gamma radiation. The exposure time that caused 50% bioluminescence inhibition was suggested as a test parameter for radiotoxicity evaluation under conditions of chronic low-dose gamma irradiation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mortality and cancer incidence in ammonium perfluorooctanoate production workers.

PubMed

Raleigh, Katherine K; Alexander, Bruce H; Olsen, Geary W; Ramachandran, Gurumurthy; Morey, Sandy Z; Church, Timothy R; Logan, Perry W; Scott, Laura L F; Allen, Elizabeth M

2014-07-01

To evaluate mortality and cancer incidence in a cohort of ammonium perfluorooctanoate (APFO) exposed workers. We linked a combined cohort (n=9027) of employees from APFO and non-APFO production facilities in Minnesota to the National Death Index and to cancer registries of Minnesota and Wisconsin. Industrial hygiene data and expert evaluation were used to create a task-based job exposure matrix to estimate APFO exposure. Standardised mortality ratios were estimated using Minnesota population rates. HRs and 95% CIs for time-dependent cumulative APFO exposure were estimated with an extended Cox model. A priori outcomes of interest included cancers of the liver, pancreas, testes, kidney, prostate and breast, and mortality from cardiovascular, cerebrovascular and chronic renal diseases. Mortality rates in the APFO-exposed cohort were at or below the expected, compared with Minnesota. The HR for dying from the cancer and non-cancer outcomes of interest did not show an association with APFO exposure. Similarly, there was little evidence that the incident cancers were associated with APFO exposure. Compared to the non-exposed population, modestly elevated, but quite imprecise HRs were observed in the higher-exposure quartiles for bladder cancer (HR=1.66, 95% CI 0.86 to 3.18) and pancreatic cancer (HR=1.36, 95% CI 0.59 to 3.11). No association was observed between APFO exposure and kidney, prostate or breast cancers. This analysis did not support an association between occupational APFO exposure and the evaluated health endpoints, however, the study had limited power to evaluate some conditions of interest. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Increased Frequency of Rheumatoid Arthritis and Allergic Rhinitis among Pesticide Sprayers and Associations with Pesticide Use

PubMed Central

Koureas, Michalis; Rachiotis, George; Tsakalof, Andreas; Hadjichristodoulou, Christos

2017-01-01

Objective: The aim of this study was to identify diseases linked with the pesticide sprayer occupation and explore possible associations with exposure history data. Methods: A cross sectional study was conducted among pesticide sprayers (n = 80) and the general population (n = 90) in Thessaly (Greece). Medical history, demographic characteristics and detailed exposure history were recorded by conducting personal interviews. Lifetime exposure indicators were calculated for several pesticide chemical subclasses. Moreover, organophosphate metabolite levels were quantified in urine samples of all participants by using gas chromatography-mass spectrometry (GC-MS). Multinomial analysis was used to determine associations between occupational pesticide exposure and diseases or disorders. Results: In the pesticide sprayers group, significantly higher frequencies for rheumatoid arthritis (RA) and allergic rhinitis were observed compared with the control group (p = 0.002 and p = 0.024 respectively). Within the pesticide sprayers group, high lifetime pesticide exposure was associated with increased risk for reporting RA (OR: 43.07 95% CI: 3.09–600.67) and allergic rhinitis (OR: 9.72 95% CI: 2.31–40.89), compared with low pesticide exposure. Exposure to organophsphate, guanidine and quinone pesticides were associated with RA while organophosphates, pyrethroids and paraquat were associated with allergic rhinitis. Despite the higher levels of certain pesticide metabolites observed among participants with rheumatoid arthritis, the differences were not statistically significant. One metabolite (diethylthiophosphate) was found to be significantly increased in allergic rhinitis cases (p = 0.037). Conclusions: The results from the current study suggest a possible association of occupational pesticide exposure with RA and allergic rhinitis that should be further investigated. PMID:28763046

Sidestream cigarette smoke toxicity increases with aging and exposure duration

PubMed Central

Schick, Suzaynn; Glantz, Stanton A

2006-01-01

Objectives To determine the effects of aging on the toxicity of sidestream tobacco smoke, the complex chemical mixture that enters the air from the lit end of burning cigarettes and constitutes the vast bulk of secondhand smoke. Design Statistical analysis of data from controlled experimental exposures of Sprague Dawley rats to fresh and aged (for more than 30 minutes) sidestream smoke for up to 90 days followed by histological sectioning of the respiratory epithelium. The data were obtained from a series of experiments conducted at Philip Morris' formerly secret INBIFO (Institut für Biologische Forschung) laboratory in Germany. Results Using total particulate material as the measure of smoke exposure, aging sidestream cigarette smoke for at least 30 minutes increases its toxicity fourfold for 21 day exposures and doubles the toxicity for 90 day exposures, relative to fresh sidestream smoke. Conclusions These results help explain the relatively large biological effects of secondhand smoke compared to equivalent mass doses of mainstream smoke. PMID:17130369

Does the Size of a Company Make a Difference in the Prevalence of Exposure to Asthmagens and in the Use of Respiratory Protective Equipment?

PubMed

El-Zaemey, Sonia; Carey, Renee N; Darcey, Ellie; Reid, Alison; Rushton, Lesley; McElvenny, Damien M; Fritschi, Lin

2018-05-08

About half of all workers in high-income countries work in small companies. However, regulatory bodies and researchers predominantly work with large companies because they are more convenient to study and easier to reach. We aimed to estimate the prevalence of exposure to asthmagens and the use of respiratory protective equipment (RPE) by company size. This analysis used data from the Australian Work Exposures Study-Asthma, a telephone survey which investigated exposure to 27 asthmagen groups. Among 4844 respondents, 18.8, 19.9, 31.9, and 29.4% of workers reported working in micro (<5 employees), small (5-19 employees), medium (20-200 employees), and large (>200 employees) companies, respectively. Compared to workers in large companies, workers in micro, small, or medium companies had higher prevalence of exposure to most asthmagens and lesser use of RPE. Our results suggest that policy actions and regulatory measures should target micro/small companies in order to have the greatest effect.

Trimethoprim use in early pregnancy and the risk of miscarriage: a register-based nationwide cohort study.

PubMed

Andersen, J T; Petersen, M; Jimenez-Solem, E; Broedbaek, K; Andersen, E W; Andersen, N L; Afzal, S; Torp-Pedersen, C; Keiding, N; Poulsen, H E

2013-08-01

The antibiotic trimethoprim acts as a folate antagonist. Since trophoblasts are very sensitive to drugs that interfere with the folic acid cycle and thereby inhibit DNA synthesis, use of trimethoprim during the first trimester could be associated with miscarriage. A nationwide cohort study including all women in Denmark with a registered pregnancy between 1997 and 2005 was conducted. We used nationwide registers to identify all women giving birth, having a record of miscarriage or induced abortion. Data on exposure to trimethoprim were obtained from the National Prescription Register. Cox proportional hazard regression analysis with exposure to trimethoprim as a time-dependent variable was used to estimate the risk of miscarriage. The adjusted hazard ratio of having a miscarriage after exposure to trimethoprim in the first trimester compared to non-exposure was 2∙04 (95% confidence interval 1∙43-2∙91). Our results indicate that trimethoprim exposure in the first trimester is associated with a doubling of the hazard of miscarriage.

A Comparative Toxidrome Analysis of Human Organophosphate and Nerve Agent Poisonings Using Social Media

PubMed Central

Colman, E

2017-01-01

Here we utilized social media to compare the toxidrome of three lethal chemical exposures worldwide. YouTube videos were the main source from which the data were collected, but published reports and news were also utilized to fill in some gaps. All videos were organized in a database detailing symptoms and severity of each victim, along with demographics such as approximate age and gender. Each symptom was rated as mild, moderate, or severe and corresponding pie graphs for each incident were compared. The videos displayed symptoms ranging from mild to severe cholinergic toxicity and life‐threatening convulsions. Social media may represent an important resource in developing a viable approach to the early detection and identification of chemical exposure, reinforce our preparedness for better antidotes, long‐term follow up, and training about deadly chemical nerve agent attacks. PMID:28238224

Affecting Factors of Secondhand Smoke Exposure in Korea: Focused on Different Exposure Locations.

PubMed

Sun, Li Yuan; Cheong, Hae Kwan; Lee, Eun Whan; Kang, Kyeong Jin; Park, Jae Hyun

2016-09-01

Exposure to secondhand smoke (SHS) not only can cause serious illness, but is also an economic and social burden. Contextual and individual factors of non-smoker exposure to SHS depend on location. However, studies focusing on this subject are lacking. In this study, we described and compared the factors related to SHS exposure according to location in Korea. Regarding individual factors related to SHS exposure, a common individual variable model and location-specific variable model was used to evaluate SHS exposure at home/work/public locations based on sex. In common individual variables, such as age, and smoking status showed different relationships with SHS exposure in different locations. Among home-related variables, housing type and family with a single father and unmarried children showed the strongest positive relationships with SHS exposure in both males and females. In the workplace, service and sales workers, blue-collar workers, and manual laborers showed the strongest positive association with SHS exposure in males and females. For multilevel analysis in public places, only SHS exposure in females was positively related with cancer screening rate. Exposure to SHS in public places showed a positive relationship with drinking rate and single-parent family in males and females. The problem of SHS embodies social policies and interactions between individuals and social contextual factors. Policy makers should consider the contextual factors of specific locations and regional and individual context, along with differences between males and females, to develop effective strategies for reducing SHS exposure.

[Wood smoke condensate induced epithelial-mesenchymal transition in human airway epithelial cells].

PubMed

Li, Wenxi; Zou, Weifeng; Li, Bing; Ran, Pixin

2014-01-01

To observe the detrimental effects of wood smoke condensate (WSC) exposure on human bronchial epithelial cells (HBEC), and to explore the expression of epithelial-mesenchymal transition (EMT) markers in HBEC exposed to WSC. HBEC were exposed respectively to 5, 10, 20, 40 and 50 mg/L of WSC /CSC for 7 days, with control groups only in cell culture medium at the same time, then the total cytoactivity was detected by cell counting kit-8. After observing the cellular morphology of WSC-stimulated HBEC. Western blot and immunofluorescence method were used to evaluate the expression levels of type I collagen, vimentin, E-cad and MMP-9 in HBEC exposed to WSC (10 mg/L) and cigarette smoke condensate (CSC) (10 mg/L) for 7 days. Statistical evaluation of the continuous data was performed by ANOVA. Independent-Samples t-test for between-group comparisons. After 7 days of exposure to WSC, HBEC manifested a morphological characteristic of loss of cell-cell contact and elongated shape. The level of E-cad was decreased in WSC exposure groups (Western blot: 0.30 ± 0.05, F = 22.07, P < 0.05) compared with the groups without WSC exposure (Western blot: 0.59 ± 0.08, F = 22.07, P < 0.05). In contrast, an upregulation in expression of type I collagen (Western blot: 0.58 ± 0.04 vs 0.26 ± 0.02, F = 119.72, P < 0.05) and MMP-9 (0.56 ± 0.08 vs 0.19 ± 0.03, F = 21.79, P < 0.05) was observed in the presence of WSC, compared with the control groups. Immunofluorescence analysis showed that after a 7-day exposure to WSC in these cells, the E-cad protein was lost whereas type I collagen, vimentin and MMP-9 were acquired. Both Western blot and immunofluorescence analysis showed no difference in expression levels of E-cad, type I collagen, vimentin and MMP-9 between WSC and CSC exposure groups. WSC exposure could induce EMT-like process in human airway epithelial cells.

Distributional benefit analysis of a national air quality rule.

PubMed

Post, Ellen S; Belova, Anna; Huang, Jin

2011-06-01

Under Executive Order 12898, the U.S. Environmental Protection Agency (EPA) must perform environmental justice (EJ) reviews of its rules and regulations. EJ analyses address the hypothesis that environmental disamenities are experienced disproportionately by poor and/or minority subgroups. Such analyses typically use communities as the unit of analysis. While community-based approaches make sense when considering where polluting sources locate, they are less appropriate for national air quality rules affecting many sources and pollutants that can travel thousands of miles. We compare exposures and health risks of EJ-identified individuals rather than communities to analyze EPA's Heavy Duty Diesel (HDD) rule as an example national air quality rule. Air pollutant exposures are estimated within grid cells by air quality models; all individuals in the same grid cell are assigned the same exposure. Using an inequality index, we find that inequality within racial/ethnic subgroups far outweighs inequality between them. We find, moreover, that the HDD rule leaves between-subgroup inequality essentially unchanged. Changes in health risks depend also on subgroups' baseline incidence rates, which differ across subgroups. Thus, health risk reductions may not follow the same pattern as reductions in exposure. These results are likely representative of other national air quality rules as well.

Support for smoke-free policies in the Cyprus hospitality industry.

PubMed

Lazuras, Lambros; Savva, Christos S; Talias, Michael A; Soteriades, Elpidoforos S

2015-12-01

The present study used attitudinal and behavioural indicators to measure support for smoke-free policies among employers and employees in the hospitality industry in Cyprus. A representative sample of 600 participants (95 % response rate) completed anonymous structured questionnaires on demographic variables, smoking status, exposure to second-hand smoke at work and related health beliefs, social norms, and smoke-free policy support. Participants were predominantly males (68.3 %), with a mean age of 40 years (SD = 12.69), and 39.7 % were employers/owners of the hospitality venue. Analysis of variance showed that employers and smokers were less supportive of smoke-free policies, as compared to employees and non-smokers. Linear regression models showed that attitudes towards smoke-free policy were predicted by smoking status, SHS exposure and related health beliefs, and social norm variables. Logistic regression analysis showed that willingness to confront a policy violator was predicted by SHS exposure, perceived prevalence of smoker clients, and smoke-free policy attitudes. SHS exposure and related health beliefs, and normative factors should be targeted by interventions aiming to promote policy support in the hospitality industry in Cyprus.

Effects of acute exposure to WIFI signals (2.45GHz) on heart variability and blood pressure in Albinos rabbit.

PubMed

Saili, Linda; Hanini, Amel; Smirani, Chiraz; Azzouz, Ines; Azzouz, Amina; Sakly, Mohsen; Abdelmelek, Hafedh; Bouslama, Zihad

2015-09-01

Electrocardiogram and arterial pressure measurements were studied under acute exposures to WIFI (2.45GHz) during one hour in adult male rabbits. Antennas of WIFI were placed at 25cm at the right side near the heart. Acute exposure of rabbits to WIFI increased heart frequency (+22%) and arterial blood pressure (+14%). Moreover, analysis of ECG revealed that WIFI induced a combined increase of PR and QT intervals. By contrast, the same exposure failed to alter maximum amplitude and P waves. After intravenously injection of dopamine (0.50ml/kg) and epinephrine (0.50ml/kg) under acute exposure to RF we found that, WIFI alter catecholamines (dopamine, epinephrine) action on heart variability and blood pressure compared to control. These results suggest for the first time, as far as we know, that exposure to WIFI affect heart rhythm, blood pressure, and catecholamines efficacy on cardiovascular system; indicating that radiofrequency can act directly and/or indirectly on cardiovascular system. Copyright © 2015 Elsevier B.V. All rights reserved.

Use of hearing protection and perceptions of noise exposure and hearing loss among construction workers.

PubMed

Lusk, S L; Kerr, M J; Kauffman, S A

1998-07-01

The purpose of this study was to describe construction workers' use of hearing protection devices (HPDs) and determine their perceptions of noise exposure and hearing loss. Operating engineers, carpenters, and plumbers/pipe fitters in the Midwest (n = 400) completed a written questionnaire regarding their use of HPDs and their perceptions of noise exposure and hearing loss. Subjects were recruited through their trade union groups. Mean reported use of HPDs and mean perceived noise exposure were compared across trade groups. Bivariate and multivariate analysis techniques were used to assess relationships between use of HPDs and trade category, education, age, years of employment, noise exposure, and hearing loss. Bivariate analyses identified significant differences in mean use of HPDs by age, years of employment, and trade group. Multivariate logistic regression assessing the independent effects of these variables found significant differences only by trade group. Results indicate a need for significant improvement in all three trade groups' use of HPDs, and suggest a need to consider use and exposure levels, demographics, and trade group membership in designing hearing conservation programs.

Assessing dietary exposure to cadmium in a metal recycling community in Vietnam: age and gender aspects.

PubMed

Ngo, Duc Minh; Hough, Rupert Lloyd; Le, Thi Thuy; Nyberg, Ylva; Le, Bach Mai; Nguyen, Cong Vinh; Nguyen, Manh Khai; Oborn, Ingrid

2012-02-01

This study estimates the dietary exposure to cadmium (Cd), and associated potential health risks, for individuals living and working in a metal recycling community (n=132) in Vietnam in comparison to an agricultural (reference) community (n=130). Individual-level exposure to Cd was estimated through analysis of staple foodstuffs combined with information from a food frequency questionnaire. Individual-level exposure estimates were compared with published 'safe' doses to derive a Hazard Quotient (HQ) for each member of the study population. Looking at the populations as a whole, there were no significant differences in the diets of the two villages. However, significantly more rice was consumed by working age adults (18-60 years) in the recycling village compared to the reference village (p<0.001). Rice was the main staple food with individuals consuming 461±162g/d, followed by water spinach (103±51kg/d). Concentrations of Cd in the studied foodstuffs were elevated in the metal recycling village. Values of HQ exceeded unity for 87% of adult participants of the metal recycling community (39% had a HQ>3), while 20% of adult participants from the reference village had an HQ>1. We found an elevated health risk from dietary exposure to Cd in the metal recycling village compared to the reference community. WHO standard of 0.4mg Cd/kg rice may not be protective where people consume large amounts of rice/have relatively low body weight. Copyright © 2011 Elsevier B.V. All rights reserved.

Iodinated Contrast Media-Induced Thyroid Dysfunction in Euthyroid Nodular Goiter Patients.

PubMed

Kornelius, Edy; Chiou, Jeng-Yuan; Yang, Yi-Sun; Lo, Shih-Chang; Peng, Chiung-Huei; Lai, Yung-Rung; Huang, Chien-Ning

2016-08-01

The risks of thyroid dysfunction after iodinated contrast media exposure in patients with euthyroid nodular goiter are largely unknown. This observational, retrospective cohort study included a random selection of one million people in Taiwan. All patients with iodinated contrast media exposure during this study period were selected. Patients with euthyroid nodular goiter were identified as cases, while patients without thyroid nodule were selected as controls. We followed these patients until the first event of thyroid dysfunction including hyperthyroidism or hypothyroidism after iodinated contrast media exposure. A total of 334 cases and 2672 matched controls were selected in this study. The mean age of cases and controls were 58.6 and 58.4 years old, and mean follow-up durations were 2.1 and 2 years respectively. After adjustment, patients with euthyroid nodular goiter had a higher risk of thyroid dysfunction (hazard ratio 5.43, [confidence interval (CI) 3.01-9.80]) compared with controls after iodinated contrast media exposure. In the subgroup analysis, the risks of hyperthyroidism and hypothyroidism in cases compared with controls were 5.77 [CI 2.64-12.62] and 4.95 [CI 2.15-11.40] respectively. Half of the euthyroid nodular goiter cases developed thyroid dysfunction within one year after iodinated contrast media exposure. Interestingly, all thyroid-related comorbidities and drug prescriptions did not increase the risk of thyroid dysfunction. Presence of euthyroid nodular goiter was associated with higher risk of thyroid dysfunction including hyperthyroidism and hypothyroidism after iodinated contrast media exposure.

Respiratory symptoms following wildfire smoke exposure: airway size as a susceptibility factor.

PubMed

Mirabelli, Maria C; Künzli, Nino; Avol, Edward; Gilliland, Frank D; Gauderman, W James; McConnell, Rob; Peters, John M

2009-05-01

Associations between exposure to smoke during wildfire events and respiratory symptoms are well documented, but the role of airway size remains unclear. We conducted this analysis to assess whether small airway size modifies these relationships. We analyzed data from 465 nonasthmatic 16- to 19-year-old participants in the Children's Health Study. Following an outbreak of wildfires in 2003, each student completed a questionnaire about smoke exposure, dry and wet cough, wheezing, and eye symptoms. We used log-binomial regression to evaluate associations between smoke exposure and fire-related health symptoms, and to assess modification of the associations by airway size. As a marker of airway size, we used the ratio of maximum midexpiratory flow to forced vital capacity. Forty percent (186 of 465) of this population (including students from 11 of 12 surveyed communities) reported the odor of wildfire smoke at home. We observed increased respiratory and eye symptoms with increasing frequency of wildfire smoke exposure. Associations between smoke exposure and having any of 4 respiratory symptoms were stronger in the lowest quartile of the lung function ratio (eg, fire smoke 6+ days: prevalence ratio: 3.8; 95% confidence interval (CI = 2.0-7.2), compared with the remaining quartiles (fire smoke 6+ days: prevalence ratio = 2.0; 1.2-3.2). Analysis of individual symptoms suggests that this interaction may be strongest for effects on wheezing. Small airways may serve as a marker of susceptibility to effects of wildfire smoke. Future studies should investigate the role of airway size for more common exposures and should include persons with asthma.

Respiratory Symptoms Following Wildfire Smoke Exposure

PubMed Central

Mirabelli, Maria C.; Künzli, Nino; Avol, Edward; Gilliland, Frank D.; Gauderman, W. James; McConnell, Rob; Peters, John M.

2015-01-01

Background Associations between exposure to smoke during wild-fire events and respiratory symptoms are well documented, but the role of airway size remains unclear. We conducted this analysis to assess whether small airway size modifies these relationships. Methods We analyzed data from 465 nonasthmatic 16- to 19-year-old participants in the Children’s Health Study. Following an outbreak of wildfires in 2003, each student completed a questionnaire about smoke exposure, dry and wet cough, wheezing, and eye symptoms. We used log-binomial regression to evaluate associations between smoke exposure and fire-related health symptoms, and to assess modification of the associations by airway size. As a marker of airway size, we used the ratio of maximum midexpiratory flow to forced vital capacity. Results Forty percent (186 of 465) of this population (including students from 11 of 12 surveyed communities) reported the odor of wildfire smoke at home. We observed increased respiratory and eye symptoms with increasing frequency of wildfire smoke exposure. Associations between smoke exposure and having any of 4 respiratory symptoms were stronger in the lowest quartile of the lung function ratio (eg, fire smoke 6+ days: prevalence ratio: 3.8; 95% confidence interval (CI = 2.0 –7.2), compared with the remaining quartiles (fire smoke 6+ days: prevalence ratio = 2.0; 1.2–3.2). Analysis of individual symptoms suggests that this interaction may be strongest for effects on wheezing. Conclusions Small airways may serve as a marker of susceptibility to effects of wildfire smoke. Future studies should investigate the role of airway size for more common exposures and should include persons with asthma. PMID:19276978

Chronic trimethyltin chloride exposure and the development of kidney stones in rats.

PubMed

Ren, Xuefeng; Wu, Xin; Sui, Gang; Gong, Zhihong; Yawson, Emmanuel; Wu, Banghua; Lai, Guanchao; Ruan, Xiaolin; Gao, Hongbin; Zhou, Feng; Su, Bing; Olson, James R; Tang, Xiaojiang

2015-05-01

We recently reported that occupational exposure to trimethyltin (TMT) is a risk factor for developing kidney stones. To further examine the association between TMT exposure and the formation of kidney stones, we conducted a 180-day animal study and exposed the randomly grouped Sprague-Dawley (SD) rats to TMT in the drinking water at doses of 0, 8.2, 32.8 and 131.3 µg kg(-1) day(-1). Transient behavioral changes were observed in the high-dose group during the first 2 weeks of exposure. TMT exposure led to a significant dose-dependent inhibition of renal H(+)/K(+)-ATPase and an increase in urinary pH. In comparison to no kidney stones being identified in the control and the lowest dose group, 1 rat in the 32.8 µg kg(-1) day(-1) dose group and 3 out of 9 rats in the 131.3 µg kg(-1) day(-1) dose group were found to have stones in the kidney/urinary tract. Pathological analysis showed that more wide spread calcium disposition was observed in kidneys of rats with TMT exposure compared with the rats in the control group. However, X-ray diffraction (XRD) analysis found that the kidney stones were mainly composed of struvite with the formula: NH4MgPO4 6H2O, while calcium-containing components were also detected. Together, this study further demonstrates through animal studies that chronic exposure to a relatively low level of TMT induces nephrotoxicity and increases the risk for developing kidney stones. Copyright © 2014 John Wiley & Sons, Ltd.

Analysis of Noise Exposure Measurements Made Onboard the International Space Station

NASA Technical Reports Server (NTRS)

Limardo, Jose G.; Allen, Christopher S.

2011-01-01

The International Space Station (ISS) is a unique workplace environment for U.S. astronauts and Russian cosmonauts to conduct research and live for a period of six months or more. Noise has been an enduring environmental physical hazard that has been a challenge for the U.S. space program since before the Apollo era. Noise exposure in ISS poses significant risks to the crewmembers, such as; hearing loss (temporary or permanent), possible disruptions of crew sleep, interference with speech intelligibility and communication, possible interference with crew task performance, and possible reduction in alarm audibility. Acoustic measurements are made aboard ISS and compared to requirements in order to assess the acoustic environment to which the crewmembers are exposed. The purpose of this paper is to describe in detail the noise exposure monitoring program as well as an assessment of the acoustic dosimeter data collected to date. The hardware currently being used for monitoring the noise exposure onboard ISS will be discussed. Acoustic data onboard ISS has been collected since the beginning of ISS (Increment 1, November 2000). Noise exposure data analysis will include acoustic dosimetry logged data from crew-worn during work and sleep periods and also fixed-location measurements from Increment 1 to present day. Noise exposure levels (8-, 16- and 24-hr), LEQ, will also be provided and discussed in this paper. Discussions related to hearing protection will also be included. Future directions and recommendations for the noise exposure monitoring program will be highlighted. This acoustic data is used to ensure a safe and healthy working and living environment for the crewmembers aboard the ISS.

Analysis of Noise Exposure Measurements Acquired Onboard the International Space Station

NASA Technical Reports Server (NTRS)

Limardo, Jose G.; Allen, Christopher S.

2011-01-01

The International Space Station (ISS) is a unique workplace environment for U.S. astronauts and Russian cosmonauts to conduct research and live for a period of six months or more. Noise has been an enduring environmental physical hazard that has been a challenge for the U.S. space program since before the Apollo era. Noise exposure in ISS poses significant risks to the crewmembers, such as; hearing loss (temporary or permanent), possible disruptions of crew sleep, interference with speech intelligibility and communication, possible interference with crew task performance, and possible reduction in alarm audibility. Acoustic measurements were made onboard ISS and compared to requirements in order to assess the acoustic environment to which the crewmembers are exposed. The purpose of this paper is to describe in detail the noise exposure monitoring program as well as an assessment of the acoustic dosimeter data collected to date. The hardware currently being used for monitoring the noise exposure onboard ISS will be discussed. Acoustic data onboard ISS has been collected since the beginning of ISS (Increment 1, November 2001). Noise exposure data analysis will include acoustic dosimetry logged data from crew-worn dosimeters during work and sleep periods and also fixed-location measurements from Increment 1 to present day. Noise exposure levels (8-, 16- and 24-hr), LEQ, will also be provided and discussed in this paper. Future directions and recommendations for the noise exposure monitoring program will be highlighted. This acoustic data is used to ensure a safe and healthy working and living environment for the crewmembers onboard the ISS.

Children's Lead Exposure: A Multimedia Modeling Analysis to Guide Public Health Decision-Making.

PubMed

Zartarian, Valerie; Xue, Jianping; Tornero-Velez, Rogelio; Brown, James

2017-09-12

Drinking water and other sources for lead are the subject of public health concerns around the Flint, Michigan, drinking water and East Chicago, Indiana, lead in soil crises. In 2015, the U.S. Environmental Protection Agency (EPA)'s National Drinking Water Advisory Council (NDWAC) recommended establishment of a "health-based, household action level" for lead in drinking water based on children's exposure. The primary objective was to develop a coupled exposure-dose modeling approach that can be used to determine what drinking water lead concentrations keep children's blood lead levels (BLLs) below specified values, considering exposures from water, soil, dust, food, and air. Related objectives were to evaluate the coupled model estimates using real-world blood lead data, to quantify relative contributions by the various media, and to identify key model inputs. A modeling approach using the EPA's Stochastic Human Exposure and Dose Simulation (SHEDS)-Multimedia and Integrated Exposure Uptake and Biokinetic (IEUBK) models was developed using available data. This analysis for the U.S. population of young children probabilistically simulated multimedia exposures and estimated relative contributions of media to BLLs across all population percentiles for several age groups. Modeled BLLs compared well with nationally representative BLLs (0-23% relative error). Analyses revealed relative importance of soil and dust ingestion exposure pathways and associated Pb intake rates; water ingestion was also a main pathway, especially for infants. This methodology advances scientific understanding of the relationship between lead concentrations in drinking water and BLLs in children. It can guide national health-based benchmarks for lead and related community public health decisions. https://doi.org/10.1289/EHP1605.

Comparative toxicogenomic analysis of oral Cr(VI) exposure effects in rat and mouse small intestinal epithelia

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

Kopec, Anna K.; Thompson, Chad M.; Kim, Suntae

2012-07-15

Continuous exposure to high concentrations of hexavalent chromium [Cr(VI)] in drinking water results in intestinal tumors in mice but not rats. Concentration-dependent gene expression effects were evaluated in female F344 rat duodenal and jejunal epithelia following 7 and 90 days of exposure to 0.3–520 mg/L (as sodium dichromate dihydrate, SDD) in drinking water. Whole-genome microarrays identified 3269 and 1815 duodenal, and 4557 and 1534 jejunal differentially expressed genes at 8 and 91 days, respectively, with significant overlaps between the intestinal segments. Functional annotation identified gene expression changes associated with oxidative stress, cell cycle, cell death, and immune response that weremore » consistent with reported changes in redox status and histopathology. Comparative analysis with B6C3F1 mouse data from a similarly designed study identified 2790 differentially expressed rat orthologs in the duodenum compared to 5013 mouse orthologs at day 8, and only 1504 rat and 3484 mouse orthologs at day 91. Automated dose–response modeling resulted in similar median EC{sub 50}s in the rodent duodenal and jejunal mucosae. Comparative examination of differentially expressed genes also identified divergently regulated orthologs. Comparable numbers of differentially expressed genes were observed at equivalent Cr concentrations (μg Cr/g duodenum). However, mice accumulated higher Cr levels than rats at ≥ 170 mg/L SDD, resulting in a ∼ 2-fold increase in the number of differentially expressed genes. These qualitative and quantitative differences in differential gene expression, which correlate with differences in tissue dose, likely contribute to the disparate intestinal tumor outcomes. -- Highlights: ► Cr(VI) elicits dose-dependent changes in gene expression in rat intestine. ► Cr(VI) elicits less differential gene expression in rats compared to mice. ► Cr(VI) gene expression can be phenotypically anchored to intestinal changes. ► Species-specific and divergent changes are consistent with species-specific tumors.« less

Environment and human exposure to persistent organic pollutants (POPs) in India: a systematic review of recent and historical data.

PubMed

Sharma, Brij Mohan; Bharat, Girija K; Tayal, Shresth; Nizzetto, Luca; Cupr, Pavel; Larssen, Thorjørn

2014-05-01

Persistent organic pollutants (POPs) have been used in a wide range of agricultural and industrial commodities, resulting in vigorous deterioration of environment and human health. A number of studies on the occurrence of POPs confirm their presence in various environmental compartments and human body. In order to deal with this global concern, India has recently prepared the National Implementation Plan (NIP) of the Stockholm Convention. Common beliefs point at India as a hot spot of POP contamination and human exposure; however no systematic analysis was ever performed so far considering all available past data on POP occurrence. This review aims to examine the distribution pattern of POPs in multicompartment environment and human samples, meta-analysis of time trends in exposure levels to environment and humans, and cross country comparison of POP contamination with China. Based on this review, it can be concluded that the Indian environment and human population are highly contaminated by DDTs and HCHs; however scarcity of data on other POPs makes it challenging to assess their nationwide human and environmental exposure. No evidence of a general decline in DDT and HCH residues in the environment and human body come out from the meta-analysis of time trend. While comparing contamination levels between India and China, tendency towards decline in POP contamination is visible in China, unlike India. Copyright © 2014 Elsevier Ltd. All rights reserved.

Comparative Transcriptomic and Phenotypic Analysis of the Responses of Bacillus cereus to Various Disinfectant Treatments▿ †

PubMed Central

Ceragioli, Mara; Mols, Maarten; Moezelaar, Roy; Ghelardi, Emilia; Senesi, Sonia; Abee, Tjakko

2010-01-01

Antimicrobial chemicals are widely applied to clean and disinfect food-contacting surfaces. However, the cellular response of bacteria to various disinfectants is unclear. In this study, the physiological and genome-wide transcriptional responses of Bacillus cereus ATCC 14579 exposed to four different disinfectants (benzalkonium chloride, sodium hypochlorite, hydrogen peroxide, and peracetic acid) were analyzed. For each disinfectant, concentrations leading to the attenuation of growth, growth arrest, and cell death were determined. The transcriptome analysis revealed that B. cereus, upon exposure to the selected concentrations of disinfectants, induced common and specific responses. Notably, the common response included genes involved in the general and oxidative stress responses. Exposure to benzalkonium chloride, a disinfectant known to induce membrane damage, specifically induced genes involved in fatty acid metabolism. Membrane damage induced by benzalkonium chloride was confirmed by fluorescence microscopy, and fatty acid analysis revealed modulation of the fatty acid composition of the cell membrane. Exposure to sodium hypochlorite induced genes involved in metabolism of sulfur and sulfur-containing amino acids, which correlated with the excessive oxidation of sulfhydryl groups observed in sodium hypochlorite-stressed cells. Exposures to hydrogen peroxide and peracetic acid induced highly similar responses, including the upregulation of genes involved in DNA damage repair and SOS response. Notably, hydrogen peroxide- and peracetic acid-treated cells exhibited high mutation rates correlating with the induced SOS response. PMID:20348290

Oxidation of stainless steel 316 and Nitronic 50 in supercritical and ultrasupercritical water

NASA Astrophysics Data System (ADS)

Rodriguez, David; Chidambaram, Dev

2015-08-01

Corrosion of stainless steel 316 and Nitronic 50 exposed to supercritical and ultrasupercritical water was studied as a function of temperature and exposure time. Post-exposure surface analysis was performed using Raman and X-ray photoelectron spectroscopies to determine the chemistry of the oxides formed as a result of the exposure. When exposed to supercritical water, Nitronic 50 and stainless steel 316 were observed to have similar weight gains; however, stainless steel 316 was found to gain less weight than Nitronic 50 in exposure tests performed in ultrasupercritical water. Stainless steel 316 developed surface films primarily composed of iron oxides, while the surface of Nitronic 50 contained a mixture of iron, chromium and manganese oxides. Based on these analyses, the differences in weight gain and oxidation characteristics of the two materials are attributed to the higher concentration of Cr and Mn in Nitronic 50 compared to stainless steel 316.

Comparison of form in potential functions while maintaining upright posture during exposure to stereoscopic video clips.

PubMed

Kutsuna, Kenichiro; Matsuura, Yasuyuki; Fujikake, Kazuhiro; Miyao, Masaru; Takada, Hiroki

2013-01-01

Visually induced motion sickness (VIMS) is caused by sensory conflict, the disagreement between vergence and visual accommodation while observing stereoscopic images. VIMS can be measured by psychological and physiological methods. We propose a mathematical methodology to measure the effect of three-dimensional (3D) images on the equilibrium function. In this study, body sway in the resting state is compared with that during exposure to 3D video clips on a liquid crystal display (LCD) and on a head mounted display (HMD). In addition, the Simulator Sickness Questionnaire (SSQ) was completed immediately afterward. Based on the statistical analysis of the SSQ subscores and each index for stabilograms, we succeeded in determining the quantity of the VIMS during exposure to the stereoscopic images. Moreover, we discuss the metamorphism in the potential functions to control the standing posture during the exposure to stereoscopic video clips.

Early life trauma exposure and stress sensitivity in young children.

PubMed

Grasso, Damion J; Ford, Julian D; Briggs-Gowan, Margaret J

2013-01-01

The current study replicates and extends work with adults that highlights the relationship between trauma exposure and distress in response to subsequent, nontraumatic life stressors. The sample included 213 2-4-year-old children in which 64.3% had a history of potential trauma exposure. Children were categorized into 4 groups based on trauma history and current life stress. In a multivariate analysis of variance, trauma-exposed children with current life stressors had elevated internalizing and externalizing problems compared with trauma-exposed children without current stress and nontrauma-exposed children with and without current stressors. The trauma-exposed groups with or without current stressors did not differ on posttraumatic stress disorder symptom severity. Accounting for number of traumatic events did not change these results. These findings suggest that early life trauma exposure may sensitize young children and place them at risk for internalizing or externalizing problems when exposed to subsequent, nontraumatic life stressors.

[The rabbit experimental study for toxicokinetics of chlorpyrifos impacted by hemoperfusion].

PubMed

Guo, Xiang; Chen, Xiao; Zhang, Hongshun; Long, Xin; He, Qian; Sun, Chengye; Huang, Xianqing; He, Jian

2015-11-01

To investigate toxicokinetic parameters impacted by hemoperfusion after oral chlorpyrifos exposure, to investigate the adsorption effect of hemoperhusion for chlorpyrifos poisoning. 12 rabbits were divided into two groups after oral exposure with chlorpyrifos 300 mg/kg body weight. Control group: without hemoperfusion; hemoperfusion group: hemoperfusion starts 0.5 h after chlorpyrifos exposure and lasts for 2h. Blood samples were collected at different times, concentrations of chlorpyrifos were tested by GC, then, toxicokinetic parameterswere calculated and analysis by DAS3.0. In hemoperfusion group, peak time was (7.19±3.74) h, peak concentrations was (1.37±0.56) mg/L, clearance rate was (13.93±10.27) L/h/kg, apparent volume of distribution was (418.18±147.15) L/kg The difference of these parameter were statistically significant compared with control group (P<0.05). Hmoperfusion will decrease the inner exposure and load dose of rabbits with chlorpyrifos poisoning.

Pediatric susceptibility to 18 industrial chemicals: a comparative analysis of newborn with young animals.

PubMed

Hasegawa, R; Hirata-Koizumi, M; Dourson, M; Parker, A; Hirose, A; Nakai, S; Kamata, E; Ema, M

2007-04-01

We comprehensively re-analyzed the toxicity data for 18 industrial chemicals from repeated oral exposures in newborn and young rats, which were previously published. Two new toxicity endpoints specific to this comparative analysis were identified, the first, the presumed no observed adverse effect level (pNOAEL) was estimated based on results of both main and dose-finding studies, and the second, the presumed unequivocally toxic level (pUETL) was defined as a clear toxic dose giving similar severity in both newborn and young rats. Based on the analyses of both pNOAEL and pUETL ratios between the different ages, newborn rats demonstrated greater susceptibility (at most 8-fold) to nearly two thirds of these 18 chemicals (mostly phenolic substances), and less or nearly equal sensitivity to the other chemicals. Exceptionally one chemical only showed toxicity in newborn rats. In addition, Benchmark Dose Lower Bound (BMDL) estimates were calculated as an alternative endpoint. Most BMDLs were comparable to their corresponding pNOAELs and the overall correlation coefficient was 0.904. We discussed how our results can be incorporated into chemical risk assessment approaches to protect pediatric health from direct oral exposure to chemicals.

Degradation of FEP thermal control materials returned from the Hubble Space Telescope

NASA Technical Reports Server (NTRS)

Zuby, Thomas M.; Degroh, Kim K.; Smith, Daniela C.

1995-01-01

After an initial 3.6 years of space flight, the Hubble Space Telescope was serviced through a joint effort with the NASA and the European Space Agency. Multi-layer insulation (MLI) was retrieved from the electronics boxes of the two magnetic sensing systems (MSS), also called the magnetometers, and from the returned solar array (SA-I) drive arm assembly. The top layer of each MLI assembly is fluorinated ethylene propylene (FEP, a type of Teflon). Dramatic changes in material properties were observed when comparing areas of high solar fluence to areas of low solar fluence. Cross sectional analysis shows atomic oxygen (AO) erosion values up to 25.4 mu m (1 mil). Greater occurrences of through-thickness cracking and surface microcracking were observed in areas of high solar exposure. Atomic force microscopy (AFM) showed increases in surface microhardness measurements with increasing solar exposure. Decreases in FEP tensile strength and elongation were measured when compared to non-flight material. Erosion yield and tensile results are compared with FEP data from the Long Duration Exposure Facility. AO erosion yield data, solar fluence values, contamination, micrometeoroid or debris impact sites, and optical properties are presented.

A geographical information system-based analysis of cancer mortality and population exposure to coal mining activities in West Virginia, United States of America.

PubMed

Hendryx, Michael; Fedorko, Evan; Anesetti-Rothermel, Andrew

2010-05-01

Cancer incidence and mortality rates are high in West Virginia compared to the rest of the United States of America. Previous research has suggested that exposure to activities of the coal mining industry may contribute to elevated cancer mortality, although exposure measures have been limited. This study tests alternative specifications of exposure to mining activity to determine whether a measure based on location of mines, processing plants, coal slurry impoundments and underground slurry injection sites relative to population levels is superior to a previously-reported measure of exposure based on tons mined at the county level, in the prediction of age-adjusted cancer mortality rates. To this end, we utilize two geographical information system (GIS) techniques--exploratory spatial data analysis and inverse distance mapping--to construct new statistical analyses. Total, respiratory and "other" age-adjusted cancer mortality rates in West Virginia were found to be more highly associated with the GIS-exposure measure than the tonnage measure, before and after statistical control for smoking rates. The superior performance of the GIS measure, based on where people in the state live relative to mining activity, suggests that activities of the industry contribute to cancer mortality. Further confirmation of observed phenomena is necessary with person-level studies, but the results add to the body of evidence that coal mining poses environmental risks to population health in West Virginia.

Exposure to the dental environment and prevalence of respiratory illness in dental student populations.

PubMed

Scannapieco, Frank A; Ho, Alex W; DiTolla, Maris; Chen, Casey; Dentino, Andrew R

2004-03-01

To determine if the prevalence of respiratory disease among dental students and dental residents varies with their exposure to the clinical dental environment. A detailed questionnaire was administered to 817 students at 3 dental schools. The questionnaire sought information concerning demographic characteristics, school year, exposure to the dental environment and dental procedures, and history of respiratory disease. The data obtained were subjected to bivariate and multiple logistic regression analysis. Respondents reported experiencing the following respiratory conditions during the previous year: asthma (26 cases), bronchitis (11 cases), chronic lung disease (6 cases), pneumonia (5 cases) and streptococcal pharyngitis (50 cases). Bivariate statistical analyses indicated no significant associations between the prevalence of any of the respiratory conditions and year in dental school, except for asthma, for which there was a significantly higher prevalence at 1 school compared to the other 2 schools. When all cases of respiratory disease were combined as a composite variable and subjected to multivariate logistic regression analysis controlling for age, sex, race, dental school, smoking history and alcohol consumption, no statistically significant association was observed between respiratory condition and year in dental school or exposure to the dental environment as a dental patient. No association was found between the prevalence of respiratory disease and a student's year in dental school or previous exposure to the dental environment as a patient. These results suggest that exposure to the dental environment does not increase the risk for respiratory infection in healthy dental health care workers.

[Effect of vanadium exposure on neurobehavioral function in workers].

PubMed

Zhu, C W; Liu, Y X; Huang, C J; Gao, W; Hu, G L; Li, J; Zhang, Q; Lan, Y J

2016-02-20

To establish the comprehensive indicators for neurobehavioral function test, and to investigate the possible adverse effect of long-time vanadium exposure on neurobehavioral function and its features in workers. From July to November, 2012, The Neurobehavioral Core Test Battery(NCTB) recommended by WHO was used to conduct tests for 128 workers in vanadium exposure group and 128 workers in control group. The t-test and analysis of covariance were used to compare the differences in each indicator in NCTB between different populations, and the principal component analysis was used to establish the comprehensive neurobehavioral index(NBI) and investigate the effect of vanadium on workers' neurobehavioral function. The vanadium exposure group had significantly lower visual retention score(6.9±1.9), digit span(order) score(8.9±2.9), lifting and turning dexterity(the non-handed hand) score (14.1±3.6), pursuit aiming test(the number of correct dots) score(65.7±24.8), and digit symbol score (31.1±15.0) than the control group (8.2±1.3, 9.4±2.7, 15.5±3.0, 76.5±23.8, and 33.7±9.5)(all P<0.05). The vanadium exposure group also had a significantly lower NBI than the control group(-0.167±0.602 vs 0.168±0.564, P<0.05). Long-term vanadium exposure can influence the workers' neurobehavioral function, with the manifestations of decreased hearing and visual memory, movement velocity, accuracy, and coordination.

Resveratrol decreases noise-induced cyclooxygenase-2 expression in the rat cochlea.

PubMed

Seidman, Michael D; Tang, Wenxue; Bai, Venkatesh Uma; Ahmad, Nadir; Jiang, Hao; Media, Joseph; Patel, Nimisha; Rubin, Cory J; Standring, Robert T

2013-05-01

Our previous studies have demonstrated the efficacy of resveratrol, a grape constituent noted for its antioxidant and anti-inflammatory properties, in reducing temporary threshold shifts and decreasing cochlear hair cell damage following noise exposure. This study was designed to identify the potential protective mechanism of resveratrol by measuring its effect on cyclooxygenase-2 (COX-2) protein expression and reactive oxygen species (ROS) formation following noise exposure. Controlled animal intervention study. Otology Laboratory, Henry Ford Health System. Twenty-two healthy male Fischer 344 rats (2-3 months old) were exposed to acoustic trauma of variable duration with or without intervention. An additional 20 healthy male rats were used to study COX-2 expression at different time points during and following treatment of 24 hours of noise exposure. Cochlear harvest was performed at various time intervals for measurement of COX-2 protein expression via Western blot analysis and immunostaining. Peripheral blood was also obtained for ROS analysis using flow cytometry. Acoustic trauma exposure resulted in a progressive up-regulation of COX-2 protein expression, commencing at 8 hours and peaking at 32 hours. Similarly, ROS production increased after noise exposure. However, treatment with resveratrol reduced noise-induced COX-2 expression as well as ROS formation in the blood as compared with the controls. COX-2 levels are induced dramatically following noise exposure. This increased expression may be a potential mechanism of noise-induced hearing loss (NIHL) and a possible mechanism of resveratrol's ability to mitigate NIHL by its ability to reduce COX-2 expression.

Genotoxicity and oxidative stress in chromium-exposed tannery workers in North India.

PubMed

Ambreen, Khushboo; Khan, Faizan Haider; Bhadauria, Smrati; Kumar, Sudhir

2014-06-01

Trivalent chromium (Cr) is an environmental contaminant, which is extensively used in tanning industries throughout the world and causes various forms of health hazards in tannery workers. Therefore, a cross-sectional study design was used to evaluate the DNA damage and oxidative stress condition in tannery workers exposed to Cr in North India. The study population comprised 100 male tanners in the exposed group and 100 healthy males (no history of Cr exposure) in the comparable control group. Baseline characteristics including age, smoking, alcohol consumption habits and duration of exposure were recorded via interviewing the subjects. Blood Cr level (measured by atomic absorption spectrophotometry), DNA damage (measured by comet assay) and oxidative stress parameters (malondialdehyde (MDA), glutathione (GSH) and superoxide dismutase (SOD)) were estimated in both the groups. As a result of statistical analysis, exposed group showed significantly higher level of Cr (p < 0.0001), DNA damage (p < 0.0001), MDA (p < 0.0001), SOD (p < 0.05) and lower level of GSH (p < 0.001) when compared with controls. Smoking, alcohol consumption habits and age had no significant effect (p > 0.05) on DNA damage and oxidative stress parameters in both the groups. In simple and multiple correlation analysis, DNA damage and oxidative stress parameters showed significant correlation with Cr level and duration of exposure in exposed group. The findings of the present study revealed that chronic occupational exposure to trivalent Cr may cause DNA damage and oxidative stress in tannery workers. © The Author(s) 2012.

Should studies of risk factors for musculoskeletal disorders be stratified by gender? Lessons from the 1998 Québec Health and Social Survey.

PubMed

Messing, Karen; Stock, Susan R; Tissot, France

2009-03-01

Several studies have reported male-female differences in the prevalence of symptoms of work-related musculoskeletal disorders (MSD), some arising from workplace exposure differences. The objective of this paper was to compare two strategies analyzing a single dataset for the relationships between risk factors and MSD in a population-based sample with a wide range of exposures. The 1998 Québec Health and Social Survey surveyed 11 735 respondents in paid work and reported "significant" musculoskeletal pain in 11 body regions during the previous 12 months and a range of personal, physical, and psychosocial risk factors. Five studies concerning risk factors for four musculoskeletal outcomes were carried out on these data. Each included analyses with multiple logistic regression (MLR) performed separately for women, men, and the total study population. The results from these gender-stratified and unstratified analyses were compared. In the unstratified MLR models, gender was significantly associated with musculoskeletal pain in the neck and lower extremities, but not with low-back pain. The gender-stratified MLR models identified significant associations between each specific musculoskeletal outcome and a variety of personal characteristics and physical and psychosocial workplace exposures for each gender. Most of the associations, if present for one gender, were also found in the total population. But several risk factors present for only one gender could be detected only in a stratified analysis, whereas the unstratified analysis added little information. Stratifying analyses by gender is necessary if a full range of associations between exposures and MSD is to be detected and understood.

Cost-effectiveness analysis of varicella vaccine as post-exposure prophylaxis in Hong Kong.

PubMed

Chui, Ka-Sing; Wu, Hiu-Lok; You, Joyce H S

2014-01-01

The varicella vaccine is an effective post-exposure prophylaxis (PEP) for chickenpox. This study aimed to analyze the cost-effectiveness of PEP using varicella vaccine for pediatric patients from the perspective of the public healthcare provider in Hong Kong. A decision tree was designed to compare cost and clinical outcomes of PEP with varicella vaccine versus no PEP in pediatric patients (aged 1-18 y) susceptible to chickenpox with household exposure. Two tiers of outcome were simulated: (1) total direct medical cost per subject exposed, and (2) the quality-adjusted life-year (QALY) loss associated with chickenpox per subject exposed. Model inputs were retrieved from local epidemiology and the medical literature. A sensitivity analysis was performed on all parameters to test the robustness of model results. The base-case analysis showed PEP with varicella vaccine to be less costly (expected cost USD 320 vs USD 731) with lower QALY loss (0.00423 QALY vs 0.01122 QALY) when compared to no PEP. The sensitivity analysis showed that PEP with varicella vaccine was less costly if PEP effectiveness was > 6.2% or the chickenpox infection rate without PEP was > 8.6%. In 10,000 Monte Carlo simulations, PEP with vaccine was cost-effective over 99% of the time, with a mean cost saving of USD 611 per patient (95% confidence interval USD 602-620; p < 0.001) and lower mean QALY loss of 0.00809 QALY (95% confidence interval 0.00802-0.00816 QALY; p < 0.001). Using varicella vaccine as PEP appears to be a cost-saving strategy to avert QALY loss in susceptible pediatric patients exposed to chickenpox in Hong Kong.

A TIERED APPROACH TO PERFORMING UNCERTAINTY ANALYSIS IN CONDUCTING EXPOSURE ANALYSIS FOR CHEMICALS

EPA Science Inventory

The WHO/IPCS draft Guidance Document on Characterizing and Communicating Uncertainty in Exposure Assessment provides guidance on recommended strategies for conducting uncertainty analysis as part of human exposure analysis. Specifically, a tiered approach to uncertainty analysis ...

Electronic Cigarettes Are as Toxic to Skin Flap Survival as Tobacco Cigarettes.

PubMed

Rau, Aline Sabrina; Reinikovaite, Viktorija; Schmidt, Eric P; Taraseviciene-Stewart, Laima; Deleyiannis, Frederic White-Brown

2017-07-01

Electronic cigarettes (e-cigarettes) have become increasingly popular. However, information about the health risks associated with e-cigarette use is sparse. Currently, no published studies examine the effects of chronic e-cigarette exposure on microcirculation or perfusion. Using a rat skin flap model, we examined the toxic microcirculatory effects e-cigarettes may have in comparison with tobacco cigarettes. Fifty-eight rats were randomized to either exposure to room air, tobacco cigarette smoke, medium-nicotine content (1.2%) e-cigarette vapor, or a high-nicotine content (2.4%) e-cigarette vapor. After 4 weeks of exposure, a random pattern, 3 × 9 cm skin flap was elevated on the dorsum of the rats. At 5 weeks, flap survival was evaluated quantitatively, and the rats were euthanized. Plasma was collected for nicotine and cotinine analysis, and flap tissues were harvested for histopathological analysis. Evaluation of the dorsal skin flaps demonstrated significantly increased necrosis in the vapor and tobacco groups. The average necrosis within the groups was as follows: control 19.23%, high-dose vapor 28.61%, medium-dose vapor 35.93%, and tobacco cigarette 30.15%. Although the e-cigarette and tobacco cigarette groups did not differ significantly, each individual group had significantly more necrosis than the control group (P<0.05). These results were corroborated with histopathological analysis of hypoxic tissue. Both the medium-content and high-nicotine content e-cigarette exposure groups had similar amounts of flap necrosis and hypoxia when compared with the tobacco cigarette exposure group. Nicotine-containing e-cigarette vapor is similarly toxic to skin flap survival as tobacco cigarettes.

High‐resolution trench photomosaics from image‐based modeling: Workflow and error analysis

USGS Publications Warehouse

Reitman, Nadine G.; Bennett, Scott E. K.; Gold, Ryan D.; Briggs, Richard; Duross, Christopher

2015-01-01

Photomosaics are commonly used to construct maps of paleoseismic trench exposures, but the conventional process of manually using image‐editing software is time consuming and produces undesirable artifacts and distortions. Herein, we document and evaluate the application of image‐based modeling (IBM) for creating photomosaics and 3D models of paleoseismic trench exposures, illustrated with a case‐study trench across the Wasatch fault in Alpine, Utah. Our results include a structure‐from‐motion workflow for the semiautomated creation of seamless, high‐resolution photomosaics designed for rapid implementation in a field setting. Compared with conventional manual methods, the IBM photomosaic method provides a more accurate, continuous, and detailed record of paleoseismic trench exposures in approximately half the processing time and 15%–20% of the user input time. Our error analysis quantifies the effect of the number and spatial distribution of control points on model accuracy. For this case study, an ∼87  m2 exposure of a benched trench photographed at viewing distances of 1.5–7 m yields a model with <2  cm root mean square error (rmse) with as few as six control points. Rmse decreases as more control points are implemented, but the gains in accuracy are minimal beyond 12 control points. Spreading control points throughout the target area helps to minimize error. We propose that 3D digital models and corresponding photomosaics should be standard practice in paleoseismic exposure archiving. The error analysis serves as a guide for future investigations that seek balance between speed and accuracy during photomosaic and 3D model construction.

Night-shift work and breast cancer--a systematic review and meta-analysis.

PubMed

Ijaz, Sharea; Verbeek, Jos; Seidler, Andreas; Lindbohm, Marja-Liisa; Ojajärvi, Anneli; Orsini, Nicola; Costa, Giovanni; Neuvonen, Kaisa

2013-09-01

The aim of this review was to synthesize the evidence on the potential relationship between nightshift work and breast cancer. We searched multiple databases for studies comparing women in shift work to those with no-shift work reporting incidence of breast cancer. We calculated incremental risk ratios (RR) per five years of night-shift work and per 300 night shift increases in exposure and combined these in a random effects dose-response meta-analysis. We assessed study quality in ten domains of bias. We identified 16 studies: 12 case-control and 4 cohort studies. There was a 9% risk increase per five years of night-shift work exposure in case-control studies [RR 1.09, 95% confidence interval (95% CI) 1.02-1.20; I (2) = 37%, 9 studies], but not in cohort studies (RR 1.01, 95% CI 0.97-1.05; I (2) = 53%, 3 studies). Heterogeneity was significant overall (I (2) = 55%, 12 studies). Results for 300 night shifts were similar (RR 1.04, 95% CI 1.00-1.10; I (2) = 58%, 8 studies). Sensitivity analysis using exposure transformations such as cubic splines, a fixed-effect model, or including only better quality studies did not change the results. None of the 16 studies had a low risk of bias, and 6 studies had a moderate risk. Based on the low quality of exposure data and the difference in effect by study design, our findings indicate insufficient evidence for a link between night-shift work and breast cancer. Objective prospective exposure measurement is needed in future studies.

Exposure to isoflavone-containing soy products and endothelial function: a Bayesian meta-analysis of randomized controlled trials.

PubMed

Beavers, D P; Beavers, K M; Miller, M; Stamey, J; Messina, M J

2012-03-01

To determine whether and to what degree exposure to isoflavone-containing soy products affects EF. Endothelial dysfunction has been identified as an independent coronary heart disease risk factor and a strong predictor of long-term cardiovascular morbidity and mortality. Data on the effects of exposure to isoflavone-containing soy products on EF are conflicting. A comprehensive literature search was conducted using the PUBMED database (National Library of Medicine, Bethesda, MD) inclusively through August 21, 2009 on RCTs using the keywords: soy, isoflavone, phytoestrogen, EF, flow mediated vasodilation, and FMD. A Bayesian meta-analysis was conducted to provide a comprehensive account of the effect of isoflavone-containing soy products on EF, as measured by FMD. A total of 17 RCTs were selected as having sufficient data for study inclusion. The overall mean absolute change in FMD (95% Bayesian CI) for isoflavone-containing soy product interventions was 1.15% (-0.52, 2.75). When the effects of separate interventions were considered, the treatment effect for isolated isoflavones was 1.98% (0.07, 3.97) compared to 0.72% (-1.39, 2.90) for isoflavone-containing soy protein. The models were not improved when considering study-specific effects such as cuff measurement location, prescribed dietary modification, and impaired baseline FMD. Cumulative evidence from the RCTs included in this meta-analysis indicates that exposure to soy isoflavones can modestly, but significantly, improve EF as measured by FMD. Therefore, exposure to isoflavone supplements may beneficially influence vascular health. Copyright © 2010 Elsevier B.V. All rights reserved.

Installation Restoration Program. Remedial Investigation Report: Minnesota Air National Guard Base Duluth International Airport, Duluth, Minnesota. Volume 7

DTIC Science & Technology

1990-01-01

Selection of Indicator Chemicals 6-36 6.2.2 Estimation of Exposure Point Concentrations or Emission Rates 6-38 6.2.2.1 Exposure Pathway Analysis 6-38...Exposure Point Concentrations or Emission Rates 6-50 j 6.3.2.1 Exposure Pathway Analysis 6-52 6.3.2.2 Exposure Point Concentrations 6-55 6.3.2.3...Exposure Point Concentrations or Emission Rates 6-62 6.4.2.1 Exposure Pathway Analysis 6-62 6.4.2.2 Exposure Point Concentrations 6-69 6.4.2.3

Proteomic Profiling of Bladders from Mice Exposed with Sodium Arsenite

EPA Science Inventory

Arsenic, an environmental contaminant, has been linked with cancer of the bladder in humans. To study the mode of action of arsenic, female CH3 mice were exposed to 85 ppm sodium arsenite in their drinking water for 30 days. Following the exposure a comparative proteomic analysis...

No Need for Lopinavir Dose Adjustment during Pregnancy: a Population Pharmacokinetic and Exposure-Response Analysis in Pregnant and Nonpregnant HIV-Infected Subjects.

PubMed

Salem, Ahmed Hamed; Jones, Aksana Kaefer; Santini-Oliveira, Marilia; Taylor, Graham P; Patterson, Kristine B; Nilius, Angela M; Klein, Cheri Enders

2016-01-01

Lopinavir-ritonavir is frequently prescribed to HIV-1-infected women during pregnancy. Decreased lopinavir exposure has been reported during pregnancy, but the clinical significance of this reduction is uncertain. This analysis aimed to evaluate the need for lopinavir dose adjustment during pregnancy. We conducted a population pharmacokinetic analysis of lopinavir and ritonavir concentrations collected from 84 pregnant and 595 nonpregnant treatment-naive and -experienced HIV-1-infected subjects enrolled in six clinical studies. Lopinavir-ritonavir doses in the studies ranged between 400/100 and 600/150 mg twice daily. In addition, linear mixed-effect analysis was used to compare the area under the concentration-time curve from 0 to 12 h (AUC0-12) and concentration prior to dosing (Cpredose) in pregnant women and nonpregnant subjects. The relationship between lopinavir exposure and virologic suppression in pregnant women and nonpregnant subjects was evaluated. Population pharmacokinetic analysis estimated 17% higher lopinavir clearance in pregnant women than in nonpregnant subjects. Lopinavir clearance values postpartum were 26.4% and 37.1% lower than in nonpregnant subjects and pregnant women, respectively. As the tablet formulation was estimated to be 20% more bioavailable than the capsule formulation, no statistically significant differences between lopinavir exposure in pregnant women receiving the tablet formulation and nonpregnant subjects receiving the capsule formulation were identified. In the range of lopinavir AUC0-12 or Cpredose values observed in the third trimester, there was no correlation between lopinavir exposure and viral load or proportion of subjects with virologic suppression. Similar efficacy was observed between pregnant women and nonpregnant subjects receiving lopinavir-ritonavir at 400/100 mg twice daily. The pharmacokinetic and pharmacodynamic results support the use of a lopinavir-ritonavir 400/100-mg twice-daily dose during pregnancy. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Reducing Periconceptional Methylmercury Exposure: Cost–Utility Analysis for a Proposed Screening Program for Women Planning a Pregnancy in Ontario, Canada

PubMed Central

Rennie, Colin; Coyle, Doug

2015-01-01

Background The assessment of neurodevelopmental effects in children associated with prenatal methylmercury exposure, from contaminated fish and seafood in the maternal diet, has recently been strengthened by adjustment for the negative confounding resulting from co-exposure to beneficial polyunsaturated fatty acids (PUFAs). Objectives We aimed to determine the cost-effectiveness of a periconceptional screening program of blood mercury concentration for women planning to become pregnant in Ontario, Canada. Fish intake recommendations would be provided for those found to have blood mercury levels above the intervention threshold. Methods Analysis was conducted using a combined decision tree/Markov model to compare the proposed screening intervention with standard care from a societal perspective over a lifetime horizon. We used the national blood mercury distributions of women 20–49 years of age reported in the Canadian Health Measures Survey from 2009 through 2011 to determine the cognitive deficits associated with prenatal methylmercury exposure for successful planned pregnancies. Outcomes modeled included the loss in quality of life and the remedial education costs. Value of information analysis was conducted to assess the underlying uncertainty around the model results and to identify which parameters contribute most to this uncertainty. Results The incremental cost per quality-adjusted life year (QALY) gained for the proposed screening intervention was estimated to be Can$18,051, and the expected value for a willingness to pay of Can$50,000/QALY to be Can$0.61. Conclusions Our findings suggest that the proposed periconceptional blood mercury screening program for women planning a pregnancy would be highly cost-effective from a societal perspective. The results of a value of information analysis confirm the robustness of the study’s conclusions. Citation Gaskin J, Rennie C, Coyle D. 2015. Reducing periconceptional methylmercury exposure: cost–utility analysis for a proposed screening program for women planning a pregnancy in Ontario, Canada. Environ Health Perspect 123:1337–1344; http://dx.doi.org/10.1289/ehp.1409034 PMID:26024213

Evaluation of the Tobacco Heating System 2.2. Part 6: 90-day OECD 413 rat inhalation study with systems toxicology endpoints demonstrates reduced exposure effects of a mentholated version compared with mentholated and non-mentholated cigarette smoke.

PubMed

Oviedo, Alberto; Lebrun, Stefan; Kogel, Ulrike; Ho, Jenny; Tan, Wei Teck; Titz, Bjoern; Leroy, Patrice; Vuillaume, Gregory; Bera, Monali; Martin, Florian; Rodrigo, Gregory; Esposito, Marco; Dempsey, Ruth; Ivanov, Nikolai V; Hoeng, Julia; Peitsch, Manuel C; Vanscheeuwijck, Patrick

2016-11-30

The toxicity of a mentholated version of the Tobacco Heating System (THS2.2M), a candidate modified risk tobacco product (MRTP), was characterized in a 90-day OECD inhalation study. Differential gene and protein expression analysis of nasal epithelium and lung tissue was also performed to record exposure effects at the molecular level. Rats were exposed to filtered air (sham), to THS2.2M (at 15, 23 and 50 μg nicotine/l), to two mentholated reference cigarettes (MRC) (at 23 μg nicotine/l), or to the 3R4F reference cigarette (at 23 μg nicotine/l). MRCs were designed to meet 3R4F specifications. Test atmosphere analyses demonstrated that aldehydes were reduced by 75%-90% and carbon monoxide by 98% in THS2.2M aerosol compared with MRC smoke; aerosol uptake was confirmed by carboxyhemoglobin and menthol concentrations in blood, and by the quantities of urinary nicotine metabolites. Systemic toxicity and alterations in the respiratory tract were significantly lower in THS2.2M-exposed rats compared with MRC and 3R4F. Pulmonary inflammation and the magnitude of the changes in gene and protein expression were also dramatically lower after THS2.2M exposure compared with MRCs and 3R4F. No menthol-related effects were observed after MRC mainstream smoke-exposure compared with 3R4F. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Study of spatiotemporal variation of atmospheric mercury and its human exposure around an integrated steel plant, India

NASA Astrophysics Data System (ADS)

Pervez, S.; Koshle, A.; Pervez, Y.

2010-01-01

Mercury release by coal combustion has been significantly increased in India. Mercury content in coal has been analyzed to 0.272 ppm by Central Pollution Control Board. Toxicological effects of elemental Hg (Hg0) exposure include respiratory and renal failures, cardiac arrest, and cerebral oedema, while subclinical exposure may induce kidney, behavioral, and cognitive dysfunctions. The present work is focused on dispersion pattern and inter-phase exchange phenomena of ambient mercury between air-particulate matter evaluations of alongwith dominance of various major routes of human exposure-dose response using regression analysis around an integrated steel plant in central India. Source-downwind type stratified random sampling plan using longitudinal study design has been adopted for ambient monitoring of total mercury, while representative sampling plant has been adopted for persona exposure-dose response study In space-time framework. Control sites and subjects have been chosen from uncontaminated area (100 km away from any industrial activities). 06 ambient air monitoring stations and 17 subjects from workers, non-workers but local residents' categories and from controlled sites have been chosen for the study. Samples of mercury biomarkers (blood, breast milk and urine) have also been collected from same subjects in each month during sampling period. The sampling period was March 2005 to February 2006 . Samples of 30% acidified KMnO4 for air-Hg absorption, PM10, RPM and biological samples were analyzed for total mercury by ICP-AES using standard methods. Local soils and ground water were also monitored for total mercury content during the sampling period. Results have shown that mercury concentration is very high compared to prescribed limits in all receptors. Results of exchange phenomenon have shown the higher transfer of mercury from air to particulate during combustion in steel plant environment due to presence of huge amount of iron particles, in contrast to results obtained in other industrial locations earlier. Plant workers have shown 1.5 to 2.5 times higher personal RPM-Hg levels compared to Category 2 and 20-30 times higher than Category 3. All biomarkers have shown higher Hg presence compared to prescribed standards. Regression analysis between exposure routes and bio-receptors has been investigated. Dominance status of selected routes of bio-accumulation has been varied from category to category.

Study of spatiotemporal variation of atmospheric mercury and its human exposure around an integrated steel plant, India

NASA Astrophysics Data System (ADS)

Pervez, S.; Koshle, A.; Pervez, Y.

2010-06-01

Mercury release by coal combustion has been significantly increased in India. Mercury content in coal has been analyzed to 0.272 ppm by Central Pollution Control Board. Toxicological effects of elemental Hg (Hg0) exposure include respiratory and renal failures, cardiac arrest, and cerebral oedema, while subclinical exposure may induce kidney, behavioral, and cognitive dysfunctions. The present work is focused on dispersion pattern and inter-phase exchange phenomena of ambient mercury between air-particulate matter evaluations of alongwith dominance of various major routes of human exposure-dose response using regression analysis around an integrated steel plant in central India. Source-downwind type stratified random sampling plan using longitudinal study design has been adopted for ambient monitoring of total mercury, while representative sampling plant has been adopted for persona exposure-dose response study In space-time framework. Control sites and subjects have been chosen from uncontaminated area (100 km away from any industrial activities). 06 ambient air monitoring stations and 17 subjects from workers, non-workers but local residents' categories and from controlled sites have been chosen for the study. Samples of mercury biomarkers (blood, breast milk and urine) have also been collected from same subjects in each month during sampling period. The sampling period was March 2005 to February 2006 . Samples of 30% acidified KMnO4 for air-Hg absorption, PM10, RPM and biological samples were analyzed for total mercury by ICP-AES using standard methods. Local soils and ground water were also monitored for total mercury content during the sampling period. Results have shown that mercury concentration is very high compared to prescribed limits in all receptors. Results of exchange phenomenon have shown the higher transfer of mercury from air to particulate during combustion in steel plant environment due to presence of huge amount of iron particles, in contrast to results obtained in other industrial locations earlier. Plant workers have shown 1.5 to 2.5 times higher personal RPM-Hg levels compared to Category 2 and 20-30 times higher than Category 3. All biomarkers have shown higher Hg presence compared to prescribed standards. Regression analysis between exposure routes and bio-receptors has been investigated. Dominance status of selected routes of bio-accumulation has been varied from category to category.

Comparison of Ordinal and Nominal Classification Trees to Predict Ordinal Expert-Based Occupational Exposure Estimates in a Case–Control Study

PubMed Central

Wheeler, David C.; Archer, Kellie J.; Burstyn, Igor; Yu, Kai; Stewart, Patricia A.; Colt, Joanne S.; Baris, Dalsu; Karagas, Margaret R.; Schwenn, Molly; Johnson, Alison; Armenti, Karla; Silverman, Debra T.; Friesen, Melissa C.

2015-01-01

Objectives: To evaluate occupational exposures in case–control studies, exposure assessors typically review each job individually to assign exposure estimates. This process lacks transparency and does not provide a mechanism for recreating the decision rules in other studies. In our previous work, nominal (unordered categorical) classification trees (CTs) generally successfully predicted expert-assessed ordinal exposure estimates (i.e. none, low, medium, high) derived from occupational questionnaire responses, but room for improvement remained. Our objective was to determine if using recently developed ordinal CTs would improve the performance of nominal trees in predicting ordinal occupational diesel exhaust exposure estimates in a case–control study. Methods: We used one nominal and four ordinal CT methods to predict expert-assessed probability, intensity, and frequency estimates of occupational diesel exhaust exposure (each categorized as none, low, medium, or high) derived from questionnaire responses for the 14983 jobs in the New England Bladder Cancer Study. To replicate the common use of a single tree, we applied each method to a single sample of 70% of the jobs, using 15% to test and 15% to validate each method. To characterize variability in performance, we conducted a resampling analysis that repeated the sample draws 100 times. We evaluated agreement between the tree predictions and expert estimates using Somers’ d, which measures differences in terms of ordinal association between predicted and observed scores and can be interpreted similarly to a correlation coefficient. Results: From the resampling analysis, compared with the nominal tree, an ordinal CT method that used a quadratic misclassification function and controlled tree size based on total misclassification cost had a slightly better predictive performance that was statistically significant for the frequency metric (Somers’ d: nominal tree = 0.61; ordinal tree = 0.63) and similar performance for the probability (nominal = 0.65; ordinal = 0.66) and intensity (nominal = 0.65; ordinal = 0.65) metrics. The best ordinal CT predicted fewer cases of large disagreement with the expert assessments (i.e. no exposure predicted for a job with high exposure and vice versa) compared with the nominal tree across all of the exposure metrics. For example, the percent of jobs with expert-assigned high intensity of exposure that the model predicted as no exposure was 29% for the nominal tree and 22% for the best ordinal tree. Conclusions: The overall agreements were similar across CT models; however, the use of ordinal models reduced the magnitude of the discrepancy when disagreements occurred. As the best performing model can vary by situation, researchers should consider evaluating multiple CT methods to maximize the predictive performance within their data. PMID:25433003

Exposure to solar ultraviolet radiation is associated with a decreased folate status in women of childbearing age.

PubMed

Borradale, D; Isenring, E; Hacker, E; Kimlin, M G

2014-02-05

In vitro studies indicate that folate in collected human blood is vulnerable to degradation after exposure to ultraviolet (UV) radiation. This has raised concerns about folate depletion in individuals with high sun exposure. Here, we investigate the association between personal solar UV radiation exposure and serum folate concentration, using a three-week prospective study that was undertaken in females aged 18-47years in Brisbane, Australia (153 E, 27 S). Following two weeks of supplementation with 500μg of folic acid daily, the change in serum folate status was assessed over a 7-day period of measured personal sun exposure. Compared to participants with personal UV exposures of <200 Joules per day, participants with personal UV exposures of 200-599 and >600 Joules per day had significantly higher depletion of serum folate (p=0.015). Multivariable analysis revealed personal UV exposure as the strongest predictor accounting for 20% of the overall change in serum folate (Standardised B=-0.49; t=-3.75; p=<0.01). These data show that increasing solar UV radiation exposures reduces the effectiveness of folic acid supplementation. The consequences of this association may be most pronounced for vulnerable individuals, such as women who are pregnant or of childbearing age with high sun exposures. Copyright © 2014 Elsevier B.V. All rights reserved.

The role of cadmium in obesity and diabetes.

PubMed

Tinkov, Alexey A; Filippini, Tommaso; Ajsuvakova, Olga P; Aaseth, Jan; Gluhcheva, Yordanka G; Ivanova, Juliana M; Bjørklund, Geir; Skalnaya, Margarita G; Gatiatulina, Eugenia R; Popova, Elizaveta V; Nemereshina, Olga N; Vinceti, Marco; Skalny, Anatoly V

2017-12-01

Multiple studies have shown an association between environmental exposure to hazardous chemicals including toxic metals and obesity, diabetes, and metabolic syndrome. At the same time, the existing data on the impact of cadmium exposure on obesity and diabetes are contradictory. Therefore, the aim of the present work was to review the impact of cadmium exposure and status on the risk and potential etiologic mechanisms of obesity and diabetes. In addition, since an effect of cadmium exposure on incidence of diabetes mellitus and insulin resistance was suggested by several epidemiologic studies, we carried out a meta-analysis of all studies assessing risk of prevalence and incidence of diabetes. By comparing the highest versus the lowest cadmium exposure category, we found a high risk of diabetes incidence (odds ratio=1.38, 95% confidence interval 1.12-1.71), which was higher for studies using urine as exposure assessment. On the converse, results of epidemiologic studies linking cadmium exposure and overweight or obesity are far less consistent and even conflicting, also depending on differences in exposure levels and the specific marker of exposure (blood, urine, hair, nails). In turn, laboratory studies demonstrated that cadmium adversely affects adipose tissue physiopathology through several mechanisms, thus contributing to increased insulin resistance and enhancing diabetes. However, intimate biological mechanisms linking Cd exposure with obesity and diabetes are still to be adequately investigated. Copyright © 2017 Elsevier B.V. All rights reserved.

Imaging Radiation-Induced Gastrointestinal, Bone Marrow Injury and Recovery Kinetics Using 18F-FDG PET

PubMed Central

Tang, Tien T.; Rendon, David A.; Zawaski, Janice A.; Afshar, Solmaz F.; Kaffes, Caterina K.; Sabek, Omaima M.

2017-01-01

Positron emission tomography using 18F-Fluro-deoxy-glucose (18F-FDG) is a useful tool to detect regions of inflammation in patients. We utilized this imaging technique to investigate the kinetics of gastrointestinal recovery after radiation exposure and the role of bone marrow in the recovery process. Male Sprague-Dawley rats were either sham irradiated, irradiated with their upper half body shielded (UHBS) at a dose of 7.5 Gy, or whole body irradiated (WBI) with 4 or 7.5 Gy. Animals were imaged using 18F-FDG PET/CT at 5, 10 and 35 days post-radiation exposure. The gastrointestinal tract and bone marrow were analyzed for 18F-FDG uptake. Tissue was collected at all-time points for histological analysis. Following 7.5 Gy irradiation, there was a significant increase in inflammation in the gastrointestinal tract as indicated by the significantly higher 18F-FDG uptake compared to sham. UHBS animals had a significantly higher activity compared to 7.5 Gy WBI at 5 days post-exposure. Animals that received 4 Gy WBI did not show any significant increase in uptake compared to sham. Analysis of the bone marrow showed a significant decrease of uptake in the 7.5 Gy animals 5 days post-irradiation, albeit not observed in the 4 Gy group. Interestingly, as the metabolic activity of the gastrointestinal tract returned to sham levels in UHBS animals it was accompanied by an increase in metabolic activity in the bone marrow. At 35 days post-exposure both gastrointestinal tract and bone marrow 18F-FDG uptake returned to sham levels. 18F-FDG imaging is a tool that can be used to study the inflammatory response of the gastrointestinal tract and changes in bone marrow metabolism caused by radiation exposure. The recovery of the gastrointestinal tract coincides with an increase in bone marrow metabolism in partially shielded animals. These findings further demonstrate the relationship between the gastrointestinal syndrome and bone marrow recovery, and that this interaction can be studied using non-invasive imaging modalities. PMID:28052129

Imaging Radiation-Induced Gastrointestinal, Bone Marrow Injury and Recovery Kinetics Using 18F-FDG PET.

PubMed

Tang, Tien T; Rendon, David A; Zawaski, Janice A; Afshar, Solmaz F; Kaffes, Caterina K; Sabek, Omaima M; Gaber, M Waleed

2017-01-01

Positron emission tomography using 18F-Fluro-deoxy-glucose (18F-FDG) is a useful tool to detect regions of inflammation in patients. We utilized this imaging technique to investigate the kinetics of gastrointestinal recovery after radiation exposure and the role of bone marrow in the recovery process. Male Sprague-Dawley rats were either sham irradiated, irradiated with their upper half body shielded (UHBS) at a dose of 7.5 Gy, or whole body irradiated (WBI) with 4 or 7.5 Gy. Animals were imaged using 18F-FDG PET/CT at 5, 10 and 35 days post-radiation exposure. The gastrointestinal tract and bone marrow were analyzed for 18F-FDG uptake. Tissue was collected at all-time points for histological analysis. Following 7.5 Gy irradiation, there was a significant increase in inflammation in the gastrointestinal tract as indicated by the significantly higher 18F-FDG uptake compared to sham. UHBS animals had a significantly higher activity compared to 7.5 Gy WBI at 5 days post-exposure. Animals that received 4 Gy WBI did not show any significant increase in uptake compared to sham. Analysis of the bone marrow showed a significant decrease of uptake in the 7.5 Gy animals 5 days post-irradiation, albeit not observed in the 4 Gy group. Interestingly, as the metabolic activity of the gastrointestinal tract returned to sham levels in UHBS animals it was accompanied by an increase in metabolic activity in the bone marrow. At 35 days post-exposure both gastrointestinal tract and bone marrow 18F-FDG uptake returned to sham levels. 18F-FDG imaging is a tool that can be used to study the inflammatory response of the gastrointestinal tract and changes in bone marrow metabolism caused by radiation exposure. The recovery of the gastrointestinal tract coincides with an increase in bone marrow metabolism in partially shielded animals. These findings further demonstrate the relationship between the gastrointestinal syndrome and bone marrow recovery, and that this interaction can be studied using non-invasive imaging modalities.

[Effects of occupational exposure to pesticides on semen quality of workers in an agricultural community of Merida state, Venezuela].

PubMed

Miranda-Contreras, Leticia; Cruz, Ibis; Osuna, Jesús A; Gómez-Pérez, Roald; Berrueta, Lisbeth; Salmen, Siham; Colmenares, Melisa; Barreto, Silvio; Balza, Alirio; Morales, Yasmin; Zavala, Leisalba; Labarca, Emilitza; García, Nelly; Sanchez, Beluardi; Contreras, Carlos A; Andrade, Henry

2015-06-01

Numerous studies report adverse effects of pesticides on male reproductive health. The objectives of this study were to investigate whether there is a relationship between occupational exposure to pesticides and semen quality, and to determine whether chronic exposure to pesticides differentially affects semen quality in men of different ages. A comparative study of 64 farmers and 64 control men was performed. The farmers were interviewed to determine their occupational history and particularly, activities that may involve exposure to pesticides. Semen parameters were evaluated and a comparative analysis of semen variables between exposed and control groups, as well as between age groups: 18-29, 30-37 and 38-60 years was done. Significant alterations of some semen parameters in the exposed group were found, such as: decreases in sperm concentration, slow progressive motility and sperm membrane integrity; at the same time, increases in eosin Y positive and sperm DNA fragmentation index. The results obtained by age groups showed significant differences between exposed and control groups for the parameters of membrane integrity, eosin Y positive and sperm DNA fragmentation index, being the exposed group between 18-29 years that showed the highest altered cases of these parameters. Our results prove that occupational pesticide exposure is associated with alterations in sperm quality, creating a risk to farm workers in their reproductive capacity.

Temporal Patterns of Exposure to Asbestos and Risk of Asbestosis: An Analysis of a Cohort of Asbestos Textile Workers.

PubMed

Farioli, Andrea; Violante, Francesco S; La Vecchia, Carlo; Negri, Eva; Pelucchi, Claudio; Spatari, Giovanna; Boffetta, Paolo; Pira, Enrico

2018-01-12

The aim of the study was to assess the risk of asbestosis death based on the temporal pattern of exposure to asbestos. We followed up a cohort of asbestos textile workers, employed in 1946 to 1984, until November 2013. We measured the duration of the employment, the time since last employment (TSLE), the age, and the year of first employment. Hazard ratios (HR) were estimated through multivariable Cox regression models. We observed 51 asbestosis deaths among 1823 workers. The HR of asbestosis death increased with exposure duration (HR 2.4 for ≥15 years compared with <5 years, P trend = 0.014) and declined with TSLE (HR 0.3 for ≥25 compared with <5 years, P = 0.004). The risk of asbestosis mortality strongly declined for exposure starting after 1968. The risk of asbestosis death strongly declines in the decades after cessation of the exposure.This is an open access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. http://creativecommons.org/licenses/by-nc-nd/4.0.

Impulsive choice and pre-exposure to delays: iv. effects of delay- and immediacy-exposure training relative to maturational changes in impulsivity.

PubMed

Renee Renda, C; Rung, Jillian M; Hinnenkamp, Jay E; Lenzini, Stephanie N; Madden, Gregory J

2018-04-23

Impulsive choice describes preference for smaller, sooner rewards over larger, later rewards. Excessive delay discounting (i.e., rapid devaluation of delayed rewards) underlies some impulsive choices, and is observed in many maladaptive behaviors (e.g., substance abuse, gambling). Interventions designed to reduce delay discounting may provide therapeutic gains. One such intervention provides rats with extended training with delayed reinforcers. When compared to a group given extended training with immediate reinforcers, delay-exposed rats make significantly fewer impulsive choices. To what extent is this difference due to delay-exposure training shifting preference toward self-control or immediacy-exposure training (the putative control group) shifting preference toward impulsivity? The current study compared the effects of delay- and immediacy-exposure training to a no-training control group and evaluated within-subject changes in impulsive choice across 51 male Wistar rats. Delay-exposed rats made significantly fewer impulsive choices than immediacy-exposed and control rats. Between-group differences in impulsive choice were not observed in the latter two groups. While delay-exposed rats showed large, significant pre- to posttraining reductions in impulsive choice, immediacy-exposed and control rats showed small reductions in impulsive choice. These results suggest that extended training with delayed reinforcers reduces impulsive choice, and that extended training with immediate reinforcers does not increase impulsive choice. © 2018 Society for the Experimental Analysis of Behavior.

Modifiable risk factors including sunlight exposure and fish consumption are associated with risk of hypertension in a large representative population from Macau.

PubMed

Ke, Liang; Ho, Jacky; Feng, Jianzhang; Mpofu, Elias; Dibley, Michael J; Feng, Xiuhua; Van, Florance; Leong, Sokman; Lau, Winne; Lueng, Petra; Kowk, Carrie; Li, Yan; Mason, Rebecca S; Brock, Kaye E

2014-10-01

Chinese populations are known to be at risk for vitamin D deficiency, with some evidence that this is due to lack of exposure to sunlight. Vitamin D deficiency and/or low sun exposure have been associated with higher incidence of hypertension in Caucasians. Thus, we investigated these associations in a Chinese population with a high rate of hypertension. From a random household survey of 1410 residents aged ≥18 years, height, weight and blood pressure were measured and demographic, exercise and dietary data were collected, as well as estimated hours of sunlight exposure on weekdays and weekends (in winter and summer). Modifiable predictors of hypertension in these data were lack of sunlight exposure and low intake of fish as well as smoking, obesity and lack of exercise. When investigated in a linear model, sunlight exposure was negatively associated with hypertension (β=-0.072, p<0.001) as was physical activity (β=-0.021, p<0.001) and fish consumption (β=-0.177, p<0.001). In contrast body mass index (weight/height(2)) was positively associated with hypertension (β=+0.62, p<0.001), as were pack-years of smoking (β=+0.27, p<0.001). On multivariate categorical analysis taking into account demographic risk factors in these data (age, gender and occupation) having more than half an hour's sun exposure per day compared to none was associated with less hypertension (OR=0.6, 95% CI: 0.4-0.8). Similarly, consuming either oily fish or seafood more than four times per week compared to less was also associated with less hypertension (oily fish (OR=0.4, 95% CI: 0.3-0.5); seafood consumption (OR=0.8, 95% CI: 0.7-0.9)). Having daily moderate physical activity compared to none was also associated with a lower risk of hypertension (OR=0.8, 95% CI: 0.7-0.9). In contrast, being obese compared to normal weight and having more than five pack-years of smoking compared to none were associated with a higher risk of hypertension (OR=4.6, 95% CI: 3.7-5.7; OR=1.4, 95% CI: 1.0-1.8, respectively). The major new findings of this study are that more sun exposure and high weekly fish consumption (especially oily fish) may be potentially modifiable independent factors for protecting against risk of hypertension in this population. This article is part of a Special Issue entitled '16th Vitamin D Workshop'. Copyright © 2013 Elsevier Ltd. All rights reserved.

ESTIMATING SYSTEMIC EXPOSURE TO ETHINYL ESTRADIOL FROM AN ORAL CONTRACEPTIVE

PubMed Central

WESTHOFF, Carolyn L.; PIKE, Malcolm C.; TANG, Rosalind; DINAPOLI, Marianne N.; SULL, Monica; CREMERS, Serge

2015-01-01

Objectives This study was conducted to compare single-dose pharmacokinetics of ethinyl estradiol in an oral contraceptive to steady-state values, and to assess whether any simpler measures could provide an adequate proxy of the ‘gold standard’ 24-hour steady-state area-under-the-curve. Identifying a simple, less expensive, measure of systemic ethinyl estradiol exposure would be useful for larger studies designed to assess the relationship between an individual’s ethinyl estradiol exposure and her side effects. Study Design We conducted a 13 samples over 24 hours pharmacokinetic analysis on day 1 and day 21 of the first cycle of a monophasic oral contraceptive containing 30 mcg ethinyl estradiol and 150 mcg levonorgestrel in 17 non-obese healthy white women. We also conducted an abbreviated single dose 9-sample pharmacokinetic analysis after a month washout. Ethinyl estradiol was measured by liquid chromatography-tandem mass spectrometry. We compared results of full 13-sample steady-state pharmacokinetic analysis with results calculated using fewer samples (9 or 5) and following the single doses. We calculated Pearson correlation coefficients to evaluate the relationships between these estimates of systemic ethinyl estradiol exposure. Results The area-under-the-curve, maximum (Cmax), and 24-hour (C24) values were similar following the two single oral contraceptive doses (area-under-the-curve, r = 0.92). The steady-state 13-sample 24-hour area-under-the-curve was highly correlated with the average 9-sample area-under-the-curve after the two single doses (r = 0.81, p = 0.0002). This correlation remained the same if the number of samples was reduced to 4, taken at time 1, 2.5, 4 and 24 hours. The C24 at steady-state was highly correlated with the 24-hour steady-state area-under-the-curve (r = 0.92, p < 0.0001). The average of the C24 values following the two single doses was also quite highly correlated with the steady-state area-under-the-curve (r = 0.72, p = 0.0026). Conclusions Limited blood sampling, including results from two single doses, gave highly correlated estimates of an oral contraceptive user’s steady-state ethinyl estradiol exposure. PMID:25511238

Estimating systemic exposure to ethinyl estradiol from an oral contraceptive.

PubMed

Westhoff, Carolyn L; Pike, Malcolm C; Tang, Rosalind; DiNapoli, Marianne N; Sull, Monica; Cremers, Serge

2015-05-01

This study was conducted to compare single-dose pharmacokinetics of ethinyl estradiol in an oral contraceptive with steady-state values and to assess whether any simpler measures could provide an adequate proxy of the "gold standard" 24-hour steady-state area under the curve (AUC) value. Identification of a simple, less expensive measure of systemic ethinyl estradiol exposure would be useful for larger studies that are designed to assess the relationship between an individual's ethinyl estradiol exposure and side-effects. We collected 13 samples over 24 hours for pharmacokinetic analysis on days 1 and 21 of the first cycle of a monophasic oral contraceptive that contained 30 μg ethinyl estradiol and 150 μg levonorgestrel in 17 nonobese healthy white women. We also conducted an abbreviated single-dose 9-sample pharmacokinetic analysis after a month washout. Ethinyl estradiol was measured by liquid chromatography-tandem mass spectrometry. We compared results of a full 13-sample steady-state pharmacokinetic analysis with results that had been calculated with the use of fewer samples (9 or 5) and after the single doses. We calculated Pearson correlation coefficients to evaluate the relationships between these estimates of systemic ethinyl estradiol exposure. The AUC, maximum, and 24-hour values were similar after the 2 single oral contraceptive doses (AUC; r=0.92). The steady-state 13-sample 24-hour AUC value was correlated highly with the average 9-sample AUC value after the 2 single doses (r=0.81; P=.0002). This correlation remained the same if the number of single-dose samples was reduced to 4, taken at time 1, 2.5, 4, and 24 hours. The 24-hour value at steady-state was correlated highly with the 24-hour steady-state AUC value (r=0.92; P<.0001). The average of the 24-hour values after the 2 single doses was also correlated quite highly with the steady-state AUC value (r=0.72; P=.0026). Limited blood sampling, including results from 2 single doses, gave highly correlated estimates of an oral contraceptive user's steady-state ethinyl estradiol exposure. Copyright © 2015 Elsevier Inc. All rights reserved.

Inverse association between age at the time of radiation exposure and extent of disease in cases of radiation-induced childhood thyroid carcinoma in Belarus.

PubMed

Farahati, J; Demidchik, E P; Biko, J; Reiners, C

2000-03-15

Increased incidence of childhood thyroid carcinoma, particularly in the youngest children, has been reported from Belarus since the nuclear reactor accident at Chernobyl in 1986. The relation between disease severity and age at the time of the accident, not previously established in this cohort, was analyzed in this study. The authors studied the association between disease severity, expressed by TNM classification, and age at radiation exposure in a cohort of 483 patients younger than 8 years at the time of the Chernobyl accident who have been diagnosed with differentiated thyroid carcinoma since 1986 at the Center for Thyroid Cancer in Minsk. The associations between age at radiation exposure and TNM categories were compared among 4 groups of patients who were ages <2, 2.1-4, 4.1-6, and 6.1-8 years at the time of the accident. Multivariate discriminant analysis was performed to examine the effects of age at the time of the accident, gender, histology, tumor stage, and N classification on the frequency of distant metastasis. Younger age at the time of the Chernobyl accident was associated with greater extrathyroidal tumor extension (P<0.01) and more lymph node involvement (P<0.0001) and tended to be associated with more distant metastases (P = 0.09). Compared with patients who were ages 6.1-8 years at the time of the accident, patients who were younger than 2 years had significantly more extrathyroidal tumor invasion (P = 0.004), lymph node involvement (P = 0.004), and distant metastases (P = 0.05). The age at diagnosis increased with older age at the time of radiation exposure (linear regression analysis; correlation coefficient = 0. 67; P<0.001). Multivariate analysis revealed that younger age at the time of the accident (P = 0.001) and advanced locoregional tumor extension (P<0.001) were the only powerful factors influencing the risk for distant metastasis of this malignancy. The severity of disease was associated inversely with age at the time of radiation exposure in these cases of radiation-induced childhood thyroid carcinoma. Copyright 2000 American Cancer Society.

Clinical Effects of Synthetic Cannabinoid Receptor Agonists Compared with Marijuana in Emergency Department Patients with Acute Drug Overdose.

PubMed

Zaurova, Milana; Hoffman, Robert S; Vlahov, David; Manini, Alex F

2016-12-01

Synthetic cannabinoid receptor agonists (SCRAs) are heterogeneous compounds originally intended as probes of the endogenous cannabinoid system or as potential therapeutic agents. We assessed the clinical toxicity associated with recent SCRA use in a large cohort of drug overdose patients. This subgroup analysis of a large (n = 3739) drug overdose cohort study involved consecutive ED patients at two urban teaching hospitals collected between 2009 and 2013. Clinical characteristics of patients with the exposure to SCRAs (SRCA subgroup) were compared with those from patients who smoked traditional cannabinoids (marijuana subgroup). Data included demographics, exposure details, vital signs, mental status, and basic chemistries gathered as part of routine clinical care. Study outcomes included altered mental status and cardiotoxicity. Eighty-seven patients reported exposure to any cannabinoid, of whom 17 reported SCRAs (17 cases, 70 controls, mean age 38.9 years, 77 % males, 31 % Hispanic). There were no significant differences between SRCA and marijuana with respect to demographics (age, gender, and race/ethnicity), exposure history (suicidality, misuse, and intent), vital signs, or serum chemistries. Mental status varied between SRCA and marijuana, with agitation significantly more likely in SCRA subgroup (OR = 3.8, CI = 1.2-11.9). Cardiotoxicity was more pronounced in the SCRA subgroup with dysrhythmia significantly more likely (OR = 9.2, CI = 1.0-108). In the first clinical study comparing the adverse effects of SCRA overdose vs. marijuana controls in an ED population, we found that SCRA overdoses had significantly pronounced neurotoxicity and cardiotoxicity compared with marijuana.

Pet exposure in utero and postnatal decreases the effects of air pollutants on hypertension in children: A large population based cohort study.

PubMed

Lawrence, Wayne R; Yang, Mo; Lin, Shao; Wang, Si-Quan; Liu, Yimin; Ma, Huimin; Chen, Duo-Hong; Yang, Bo-Yi; Zeng, Xiao-Wen; Hu, Li-Wen; Dong, Guang-Hui

2018-07-01

The effect of ambient air pollution exposure on childhood hypertension has emerged as a concern in China, and previous studies suggested pet ownership is associated with lower blood pressure (BP). However, limited information exists on the interactive effects pet ownership and air pollution exposure has on hypertension. We investigated the interactions between exposure to pet ownership and air pollutants on hypertension in Chinese children. 9354 students in twenty-four elementary and middle schools (aged 5-17 years) in Northeastern China were evaluated during 2012-2013. Four-year average concentrations of particulate matter with aerodynamic diameter of ≤10 μm (PM 10 ), SO 2 , NO 2 , and O 3 , were collected in the 24 districts from 2009 to 2012. Hypertension was defined as average diastolic or systolic BP (three time measurements) in the 95th percentile or higher based on height, age, and sex. To examine effects, two-level regression analysis was used, controlling covariates. Consistent interactions between exposure to pet and air pollutants were observed. Compared to children exposed to pet, those not exposed exhibited consistently stronger effects of air pollution. The highest odds ratios (ORs) per 30.6 μg/m 3 increase in PM 10 were 1.79 (95%confidence interval [95%CI]: 1.29-2.50) in children without current pet exposure compared to 1.24 (95%CI: 0.85-1.82) in children with current pet exposure. As for BP, only O 3 had an interaction for all exposure to pet ownership types, and showed lower BP in children exposed to pet. The increases in mean diastolic BP per 46.3 μg/m 3 increase in O 3 were 0.60  mmHg (95%CI: 0.21, 0.48) in children without pet exposure in utero compared with 0.34  mmHg (95%CI: 0.21, 0.48) in their counterparts. When stratified by age, pet exposure was more protective among younger children. In conclusion, in this large population-based cohort, pet ownership is associated with smaller associations between air pollution and hypertension in children, suggesting pet ownership reduces susceptibility to the health effects of pollutants. Copyright © 2018 Elsevier Ltd. All rights reserved.

Attention Restoration Theory: A systematic review of the attention restoration potential of exposure to natural environments.

PubMed

Ohly, Heather; White, Mathew P; Wheeler, Benedict W; Bethel, Alison; Ukoumunne, Obioha C; Nikolaou, Vasilis; Garside, Ruth

2016-01-01

Attention Restoration Theory (ART) suggests the ability to concentrate may be restored by exposure to natural environments. Although widely cited, it is unclear as to the quantity of empirical evidence that supports this. A systematic review regarding the impact of exposure to natural environments on attention was conducted. Seven electronic databases were searched. Studies were included if (1) they were natural experiments, randomized investigations, or recorded "before and after" measurements; (2) compared natural and nonnatural/other settings; and (3) used objective measures of attention. Screening of articles for inclusion, data extraction, and quality appraisal were performed by one reviewer and checked by another. Where possible, random effects meta-analysis was used to pool effect sizes. Thirty-one studies were included. Meta-analyses provided some support for ART, with significant positive effects of exposure to natural environments for three measures (Digit Span Forward, Digit Span Backward, and Trail Making Test B). The remaining 10 meta-analyses did not show marked beneficial effects. Meta-analysis was limited by small numbers of investigations, small samples, heterogeneity in reporting of study quality indicators, and heterogeneity of outcomes. This review highlights the diversity of evidence around ART in terms of populations, study design, and outcomes. There is uncertainty regarding which aspects of attention may be affected by exposure to natural environments.

Hepatic gene expression in rainbow trout (Oncorhynchus mykiss) exposed to different hydrocarbon mixtures.

PubMed

Hook, Sharon E; Lampi, Mark A; Febbo, Eric J; Ward, Jeff A; Parkerton, Thomas F

2010-09-01

Traditional biomarkers for hydrocarbon exposure are not induced by all petroleum substances. The objective of this study was to determine if exposure to a crude oil and different refined oils would generate a common hydrocarbon-specific response in gene expression profiles that could be used as generic biomarkers of hydrocarbon exposure. Juvenile rainbow trout (Oncorhynchus mykiss) were exposed to the water accommodated fraction (WAF) of either kerosene, gas oil, heavy fuel oil, or crude oil for 96 h. Tissue was collected for RNA extraction and microarray analysis. Exposure to each WAF resulted in a different list of differentially regulated genes, with few genes in common across treatments. Exposure to crude oil WAF changed the expression of genes including cytochrome P4501A (CYP1A) and glutathione-S-transferase (GST) with known roles in detoxification pathways. These gene expression profiles were compared to others from previous experiments that used a diverse suite of toxicants. Clustering algorithms successfully identified gene expression profiles resulting from hydrocarbon exposure. These preliminary analyses highlight the difficulties of using single genes as diagnostic of petroleum hydrocarbon exposures. Further work is needed to determine if multivariate transcriptomic-based biomarkers may be a more effective tool than single gene studies for exposure monitoring of different oils. Copyright 2010 SETAC.

Association between occupational exposure to benzene and chromosomal alterations in lymphocytes of Brazilian petrochemical workers removed from exposure.

PubMed

Gonçalves, Rozana Oliveira; de Almeida Melo, Neli; Rêgo, Marco Antônio Vasconcelos

2016-06-01

We aimed to investigate the association between chronic exposure to benzene and genotoxicity in the lymphocytes of workers removed from exposure. The study included 20 workers with hematological disorders who had previously worked in the petrochemical industry of Salvador, Bahia, Brazil; 16 workers without occupational exposure to benzene served as the control group. Chromosomal analysis was performed on lymphocytes from peripheral blood, to assess chromosomal breaks and gaps and to identify aneuploidy. The Kruskal-Wallis test was used to compare the mean values between two groups, and Student's t test for comparison of two independent means. The frequency of gaps was statistically higher in and the exposed group than in the controls (2.13 ± 2.86 vs. 0.97 ± 1.27, p = 0.001). The frequency of chromosomal breaks was significantly higher among cases (0.21 ± 0.58) than among controls (0.12 ± 0.4) (p = 0.0002). An association was observed between chromosomal gaps and breaks and occupational exposure to benzene. Our study showed that even when removed from exposure for several years, workers still demonstrated genotoxic damage. Studies are still needed to clarify the long-term genotoxic potential of benzene after removal from exposure.

Comparative pharmacokinetic study of the role of gender and developmental differences in occupational and environmental exposure to benzene. Master's thesis

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

Brown, E.A.

The purpose of this study is two-fold. First, it shows that physiological differences between men and women result in gender-specific exposures with respect to benzene. Second, it assesses the potential for a lactating woman's occupational and personal benzene exposure to impact a nursing infant's exposure, highlighting the possibility of subjecting an infant to the effects of industrial chemicals via breast feeding. This study employs physiologically based pharmacokinetic (PBPK) modeling to investigate the influence of physiological parameters and to evaluate the ability of inhaled benzene to transfer from mother to infant through breastmilk. The models are run through scenarios that simulatemore » occupational, smoking, and background exposures. The gender comparison is facilitated by a sensitivity analysis. The blood/air partition coefficient and maximum velocity of metabolism were found to substantially impact model output. These values were both higher in women and caused an increase in the percentage of benzene metabolized in all of the exposure scenarios. The study of lactating women and infants is essentially theoretical. There is evidence that over 65% of an infant's benzene exposure can be attributed to contaminated breastmilk. A large portion of the ingested exposure can be eliminated by adjusting the mother's working or nursing schedule. Benzene, Physiologically based pharmacokinetics, PBPK.« less

An Assessment of Potential Exposure and Risk from Estrogens in Drinking Water

PubMed Central

Caldwell, Daniel J.; Mastrocco, Frank; Nowak, Edward; Johnston, James; Yekel, Harry; Pfeiffer, Danielle; Hoyt, Marilyn; DuPlessie, Beth M.; Anderson, Paul D.

2010-01-01

Background Detection of estrogens in the environment has raised concerns in recent years because of their potential to affect both wildlife and humans. Objectives We compared exposures to prescribed and naturally occurring estrogens in drinking water to exposures to naturally occurring background levels of estrogens in the diet of children and adults and to four independently derived acceptable daily intakes (ADIs) to determine whether drinking water intakes are larger or smaller than dietary intake or ADIs. Methods We used the Pharmaceutical Assessment and Transport Evaluation (PhATE) model to predict concentrations of estrogens potentially present in drinking water. Predicted drinking water concentrations were combined with default water intake rates to estimate drinking water exposures. Predicted drinking water intakes were compared to dietary intakes and also to ADIs. We present comparisons for individual estrogens as well as combined estrogens. Results In the analysis we estimated that a child’s exposures to individual prescribed estrogens in drinking water are 730–480,000 times lower (depending upon estrogen type) than exposure to background levels of naturally occurring estrogens in milk. A child’s exposure to total estrogens in drinking water (prescribed and naturally occurring) is about 150 times lower than exposure from milk. Adult margins of exposure (MOEs) based on total dietary exposure are about 2 times smaller than those for children. Margins of safety (MOSs) for an adult’s exposure to total prescribed estrogens in drinking water vary from about 135 to > 17,000, depending on ADI. MOSs for exposure to total estrogens in drinking water are about 2 times lower than MOSs for prescribed estrogens. Depending on the ADI that is used, MOSs for young children range from 28 to 5,120 for total estrogens (including both prescribed and naturally occurring sources) in drinking water. Conclusions The consistently large MOEs and MOSs strongly suggest that prescribed and total estrogens that may potentially be present in drinking water in the United States are not causing adverse effects in U.S. residents, including sensitive subpopulations. PMID:20194073

Local connected fractal dimension analysis in gill of fish experimentally exposed to toxicants.

PubMed

Manera, Maurizio; Giari, Luisa; De Pasquale, Joseph A; Sayyaf Dezfuli, Bahram

2016-06-01

An operator-neutral method was implemented to objectively assess European seabass, Dicentrarchus labrax (Linnaeus, 1758) gill pathology after experimental exposure to cadmium (Cd) and terbuthylazine (TBA) for 24 and 48h. An algorithm-derived local connected fractal dimension (LCFD) frequency measure was used in this comparative analysis. Canonical variates (CVA) and linear discriminant analysis (LDA) were used to evaluate the discrimination power of the method among exposure classes (unexposed, Cd exposed, TBA exposed). Misclassification, sensitivity and specificity, both with original and cross-validated cases, were determined. LCFDs frequencies enhanced the differences among classes which were visually selected after their means, respective variances and the differences between Cd and TBA exposed means, with respect to unexposed mean, were analyzed by scatter plots. Selected frequencies were then scanned by means of LDA, stepwise analysis, and Mahalanobis distance to detect the most discriminative frequencies out of ten originally selected. Discrimination resulted in 91.7% of cross-validated cases correctly classified (22 out of 24 total cases), with sensitivity and specificity, respectively, of 95.5% (1 false negative with respect to 21 really positive cases) and 75% (1 false positive with respect to 3 really negative cases). CVA with convex hull polygons ensured prompt, visually intuitive discrimination among exposure classes and graphically supported the false positive case. The combined use of semithin sections, which enhanced the visual evaluation of the overall lamellar structure; of LCFD analysis, which objectively detected local variation in complexity, without the possible bias connected to human personnel; and of CVA/LDA, could be an objective, sensitive and specific approach to study fish gill lamellar pathology. Furthermore this approach enabled discrimination with sufficient confidence between exposure classes or pathological states and avoided misdiagnosis. Copyright © 2016 Elsevier B.V. All rights reserved.

Changes in Biomarkers of Exposure on Switching From a Conventional Cigarette to Tobacco Heating Products: A Randomized, Controlled Study in Healthy Japanese Subjects.

PubMed

Gale, Nathan; McEwan, Mike; Eldridge, Alison C; Fearon, Ian M; Sherwood, Neil; Bowen, Edward; McDermott, Simon; Holmes, Emma; Hedge, Andrew; Hossack, Stuart; Wakenshaw, Louise; Glew, James; Camacho, Oscar M; Errington, Graham; McAughey, John; Murphy, James; Liu, Chuan; Proctor, Christopher J

2018-06-15

Smoking is a leading cause of numerous human disorders including pulmonary disease, cardiovascular disease, and cancer. Disease development is primarily caused by exposure to cigarette smoke constituents, many of which are known toxicants. Switching smokers to modified risk tobacco products (MRTPs) has been suggested as a potential means to reduce the risks of tobacco use, by reducing such exposure. This randomized, controlled study investigated whether biomarkers of toxicant exposure (BoE) were reduced when smokers switched from smoking combustible cigarettes to using a novel (glo™/THP1.0) or in-market comparator (iQOS/THS) tobacco heating product (THP). One hundred eighty Japanese smokers smoked combustible cigarettes during a 2-day baseline period, followed by randomization to either continue smoking cigarettes, switch to using mentholated or non-mentholated variants of glo™, switch to using a non-mentholated variant of iQOS, or quit nicotine and tobacco product use completely for 5 days. Baseline and post-randomization 24-h urine samples were collected for BoE analysis. Carbon monoxide was measured daily in exhaled breath (eCO). On day 5 after switching, urinary BoE (excluding for nicotine) and eCO levels were significantly (p < .05) reduced by medians between 20.9% and 92.1% compared with baseline in all groups either using glo™ or iQOS or quitting tobacco use. Between-group comparisons revealed that the reductions in the glo™ groups were similar (p > .05) to quitting in many cases. glo™ or iQOS use for 5 days reduced exposure to smoke toxicants in a manner comparable to quitting tobacco use. THPs are reduced exposure tobacco products with the potential to be MRTPs. This clinical study demonstrates that when smokers switched from smoking combustible cigarettes to using tobacco heating products their exposure to smoke toxicants was significantly decreased. In many cases, this was to the same extent as that seen when they quit smoking completely. This may indicate that these products have the potential to be reduced exposure and/or reduced risk tobacco products when used by smokers whose cigarette consumption is displaced completely. ISRCTN14301360 and UMIN000024988.

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

PubMed

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

2018-02-01

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

A comparative analysis of modeled and monitored ambient hazardous air pollutants in Texas: a novel approach using concordance correlation.

PubMed

Lupo, Philip J; Symanski, Elaine

2009-11-01

Often, in studies evaluating the health effects of hazardous air pollutants (HAPs), researchers rely on ambient air levels to estimate exposure. Two potential data sources are modeled estimates from the U.S. Environmental Protection Agency (EPA) Assessment System for Population Exposure Nationwide (ASPEN) and ambient air pollutant measurements from monitoring networks. The goal was to conduct comparisons of modeled and monitored estimates of HAP levels in the state of Texas using traditional approaches and a previously unexploited method, concordance correlation analysis, to better inform decisions regarding agreement. Census tract-level ASPEN estimates and monitoring data for all HAPs throughout Texas, available from the EPA Air Quality System, were obtained for 1990, 1996, and 1999. Monitoring sites were mapped to census tracts using U.S. Census data. Exclusions were applied to restrict the monitored data to measurements collected using a common sampling strategy with minimal missing values over time. Comparisons were made for 28 HAPs in 38 census tracts located primarily in urban areas throughout Texas. For each pollutant and by year of assessment, modeled and monitored air pollutant annual levels were compared using standard methods (i.e., ratios of model-to-monitor annual levels). Concordance correlation analysis was also used, which assesses linearity and agreement while providing a formal method of statistical inference. Forty-eight percent of the median model-to-monitor values fell between 0.5 and 2, whereas only 17% of concordance correlation coefficients were significant and greater than 0.5. On the basis of concordance correlation analysis, the findings indicate there is poorer agreement when compared with the previously applied ad hoc methods to assess comparability between modeled and monitored levels of ambient HAPs.

Genome-wide association analysis accounting for environmental factors through propensity-score matching: application to stressful live events in major depressive disorder.

PubMed

Power, Robert A; Cohen-Woods, Sarah; Ng, Mandy Y; Butler, Amy W; Craddock, Nick; Korszun, Ania; Jones, Lisa; Jones, Ian; Gill, Michael; Rice, John P; Maier, Wolfgang; Zobel, Astrid; Mors, Ole; Placentino, Anna; Rietschel, Marcella; Aitchison, Katherine J; Tozzi, Federica; Muglia, Pierandrea; Breen, Gerome; Farmer, Anne E; McGuffin, Peter; Lewis, Cathryn M; Uher, Rudolf

2013-09-01

Stressful life events are an established trigger for depression and may contribute to the heterogeneity within genome-wide association analyses. With depression cases showing an excess of exposure to stressful events compared to controls, there is difficulty in distinguishing between "true" cases and a "normal" response to a stressful environment. This potential contamination of cases, and that from genetically at risk controls that have not yet experienced environmental triggers for onset, may reduce the power of studies to detect causal variants. In the RADIANT sample of 3,690 European individuals, we used propensity score matching to pair cases and controls on exposure to stressful life events. In 805 case-control pairs matched on stressful life event, we tested the influence of 457,670 common genetic variants on the propensity to depression under comparable level of adversity with a sign test. While this analysis produced no significant findings after genome-wide correction for multiple testing, we outline a novel methodology and perspective for providing environmental context in genetic studies. We recommend contextualizing depression by incorporating environmental exposure into genome-wide analyses as a complementary approach to testing gene-environment interactions. Possible explanations for negative findings include a lack of statistical power due to small sample size and conditional effects, resulting from the low rate of adequate matching. Our findings underscore the importance of collecting information on environmental risk factors in studies of depression and other complex phenotypes, so that sufficient sample sizes are available to investigate their effect in genome-wide association analysis. Copyright © 2013 Wiley Periodicals, Inc.

Hair drug testing of children suspected of exposure to the manufacture of methamphetamine.

PubMed

Farst, Karen; Reading Meyer, J A; Mac Bird, T; James, Laura; Robbins, James M

2011-04-01

This study compares hair color and age in children tested for methamphetamine by hair analysis due to suspicion of exposure to the manufacture of methamphetamine by their caregivers. A retrospective analysis evaluated differences in hair drug testing results of 107 children less than 12 years of age tested due to clinical suspicion of having been exposed to the manufacture of methamphetamine. Results (confirmed by gas chromatography-mass spectroscopy) were compared for differences in likelihood of testing positive in relation to the subject's age and having light or dark colored hair and reported with crude and adjusted odds ratios with 95% confidence intervals. Of 107 children, 103 had a sufficient hair specimen for analysis. A third (36%) of the study population was less than 3 years of age. Almost half (45%) of the children tested positive for methamphetamine. 15% of the total study population tested positive for methamphetamine in combination with amphetamine indicating some degree of systemic exposure. No children were positive for amphetamine without also being positive for methamphetamine. Children less than 3 years of age were more likely to test positive. Positive hair drug tests for the combination of methamphetamine and amphetamine occurred in children with both light and dark colored hair. Children living in homes where methamphetamine is being manufactured can have drug identified in their hair regardless of hair color. This testing can aid in illuminating the child's presence in an at-risk environment and a family in need of services. Copyright © 2011 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Evaluation and recommendation of sensitivity analysis methods for application to Stochastic Human Exposure and Dose Simulation models.

PubMed

Mokhtari, Amirhossein; Christopher Frey, H; Zheng, Junyu

2006-11-01

Sensitivity analyses of exposure or risk models can help identify the most significant factors to aid in risk management or to prioritize additional research to reduce uncertainty in the estimates. However, sensitivity analysis is challenged by non-linearity, interactions between inputs, and multiple days or time scales. Selected sensitivity analysis methods are evaluated with respect to their applicability to human exposure models with such features using a testbed. The testbed is a simplified version of a US Environmental Protection Agency's Stochastic Human Exposure and Dose Simulation (SHEDS) model. The methods evaluated include the Pearson and Spearman correlation, sample and rank regression, analysis of variance, Fourier amplitude sensitivity test (FAST), and Sobol's method. The first five methods are known as "sampling-based" techniques, wheras the latter two methods are known as "variance-based" techniques. The main objective of the test cases was to identify the main and total contributions of individual inputs to the output variance. Sobol's method and FAST directly quantified these measures of sensitivity. Results show that sensitivity of an input typically changed when evaluated under different time scales (e.g., daily versus monthly). All methods provided similar insights regarding less important inputs; however, Sobol's method and FAST provided more robust insights with respect to sensitivity of important inputs compared to the sampling-based techniques. Thus, the sampling-based methods can be used in a screening step to identify unimportant inputs, followed by application of more computationally intensive refined methods to a smaller set of inputs. The implications of time variation in sensitivity results for risk management are briefly discussed.

Pharmacokinetics and Target Attainment of Ceftobiprole in Asian and Non-Asian Subjects.

PubMed

Muller, A E; Punt, N; Engelhardt, M; Schmitt-Hoffmann, A H; Mouton, J W

2018-05-16

Ceftobiprole is a broad-spectrum cephalosporin. The objective of this study was to test the hypothesis that the pharmacokinetics (PK) and exposure of ceftobiprole in Asian subjects are similar to those in non-Asian subjects. Three approaches were followed. The first compared the individual PK estimates between the 2 subgroups derived from a population PK model previously built. Next, it was determined whether "Asian subject" was a significant covariate. Finally, a pharmacodynamic analysis was performed by comparing measures of exposure and target attainment. No significant differences were found between PK parameter estimates for Asian and non-Asian subjects, with median values (range) for clearance of 4.82 L/h (2.12-10.47) and 4.97 L/h (0.493-20.6), respectively (P = .736). "Asian subject" was not a significant covariate in the population PK model. There were no significant differences between the measures of exposure. The geometric mean ratio for the fAUC was 1.022 (90%CI, 0.91-1.15), indicating bioequivalence. Taking a target of 60% coverage of the dose interval, more than 90% of the population in both subgroups was adequately exposed. This analysis demonstrated that there are no PK or pharmacodynamic differences between Asian and non-Asian subjects for a ceftobiprole dose of 500 mg every 8 hours as a 2-hour infusion. © 2018, The American College of Clinical Pharmacology.

Analysis of Shear Bond Strength and Morphology of Er:YAG Laser-Recycled Ceramic Orthodontic Brackets

PubMed Central

Han, Ruo-qiao; Ji, Ling-fei; Ling, Chen

2016-01-01

Objective. The aim of this study was to compare the recycling of deboned ceramic brackets via an Er:YAG laser or via the traditional chairside processing methods of flaming and sandblasting; shear bond strength and morphological changes were evaluated in recycled brackets versus new brackets. Materials and Methods. 3M Clarity Self-Ligating Ceramic Brackets with a microcrystalline base were divided into groups subjected to flaming, sandblasting, or exposure to an Er:YAG laser. New ceramic brackets served as a control group. Shear bond strengths were determined with an Electroforce test machine and tested for statistical significance through analysis of variance. Morphological examinations of the recycled ceramic bracket bases were conducted with scanning electron microscopy and confocal laser scanning microscopy. Residue on the bracket base was analyzed with Raman spectroscopy. Results. Faded, dark adhesive was left on recycled bracket bases processed via flaming. Adhesive was thoroughly removed by both sandblasting and exposure to an Er:YAG laser. Compared with new brackets, shear bond strength was lower after sandblasting (p < 0.05), but not after exposure to an Er:YAG laser. The Er:YAG laser caused no damage to the bracket. Conclusion. Er:YAG lasers effectively remove adhesive from the bases of ceramic brackets without damaging them; thus, this method may be preferred over other recycling methods. PMID:27047964

Challenges in evaluating PM concentration levels, commuting exposure, and mask efficacy in reducing PM exposure in growing, urban communities in a developing country.

PubMed

Patel, Disa; Shibata, Tomoyuki; Wilson, James; Maidin, Alimin

2016-02-01

Particulate matter (PM) contributes to an increased risk of respiratory and cardiovascular illnesses, cancer, and preterm birth complications. This project assessed PM exposure in Eastern Indonesia's largest city, where air quality has not been comprehensively monitored. We examined the efficacy of wearing masks as an individual intervention effort to reduce in-transit PM exposures. Handheld particulate counters were used to investigate ambient air quality for spatial analysis, as well as the differences in exposure to PM2.5 and PM10 (μg/m(3)) by different transportation methods [e.g. motorcycle (n=97), pete-pete (n=53), and car (n=55); note: n=1 means 1m(3) of air sample]. Mask efficacy to reduce PM exposure was evaluated [e.g. surgical masks (n=39), bandanas (n=52), and motorcycle masks (n=39)]. A Monte Carlo simulation was used to provide a range of uncertainty in exposure assessment. Overall PM10 levels (91±124 μg/m(3)) were elevated compared to the World Health Organization (WHO)'s 24-hour air quality guideline (50 μg/m(3)). While average PM2.5 levels (9±14 μg/m(3)) were below the WHO's guideline (25 μg/m(3)), measurements up to 139 μg/m(3) were observed. Compared to cars, average motorcycle and pete-pete PM exposures were four and three times higher for PM2.5, and 13 and 10 times higher for PM10, respectively. Only surgical masks were consistent in lowering PM2.5 and PM10 (p<0.01). Young children (≤5) were the most vulnerable age group, and could not reach the safe dosage even when wearing surgical masks. Individual interventions can effectively reduce individual PM exposures; however, policy interventions will be needed to improve the overall air quality and create safer transportation. Copyright © 2015 Elsevier B.V. All rights reserved.

Crystalline silica exposure and lung cancer mortality in diatomaceous earth industry workers: a quantitative risk assessment.

PubMed

Rice, F L; Park, R; Stayner, L; Smith, R; Gilbert, S; Checkoway, H

2001-01-01

To use various exposure-response models to estimate the risk of mortality from lung cancer due to occupational exposure to respirable crystalline silica dust. Data from a cohort mortality study of 2342 white male California diatomaceous earth mining and processing workers exposed to crystalline silica dust (mainly cristobalite) were reanalyzed with Poisson regression and Cox's proportional hazards models. Internal and external adjustments were used to control for potential confounding from the effects of time since first observation, calendar time, age, and Hispanic ethnicity. Cubic smoothing spline models were used to assess the fit of the models. Exposures were lagged by 10 years. Evaluations of the fit of the models were performed by comparing their deviances. Lifetime risks of lung cancer were estimated up to age 85 with an actuarial approach that accounted for competing causes of death. Exposure to respirable crystalline silica dust was a significant predictor (p<0.05) in nearly all of the models evaluated and the linear relative rate model with a 10 year exposure lag seemed to give the best fit in the Poisson regression analysis. For those who died of lung cancer the linear relative rate model predicted rate ratios for mortality from lung cancer of about 1.6 for the mean cumulative exposure to respirable silica compared with no exposure. The excess lifetime risk (to age 85) of mortality from lung cancer for white men exposed for 45 years and with a 10 year lag period at the current Occupational Safety and Health Administration (OSHA) standard of about 0.05 mg/m(3) for respirable cristobalite dust is 19/1000 (95% confidence interval (95% CI) 5/1000 to 46/1000). There was a significant risk of mortality from lung cancer that increased with cumulative exposure to respirable crystalline silica dust. The predicted number of deaths from lung cancer suggests that current occupational health standards may not be adequately protecting workers from the risk of lung cancer.

Is farm-related job title an adequate surrogate for pesticide exposure in occupational cancer epidemiology?

PubMed

MacFarlane, E; Glass, D; Fritschi, L

2009-08-01

Accurate assessment of exposure is a key factor in occupational epidemiology but can be problematic, particularly where exposures of interest may be many decades removed from relevant health outcomes. Studies have traditionally relied on crude surrogates of exposure based on job title only, for instance farm-related job title as a surrogate for pesticide exposure. This analysis was based on data collected in Western Australia in 2000-2001. Using a multivariate regression model, we compared expert-assessed likelihood of pesticide exposure based on detailed, individual-specific questionnaire and job specific module interview information with reported farm-related job titles as a surrogate for pesticide exposure. Most (68.8%) jobs with likely pesticide exposure were farm jobs, but 78.3% of farm jobs were assessed as having no likelihood of pesticide exposure. Likely pesticide exposure was more frequent among jobs on crop farms than on livestock farms. Likely pesticide exposure was also more frequent among jobs commenced in more recent decades and jobs of longer duration. Our results suggest that very little misclassification would have resulted from the inverse assumption that all non-farming jobs are not pesticide exposed since only a very small fraction of non-agricultural jobs were likely to have had pesticide exposure. Classification of all farm jobs as pesticide exposed is likely to substantially over-estimate the number of individuals exposed. Our results also suggest that researchers should pay special attention to farm type, length of service and historical period of employment when assessing the likelihood of pesticide exposure in farming jobs.

Identification of target genes responsive to JP-8 exposure in the rat central nervous system.

PubMed

Lin, B; Ritchie, G D; Rossi, J; Pancrazio, J J

2001-06-01

Concern for the health risk associated with occupational exposure to jet fuel has emerged in the Department of Defense. Jet propulsion fuel-8 (JP-8) is the fuel used in most US and North Atlantic Treaty Organization (NATO) jet aircraft, and will be the predominant fuel both for military land vehicles and aircraft into the twenty-first century. JP-8 exhibits reduced volatility and lower benzene content as compared to JP-4, the predominant military aircraft fuel before 1992, possibly suggesting greater occupational exposure safety. However, the higher rates of occupational exposure through fueling and maintenance of increasingly larger numbers of aircraft/vehicles raise concerns with respect to toxicity. Clinical studies of workers experiencing long-term exposure to certain jet fuels demonstrated deficits in CNS function, including fatigue, neurobehavioral changes, psychiatric disorders, and abnormal electroencephalogram (EEG). In the present study, cDNA nylon arrays (Atlas Rat 1.2 Array, Clontech Laboratories, Palo Alto, CA) were utilized to measure changes in gene expression in whole brain tissue of rats exposed repeatedly to JP-8, under conditions that simulated possible real-world occupational exposure (6 h/day for 91 days) to JP-8 vapor at 1,000 mg/m3. Gene expression analysis of the exposure group compared to the control group revealed a modulation of several genes, including glutathione S-transferase Yb2 subunit (GST Yb2); cytochrome P450 IIIAl (CYP3A1); glucose-dependent insulinotropic peptide (GIP); alpha1-proteinase inhibitor (alpha1-AT); polyubiquitin; GABA transporter 3 (GAT-3); and plasma membrane Ca2+-transporting ATPase (brain isoform 2) (PMCA2). The implications of these vapor-induced changes in gene expression are discussed.

Does short-term exposure to mobile phone base station signals increase symptoms in individuals who report sensitivity to electromagnetic fields? A double-blind randomized provocation study.

PubMed

Eltiti, Stacy; Wallace, Denise; Ridgewell, Anna; Zougkou, Konstantina; Russo, Riccardo; Sepulveda, Francisco; Mirshekar-Syahkal, Dariush; Rasor, Paul; Deeble, Roger; Fox, Elaine

2007-11-01

Individuals with idiopathic environmental illness with attribution to electromagnetic fields (IEI-EMF) believe they suffer negative health effects when exposed to electromagnetic fields from everyday objects such as mobile phone base stations. This study used both open provocation and double-blind tests to determine if sensitive and control individuals experience more negative health effects when exposed to base station-like signals compared with sham. Fifty-six self-reported sensitive and 120 control participants were tested in an open provocation test. Of these, 12 sensitive and 6 controls withdrew after the first session. The remainder completed a series of double-blind tests. Subjective measures of well-being and symptoms as well as physiological measures of blood volume pulse, heart rate, and skin conductance were obtained. During the open provocation, sensitive individuals reported lower levels of well-being in both the global system for mobile communication (GSM) and universal mobile telecommunications system (UMTS) compared with sham exposure, whereas controls reported more symptoms during the UMTS exposure. During double-blind tests the GSM signal did not have any effect on either group. Sensitive participants did report elevated levels of arousal during the UMTS condition, whereas the number or severity of symptoms experienced did not increase. Physiological measures did not differ across the three exposure conditions for either group. Short-term exposure to a typical GSM base station-like signal did not affect well-being or physiological functions in sensitive or control individuals. Sensitive individuals reported elevated levels of arousal when exposed to a UMTS signal. Further analysis, however, indicated that this difference was likely to be due to the effect of order of exposure rather than the exposure itself.

The effects of standing, lifting and noise exposure on preterm birth, growth restriction, and perinatal death in healthy low-risk working military women.

PubMed

Magann, Everett F; Evans, Sharon F; Chauhan, Suneet P; Nolan, Thomas E; Henderson, Jenni; Klausen, Jack H; Newnham, John P; Morrison, John C

2005-09-01

The effects of standing, lifting and noise in low-risk, healthy pregnant women are uncertain. In the past, the heterogeneity of the populations studied, the limitations of the designs of the retrospective and case control studies, and a failure of some of the larger investigations to evaluate all the potential confounding variables has hampered many studies. The purpose of this investigation was to evaluate, throughout pregnancy, the effects of standing, repetitive lifting, and noise in the workplace compared with no standing, lifting or noise exposure, on maternal and perinatal outcomes in a large prospective study of a low-risk healthy population of working women cared for by a single group of health providers. This prospective observational study used an extensive questionnaire to collect antepartum, intrapartum, and postpartum information. Information was collected on the initial visit, each subsequent visit, and immediately after delivery. The participating women were divided into groups based on the amount of time spent standing, the amount and extent of repetitive lifting, and noise exposure in the workplace. Eight hundred and fourteen low-risk active duty women participated in this investigation over a 4-year period. Multivariate analysis with non-exposure compared with exposure reinforced the effect of standing on preterm labor (OR 1.80, 95% CI 1.05, 3.16) and preterm birth (OR 1.69, 95% CI 1.03, 2.80) and showed a trend toward an effect of noise exposure on preterm labor (OR 1.76, 95% CI 0.78, 3.39) after controlling for other exposures. This investigation suggests an association of occupational standing with preterm labor and preterm birth.

Genotoxicity of multi-walled carbon nanotubes at occupationally relevant doses

PubMed Central

2014-01-01

Carbon nanotubes are commercially-important products of nanotechnology; however, their low density and small size makes carbon nanotube respiratory exposures likely during their production or processing. We have previously shown mitotic spindle aberrations in cultured primary and immortalized human airway epithelial cells exposed to single-walled carbon nanotubes (SWCNT). In this study, we examined whether multi-walled carbon nanotubes (MWCNT) cause mitotic spindle damage in cultured cells at doses equivalent to 34 years of exposure at the NIOSH Recommended Exposure Limit (REL). MWCNT induced a dose responsive increase in disrupted centrosomes, abnormal mitotic spindles and aneuploid chromosome number 24 hours after exposure to 0.024, 0.24, 2.4 and 24 μg/cm2 MWCNT. Monopolar mitotic spindles comprised 95% of disrupted mitoses. Three-dimensional reconstructions of 0.1 μm optical sections showed carbon nanotubes integrated with microtubules, DNA and within the centrosome structure. Cell cycle analysis demonstrated a greater number of cells in S-phase and fewer cells in the G2 phase in MWCNT-treated compared to diluent control, indicating a G1/S block in the cell cycle. The monopolar phenotype of the disrupted mitotic spindles and the G1/S block in the cell cycle is in sharp contrast to the multi-polar spindle and G2 block in the cell cycle previously observed following exposure to SWCNT. One month following exposure to MWCNT there was a dramatic increase in both size and number of colonies compared to diluent control cultures, indicating a potential to pass the genetic damage to daughter cells. Our results demonstrate significant disruption of the mitotic spindle by MWCNT at occupationally relevant exposure levels. PMID:24479647

Validity of a traffic air pollutant dispersion model to assess exposure to fine particles.

PubMed

Kostrzewa, Aude; Reungoat, Patrice; Raherison, Chantal

2009-08-01

Fine particles (PM(2.5)) are an important component of air pollution. Epidemiological studies have shown health effects due to ambient air particles, particularly allergies in children. Since the main difficulty is to determine exposure to such pollution, traffic air pollutant (TAP) dispersions models have been developed to improve the estimation of individual exposure levels. One such model, the ExTra index, has been validated for nitrogen oxide concentrations but not for other pollutants. The purpose of this study was to assess the validity of the ExTra index to assess PM(2.5) exposure. We compared PM(2.5) concentrations calculated by the ExTra index to reference measures (passive samplers situated under the covered part of the playground), in 15 schools in Bordeaux, in 2000. First, we collected the input data required by the ExTra index: background and local pollution depending on traffic, meteorology and topography. Second, the ExTra index was calculated for each school. Statistical analysis consisted of a graphic description; then, we calculated an intraclass correlation coefficient. Concentrations calculated with the ExTra index and the reference method were similar. The ExTra index underestimated exposure by 2.2 microg m(-3) on average compared to the reference method. The intraclass correlation coefficient was 0.85 and its 95% confidence interval was [0.62; 0.95]. The results suggest that the ExTra index provides an assessment of PM(2.5) exposure similar to that of the reference method. Although caution is required in interpreting these results owing to the small number of sites, the ExTra index could be a useful epidemiological tool for reconstructing individual exposure, an important challenge in epidemiology.

Does Short-Term Exposure to Mobile Phone Base Station Signals Increase Symptoms in Individuals Who Report Sensitivity to Electromagnetic Fields? A Double-Blind Randomized Provocation Study

PubMed Central

Eltiti, Stacy; Wallace, Denise; Ridgewell, Anna; Zougkou, Konstantina; Russo, Riccardo; Sepulveda, Francisco; Mirshekar-Syahkal, Dariush; Rasor, Paul; Deeble, Roger; Fox, Elaine

2007-01-01

Background Individuals with idiopathic environmental illness with attribution to electromagnetic fields (IEI-EMF) believe they suffer negative health effects when exposed to electromagnetic fields from everyday objects such as mobile phone base stations. Objectives This study used both open provocation and double-blind tests to determine if sensitive and control individuals experience more negative health effects when exposed to base station-like signals compared with sham. Methods Fifty-six self-reported sensitive and 120 control participants were tested in an open provocation test. Of these, 12 sensitive and 6 controls withdrew after the first session. The remainder completed a series of double-blind tests. Subjective measures of well-being and symptoms as well as physiological measures of blood volume pulse, heart rate, and skin conductance were obtained. Results During the open provocation, sensitive individuals reported lower levels of well-being in both the global system for mobile communication (GSM) and universal mobile telecommunications system (UMTS) compared with sham exposure, whereas controls reported more symptoms during the UMTS exposure. During double-blind tests the GSM signal did not have any effect on either group. Sensitive participants did report elevated levels of arousal during the UMTS condition, whereas the number or severity of symptoms experienced did not increase. Physiological measures did not differ across the three exposure conditions for either group. Conclusions Short-term exposure to a typical GSM base station-like signal did not affect well-being or physiological functions in sensitive or control individuals. Sensitive individuals reported elevated levels of arousal when exposed to a UMTS signal. Further analysis, however, indicated that this difference was likely to be due to the effect of order of exposure rather than the exposure itself. PMID:18007992

Comparison of exposure assessment methods in a lung cancer case-control study: performance of a lifelong task-based questionnaire for asbestos and PAHs.

PubMed

Bourgkard, Eve; Wild, Pascal; Gonzalez, Maria; Févotte, Joëlle; Penven, Emmanuelle; Paris, Christophe

2013-12-01

To describe the performance of a lifelong task-based questionnaire (TBQ) in estimating exposures compared with other approaches in the context of a case-control study. A sample of 93 subjects was randomly selected from a lung cancer case-control study corresponding to 497 jobs. For each job, exposure assessments for asbestos and polycyclic aromatic hydrocarbons (PAHs) were obtained by expertise (TBQ expertise) and by algorithm using the TBQ (TBQ algorithm) as well as by expert appraisals based on all available occupational data (REFERENCE expertise) considered to be the gold standard. Additionally, a Job Exposure Matrix (JEM)-based evaluation for asbestos was also obtained. On the 497 jobs, the various evaluations were contrasted using Cohen's κ coefficient of agreement. Additionally, on the total case-control population, the asbestos dose-response relationship based on the TBQ algorithm was compared with the JEM-based assessment. Regarding asbestos, the TBQ-exposure estimates agreed well with the REFERENCE estimate (TBQ expertise: level-weighted κ (lwk)=0.68; TBQ algorithm: lwk=0.61) but less so with the JEM estimate (TBQ expertise: lwk=0.31; TBQ algorithm: lwk=0.26). Regarding PAHs, the agreements between REFERENCE expertise and TBQ were less good (TBQ expertise: lwk=0.43; TBQ algorithm: lwk=0.36). In the case-control study analysis, the dose-response relationship between lung cancer and cumulative asbestos based on the JEM is less steep than with the TBQ-algorithm exposure assessment and statistically non-significant. Asbestos-exposure estimates based on the TBQ were consistent with the REFERENCE expertise and yielded a steeper dose-response relationship than the JEM. For PAHs, results were less clear.

Associations of hip osteoarthritis with history of recurrent exposure to manual handling of loads over 20 kg and work participation: a population-based study of men and women.

PubMed

Kaila-Kangas, Leena; Arokoski, Jari; Impivaara, Olli; Viikari-Juntura, Eira; Leino-Arjas, Päivi; Luukkonen, Ritva; Heliövaara, Markku

2011-10-01

We reviewed work histories of manual handling of loads >20 kg in relation to hip osteoarthritis by age, exposure and work participation. A nationally representative sample of 3110 Finnish men and 3446 women aged 30-97 was recruited. Diagnosis of hip osteoarthritis was based on standardised clinical examination by trained physicians. Previous exposure to physically loading work was evaluated through interviews. Logistic regression was used to estimate associations between work factors and hip osteoarthritis. 1.9% of men and 2.1% of women had hip osteoarthritis. Almost half the men and a quarter of the women had recurrently handled heavy loads at work. Subjects who had manually handled loads >20 kg had a 1.8-fold increased risk of hip osteoarthritis compared to non-exposed references, when age, body mass index, traumatic fractures and smoking were accounted for. Results were similar for men (OR 2.0; 95% CI 1.0 to 4.0) and women (1.8; 1.1 to 2.8). In a sub-analysis of subjects with hip replacement, the OR was 1.7 (1.0 to 2.9). Risk increased first after 12 years' exposure: among men it was 2.2 (0.8 to 5.9) for 13-24 years' exposure, and 2.3 (1.2 to 4.3) for >24 years' exposure. Among women it was 3.8 (1.7 to 8.1) for 13-24 years' exposure. Work participation among men aged <60 years with hip osteoarthritis was 20% lower compared with subjects without osteoarthritis. A work history of manual handling of loads >20 kg showed a strong association with hip osteoarthritis in all age groups except the youngest.

Community exposures to airborne agricultural pesticides in California: ranking of inhalation risks.

PubMed Central

Lee, Sharon; McLaughlin, Robert; Harnly, Martha; Gunier, Robert; Kreutzer, Richard

2002-01-01

We assessed inhalation risks to California communities from airborne agricultural pesticides by probability distribution analysis using ambient air data provided by the California Air Resources Board and the California Department of Pesticide Regulation. The pesticides evaluated include chloropicrin, chlorothalonil, chlorpyrifos, S,S,S-tributyl phosphorotrithioate, diazinon, 1,3-dichloropropene, dichlorvos (naled breakdown product), endosulfan, eptam, methidathion, methyl bromide, methyl isothiocyanate (MITC; metam sodium breakdown product), molinate, propargite, and simazine. Risks were estimated for the median and 75th and 95th percentiles of probability (50, 25, and 5% of the exposed populations). Exposure estimates greater than or equal to noncancer reference values occurred for 50% of the exposed populations (adults and children) for MITC subchronic and chronic exposures, methyl bromide subchronic exposures (year 2000 monitoring), and 1,3-dichloropropene subchronic exposures (1990 monitoring). Short-term chlorpyrifos exposure estimates exceeded the acute reference value for 50% of children (not adults) in the exposed population. Noncancer risks were uniformly higher for children due to a proportionately greater inhalation rate-to-body weight ratio compared to adults and other factors. Target health effects of potential concern for these exposures include neurologic effects (methyl bromide and chlorpyrifos) and respiratory effects (1,3-dichloropropene and MITC). The lowest noncancer risks occurred for simazine and chlorothalonil. Lifetime cancer risks of one-in-a-million or greater were estimated for 50% of the exposed population for 1,3-dichloropropene (1990 monitoring) and 25% of the exposed populations for methidathion and molinate. Pesticide vapor pressure was found to be a better predictor of inhalation risk compared to other methods of ranking pesticides as potential toxic air contaminants. PMID:12460795

Analysis of estimation of electromagnetic dosimetric values from non-ionizing radiofrequency fields in conventional road vehicle environments.

PubMed

Aguirre, Erik; Iturri, Peio Lopez; Azpilicueta, Leire; de Miguel-Bilbao, Silvia; Ramos, Victoria; Gárate, Uxue; Falcone, Francisco

2015-03-01

A high number of wireless technologies can be found operating in vehicular environments with the aim of offering different services. The dosimetric evaluation of this kind of scenarios must be performed in order to assess their compatibility with current exposure limits. In this work, a dosimetric evaluation inside a conventional car is performed, with the aid of an in-house 3D Ray Launching computational code, which has been compared with measurement results of wireless sensor networks located inside the vehicle. These results can aid in an adequate assessment of human exposure to non-ionizing radiofrequency fields, taking into account the impact of the morphology and the topology of the vehicle for current as well as for future exposure limits.

Childhood adversity and the continued exposure to trauma and violence among adolescent gang members

PubMed Central

Quinn, Katherine; Pacella, Maria L.; Dickson-Gomez, Julia; Nydegger, Liesl A.

2017-01-01

This study examines experiences of childhood adversity, trauma, and violence among adolescent gang members prior to and during adolescent gang involvement to better understand the effects of violence and trauma on gang members. We conducted 58 qualitative semi-structured interviews with members of six adolescent gangs. Data was analyzed using thematic content analysis and the constant comparative method in MAXQDA. Findings revealed that frequent and ongoing exposure to neighborhood violence and personal and familial trauma led many youth to normalize experiences of violence. Furthermore, although they believed gangs would offer protection and social support, gang membership led to additional exposure to violence and trauma and bleak future expectations. Interventions for adolescent gang members should address the complex childhoods and cumulative traumatic experiences of these adolescents. PMID:28262961

Microplastic Exposure Assessment in Aquatic Environments: Learning from Similarities and Differences to Engineered Nanoparticles.

PubMed

Hüffer, Thorsten; Praetorius, Antonia; Wagner, Stephan; von der Kammer, Frank; Hofmann, Thilo

2017-03-07

Microplastics (MPs) have been identified as contaminants of emerging concern in aquatic environments and research into their behavior and fate has been sharply increasing in recent years. Nevertheless, significant gaps remain in our understanding of several crucial aspects of MP exposure and risk assessment, including the quantification of emissions, dominant fate processes, types of analytical tools required for characterization and monitoring, and adequate laboratory protocols for analysis and hazard testing. This Feature aims at identifying transferrable knowledge and experience from engineered nanoparticle (ENP) exposure assessment. This is achieved by comparing ENP and MPs based on their similarities as particulate contaminants, whereas critically discussing specific differences. We also highlight the most pressing research priorities to support an efficient development of tools and methods for MPs environmental risk assessment.

Nanosilica and Polyacrylate/Nanosilica: A Comparative Study of Acute Toxicity

PubMed Central

Niu, Ying-Mei; Zhu, Xiao-Li; Chang, Bing; Tong, Zhao-Hui; Cao, Wen; Qiao, Pei-Huan; Zhang, Lin-Yuan; Zhao, Jing; Song, Yu-Guo

2016-01-01

We compared the acute toxicity of nanosilica and polyacrylate/nanosilica instillation in Wistar rats (n = 60). Exposure to nanosilica and polyacrylate/nanosilica showed a 30% mortality rate. When compared with saline-treated rats, animals in both exposure groups exhibited a significant reduction of PO2 (P < 0.05) at both 24 and 72 hr. after exposure. Both exposure groups exhibited a significant reduction of neutrophils in arterial blood compared to saline controls (P < 0.05) 24 hr. after exposure. The levels of blood ALT and LDH in exposed groups were found to be significantly increased (P < 0.05) 24 hr. following exposure. The exposed groups exhibited various degrees of pleural effusion and pericardial effusion. Our findings indicated respiratory exposure to polyacrylate/nanosilica and nanosilica is likely to cause multiple organ toxicity. PMID:26981538

Therapists' and patients' stress responses during graduated versus flooding in vivo exposure in the treatment of specific phobia: A preliminary observational study.

PubMed

Schumacher, Sarah; Miller, Robert; Fehm, Lydia; Kirschbaum, Clemens; Fydrich, Thomas; Ströhle, Andreas

2015-12-15

Exposure therapy is considered an effective treatment strategy for phobic anxiety, however, it is rarely applied in clinical practice. The under-usage might be due to various factors of which heightened stress levels not only in patients but also in therapists are presumed to be of particular relevance. The present study aimed to investigate whether different forms of exposure might lead to varying physiological and psychological stress responses in therapists and phobic patients. 25 patients with specific phobia underwent individual cognitive behavioural therapy, performed by 25 psychotherapist trainees, applying exposure sessions in graduated form or the flooding technique. Patients and therapists provided subjective evaluations of stress and five saliva samples for analysis of salivary cortisol and alpha-amylase either during two graduated exposure sessions or during one flooding session, while a regular therapy session served as control condition. Therapists displayed heightened salivary alpha-amylase release during exposure of the flooding, but not the graduated, type. Patients showed elevated salivary cortisol during flooding exposure numerically, however, not on a statistically significant level. Therapists reported more pronounced subjective stress during flooding compared to graduated exposure. Elevated stress levels should be addressed in clinical training in order to improve application of exposure in routine practice. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Children’s Lead Exposure: A Multimedia Modeling Analysis to Guide Public Health Decision-Making

PubMed Central

Xue, Jianping; Tornero-Velez, Rogelio; Brown, James

2017-01-01

Background: Drinking water and other sources for lead are the subject of public health concerns around the Flint, Michigan, drinking water and East Chicago, Indiana, lead in soil crises. In 2015, the U.S. Environmental Protection Agency (EPA)’s National Drinking Water Advisory Council (NDWAC) recommended establishment of a “health-based, household action level” for lead in drinking water based on children’s exposure. Objectives: The primary objective was to develop a coupled exposure–dose modeling approach that can be used to determine what drinking water lead concentrations keep children’s blood lead levels (BLLs) below specified values, considering exposures from water, soil, dust, food, and air. Related objectives were to evaluate the coupled model estimates using real-world blood lead data, to quantify relative contributions by the various media, and to identify key model inputs. Methods: A modeling approach using the EPA’s Stochastic Human Exposure and Dose Simulation (SHEDS)-Multimedia and Integrated Exposure Uptake and Biokinetic (IEUBK) models was developed using available data. This analysis for the U.S. population of young children probabilistically simulated multimedia exposures and estimated relative contributions of media to BLLs across all population percentiles for several age groups. Results: Modeled BLLs compared well with nationally representative BLLs (0–23% relative error). Analyses revealed relative importance of soil and dust ingestion exposure pathways and associated Pb intake rates; water ingestion was also a main pathway, especially for infants. Conclusions: This methodology advances scientific understanding of the relationship between lead concentrations in drinking water and BLLs in children. It can guide national health-based benchmarks for lead and related community public health decisions. https://doi.org/10.1289/EHP1605 PMID:28934096

Quantitative cancer risk assessment for occupational exposures to asphalt fumes during built-up roofing asphalt (BURA) operations.

PubMed

Rhomberg, Lorenz R; Mayfield, David B; Goodman, Julie E; Butler, Eric L; Nascarella, Marc A; Williams, Daniel R

2015-01-01

The International Agency for Research on Cancer qualitatively characterized occupational exposure to oxidized bitumen emissions during roofing as probably carcinogenic to humans (Group 2A). We examine chemistry, exposure, epidemiology and animal toxicity data to explore quantitative risks for roofing workers applying built-up roofing asphalt (BURA). Epidemiology studies do not consistently report elevated risks, and generally do not have sufficient exposure information or adequately control for confounders, precluding their use for dose-response analysis. Dermal carcinogenicity bioassays using mice report increased tumor incidence with single high doses. In order to quantify potential cancer risks, we develop time-to-tumor model methods [consistent with U.S. Environmental Protection Agency (EPA) dose-response analysis and mixtures guidelines] using the dose-time-response shape of concurrent exposures to benzo[a]pyrene (B[a]P) as concurrent controls (which had several exposure levels) to infer presumed parallel dose-time-response curves for BURA-fume condensate. We compare EPA relative potency factor approaches, based on observed relative potency of BURA to B[a]P in similar experiments, and direct observation of the inferred BURA dose-time-response (scaled to humans) as means for characterizing a dermal unit risk factor. We apply similar approaches to limited data on asphalt-fume inhalation and respiratory cancers in rats. We also develop a method for adjusting potency estimates for asphalts that vary in composition using measured fluorescence. Overall, the various methods indicate that cancer risks to roofers from both dermal and inhalation exposure to BURA are within a range typically deemed acceptable within regulatory frameworks. The approaches developed may be useful in assessing carcinogenic potency of other complex mixtures of polycyclic aromatic compounds.

Civil construction work: The unseen contributor to the occupational and global disease burden.

PubMed

Sitalakshmi, R; Saikumar, P; Jeyachandran, P; Manoharan; Thangavel; Thomas, Jayakar

2016-01-01

Construction industry is the second largest employment giving industry in India with many semi-skilled or unskilled workers taking up the occupation for livelihood without any training and proper guidance. To evaluate the pathogenic association of cement exposure to occupational contact dermatoses as evidenced by immune markers and to correlate their pulmonary functions with years of exposure to cement. This was a cross-sectional study conducted among randomly selected cement workers. Methods and material: Evaluation of socioeconomic status (SES) and years of exposure of cement workers was done using a questionnaire. Clinical examination of skin lesions and strip patch test with application of potassium dichromate on unexposed skin was performed. Results were interpreted after 48 hours. Absolute eosinophil count (AEC) and IgE levels measured, and spirometric evaluation was performed. Analysis of variance and Pearson's correlation test were used for data analysis. P < 0.05 was considered to be statistically significant. Clinically, skin lesions were noticed in 51%, elevated AEC in 47%, and raised Anti IgE in 73%. Two participants developed positive reactions to the skin strip patch test. Duration of exposure to cement and SES were compared with clinical skin lesions. Spirometry result was normal in 81%, obstruction in 8%, restriction in 10%, and mixed pattern in 1%. Forced expiratory volume at 1.0 second, forced expiratory flow (25-75%), and  (PEFR) Peak Expiratory Flow Rate were markedly reduced with years of exposure. Workers who had greater skin lesions and with increase in exposure had increased AEC and IgE levels, although statistically not significant. Exposure to cement and poor SES is strongly correlated to increased prevalence of skin lesions and reduced pulmonary functions.

Chronic arsenic exposure and risk of infant mortality in two areas of Chile.

PubMed Central

Hopenhayn-Rich, C; Browning, S R; Hertz-Picciotto, I; Ferreccio, C; Peralta, C; Gibb, H

2000-01-01

Chronic arsenic exposure has been associated with a range of neurologic, vascular, dermatologic, and carcinogenic effects. However, limited research has been directed at the association of arsenic exposure and human reproductive health outcomes. The principal aim of this study was to investigate the trends in infant mortality between two geographic locations in Chile: Antofagasta, which has a well-documented history of arsenic exposure from naturally contaminated water, and Valparaíso, a comparable low-exposure city. The arsenic concentration in Antofagasta's public drinking water supply rose substantially in 1958 with the introduction of a new water source, and remained elevated until 1970. We used a retrospective study design to examine time and location patterns in infant mortality between 1950 and 1996, using univariate statistics, graphical techniques, and Poisson regression analysis. Results of the study document the general declines in late fetal and infant mortality over the study period in both locations. The data also indicate an elevation of the late fetal, neonatal, and postneonatal mortality rates for Antofagasta, relative to Valparaíso, for specific time periods, which generally coincide with the period of highest arsenic concentration in the drinking water of Antofagasta. Poisson regression analysis yielded an elevated and significant association between arsenic exposure and late fetal mortality [rate ratio (RR) = 1.7; 95% confidence interval (CI), 1.5-1.9], neonatal mortality (RR = 1.53; CI, 1.4-1.7), and postneonatal mortality (RR = 1.26; CI, 1.2-1.3) after adjustment for location and calendar time. The findings from this investigation may support a role for arsenic exposure in increasing the risk of late fetal and infant mortality. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:10903622

Male rats with the testicular feminization mutation of the androgen receptor display elevated anxiety-related behavior and corticosterone response to mild stress

PubMed Central

Zuloaga, Damian G.; Poort, Jessica E.; Jordan, Cynthia L.; Breedlove, S. Marc

2011-01-01

Testosterone influences the hypothalamic-pituitary-adrenal axis, anxiety-related behavior, and sensorimotor gating in rodents, but little is known about the role of the androgen receptor (AR) in mediating these influences. We compared levels of the stress hormone corticosterone at baseline and following exposure to a novel object in an open field in wild type (wt) male and female rats, and male rats with the testicular feminization mutation (Tfm) of the AR, which disables its function. Basal corticosterone was equivalent in all groups, but exposure to a novel object in an open field elicited a greater increase in corticosterone in Tfm males and wt females than in wt males. Tfm males also showed increased behavioral indices of anxiety compared to wt males and females in the test. Analysis of the immediate early gene c-Fos expression after exposure to a novel object revealed greater activation in Tfm males than wt males in some regions (medial preoptic area) and lesser activation in others (dentate gyrus, posterodorsal medial amygdala). No differences were found in a measure of sensorimotor gating (prepulse inhibition of the acoustic startle response), although Tfm males had an increased acoustic startle response compared to wt males and females. These findings demonstrate that ARs play a role in regulating anxiety-related behaviors, as well as corticosterone responses and neural activation following exposure to a mild stressor in rats. PMID:21801726

Developmental Exposure to Diethylstilbestrol Alters Uterine Gene Expression That May Be Associated With Uterine Neoplasia Later in Life

PubMed Central

Newbold, Retha R.; Jefferson, Wendy N.; Grissom, Sherry F.; Padilla-Banks, Elizabeth; Snyder, Ryan J.; Lobenhofer, Edward K.

2008-01-01

Previously, we described a mouse model where the well-known reproductive carcinogen with estrogenic activity, diethylstilbestrol (DES), caused uterine adenocarcinoma following neonatal treatment. Tumor incidence was dose-dependent reaching >90% by 18 mo following neonatal treatment with 1000 μg/kg/d of DES. These tumors followed the initiation/promotion model of hormonal carcinogenesis with developmental exposure as initiator, and exposure to ovarian hormones at puberty as the promoter. To identify molecular pathways involved in DES-initiation events, uterine gene expression profiles were examined in prepubertal mice exposed to DES (1, 10, or 1000 μg/kg/d) on days 1–5 and compared to controls. Of more than 20 000 transcripts, approximately 3% were differentially expressed in at least one DES treatment group compared to controls; some transcripts demonstrated dose–responsiveness. Assessment of gene ontology annotation revealed alterations in genes associated with cell growth, differentiation, and adhesion. When expression profiles were compared to published studies of uteri from 5-d-old DES-treated mice, or adult mice treated with 17β estradiol, similarities were seen suggesting persistent differential expression of estrogen responsive genes following developmental DES exposure. Moreover, several altered genes were identified in human uterine adenocarcinomas. Four altered genes [lactotransferrin (Ltf), transforming growth factor beta inducible (Tgfb1), cyclin D1 (Ccnd1), and secreted frizzled-related protein 4 (Sfrp4)], selected for real-time RT-PCR analysis, correlated well with the directionality of the microarray data. These data suggested altered gene expression profiles observed 2 wk after treatment ceased, were established at the time of developmental exposure and maybe related to the initiation events resulting in carcinogenesis. PMID:17394237

Developmental exposure to diethylstilbestrol alters uterine gene expression that may be associated with uterine neoplasia later in life.

PubMed

Newbold, Retha R; Jefferson, Wendy N; Grissom, Sherry F; Padilla-Banks, Elizabeth; Snyder, Ryan J; Lobenhofer, Edward K

2007-09-01

Previously, we described a mouse model where the well-known reproductive carcinogen with estrogenic activity, diethylstilbestrol (DES), caused uterine adenocarcinoma following neonatal treatment. Tumor incidence was dose-dependent reaching >90% by 18 mo following neonatal treatment with 1000 microg/kg/d of DES. These tumors followed the initiation/promotion model of hormonal carcinogenesis with developmental exposure as initiator, and exposure to ovarian hormones at puberty as the promoter. To identify molecular pathways involved in DES-initiation events, uterine gene expression profiles were examined in prepubertal mice exposed to DES (1, 10, or 1000 microg/kg/d) on days 1-5 and compared to controls. Of more than 20 000 transcripts, approximately 3% were differentially expressed in at least one DES treatment group compared to controls; some transcripts demonstrated dose-responsiveness. Assessment of gene ontology annotation revealed alterations in genes associated with cell growth, differentiation, and adhesion. When expression profiles were compared to published studies of uteri from 5-d-old DES-treated mice, or adult mice treated with 17beta estradiol, similarities were seen suggesting persistent differential expression of estrogen responsive genes following developmental DES exposure. Moreover, several altered genes were identified in human uterine adenocarcinomas. Four altered genes [lactotransferrin (Ltf), transforming growth factor beta inducible (Tgfb1), cyclin D1 (Ccnd1), and secreted frizzled-related protein 4 (Sfrp4)], selected for real-time RT-PCR analysis, correlated well with the directionality of the microarray data. These data suggested altered gene expression profiles observed 2 wk after treatment ceased, were established at the time of developmental exposure and maybe related to the initiation events resulting in carcinogenesis. (c) 2007 Wiley-Liss, Inc.

Tumor Necrosis Factor Inhibitor Primary Failure Predicts Decreased Ustekinumab Efficacy in Psoriasis Patients.

PubMed

Sorensen, Eric P; Fanucci, Kristina A; Saraiya, Ami; Volf, Eva; Au, Shiu-chung; Argobi, Yahya; Mansfield, Ryan; Gottlieb, Alice B

2015-08-01

Additional studies are needed to examine the efficacy of ustekinumab in psoriasis patients who have previously been exposed to tumor necrosis factor inhibitors (TNFi). To examine the predictive effect of TNFi primary failure and the number of TNFi exposures on the efficacy of ustekinumab in psoriasis treatment. This retrospective study examined 44 psoriasis patients treated at the Tufts Medical Center Department of Dermatology between January 2008 and July 2014. Patients were selected if they were treated with ustekinumab and had ≥ 1 previous TNFi exposure. The following subgroups were compared: patients with vs without a previous TNFi primary failure, and patients with one vs multiple previous TNFi exposures. The efficacy measure used was the previously validated Simple Measure for Assessing Psoriasis Activity (S-MAPA), which is calculated by the product of the body surface area and physician global assessment. The primary outcome was the percentage improvement S-MAPA from course baseline at week 12 of ustekinumab treatment. Secondary outcomes were the psoriasis clearance, primary failure, and secondary failure rates with ustekinumab treatment. Patients with a previous TNFi primary failure had a significantly lower percentage improvement in S-MAPA score at week 12 of ustekinumab treatment compared with patients without TNFi primary failure (36.2% vs 61.1%, P=.027). Multivariate analysis demonstrated that this relationship was independent of patient demographics and medical comorbidities. Patients with multiple TNFi exposures had a non-statistically significant lower percentage S-MAPA improvement at week 12 (40.5% vs 52.9%, P=.294) of ustekinumab treatment compared with patients with a single TNFi exposure. Among psoriasis patients previously exposed to TNFi, a history of a previous TNFi primary failure predicts a decreased response to ustekinumab independent of patient demographics and medical comorbidities.

A systems toxicology approach for comparative assessment: Biological impact of an aerosol from a candidate modified-risk tobacco product and cigarette smoke on human organotypic bronchial epithelial cultures.

PubMed

Iskandar, Anita R; Mathis, Carole; Schlage, Walter K; Frentzel, Stefan; Leroy, Patrice; Xiang, Yang; Sewer, Alain; Majeed, Shoaib; Ortega-Torres, Laura; Johne, Stephanie; Guedj, Emmanuel; Trivedi, Keyur; Kratzer, Gilles; Merg, Celine; Elamin, Ashraf; Martin, Florian; Ivanov, Nikolai V; Peitsch, Manuel C; Hoeng, Julia

2017-03-01

This study reports a comparative assessment of the biological impact of a heated tobacco aerosol from the tobacco heating system (THS) 2.2 and smoke from a combustible 3R4F cigarette. Human organotypic bronchial epithelial cultures were exposed to an aerosol from THS2.2 (a candidate modified-risk tobacco product) or 3R4F smoke at similar nicotine concentrations. A systems toxicology approach was applied to enable a comprehensive exposure impact assessment. Culture histology, cytotoxicity, secreted pro-inflammatory mediators, ciliary beating, and genome-wide mRNA/miRNA profiles were assessed at various time points post-exposure. Series of experimental repetitions were conducted to increase the robustness of the assessment. At similar nicotine concentrations, THS2.2 aerosol elicited lower cytotoxicity compared with 3R4F smoke. No morphological change was observed following exposure to THS2.2 aerosol, even at nicotine concentration three times that of 3R4F smoke. Lower levels of secreted mediators and fewer miRNA alterations were observed following exposure to THS2.2 aerosol than following 3R4F smoke. Based on the computational analysis of the gene expression changes, 3R4F (0.13 mg nicotine/L) elicited the highest biological impact (100%) in the context of Cell Fate, Cell Proliferation, Cell Stress, and Inflammatory Network Models at 4 h post-exposure. Whereas, the corresponding impact of THS2.2 (0.14 mg nicotine/L) was 7.6%. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

CREATING A DECISION CONTEXT FOR COMPARATIVE ANALYSIS AND CONSISTENT APPLICATION OF INHALATION DOSIMETRY MODELS IN CHILDREN'S RISK ASSESSMENT

EPA Science Inventory

Estimation of risks to children from exposure to airborne pollutants is often complicated by the lack of reliable epidemiological data specific to this age group. As a result, risks are generally estimated from extrapolations based on data obtained in other human age groups (e.g....

Development and validation of a rapid method for microcystins in fish and comparing LC-MS/MS results with ELISA

USDA-ARS?s Scientific Manuscript database

Microcystins (MCs) are the most common cyanotoxins found world-wide in freshwater, brackish and marine environments. The rapid and accurate analysis of microcystins and nodularin in fish tissue is important for determining occurrence, monitoring trends, and exposure monitoring for risk assessment a...

Gestational high-fat diet and bisphenol A exposure heightens mammary cancer risk

PubMed Central

Leung, Yuet-Kin; Govindarajah, Vinothini; Cheong, Ana; Veevers, Jennifer; Song, Dan; Gear, Robin; Zhu, Xuegong; Ying, Jun; Kendler, Ady; Medvedovic, Mario; Belcher, Scott

2017-01-01

In utero exposure to bisphenol A (BPA) increases mammary cancer susceptibility in offspring. High-fat diet is widely believed to be a risk factor of breast cancer. The objective of this study was to determine whether maternal exposure to BPA in addition to high-butterfat (HBF) intake during pregnancy further influences carcinogen-induced mammary cancer risk in offspring, and its dose–response curve. In this study, we found that gestational HBF intake in addition to a low-dose BPA (25 µg/kg BW/day) exposure increased mammary tumor incidence in a 50-day-of-age chemical carcinogen administration model and altered mammary gland morphology in offspring in a non-monotonic manner, while shortening tumor-free survival time compared with the HBF-alone group. In utero HBF and BPA exposure elicited differential effects at the gene level in PND21 mammary glands through DNA methylation, compared with HBF intake in the absence of BPA. Top HBF + BPA-dysregulated genes (ALDH1B1, ASTL, CA7, CPLX4, KCNV2, MAGEE2 and TUBA3E) are associated with poor overall survival in The Cancer Genomic Atlas (TCGA) human breast cancer cohort (n = 1082). Furthermore, the prognostic power of the identified genes was further enhanced in the survival analysis of Caucasian patients with estrogen receptor-positive tumors. In conclusion, concurrent HBF dietary and a low-dose BPA exposure during pregnancy increases mammary tumor incidence in offspring, accompanied by alterations in mammary gland development and gene expression, and possibly through epigenetic reprogramming. PMID:28487351

Development, qualification, validation and application of the neutral red uptake assay in Chinese Hamster Ovary (CHO) cells using a VITROCELL® VC10® smoke exposure system.

PubMed

Fields, Wanda; Fowler, Kathy; Hargreaves, Victoria; Reeve, Lesley; Bombick, Betsy

2017-04-01

Cytotoxicity assessment of combustible tobacco products by neutral red uptake (NRU) has historically used total particulate matter (TPM) or solvent captured gas vapor phase (GVP), rather than fresh whole smoke. Here, the development, validation and application of the NRU assay in Chinese Hamster Ovary (CHO) cells, following exposure to fresh whole smoke generated with the VITROCELL® VC10® system is described. Whole smoke exposure is particularly important as both particulate and vapor phases of tobacco smoke show cytotoxicity in vitro. The VITROCELL® VC10® system provides exposure at the air liquid interface (ALI) to mimic in vivo conditions for assessing the toxicological impact of smoke in vitro. Instrument and assay validations are crucial for comparative analyses. 1) demonstrate functionality of the VITROCELL® VC10® system by installation, operational and performance qualification, 2) develop and validate a cellular system for assessing cytotoxicity following whole smoke exposure and 3) assess the whole smoke NRU assay sensitivity for statistical differentiation between a reference combustible cigarette (3R4F) and a primarily "heat-not-burn" cigarette (Eclipse). The VITROCELL® VC10® provided consistent generation and delivery of whole smoke; exposure-related changes in in vitro cytotoxicity were observed with reproducible IC 50 values; comparative analysis showed that the heat-not-burn cigarette was significantly (P<0.001) less cytotoxic than the 3R4F combustible cigarette, consistent with the lower levels of chemical constituents liberated by primarily-heating the cigarette versus burning. Copyright © 2017. Published by Elsevier Ltd.

Sunlight exposure and cardiovascular risk factors in the REGARDS study: a cross-sectional split-sample analysis

PubMed Central

2014-01-01

Background Previous research has suggested that vitamin D and sunlight are related to cardiovascular outcomes, but associations between sunlight and risk factors have not been investigated. We examined whether increased sunlight exposure was related to improved cardiovascular risk factor status. Methods Residential histories merged with satellite, ground monitor, and model reanalysis data were used to determine previous-year sunlight radiation exposure for 17,773 black and white participants aged 45+ from the US. Exploratory and confirmatory analyses were performed by randomly dividing the sample into halves. Logistic regression models were used to examine relationships with cardiovascular risk factors. Results The lowest, compared to the highest quartile of insolation exposure was associated with lower high-density lipoprotein levels in adjusted exploratory (−2.7 mg/dL [95% confidence interval: −4.2, −1.2]) and confirmatory (−1.5 mg/dL [95% confidence interval: −3.0, −0.1]) models. The lowest, compared to the highest quartile of insolation exposure was associated with higher systolic blood pressure levels in unadjusted exploratory and confirmatory, as well as the adjusted exploratory model (2.3 mmHg [95% confidence interval: 0.8, 3.8]), but not the adjusted confirmatory model (1.6 mg/dL [95% confidence interval: −0.5, 3.7]). Conclusions The results of this study suggest that lower long-term sunlight exposure has an association with lower high-density lipoprotein levels. However, all associations were weak, thus it is not known if insolation may affect cardiovascular outcomes through these risk factors. PMID:24946776

The nasal microbiota of dairy farmers is more complex than oral microbiota, reflects occupational exposure, and provides competition for staphylococci

PubMed Central

Sandberg, Scott; Reyes, Iris; Fritsche, Thomas R.

2017-01-01

Allergic and autoimmune diseases had been attributed to lack of exposure to biodiversity, an important factor in regulating immune homeostasis in a healthy host. We posit that the microbiome of healthy dairy farmers (DF) will be richer than non-farmers (NF) living in urban settings due to exposure to a greater biodiversity in the dairy environment. However, no studies have investigated the relationships between microbiota of dairy farmers (DF) compared with urban non-farmers (NF). We compared the nasal and oral microbiota of dairy farmers (N_DF, O_DF, respectively) with nasal and oral microbiota of NF in the same geographical area. The N_DF showed high microbial diversity with hundreds of unique genera that reflected environmental/occupational exposures. The nasal and oral microbiomes clustered separately from each other using Principal Coordinate Analysis, and with DF harboring two-fold and 1.5-fold greater exclusive genera in their nose and mouth respectively, than did non-farmers. Additionally, the N_DF group had a lower burden of Staphylococcus spp. suggesting a correlation between higher microbial diversity and competition for colonization by staphylococci. The N_DF samples were negative for the mecA gene, a marker of methicillin-resistance in staphylococci. The lower burden of staphylococci was found to be independent of the abundance of Corynebacterium spp. Exposure to greater biodiversity could enhance microbial competition, thereby reducing colonization with opportunistic pathogens. Future studies will analyze whether exposure to livestock microbiomes offers protection from acute and chronic diseases. PMID:28850578

The nasal microbiota of dairy farmers is more complex than oral microbiota, reflects occupational exposure, and provides competition for staphylococci.

PubMed

Shukla, Sanjay K; Ye, Zhan; Sandberg, Scott; Reyes, Iris; Fritsche, Thomas R; Keifer, Matthew

2017-01-01

Allergic and autoimmune diseases had been attributed to lack of exposure to biodiversity, an important factor in regulating immune homeostasis in a healthy host. We posit that the microbiome of healthy dairy farmers (DF) will be richer than non-farmers (NF) living in urban settings due to exposure to a greater biodiversity in the dairy environment. However, no studies have investigated the relationships between microbiota of dairy farmers (DF) compared with urban non-farmers (NF). We compared the nasal and oral microbiota of dairy farmers (N_DF, O_DF, respectively) with nasal and oral microbiota of NF in the same geographical area. The N_DF showed high microbial diversity with hundreds of unique genera that reflected environmental/occupational exposures. The nasal and oral microbiomes clustered separately from each other using Principal Coordinate Analysis, and with DF harboring two-fold and 1.5-fold greater exclusive genera in their nose and mouth respectively, than did non-farmers. Additionally, the N_DF group had a lower burden of Staphylococcus spp. suggesting a correlation between higher microbial diversity and competition for colonization by staphylococci. The N_DF samples were negative for the mecA gene, a marker of methicillin-resistance in staphylococci. The lower burden of staphylococci was found to be independent of the abundance of Corynebacterium spp. Exposure to greater biodiversity could enhance microbial competition, thereby reducing colonization with opportunistic pathogens. Future studies will analyze whether exposure to livestock microbiomes offers protection from acute and chronic diseases.

Methodology for assessing exposure and impacts of air pollutants in school children: Data collection, analysis and health effects - A literature review

NASA Astrophysics Data System (ADS)

Mejía, Jaime F.; Choy, Samantha Low; Mengersen, Kerrie; Morawska, Lidia

2011-02-01

The aim of this review is to explore the methodologies employed to assess the exposure of children to air pollutants, in particular traffic emissions, at school, and how these methodologies influence the assessment of the impact of this exposure on the children's health. This involves four main steps: the measurement of air quality at school level, the association between measured air quality and children's exposure, the association between children's exposure and health; and source identification. The comparative advantages and disadvantages of the methods used at each of these steps are discussed. Air quality in schools can be measured at three scales: broad scale, across several city blocks using remote monitors; school-based scale, through ground-level monitors installed within the schools or their immediate surroundings (i.e. only a few metres outside the school); and personal exposure scale using portable monitors attached to a sample of children. Although studies have reported high exposure to PAHs (polycyclic aromatic hydrocarbons), submicrometre (<1.0 μm) and ultrafine particles (<100 nm) at school, no study has investigated the formation of new particles in school facilities and only a handful of studies have analysed children's exposure at school. Associating air quality measurements at the broad and medium scale with children's exposure is challenging: there is spatial and temporal heterogeneity in the distribution of air quality within a school, indoor measurements can often exceed outdoor measurements; and exposure in the classroom is affected by the penetration of outdoor pollutants, wall absorption, emissions from furniture and other materials, level and length of occupancy, and quality of ventilation. This is further exacerbated by the fact that children move around during their school day. Quantifying the contribution of school exposure with observed health symptoms presents further challenges. In addition to ascertaining the impact of non-school-based exposures and co-morbidities, the air pollutant dose intake is affected by daily patterns of physical and traffic activity during and outside school hours which make it difficult to compare the contribution of school-based and non-school-based exposures to the health effect under investigation. Finally, there is strong evidence that low socioeconomic level is highly correlated with the proximity of the school to pollution sources, yet this area of socioeconomic research has been largely unexplored in the assessment of traffic emission exposure.

Comparison of time to PRRSv-stability and production losses between two exposure programs to control PRRSv in sow herds.

PubMed

Linhares, D C L; Cano, J P; Torremorell, M; Morrison, R B

2014-09-01

To control and eliminate porcine reproductive and respiratory syndrome virus (PRRSv) from breeding herds, some veterinarians adopt a strategy called load-close-expose which consists of interrupting replacement pig introduction for several months and exposing the pigs to a replicating PRRSv. This was a prospective quasi-experiment that followed 61 breeding herds acutely infected with PRRSv that adopted one of two exposure programs: modified-live virus (MLV) vaccine or live-resident virus inoculation (LVI). Treatment groups (load-close-expose with MLV or LVI) were compared for: (a) time-to-PRRSv stability (TTS), defined as time in weeks it took to produce PRRSv negative pigs at weaning; (b) the time-to-baseline production (TTBP), defined using statistical process control methods to represent time to recover to the number of pigs weaned per week that herds had prior to PRRSv-detection; and (c) the total production loss in terms of number of pigs weaned per week. TTS and TTBP were compared between treatments using survival analysis. Day 1 of the program was considered to be the day that treatment was administered. Sampling at herds consisted of bleeding 30 due-to-wean piglets on a monthly basis. Serum was tested for PRRSv RNA by RT-PCR. Herds in which PRRSv was not detected over a 90-day period were classified as reaching stability. Multivariate analysis using proportional hazards regression was performed adjusting the effect of treatment on TTBP and TTS to 'severity of PRRSv infection', 'number of whole-herd exposures', 'days from PRRSv-detection to intervention', 'prior PRRSv-infection status' and 'veterinary clinic associated with the herd'. Total loss was compared between groups using multivariate regression analysis adjusted by selected covariates. The median TTS among participating herds was 26.6 weeks (25th to 75th percentile, 21.6-33.0 weeks). The overall TTBP was 16.5 weeks (range 0-29 weeks). The magnitude of production losses following whole-herd exposure averaged 2217 pigs not weaned/1000 sows and was correlated with TTBP. Herds in the MLV group recovered production sooner and had less total loss than herds in the LVI group. TTBP and TTS were significantly shorter and the total loss was significantly less in herds assisted by a specific veterinary clinic and herds that were infected with PRRSv in the 3 years prior to the study. This study provided new metrics to assist veterinarians to decide between methods of exposure to control and eliminate PRRSv from breeding herds. Copyright © 2014 Elsevier B.V. All rights reserved.

Dipeptidyl peptidase-IV inhibitor use associated with increased risk of ACE inhibitor-associated angioedema.

PubMed

Brown, Nancy J; Byiers, Stuart; Carr, David; Maldonado, Mario; Warner, Barbara Ann

2009-09-01

Dipeptidyl peptidase-IV (DPP-IV) inhibitors decrease degradation of the incretins. DPP-IV inhibitors also decrease degradation of peptides, such as substance P, that may be involved in the pathogenesis of angiotensin-converting enzyme (ACE) inhibitor-associated angioedema. This study tested the hypothesis that DPP-IV inhibition affects risk of clinical angioedema, by comparing the incidence of angioedema in patients treated with the DPP-IV inhibitor vildagliptin versus those treated with comparator in Phase III randomized clinical trials. Prospectively defined angioedema-related events were adjudicated in a blinded fashion by an internal medicine adjudication committee and expert reviewer. Concurrent ACE inhibitor or angiotensin receptor blocker exposure was ascertained from case report forms. Study drug exposure was ascertained from unblinded data from phase III studies. Odds ratios and 95% confidence intervals comparing angioedema risk in vildagliptin-treated and comparator-treated patients were calculated for the overall population and for patients taking ACE inhibitors or angiotensin receptor blockers, using both an analysis of pooled data and a meta-analysis (Peto method). Overall, there was no association between vildagliptin use and angioedema. Among individuals taking an ACE inhibitor, however, vildagliptin use was associated with an increased risk of angioedema (14 confirmed cases among 2754 vildagliptin users versus 1 case among 1819 comparator users: odds ratio 4.57 [95% confidence interval 1.57 to 13.28]) in the meta-analysis. Vildagliptin use may be associated with increased risk of angioedema among patients taking ACE inhibitors, although absolute risk is small. Physicians confronted with angioedema in a patient taking an ACE inhibitor and DPP-IV inhibitor should consider this possible drug-drug interaction.

Particulate metals and organic compounds from electronic and tobacco-containing cigarettes: comparison of emission rates and secondhand exposure.

PubMed

Saffari, Arian; Daher, Nancy; Ruprecht, Ario; De Marco, Cinzia; Pozzi, Paolo; Boffi, Roberto; Hamad, Samera H; Shafer, Martin M; Schauer, James J; Westerdahl, Dane; Sioutas, Constantinos

2014-01-01

In recent years, electronic cigarettes have gained increasing popularity as alternatives to normal (tobacco-containing) cigarettes. In the present study, particles generated by e-cigarettes and normal cigarettes have been analyzed and the degree of exposure to different chemical agents and their emission rates were quantified. Despite the 10-fold decrease in the total exposure to particulate elements in e-cigarettes compared to normal cigarettes, specific metals (e.g. Ni and Ag) still displayed a higher emission rate from e-cigarettes. Further analysis indicated that the contribution of e-liquid to the emission of these metals is rather minimal, implying that they likely originate from other components of the e-cigarette device or other indoor sources. Organic species had lower emission rates during e-cigarette consumption compared to normal cigarettes. Of particular note was the non-detectable emission of polycyclic aromatic hydrocarbons (PAHs) from e-cigarettes, while substantial emission of these species was observed from normal cigarettes. Overall, with the exception of Ni, Zn, and Ag, the consumption of e-cigarettes resulted in a remarkable decrease in secondhand exposure to all metals and organic compounds. Implementing quality control protocols on the manufacture of e-cigarettes would further minimize the emission of metals from these devices and improve their safety and associated health effects.

Risk of cancer in workers exposed to styrene at eight British companies making glass-reinforced plastics.

PubMed

Coggon, David; Ntani, Georgia; Harris, E Clare; Palmer, Keith T

2015-03-01

To provide further information on the risks of lymphohaematopoietic (LH) and other cancers associated with styrene. We extended follow-up to December 2012 for 7970 workers at eight companies in England which used styrene in the manufacture of glass-reinforced plastics. Mortality was compared with that for England and Wales by the person-years method, and summarised by SMRs with 95% CIs. A supplementary nested case-control analysis compared styrene exposures, lagged by 5 years, in 122 incident or fatal cases of LH cancer and 1138 matched controls. A total of 3121 cohort members had died (2022 since the last follow-up). No elevation of mortality was observed for LH cancer, either in the full cohort (62 deaths, SMR 0.90, 95% CI 0.69 to 1.15), or in those with more than background exposure to styrene (38 deaths, SMR 0.82, 95% CI 0.58 to 1.14). Nor did the case-control analysis suggest any association with LH cancer. In comparison with background exposure, the OR for non-Hodgkin's lymphoma/chronic lymphocytic leukaemia in workers with high exposure (estimated 8-h time-weighted average of 40-100 ppm) for ≥1 year was 0.54 (95% CI 0.23 to 1.27). Mortality from lung cancer was significantly elevated, and risk increased progressively across exposure categories, with an SMR of 1.44 (95% CI 1.10 to 1.86) in workers highly exposed for ≥1 year. We found no evidence that styrene causes LH cancer. An association with lung cancer is not consistently supported by other studies. It may have been confounded by smoking, but would be worth checking further. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Oxidative Stress Induced in Nurses by Exposure to Preparation and Handling of Antineoplastic Drugs in Mexican Hospitals: A Multicentric Study

PubMed Central

Gómez-Oliván, Leobardo Manuel; Miranda-Mendoza, Gerardo Daniel; Cabrera-Galeana, Paula Anel; Galar-Martínez, Marcela; Islas-Flores, Hariz; SanJuan-Reyes, Nely; Neri-Cruz, Nadia; García-Medina, Sandra

2014-01-01

The impact of involuntary exposure to antineoplastic drugs (AD) was studied in a group of nurses in diverse hospitals in Mexico. The results were compared with a group of unexposed nurses. Anthropometric characteristics and the biochemical analysis were analyzed in both groups. Also, lipid peroxidation level (LPX), protein carbonyl content (PCC), and activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were evaluated in blood of study participants as oxidative stress (OS) biomarkers. The group of occupationally exposed (OE) nurses consisted of 30 individuals ranging in age from 25 to 35 years. The control group included 30 nurses who were not occupationally exposed to the preparation and handling of AD and whose anthropometric and biochemical characteristics were similar to those of the OE group. All biomarkers evaluated were significantly increased (P < 0.5) in OE nurses compared to the control group. Results show that the assessment of OS biomarkers is advisable in order to evaluate exposure to AD in nurses. PMID:24719678

Oxidative stress induced in nurses by exposure to preparation and handling of antineoplastic drugs in Mexican hospitals: a multicentric study.

PubMed

Gómez-Oliván, Leobardo Manuel; Miranda-Mendoza, Gerardo Daniel; Cabrera-Galeana, Paula Anel; Galar-Martínez, Marcela; Islas-Flores, Hariz; Sanjuan-Reyes, Nely; Neri-Cruz, Nadia; García-Medina, Sandra

2014-01-01

The impact of involuntary exposure to antineoplastic drugs (AD) was studied in a group of nurses in diverse hospitals in Mexico. The results were compared with a group of unexposed nurses. Anthropometric characteristics and the biochemical analysis were analyzed in both groups. Also, lipid peroxidation level (LPX), protein carbonyl content (PCC), and activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were evaluated in blood of study participants as oxidative stress (OS) biomarkers. The group of occupationally exposed (OE) nurses consisted of 30 individuals ranging in age from 25 to 35 years. The control group included 30 nurses who were not occupationally exposed to the preparation and handling of AD and whose anthropometric and biochemical characteristics were similar to those of the OE group. All biomarkers evaluated were significantly increased (P < 0.5) in OE nurses compared to the control group. Results show that the assessment of OS biomarkers is advisable in order to evaluate exposure to AD in nurses.

Exposure to lead in South African shooting ranges.

PubMed

Mathee, Angela; de Jager, Pieter; Naidoo, Shan; Naicker, Nisha

2017-02-01

Lead exposure in shooting ranges has been under scrutiny for decades, but no information in this regard is available in respect of African settings, and in South Africa specifically. The aim of this study was to determine the blood lead levels in the users of randomly selected private shooting ranges in South Africa's Gauteng province. An analytical cross sectional study was conducted, with participants recruited from four randomly selected shooting ranges and three archery ranges as a comparator group. A total of 118 (87 shooters and 31 archers) were included in the analysis. Shooters had significantly higher blood lead levels (BLL) compared to archers with 36/85 (42.4%) of shooters versus 2/34 (5.9%) of archers found to have a BLL ≥10μg/dl (p<0.001). Shooting ranges may constitute an import site of elevated exposure to lead. Improved ventilation, low levels of awareness of lead hazards, poor housekeeping, and inadequate personal hygiene facilities and practices at South African shooting ranges need urgent attention. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Generational comparisons (F1 versus F3) of vinclozolin induced epigenetic transgenerational inheritance of sperm differential DNA methylation regions (epimutations) using MeDIP-Seq.

PubMed

Beck, Daniel; Sadler-Riggleman, Ingrid; Skinner, Michael K

2017-07-01

Environmentally induced epigenetic transgenerational inheritance of disease and phenotypic variation has been shown to involve DNA methylation alterations in the germline (e.g. sperm). These differential DNA methylation regions (DMRs) are termed epimutations and in part transmit the transgenerational phenotypes. The agricultural fungicide vinclozolin exposure of a gestating female rat has previously been shown to promote transgenerational disease and epimutations in F3 generation (great-grand-offspring) animals. The current study was designed to investigate the actions of direct fetal exposure on the F1 generation rat sperm DMRs compared to the F3 transgenerational sperm DMRs. A protocol involving methylated DNA immunoprecipitation (MeDIP) followed by next-generation sequencing (Seq) was used in the current study. Bioinformatics analysis of the MeDIP-Seq data was developed and several different variations in the bioinformatic analysis were evaluated. Observations indicate needs to be considered. Interestingly, the F1 generation DMRs were found to be fewer in number and for the most part distinct from the F3 generation epimutations. Observations suggest the direct exposure induced F1 generation sperm DMRs appear to promote in subsequent generations alterations in the germ cell developmental programming that leads to the distinct epimutations in the F3 generation. This may help explain the differences in disease and phenotypes between the direct exposure F1 generation and transgenerational F3 generation. Observations demonstrate a distinction between the direct exposure versus transgenerational epigenetic programming induced by environmental exposures and provide insights into the molecular mechanisms involved in the epigenetic transgenerational inheritance phenomenon.

A metabolomic, geographic, and seasonal analysis of the contribution of pollen-derived adenosine to allergic sensitization.

PubMed

Mueller, Geoffrey A; Thompson, Peter M; DeRose, Eugene F; O'Connell, Thomas M; London, Robert E

2016-12-01

Studies on ragweed and birch pollen extracts suggested that the adenosine content is an important factor in allergic sensitization. However, exposure levels from other pollens and considerations of geographic and seasonal factors have not been evaluated. This study compared the metabolite profile of pollen species important for allergic disease, specifically measured the adenosine content, and evaluated exposure to pollen-derived adenosine. An NMR metabolomics approach was used to measure metabolite concentrations in twenty-six pollen extracts. Pollen count data was analyzed from five cities to model exposure. A principal component analysis of the various metabolites identified by NMR showed that pollen extracts could be differentiated primarily by sugar content: glucose, fructose, sucrose, and myo-inositol. In extracts of 10 mg of pollen/ml, the adenosine was highest for grasses (45 μM) followed by trees (23 μM) and weeds (19 μM). Pollen count data showed that tree pollen was typically 5-10 times the amount of other pollens. At the daily peaks of tree, grass, and weed season the pollen-derived adenosine exposure per day is likely to only be 1.1, 0.11, and 0.12 μg, respectively. Seasonal models of pollen exposure and respiration suggest that it would be a rare event limited to tree pollen season for concentrations of pollen-derived adenosine to approach physiological levels. Sugar content and other metabolites may be useful in classifying pollens. Unless other factors create localized exposures that are very different from these models, pollen-derived adenosine is unlikely to be a major factor in allergic sensitization.

Traumatic events, other operational stressors and physical and mental health reported by Australian Defence Force personnel following peacekeeping and war-like deployments

PubMed Central

2012-01-01

Background The association between stressful events on warlike deployments and subsequent mental health problems has been established. Less is known about the effects of stressful events on peacekeeping deployments. Methods Two cross sectional studies of the Australian Defence Force were used to contrast the prevalence of exposures reported by a group deployed on a peacekeeping operation (Bougainville, n = 1704) and those reported by a group deployed on operations which included warlike and non-warlike exposures (East Timor, n = 1333). A principal components analysis was used to identify groupings of non-traumatic exposures on deployment. Multiple regression models were used to assess the association between self-reported objective and subjective exposures, stressors on deployment and subsequent physical and mental health outcomes. Results The principal components analysis produced four groups of non-traumatic stressors which were consistent between the peacekeeping and more warlike deployments. These were labelled ‘separation’, ‘different culture’, ‘other people’ and ‘work frustration’. Higher levels of traumatic and non-traumatic exposures were reported by veterans of East Timor compared to Bougainville. Higher levels of subjective traumatic exposures were associated with increased rates of PTSD in East Timor veterans and more physical and psychological health symptoms in both deployed groups. In Bougainville and East Timor veterans some non-traumatic deployment stressors were also associated with worse health outcomes. Conclusion Strategies to best prepare, identify and treat those exposed to traumatic events and other stressors on deployment should be considered for Defence personnel deployed on both warlike and peacekeeping operations. PMID:22830494

Traumatic events, other operational stressors and physical and mental health reported by Australian Defence Force personnel following peacekeeping and war-like deployments.

PubMed

Waller, Michael; Treloar, Susan A; Sim, Malcolm R; McFarlane, Alexander C; McGuire, Annabel C L; Bleier, Jonathan; Dobson, Annette J

2012-07-26

The association between stressful events on warlike deployments and subsequent mental health problems has been established. Less is known about the effects of stressful events on peacekeeping deployments. Two cross sectional studies of the Australian Defence Force were used to contrast the prevalence of exposures reported by a group deployed on a peacekeeping operation (Bougainville, n = 1704) and those reported by a group deployed on operations which included warlike and non-warlike exposures (East Timor, n = 1333). A principal components analysis was used to identify groupings of non-traumatic exposures on deployment. Multiple regression models were used to assess the association between self-reported objective and subjective exposures, stressors on deployment and subsequent physical and mental health outcomes. The principal components analysis produced four groups of non-traumatic stressors which were consistent between the peacekeeping and more warlike deployments. These were labelled 'separation', 'different culture', 'other people' and 'work frustration'. Higher levels of traumatic and non-traumatic exposures were reported by veterans of East Timor compared to Bougainville. Higher levels of subjective traumatic exposures were associated with increased rates of PTSD in East Timor veterans and more physical and psychological health symptoms in both deployed groups. In Bougainville and East Timor veterans some non-traumatic deployment stressors were also associated with worse health outcomes. Strategies to best prepare, identify and treat those exposed to traumatic events and other stressors on deployment should be considered for Defence personnel deployed on both warlike and peacekeeping operations.

Comparative analysis of radioecological monitoring dosimeters

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

Sobolev, A.I.; Pol`skii, O.G.; Shanin, O.B.

1995-03-01

This paper describes comparative estimates of radiation doses measured by two types of thermoluminescence dosimeters and two types of background radiation radiometers. The dosimetry systems were tested by simultaneously recording background radiation and standard radiation sources at a radioactive waste storage facility. Statistical analysis of the measurement results is summarized. The maximum recorded exposure dose rate for the experiment was 19 microrads per hour. The DTK-2 dosimeter overestimated dose rates by 6 to 43% and the DTU-2 dosimeter underestimated dose rates by 7 to 21%. Both devices are recommended for radioecological monitoring in populated areas. 4 refs., 3 figs., 5more » tabs.« less

Neonatal outcomes after fetal exposure to methadone and buprenorphine: national registry studies from the Czech Republic and Norway.

PubMed

Nechanská, Blanka; Mravčík, Viktor; Skurtveit, Svetlana; Lund, Ingunn Olea; Gabrhelík, Roman; Engeland, Anders; Handal, Marte

2018-02-14

Opioid maintenance treatment (OMT) is recommended to opioid-dependent females during pregnancy. However, it is not clear which medication should be preferred. We aimed to compare neonatal outcomes after prenatal exposure to methadone (M) and buprenorphine (B) in two European countries. Nation-wide register-based cohort study using personalized IDs assigned to all citizens for data linkage. The Czech Republic (2000-14) and Norway (2004-13). [Correction added after online publication on 26 April 2018: The Czech Republic (2000-04) corrected to (2000-14).] PARTICIPANTS: Opioid-dependent pregnant Czech (n = 333) and Norwegian (n = 235) women in OMT who received either B or M during pregnancy and their newborns. We linked data from health registries to identify the neonatal outcomes: gestational age, preterm birth, birth weight, length and head circumference, small for gestational age, miscarriages and stillbirth, neonatal abstinence syndrome (NAS) and Apgar score. We performed multivariate linear regression and binary logistic regression to explore the associations between M and B exposure and outcomes. Regression coefficient (β) and odds ratio (OR) were computed. Most neonatal outcomes were more favourable after exposure to B compared with M, but none of the differences was statistically significant. For instance, in the multivariate analysis, birth weight was β = 111.6 g [95% confidence interval (CI) = -10.5 to 233.6 and β = 83.1 g, 95% CI = -100.8 to 267.0] higher after B exposure in the Czech Republic and Norway, respectively. Adjusted OR of NAS for B compared with M was 0.94 (95% CI = 0.46-1.92) in the Norwegian cohort. Two national cohorts of women receiving opioid maintenance treatment during pregnancy showed small but not statistically significant differences in neonatal outcomes in favour of buprenorphine compared with methadone. © 2018 Society for the Study of Addiction.

Including the effect of motion artifacts in noise and performance analysis of dual-energy contrast-enhanced mammography

NASA Astrophysics Data System (ADS)

Allec, N.; Abbaszadeh, S.; Scott, C. C.; Lewin, J. M.; Karim, K. S.

2012-12-01

In contrast-enhanced mammography (CEM), the dual-energy dual-exposure technique, which can leverage existing conventional mammography infrastructure, relies on acquiring the low- and high-energy images using two separate exposures. The finite time between image acquisition leads to motion artifacts in the combined image. Motion artifacts can lead to greater anatomical noise in the combined image due to increased mismatch of the background tissue in the images to be combined, however the impact has not yet been quantified. In this study we investigate a method to include motion artifacts in the dual-energy noise and performance analysis. The motion artifacts are included via an extended cascaded systems model. To validate the model, noise power spectra of a previous dual-energy clinical study are compared to that of the model. The ideal observer detectability is used to quantify the effect of motion artifacts on tumor detectability. It was found that the detectability can be significantly degraded when motion is present (e.g., detectability of 2.5 mm radius tumor decreased by approximately a factor of 2 for translation motion on the order of 1000 μm). The method presented may be used for a more comprehensive theoretical noise and performance analysis and fairer theoretical performance comparison between dual-exposure techniques, where motion artifacts are present, and single-exposure techniques, where low- and high-energy images are acquired simultaneously and motion artifacts are absent.

Including the effect of motion artifacts in noise and performance analysis of dual-energy contrast-enhanced mammography.

PubMed

Allec, N; Abbaszadeh, S; Scott, C C; Lewin, J M; Karim, K S

2012-12-21

In contrast-enhanced mammography (CEM), the dual-energy dual-exposure technique, which can leverage existing conventional mammography infrastructure, relies on acquiring the low- and high-energy images using two separate exposures. The finite time between image acquisition leads to motion artifacts in the combined image. Motion artifacts can lead to greater anatomical noise in the combined image due to increased mismatch of the background tissue in the images to be combined, however the impact has not yet been quantified. In this study we investigate a method to include motion artifacts in the dual-energy noise and performance analysis. The motion artifacts are included via an extended cascaded systems model. To validate the model, noise power spectra of a previous dual-energy clinical study are compared to that of the model. The ideal observer detectability is used to quantify the effect of motion artifacts on tumor detectability. It was found that the detectability can be significantly degraded when motion is present (e.g., detectability of 2.5 mm radius tumor decreased by approximately a factor of 2 for translation motion on the order of 1000 μm). The method presented may be used for a more comprehensive theoretical noise and performance analysis and fairer theoretical performance comparison between dual-exposure techniques, where motion artifacts are present, and single-exposure techniques, where low- and high-energy images are acquired simultaneously and motion artifacts are absent.

Variability of total exposure to PM2.5 related to indoor and outdoor pollution sources Krakow study in pregnant women.

PubMed

Jedrychowski, Wieslaw A; Perera, Frederica P; Pac, Agnieszka; Jacek, Ryszard; Whyatt, Robin M; Spengler, John D; Dumyahn, Thomas S; Sochacka-Tatara, Elzbieta

2006-07-31

The study is a part of an ongoing prospective cohort study on the relationship between the exposure to environmental factors during pregnancy and birth outcomes and health of newborns. We have measured personal PM(2.5) level in the group of 407 non-smoking pregnant women during the 2nd trimester of pregnancy. On average, the participants from the city center were exposed to higher exposure than those from the outer city area (GM=42.0 microg/m(3), 95% CI: 36.8-48.0 vs. 35.8 microg/m(3), 95% CI: 33.5-38.2 microg/m(3)). More than 20% of study subjects were affected by high level of PM(2.5) pollution (above 65 microg/m(3)). PM(2.5) concentrations were higher during the heating season (GM=43.4 microg/m(3), 95% CI: 40.1-46.9 microg/m(3)) compared to non-heating season (GM=29.8 microg/m(3), 95% CI: 27.5-32.2 microg/m(3)). Out of all potential outdoor air pollution sources (high traffic density, bus depot, waste incinerator, industry etc.) considered in the bivariate analysis, only the proximity of industrial plant showed significant impact on the personal exposure (GM=54.3 microg/m(3), 95% CI: 39.4-74.8 microg/m(3)) compared with corresponding figure for those who did not declare living near the industrial premises (GM=36.2 microg/m(3), 95% CI: 34.1-38.4 microg/m(3)). The subjects declaring high exposure to ETS (>10 cigarettes daily) have shown very high level of personal exposure (GM=88.8 microg/m(3), 95% CI: 73.9-106.7 microg/m(3)) compared with lower ETS exposure (< or =10 cigarettes) (GM=46.3 microg/m(3), 95% CI: 40.0-53.5 microg/m(3)) and no-ETS exposure group (GM=33.9 microg/m(3), 95% CI: 31.8-36.1 microg/m(3)). The contribution of the background ambient PM(10) level was very strong determinant of the total personal exposure to PM(2.5) and it explained about 31% of variance between the subjects followed by environmental tobacco smoke (10%), home heating by coal/wood stoves (2%), other types of heating (2%) and the industrial plant localization in the proximity of household (1%).

Urban–rural differentials in the factors associated with exposure to second-hand smoke in India

PubMed Central

Singh, Akansha; Sahoo, Namita

2013-01-01

Objectives This study aims to investigate the role of different factors associated with exposure to second-hand smoke (SHS) in the workplace and home in the urban and rural areas of India. Design Secondary analysis of the data from the Global Adult Tobacco Survey conducted in 2009–2010. Setting and participants Data were analysed from 32 738 rural and 23 202 urban non-smokers at home and 4809 rural and 6227 urban non-smokers in the workplace in India. Outcomes and methods We used two measures of SHS: exposure to SHS at home and exposure to SHS in the workplace. SHS exposure at home is estimated for non-smokers who reported anyone smoking inside his/her home. Exposure to SHS in the workplace is estimated for non-smokers who reported anyone smoking in the workplace in the past 30 days before the survey. Statistical techniques such as χ2 test, logistic regression and discriminant function analysis were used. Results The results showed that SHS exposure in the workplace and home is higher in the rural areas than in the urban areas. As compared with men, women are significantly more likely to be exposed to SHS at home (OR=1.20, 95% CI 1.10 to 1.30) in the rural areas, and less likely at the workplace in the urban areas (OR=0.49, 95% CI 0.40 to 0.59). Education and region are significant predictors of exposure levels to SHS at home and the workplace in the rural and urban areas. The knowledge of number of smoking-related hazards significantly discriminates the SHS exposure in the rural workplace. SHS exposure at home is most affected by region in the rural areas and education in the urban areas. Conclusions The factors which affect SHS exposure differ in the rural and urban areas of India. The study concludes that the risk of getting exposed to SHS at home and the workplace among non-smokers is higher in the rural areas of the country. PMID:24282245

Development of an Automated Reader for Analysis and Storage of Personnel Dosimeter Badge Data

NASA Technical Reports Server (NTRS)

Meneghelli, B. J.; Hodge, T. R.; Robinson, L. J.; Lueck, D. E.

1997-01-01

The collection and archiving of data from personnel dosimeters has become increasingly important in light of the lowered threshold limit values (TLV) for hydrazine (HZ), monomethylhydrazine (MMH), and unsymmetrical dimethylhydrazine (UDMH). The American Conference of Government Industrial Hygienists (ACGIH) lowered the TLV from 100 parts per billion (ppb) to 10 ppb and has caused increased concern over long term exposures of personnel to trace levels of these hypergols and other potentially harmful chemicals. An automated system of reading the exposure levels of personnel dosimeters and storing exposure data for subsequent evaluation has been developed. The reading of personnel dosimeter badges for exposure lo potentially harmful vapor concentrations of hydrazines or other chemicals is performed visually by comparing the color developed by the badge with a calibrated color comparator. The result obtained using visual comparisons of the developed badge color with the comparator may vary widely from user to user. The automated badge reader takes the variability out of the dosimeter reading by accurately comparing the reflectance obtained from a colored spot on the badge with a reading on the same spot prior to any exposure to chemical vapors. The observed difference between the reflectance values is used as part of a calculation of the dose value for the badge based on a stored calibration curve. The badge reader also stores bar-code data unique to each badge, as well as bar-code information on the user, as part of the permanent badge record. The start and stop exposure times for each badge are recorded and can be used as part of the calculated concentration, in ppm, for each badge logged during a recording period. The badge reader is equipped with a number of badge holders, each of which is unique to a specific type of personnel dosimeter badge. This gives the reader maximum flexibility to allow for the reading of several different types of badges. Test results of the badge reader for several different types of personnel dosimeter badges are presented within the body of this paper.

Development of an Automated Reader for Analysis and Storage of Personnel Dosimeter Badge Data

NASA Technical Reports Server (NTRS)

Meneghelli, B. J.; Hodge, T. R.; Robinson, L. J.; Lueck, D. E.

1997-01-01

The collection and archiving of data from personnel dosimeters has become increasingly important in light of the lowered Threshold Limit Values (TLV) for HydraZine (HZ), MonoMethylHydrazine (MMH), and Unsymmetrical DiMethylHydrazine (UDMH). The American Conference of Government Industrial Hygienists (ACGIH) lowered the TLV from 100 parts per billion (ppb) to IO ppb and has caused increased concern over long term exposures of personnel to trace levels of these hypergols and other potentially harmful chemicals. An automated system of reading the exposure levels of personnel dosimeters and storing exposure data for subsequent evaluation has been developed. The reading of personnel dosimeter badges for exposure to potentially harmful vapor concentrations of hydrazines or other chemicals is performed visually by comparing the color developed by the badge with a calibrated color comparator. The result obtained using visual comparisons of the developed badge color with the comparator may vary widely from user to user. The automated badge reader takes the variability out of the dosimeter reading by accurately comparing the reflectance obtained from a colored spot on the badge with a reading on the same spot prior to any exposure to chemical vapors. The observed difference between the reflectance values is used as part of a calculation of the dose value for the badge based on a stored calibration curve. The badge reader also stores bar-code data unique to each badge, as well as bar-code information on the user, as part of the permanent badge record. The start and stop exposure times for each badge are recorded and can be used as part of the calculated concentration, in ppm, for each badge logged during a recording period. The badge reader is equipped with a number of badge holders, each of which is unique to a specific type of personnel dosimeter badge. This gives the reader maximum flexibility to allow for the reading of several different types of badges. Test results of the badge reader for several different types of personnel dosimeter badges are presented within the body of this paper.

The effect of low-intensity pulsed ultrasound on wound healing using scratch assay in epithelial cells.

PubMed

Iwanabe, Yujiro; Masaki, Chihiro; Tamura, Akiko; Tsuka, Shintaro; Mukaibo, Taro; Kondo, Yusuke; Hosokawa, Ryuji

2016-10-01

Low-intensity pulsed ultrasound (LIPUS) is widely used in medical fields because it shortens the time required for biologic wound healing in fracture treatment. Also, in dental fields, LIPUS should be effectively employed for implant treatment. However, most of the relevant reports have been published on its effects on bone formation around implants, and the effects of LIPUS on soft tissue healing remain unclear. In the present study, we examined the effects of LIPUS on soft tissue healing using gingival epithelial cells. Gingival epithelial cells were cultured on a dish, followed by LIPUS exposure at a frequency of 3MHz for 15min. The cells were counted with a hemocytometer, and a scratch assay was conducted by measuring the closing area of the scratch wound using a microscope. Following LIPUS exposure, total RNA was collected for microarray analysis. In addition, real-time PCR was performed to examine the mRNA expression level of integrin α6β4. Furthermore, total protein was collected to examine the protein expression level of integrin α6β4 by western blotting. The cell count and scratch assay demonstrated that LIPUS exposure promoted cell proliferation and scratch-wound closure. Microarray analysis demonstrated the increased expression levels of adhesion-related genes, including integrin. Real-time PCR analysis demonstrated that LIPUS exposure significantly up-regulated the mRNA expression level of integrin α6β4. Western blotting showed intense staining of integrin α6β4. LIPUS exposure promotes wound closure in the scratch assay and up-regulates the expression level of integrin α6β4 as compared with the control. Copyright © 2016 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Influence of pregnancy stage and fetus position on the whole-body and local exposure of the fetus to RF-EMF

NASA Astrophysics Data System (ADS)

Varsier, N.; Dahdouh, S.; Serrurier, A.; De la Plata, J.-P.; Anquez, J.; Angelini, E. D.; Bloch, I.; Wiart, J.

2014-09-01

This paper analyzes the influence of pregnancy stage and fetus position on the whole-body and brain exposure of the fetus to radiofrequency electromagnetic fields. Our analysis is performed using semi-homogeneous pregnant woman models between 8 and 32 weeks of amenorrhea. By analyzing the influence of the pregnancy stage on the environmental whole-body and local exposure of a fetus in vertical position, head down or head up, in the 2100 MHz frequency band, we concluded that both whole-body and average brain exposures of the fetus decrease during the first pregnancy trimester, while they advance during the pregnancy due to the rapid weight gain of the fetus in these first stages. From the beginning of the second trimester, the whole-body and the average brain exposures are quite stable because the weight gains are quasi proportional to the absorbed power increases. The behavior of the fetus whole-body and local exposures during pregnancy for a fetus in the vertical position with the head up were found to be of a similar level, when compared to the position with the head down they were slightly higher, especially in the brain.

Dietary exposure to trace elements and health risk assessment in the 2nd French Total Diet Study.

PubMed

Arnich, Nathalie; Sirot, Véronique; Rivière, Gilles; Jean, Julien; Noël, Laurent; Guérin, Thierry; Leblanc, Jean-Charles

2012-07-01

Dietary exposure of the French population to trace elements has been assessed in the second national Total Diet Study (TDS). Food samples (n = 1319) were collected between 2007 and 2009 to be representative of the whole diet of the population, prepared as consumed, and analyzed. Occurrence data were combined with national individual consumption data to estimate dietary exposure for adults and children mean and high consumers. Compared to the 1st French TDS performed in 2000-2004, exposure is higher for cadmium, aluminium, antimony, nickel, cobalt and lower for lead, mercury and arsenic. For aluminium, methylmercury, cadmium, lead and inorganic arsenic risk cannot be ruled out for certain consumer groups. It still appears necessary to continue undertaking efforts to reduce exposure to these elements. Due to the lack of robust toxicological data and/or speciation analysis in food on chromium, tin, silver and vanadium to perform a risk assessment, data on occurrence and dietary exposure are provided as Supplementary material. In order to minimize nutritional and chemical risks, the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) reiterates its recommendation for a diversified diet (food items and origins). Copyright © 2012 Elsevier Ltd. All rights reserved.

Carbonaceous particulate matter on the lung surface from adults living in São Paulo, Brazil.

PubMed

Padovan, Michele Galhardoni; Whitehouse, Abigail; Gouveia, Nelson; Habermann, Mateus; Grigg, Jonathan

2017-01-01

We therefore sought to identify the exposures associated with lung surface in long-term residents of São Paulo, Brazil. Lung surface carbon were analyzed in 72 autopsy specimens by image analysis. Smoking history, measured PM10 nearest to the home, distance to main road, and distance-weighted traffic density were used as exposure variables. Data are summarized as median (IQR), and compared by Mann Whitney Test, with correlations done by Spearman's correlation. There was no association between lung surface and age or gender. There was no statistically significant association in lung surface between smokers and non-smokers 6.74 cm2 (3.47 to 10.02) versus 5.20cm2 (2.29 to 7.54), and there was no significant association between lung surface carbon and exposure to environmental PM and markers of traffic exposure. We did not find a statistically significant association between lung surface and smokers and non-smokers, and no statistically significant association between lung surface carbon and environmental exposure variables. These results suggest that lung surface carbon in long-term residents of São Paulo may predominately be from environmental PM, but the most appropriate environmental exposure marker remains unclear.

Perfluorooctanoic acid exposure for 28 days affects glucose homeostasis and induces insulin hypersensitivity in mice

NASA Astrophysics Data System (ADS)

Yan, Shengmin; Zhang, Hongxia; Zheng, Fei; Sheng, Nan; Guo, Xuejiang; Dai, Jiayin

2015-06-01

Perfluoroalkyl acids (PFAAs) are widely used in many applications due to their unique physical and chemical characteristics. Because of the increasing prevalence of metabolic syndromes, including obesity, dyslipidemia and insulin resistance, concern has arisen about the roles of environmental pollutants in such diseases. Earlier epidemiologic studies showed a potential association between perfluorooctanoic acid (PFOA) and glucose metabolism, but how PFOA influences glucose homeostasis is still unknown. Here, we report on the modulation of the phosphatidylinositol 3-kinase-serine/threonine protein kinase (PI3K-AKT) signaling pathway in the livers of mice after 28 d of exposure to PFOA. Compared with normal mice, PFOA exposure significantly decreased the expression of the phosphatase and tensin homologue (PTEN) protein and affected the PI3K-AKT signaling pathway in the liver. Tolerance tests further indicated that PFOA exposure induced higher insulin sensitivity and glucose tolerance in mice. Biochemical analysis revealed that PFOA exposure reduced hepatic glycogen synthesis, which might be attributed to gluconeogenesis inhibition. The levels of several circulating proteins were altered after PFOA exposure, including proteins potentially related to diabetes and liver disease. Our results suggest that PFOA affected glucose metabolism and induced insulin hypersensitivity in mice.

Virtual reality exposure therapy for social anxiety disorder: a randomized controlled trial.

PubMed

Anderson, Page L; Price, Matthew; Edwards, Shannan M; Obasaju, Mayowa A; Schmertz, Stefan K; Zimand, Elana; Calamaras, Martha R

2013-10-01

This is the first randomized trial comparing virtual reality exposure therapy to in vivo exposure for social anxiety disorder. Participants with a principal diagnosis of social anxiety disorder who identified public speaking as their primary fear (N = 97) were recruited from the community, resulting in an ethnically diverse sample (M age = 39 years) of mostly women (62%). Participants were randomly assigned to and completed 8 sessions of manualized virtual reality exposure therapy, exposure group therapy, or wait list. Standardized self-report measures were collected at pretreatment, posttreatment, and 12-month follow-up, and process measures were collected during treatment. A standardized speech task was delivered at pre- and posttreatment, and diagnostic status was reassessed at 3-month follow-up. Analysis of covariance showed that, relative to wait list, people completing either active treatment significantly improved on all but one measure (length of speech for exposure group therapy and self-reported fear of negative evaluation for virtual reality exposure therapy). At 12-month follow-up, people showed significant improvement from pretreatment on all measures. There were no differences between the active treatments on any process or outcome measure at any time, nor differences on achieving partial or full remission. Virtual reality exposure therapy is effective for treating social fears, and improvement is maintained for 1 year. Virtual reality exposure therapy is equally effective as exposure group therapy; further research with a larger sample is needed, however, to better control and statistically test differences between the treatments.

Bacterial population dynamics during the ensiling of Medicago sativa (alfalfa) and subsequent exposure to air.

PubMed

McGarvey, J A; Franco, R B; Palumbo, J D; Hnasko, R; Stanker, L; Mitloehner, F M

2013-06-01

To describe, at high resolution, the bacterial population dynamics and chemical transformations during the ensiling of alfalfa and subsequent exposure to air. Samples of alfalfa, ensiled alfalfa and silage exposed to air were collected and their bacterial population structures compared using 16S rRNA gene libraries containing approximately 1900 sequences each. Cultural and chemical analyses were also performed to complement the 16S gene sequence data. Sequence analysis revealed significant differences (P < 0·05) in the bacterial populations at each time point. The alfalfa-derived library contained mostly sequences associated with the Gammaproteobacteria (including the genera: Enterobacter, Erwinia and Pantoea); the ensiled material contained mostly sequences associated with the lactic acid bacteria (LAB) (including the genera: Lactobacillus, Pediococcus and Lactococcus). Exposure to air resulted in even greater percentages of LAB, especially among the genus Lactobacillus, and a significant drop in bacterial diversity. In-depth 16S rRNA gene sequence analysis revealed significant bacterial population structure changes during ensiling and again during exposure to air. This in-depth description of the bacterial population dynamics that occurred during ensiling and simulated feed out expands our knowledge of these processes. © 2013 The Society for Applied Microbiology No claim to US Government works.

Suitability of the AUC Ratio as an Indicator of the Pharmacokinetic Advantage in HIPEC.

PubMed

Mas-Fuster, Maria Isabel; Ramon-Lopez, Amelia; Lacueva, Javier; Más-Serrano, Patricio; Nalda-Molina, Ricardo

2018-02-01

The purpose of this study was to evaluate the area under the concentration-time curve (AUC) ratio as an optimal indicator of the pharmacokinetic advantage during hyperthermic intraperitoneal perioperative chemotherapy. The impact on the AUC ratio on the variables related to the calculation of systemic drug exposure, instillation time, and peripheral drug distribution was evaluated through simulations as well as through a retrospective analysis of studies published in the literature. Both model simulations and the retrospective analysis showed that the 3 variables evaluated had an impact on the AUC ratio value if the complete systemic exposure was not fully considered. However, when that complete systemic exposure was considered, none of these variables affected the AUC ratio value. AUC ratio is not a characteristic parameter of a drug if the calculated systemic drug exposure is not complete. Thus, AUC ratio is not valid for comparing the pharmacokinetic advantage of 2 drugs, and it should not be employed to prove whether a drug can be used in hyperthermic intraperitoneal perioperative chemotherapy safely with regard to toxicity. As an alternative, the study of the absorption rate constant and the bioavailability are proposed as the true and independent parameters that reflect the amount of drug absorbed. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

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

USGS Publications Warehouse

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

2018-01-01

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

Testing the effects of a decision aid for prostate cancer screening.

PubMed

Rubel, Stephanie K; Miller, Jacqueline W; Stephens, Robert L; Xu, Ye; Scholl, Lawrence E; Holden, E Wayne; Stroud, Leonardo A; Volk, Robert J

2010-04-01

There is an ever-growing trend toward more patient involvement in making health care decisions. This trend has been accompanied by the development of "informed decision-making" interventions to help patients become more engaged and comfortable with making these decisions. We describe the effects of a prostate cancer screening decision aid on knowledge, beliefs about screening, risk perception, control preferences, decisional conflict, and decisional anxiety. Data were collected from 200 males aged 50-70 years in the general population who randomly were assigned to exposure to the decision aid or no exposure as a control condition. A Solomon four-group design was used to test for possible pretest sensitization effects and to assess the effects of exposure to the decision aid. No significant pretest sensitization effects were found. Analysis of the exposure effects found that knowledge increased significantly for those exposed to the decision aid compared with those unexposed. Exposure to the decision aid also had some influence on decreasing both decisional conflict and decisional anxiety. Decision aids can play an important role in increasing patients' knowledge and decreasing anxiety when asked to make health care decisions.

Neurosensory effects of chronic exposure to arsenic via drinking water in Inner Mongolia: II. Vibrotactile and visual function.

PubMed

Otto, David; He, Linlin; Xia, Yanhong; Li, Yajuan; Wu, Kegong; Ning, Zhixiong; Zhao, Baixiao; Hudnell, H Kenneth; Kwok, Richard; Mumford, Judy; Geller, Andrew; Wade, Timothy

2006-03-01

This study was designed to assess the effects of exposure to arsenic in drinking water on visual and vibrotactile function in residents of the Bamen region of Inner Mongolia, China. Arsenic was measured by hydride generation atomic fluorescence. 321 participants were divided into three exposure groups- low (non-detectable-20), medium (100-300) and high (400-700 microg/l) arsenic in drinking water (AsW). Three visual tests were administered: acuity, contrast sensitivity and color discrimination (Lanthony's Desaturated 15 Hue Test). Vibration thresholds were measured with a vibrothesiometer. Vibration thresholds were significantly elevated in the high exposure group compared to other groups. Further analysis using a spline regression model suggested that the threshold for vibratory effects is between 150-170 microg/l AsW. These findings provide the first evidence that chronic exposure to arsenic in drinking water impairs vibrotactile thresholds. The results also indicate that arsenic affects neurological function well below the 1000 microg/I concentration reported by NRC (1999). No evidence of arsenic-related effects on visual function was found.

Impact of urban air pollution on the allergenicity of Aspergillus fumigatus conidia: Outdoor exposure study supported by laboratory experiments.

PubMed

Lang-Yona, Naama; Shuster-Meiseles, Timor; Mazar, Yinon; Yarden, Oded; Rudich, Yinon

2016-01-15

Understanding the chemical interactions of common allergens in urban environments may help to decipher the general increase in susceptibility to allergies observed in recent decades. In this study, asexual conidia of the allergenic mold Aspergillus fumigatus were exposed to air pollution under natural (ambient) and controlled (laboratory) conditions. The allergenic activity was measured using two immunoassays and supported by a protein mass spectrometry analysis. The allergenicity of the conidia was found to increase by 2-5 fold compared to the control for short exposure times of up to 12h (accumulated exposure of about 50 ppb NO2 and 750 ppb O3), possibly due to nitration. At higher exposure times, the allergenicity increase lessened due to protein deamidation. These results indicate that during the first 12h of exposure, the allergenic potency of the fungal allergen A. fumigatus in polluted urban environments is expected to increase. Additional work is needed in order to determine if this behavior occurs for other allergens. Copyright © 2015 Elsevier B.V. All rights reserved.

Dermal Exposure Assessment to Pesticides in Farming Systems in Developing Countries: Comparison of Models

PubMed Central

Lesmes Fabian, Camilo; Binder, Claudia R.

2015-01-01

In the field of occupational hygiene, researchers have been working on developing appropriate methods to estimate human exposure to pesticides in order to assess the risk and therefore to take the due decisions to improve the pesticide management process and reduce the health risks. This paper evaluates dermal exposure models to find the most appropriate. Eight models (i.e., COSHH, DERM, DREAM, EASE, PHED, RISKOFDERM, STOFFENMANAGER and PFAM) were evaluated according to a multi-criteria analysis and from these results five models (i.e., DERM, DREAM, PHED, RISKOFDERM and PFAM) were selected for the assessment of dermal exposure in the case study of the potato farming system in the Andean highlands of Vereda La Hoya, Colombia. The results show that the models provide different dermal exposure estimations which are not comparable. However, because of the simplicity of the algorithm and the specificity of the determinants, the DERM, DREAM and PFAM models were found to be the most appropriate although their estimations might be more accurate if specific determinants are included for the case studies in developing countries. PMID:25938911

Dispelling the Myth: Training in Education or Neuroscience Decreases but Does Not Eliminate Beliefs in Neuromyths

PubMed Central

Macdonald, Kelly; Germine, Laura; Anderson, Alida; Christodoulou, Joanna; McGrath, Lauren M.

2017-01-01

Neuromyths are misconceptions about brain research and its application to education and learning. Previous research has shown that these myths may be quite pervasive among educators, but less is known about how these rates compare to the general public or to individuals who have more exposure to neuroscience. This study is the first to use a large sample from the United States to compare the prevalence and predictors of neuromyths among educators, the general public, and individuals with high neuroscience exposure. Neuromyth survey responses and demographics were gathered via an online survey hosted at TestMyBrain.org. We compared performance among the three groups of interest: educators (N = 598), high neuroscience exposure (N = 234), and the general public (N = 3,045) and analyzed predictors of individual differences in neuromyths performance. In an exploratory factor analysis, we found that a core group of 7 “classic” neuromyths factored together (items related to learning styles, dyslexia, the Mozart effect, the impact of sugar on attention, right-brain/left-brain learners, and using 10% of the brain). The general public endorsed the greatest number of neuromyths (M = 68%), with significantly fewer endorsed by educators (M = 56%), and still fewer endorsed by the high neuroscience exposure group (M = 46%). The two most commonly endorsed neuromyths across all groups were related to learning styles and dyslexia. More accurate performance on neuromyths was predicted by age (being younger), education (having a graduate degree), exposure to neuroscience courses, and exposure to peer-reviewed science. These findings suggest that training in education and neuroscience can help reduce but does not eliminate belief in neuromyths. We discuss the possible underlying roots of the most prevalent neuromyths and implications for classroom practice. These empirical results can be useful for developing comprehensive training modules for educators that target general misconceptions about the brain and learning. PMID:28848461

DEARS particulate matter relationships for personal, indoor, outdoor, and central site settings for a general population

NASA Astrophysics Data System (ADS)

Rodes, Charles E.; Lawless, Phil A.; Thornburg, Jonathan W.; Williams, Ronald W.; Croghan, Carry W.

2010-04-01

This analysis provides the initial summary of PM 2.5 mass concentrations relationships for all seasons and participants for a general population in the Detroit Exposure and Aerosol Research Study (DEARS). The summary presented highlights the utility of the new methodologies applied, in addition to summarizing the particulate matter (PM) data. Results include the requirement to adjust the exposure data for monitor wearing compliance and measured environmental tobacco smoke (ETS) levels, even though the study design specified a non-smoking household. A 40% wearing compliance acceptance level was suggested as necessary to balance minimizing exposure misclassification (from poor compliance) and having sufficient data to conduct robust statistical analyses. An ETS threshold level equivalent to adding more than 1.5 μg m -3 to the collected sample was found to be necessary to detect changes in the personal exposure factor ( Fpex). It is not completely clear why such a large threshold level was necessary. Statistically significant spatial PM 2.5 gradients were identified in three of the six DEARS neighborhoods in Wayne County. These were expected, given the number of strong, localized PM sources in the Detroit (Michigan) metro area. Some residential outdoor bias levels compared with the central site at Allen Park exceeded 15%. After adjusting for ETS biases, the outdoor contributions to the personal exposure were typically larger by factors from 1.75 to 2.2 compared with those of the non-outdoor sources. The outdoor contribution was larger in the summer than in the winter, which is consistent with the fractions of time spent outdoors in the summer vs. the winter (6.7% vs. 1.1% of the time). Mean personal PM 2.5 cloud levels for the general population DEARS cohort ranged from 1.5 to 3.8 (after ETS adjustment) and were comparable to those reported previously. The personal exposure collections indoors were typically at least 13 times greater than those contributed outdoors.

Dispelling the Myth: Training in Education or Neuroscience Decreases but Does Not Eliminate Beliefs in Neuromyths.

PubMed

Macdonald, Kelly; Germine, Laura; Anderson, Alida; Christodoulou, Joanna; McGrath, Lauren M

2017-01-01

Neuromyths are misconceptions about brain research and its application to education and learning. Previous research has shown that these myths may be quite pervasive among educators, but less is known about how these rates compare to the general public or to individuals who have more exposure to neuroscience. This study is the first to use a large sample from the United States to compare the prevalence and predictors of neuromyths among educators, the general public, and individuals with high neuroscience exposure. Neuromyth survey responses and demographics were gathered via an online survey hosted at TestMyBrain.org. We compared performance among the three groups of interest: educators ( N = 598), high neuroscience exposure ( N = 234), and the general public ( N = 3,045) and analyzed predictors of individual differences in neuromyths performance. In an exploratory factor analysis, we found that a core group of 7 "classic" neuromyths factored together (items related to learning styles, dyslexia, the Mozart effect, the impact of sugar on attention, right-brain/left-brain learners, and using 10% of the brain). The general public endorsed the greatest number of neuromyths ( M = 68%), with significantly fewer endorsed by educators ( M = 56%), and still fewer endorsed by the high neuroscience exposure group ( M = 46%). The two most commonly endorsed neuromyths across all groups were related to learning styles and dyslexia. More accurate performance on neuromyths was predicted by age (being younger), education (having a graduate degree), exposure to neuroscience courses, and exposure to peer-reviewed science. These findings suggest that training in education and neuroscience can help reduce but does not eliminate belief in neuromyths. We discuss the possible underlying roots of the most prevalent neuromyths and implications for classroom practice. These empirical results can be useful for developing comprehensive training modules for educators that target general misconceptions about the brain and learning.

Exposure to Upper Arm Elevation During Work Compared to Leisure Among 12 Different Occupations Measured with Triaxial Accelerometers.

PubMed

Palm, Peter; Gupta, Nidhi; Forsman, Mikael; Skotte, Jørgen; Nordquist, Tobias; Holtermann, Andreas

2018-06-26

Regarding prevention of neck and shoulder pain (NSP), unsupported arm elevation is one factor that should be taken into account when performing work risk assessment. Triaxial accelerometers can be used to measure arm elevation over several days but it is not possible to differentiate between supported and unsupported arm elevation from accelerometers only. Supported arm elevation is more likely to exist during sitting than standing. The aim of the study was to evaluate the use of whole workday measurements of arm elevation with accelerometers to assess potentially harmful work exposure of arm elevation, by comparing arm elevation at work with arm elevation during leisure, in a population with diverse work tasks, and to assess how the exposure parameters were modified when upper arm elevation during sitting time was excluded. The participants, 197 workers belonging to 12 occupational groups with diverse work tasks, wore triaxial accelerometers on the dominant arm, hip, and back for 1-4 days to measure arm elevation and periods of sitting. None of the groups were found to have higher exposure to arm elevation during work compared to leisure. Even though some occupations where known to have work tasks that forced them to work with elevated arms to a large extent. A high proportion of arm elevation derived from sitting time, especially so during leisure. When arm elevation during sitting time was excluded from the analysis, arm elevation was significantly higher at work than during leisure among construction workers, garbage collectors, manufacturing workers, and domestic cleaners. Together this illustrates that it is not suitable to use whole workday measurments of arm elevation with accelerometer as a sole information source when assessing the risk for NSP due to arm elevation. Information on body posture can provide relevant contextual information in exposure assessments when it is known that the potential harmful exposure is performed in standing or walking.

Fatty acid ethyl esters (FAEE); comparative accumulation in human and guinea pig hair as a biomarker for prenatal alcohol exposure.

PubMed

Kulaga, Vivian; Caprara, Daniela; Iqbal, Umar; Kapur, Bhushan; Klein, Julia; Reynolds, James; Brien, James; Koren, Gideon

2006-01-01

To compare the incorporation rate (ICR) of fatty acid ethyl esters (FAEE) in hair between guinea pigs and humans, and to assess the relationship between ethanol exposure and FAEE concentrations in hair. Published data from pregnant guinea pigs, including maximum blood ethanol concentration (BEC), dosage regimen, and total hair FAEE concentration, were compared with published data from alcoholic patients, where dose of ethanol consumed and total hair FAEE concentration were reported. Mean values of ethanol Vmax for pregnant guinea pigs and humans were obtained from published data (26.2 and 24 mg/dl/h, respectively). Total and individual FAEE ICRs, defined as the ratio of hair FAEE to the area under the BEC-time curve (total systemic ethanol exposure), were found to be on average an order of magnitude lower in the guinea pig than in the human. The profiles of ester incorporation also differed slightly between species, with ethyl stearate being highly incorporated in guinea pig hair and less so in human hair. The results may reflect in the human greater FAEE production, greater FAEE deposition in hair, slower FAEE catabolism, differential sebum production and composition, or a combination thereof. Also, ethyl oleate was found to correlate with total systemic ethanol exposure for both guinea pigs and humans, correlation coefficients equalling 0.67 (P < 0.05) and 0.49 (P < 0.05), respectively. No other ethyl esters, nor total FAEE, were found to correlate with systemic ethanol exposure. When extrapolating FAEE concentrations in hair from guinea pigs to humans, an order of magnitude difference should be considered, with humans incorporating more FAEE per unit of ethanol exposure. Also, the results suggest caution should be taken when interpreting values of single esters because of their differential incorporation among species. Lastly, our findings suggest ethyl oleate may be of keen interest in FAEE hair analysis, particularly across species.

Thoracoabdominal Computed Tomography in Trauma Patients: A Cost-Consequences Analysis

PubMed Central

van Vugt, Raoul; Kool, Digna R.; Brink, Monique; Dekker, Helena M.; Deunk, Jaap; Edwards, Michael J.

2014-01-01

Background: CT is increasingly used during the initial evaluation of blunt trauma patients. In this era of increasing cost-awareness, the pros and cons of CT have to be assessed. Objectives: This study was performed to evaluate cost-consequences of different diagnostic algorithms that use thoracoabdominal CT in primary evaluation of adult patients with high-energy blunt trauma. Materials and Methods: We compared three different algorithms in which CT was applied as an immediate diagnostic tool (rush CT), a diagnostic tool after limited conventional work-up (routine CT), and a selective tool (selective CT). Probabilities of detecting and missing clinically relevant injuries were retrospectively derived. We collected data on radiation exposure and performed a micro-cost analysis on a reference case-based approach. Results: Both rush and routine CT detected all thoracoabdominal injuries in 99.1% of the patients during primary evaluation (n = 1040). Selective CT missed one or more diagnoses in 11% of the patients in which a change of treatment was necessary in 4.8%. Rush CT algorithm costed € 2676 (US$ 3660) per patient with a mean radiation dose of 26.40 mSv per patient. Routine CT costed € 2815 (US$ 3850) and resulted in the same radiation exposure. Selective CT resulted in less radiation dose (23.23 mSv) and costed € 2771 (US$ 3790). Conclusions: Rush CT seems to result in the least costs and is comparable in terms of radiation dose exposure and diagnostic certainty with routine CT after a limited conventional work-up. However, selective CT results in less radiation dose exposure but a slightly higher cost and less certainty. PMID:25337521

Biomarkers of acute respiratory allergen exposure: Screening for sensitization potential

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

Pucheu-Haston, Cherie M., E-mail: Pucheu-Haston.Cherie@epa.go; Copeland, Lisa B.; Vallanat, Beena

2010-04-15

Effective hazard screening will require the development of high-throughput or in vitro assays for the identification of potential sensitizers. The goal of this preliminary study was to identify potential biomarkers that differentiate the response to allergens vs non-allergens following an acute exposure in naive individuals. Female BALB/c mice received a single intratracheal aspiration exposure to Metarhizium anisopliae crude antigen (MACA) or bovine serum albumin (BSA) in Hank's Balanced Salt Solution (HBSS) or HBSS alone. Mice were terminated after 1, 3, 6, 12, 18 and 24 h. Bronchoalveolar lavage fluid (BALF) was evaluated to determine total and differential cellularity, total proteinmore » concentration and LDH activity. RNA was isolated from lung tissue for microarray analysis and qRT-PCR. MACA administration induced a rapid increase in BALF neutrophils, lymphocytes, eosinophils and total protein compared to BSA or HBSS. Microarray analysis demonstrated differential expression of genes involved in cytokine production, signaling, inflammatory cell recruitment, adhesion and activation in 3 and 12 h MACA-treated samples compared to BSA or HBSS. Further analyses allowed identification of approx 100 candidate biomarker genes. Eleven genes were selected for further assessment by qRT-PCR. Of these, 6 demonstrated persistently increased expression (Ccl17, Ccl22, Ccl7, Cxcl10, Cxcl2, Saa1), while C3ar1 increased from 6-24 h. In conclusion, a single respiratory exposure of mice to an allergenic mold extract induces an inflammatory response which is distinct in phenotype and gene transcription from the response to a control protein. Further validation of these biomarkers with additional allergens and irritants is needed. These biomarkers may facilitate improvements in screening methods.« less

What is the potential for interventions designed to prevent violence against women to reduce children's exposure to violence? Findings from the SASA! study, Kampala, Uganda.

PubMed

Kyegombe, Nambusi; Abramsky, Tanya; Devries, Karen M; Michau, Lori; Nakuti, Janet; Starmann, Elizabeth; Musuya, Tina; Heise, Lori; Watts, Charlotte

2015-12-01

Intimate partner violence (IPV) and child maltreatment often co-occur in households and lead to negative outcomes for children. This article explores the extent to which SASA!, an intervention to prevent violence against women, impacted children's exposure to violence. Between 2007 and 2012 a cluster randomized controlled trial was conducted in Kampala, Uganda. An adjusted cluster-level intention to treat analysis, compares secondary outcomes in intervention and control communities at follow-up. Under the qualitative evaluation, 82 in-depth interviews were audio recorded at follow-up, transcribed verbatim, and analyzed using thematic analysis complemented by constant comparative methods. This mixed-methods article draws mainly on the qualitative data. The findings suggest that SASA! impacted on children's experience of violence in three main ways. First, quantitative data suggest that children's exposure to IPV was reduced. We estimate that reductions in IPV combined with reduced witnessing by children when IPV did occur, led to a 64% reduction in prevalence of children witnessing IPV in their home (aRR 0.36, 95% CI 0.06-2.20). Second, among couples who experienced reduced IPV, qualitative data suggests parenting and discipline practices sometimes also changed-improving parent-child relationships and for a few parents, resulting in the complete rejection of corporal punishment as a disciplinary method. Third, some participants reported intervening to prevent violence against children. The findings suggest that interventions to prevent IPV may also impact on children's exposure to violence, and improve parent-child relationships. They also point to potential synergies for violence prevention, an area meriting further exploration. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Electronic cigarette aerosol induces significantly less cytotoxicity than tobacco smoke

PubMed Central

Azzopardi, David; Patel, Kharishma; Jaunky, Tomasz; Santopietro, Simone; Camacho, Oscar M.; McAughey, John; Gaça, Marianna

2016-01-01

Abstract Electronic cigarettes (E-cigarettes) are a potential means of addressing the harm to public health caused by tobacco smoking by offering smokers a less harmful means of receiving nicotine. As e-cigarettes are a relatively new phenomenon, there are limited scientific data on the longer-term health effects of their use. This study describes a robust in vitro method for assessing the cytotoxic response of e-cigarette aerosols that can be effectively compared with conventional cigarette smoke. This was measured using the regulatory accepted Neutral Red Uptake assay modified for air–liquid interface (ALI) exposures. An exposure system, comprising a smoking machine, traditionally used for in vitro tobacco smoke exposure assessments, was adapted for use with e-cigarettes to expose human lung epithelial cells at the ALI. Dosimetric analysis methods using real-time quartz crystal microbalances for mass, and post-exposure chemical analysis for nicotine, were employed to detect/distinguish aerosol dilutions from a reference Kentucky 3R4F cigarette and two commercially available e-cigarettes (Vype eStick and ePen). ePen aerosol induced 97%, 94% and 70% less cytotoxicity than 3R4F cigarette smoke based on matched EC50 values at different dilutions (1:5 vs. 1:153 vol:vol), mass (52.1 vs. 3.1 μg/cm2) and nicotine (0.89 vs. 0.27 μg/cm2), respectively. Test doses where cigarette smoke and e-cigarette aerosol cytotoxicity were observed are comparable with calculated daily doses in consumers. Such experiments could form the basis of a larger package of work including chemical analyses, in vitro toxicology tests and clinical studies, to help assess the safety of current and next generation nicotine and tobacco products. PMID:27690199