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At least 649 records · Page 36Linked to original sources
PubMed2004

Alterations of gene expression in skin and lung of mice exposed to light and cigarette smoke.

We previously showed that sunlight-mimicking light induces genotoxic damage not only in skin but also even in lung, bone marrow, and peripheral blood of hairless mice. Moreover, light and smoke acted synergically in the respiratory tract. To clarify the mechanisms involved, we investigated by cDNA-arrays the expression of 746 toxicologically relevant genes in skin and lungs of mice exposed for 28 days to light and/or environmental cigarette smoke. Glutathione-S-transferase-Pi and catalase were overexpressed in the lungs of mice exposed to light only. Moreover, the light induced in skin the expression of genes involved in carcinogenesis, photoaging, and production of genotoxic and oxidizing derivatives traveling at a distance. Smoke induced the expression of multiple genes in both skin and lung, which reflect adaptive responses and mechanisms related to cancer and, possibly, to emphysema and stroke. As shown in mice exposed to both light and smoke, the light tended to increase smoke-induced gene expression in lungs, while smoke tended to attenuate light-induced gene expression in skin. The oral administration of the nonsteroidal anti-inflammatory drug sulindac inhibited the light-induced overexpression of cyclooxygenase-2 and oxidative stress-related genes in skin, and down-regulated smoke-induced genes involved in oxidative stress, removal of damaged proteins, inflammation, and immune response in lung. These results provide a mechanistic insight explaining the systemic alterations induced by both light and smoke in mouse skin and lungs.

Animals↗
PubMed1997

Calibration of a portable tritium-in-air monitor for various radioactive gases.

A commercially available portable tritium-in-air monitor was calibrated for detecting the concentration of tritium-in-air, 14C-in-air, and various radioactive noble gases. Calibrations were performed both experimentally, using assayed quantities of the calibration gases, and theoretically, by simulating the monitor's response using Monte Carlo code. The experimental and theoretical calibrations agreed within +/- 10% for all gases tested with the exception of 41Ar-in-air where the agreement was approximately 20%. The results show that, although the monitor can be used to measure a wide range of radioactive gases, if more than one gas is present the monitor can not be used to accurately determine the concentration of, and hazard posed by, these gases. It is also shown that the monitor's ability to accurately assess tritium-in-air hazards would be seriously compromised by the presence of other radioactive gases.

Air Pollutants, Radioactive↗
PubMed1975

Photoreactivation of Pseudomonas cepacia after ultraviolet exposure: a potential source of contamination in ultraviolet-treated waters.

Cells of a naturally occurring strain of Pseudomonas cepacia grown in distilled water were exposed to ultraviolet radiation. Irradiated samples incubated on membrane filters or in fluid recovery media in the absence of light showed no evidence of dark repair mechanisms. When samples were exposed to fluorescent light ranging from 50 to 950 foot candles (538 to 10,222 lux) of illumination, apparent photo-induced repair of ultraviolet injury resulted in 1- to 4-log increases in viable cells recovered.

Light↗
PubMed2005

Comparison of a partial life-cycle bioassay in artificial streams to a standard beaker bioassay to assess effects of metal mine effluent on Chironomus tentans.

A novel, partial life-cycle bioassay using Chironomus tentans in artificial streams was developed for evaluating the effects of metal mine effluent. The utility of this bioassay was compared to an existing beaker life-cycle bioassay under laboratory conditions. Chironomus tentans larvae were exposed to 45% (v/v) treated metal mine effluent from day 11 through hatching of the second generation. Response patterns were consistent between the two bioassays for hatching success and time to emergence but inconsistent for other endpoints. Significant effects of effluent were obtained for growth, survival, number of adults emerged, and number of eggs per egg case in the artificial stream bioassay but not in the beaker bioassay. Conversely, significant effects on sex ratio and number of egg cases per female were observed in the beaker bioassay but not in the artificial stream bioassay. These differences are believed to be a consequence of the number of organisms per replicate used in each bioassay, which results in a difference in statistical power. As a result, higher coefficients of variation and effects sizes were observed in the beaker bioassay relative to the artificial stream bioassay for almost all endpoints. These results provide evidence that the bioassay in artificial streams can be an effective tool for evaluating the effects of metal mine effluent on life-cycle endpoints in C. tentans.

Animals↗
PubMed1983

[Current data of occupational asthma].

The problem of occupational asthma is in state of change as evidenced by the official reports: The official Journal of the 23 January 1982 contains important alterations in the lists of occupational asthma, changing some and creating others, as with table 66 in which numerous occupational allergies are listed. The authors discuss current diagnostic methods in which realistic provocation tests play an important part; current causes are considered and are duly allocated between natural animal or vegetable products or chemicals produced by industry. The authors strive to define which aetiologies are declining and which remain every day problems. Occupational asthma should be treated at source though the offending agent is not always apparent. The mechanism may be allergic, or often non allergic histamine-liberation or other pharmacodynamic mechanisms. Finally, the understanding of occupational asthmas throws light on the mechanism of asthma itself.

Adult↗
PubMed2003

[Urban particulate air pollution: from epidemiology to health impact in public health].

Major air pollution accidents which occurred in the 1950s led to public awareness of the health hazards involved. Since that period, levels of air pollution have decreased, but several studies conducted in North America and Europe indicate that particulate air pollution is linked to increased cardiorespiratory morbidity and mortality. Despite this evidence, several questions were raised concerning the interpretation of the results (threshold effect, harvesting effect and biological plausibility). The aim of this review is to present the link between epidemiological findings and their use in health impact assessment. We review the main causal criteria applied to epidemiology in light of scientific evidence currently available. Some causality criteria are more important than others, but they all support the causal nature of the relationship between air pollution and health, and thus justify the feasibility of health impact assessment calculations. Recent studies on relative risk assessment show that even if the risk linked to worsening air quality is low, public health consequences are high. Such information must be made accessible to policy makers and the population in general so that, together with the public health workers, they can all contribute to improving air quality and health in their communities.

Adolescent↗
PubMed1999

A theoretical basis for investigating ambient air pollution and children's respiratory health.

Acute respiratory health effects in children from exposure at current ambient levels of ozone are well documented; however, evidence for acute effects from other criteria pollutants such as nitrogen dioxide and respirable particles is inconsistent. Whether chronic effects result from long-term exposure to any of these pollutants during childhood is an important unresolved question. Establishing whether acute or chronic effects result from childhood exposure and identifying sensitive subgroups may require integration of biologic mechanisms of lung defenses, injury, and response into the study design and statistical models used in analyses. This review explores the theoretical basis for explaining such adverse effects in light of our contemporary understanding of mechanisms of lung injury and response at the cellular and molecular levels. The rapidly evolving understanding of the effects of air pollution on cellular and molecular levels presents an opportunity to develop and refine innovative biologically based hypotheses about the effects of childhood exposure. We hypothesize that children with low fruit and vegetable intake, low antioxidant levels, high polyunsaturated fat intake, or who have inherited certain alleles for genes involved in lung defenses and immune response regulation may be at increased risk for adverse effects. Because responses to air pollutants of interest are complex and involve a number of pathophysiologic processes, the magnitude of main effects of dietary factors, genes, and gene-environment interactions may be modest for individuals; however, each may make an important contribution to the population burden of preventable respiratory diseases.

Air Pollution↗
PubMed2026

Comparison of black carbon measurements using filter-specific reference transmittance to those using lab blanks or an average of unloaded filters.

Filter-based optical techniques compare light transmission intensities between loaded (I) and unloaded (I0) filters as a measure of light-absorbing mass for subsequent estimations of equivalent black carbon (eBC). We analyzed 5,379 15 mm Teflon filters from the Household Air Pollution Intervention Network (HAPIN) trial to assess the influence that different methods of I0 estimations have on eBC measures. We compared eBC measurements using filter-specific I0 values (Method 1) to those using three other methods of I0 estimation: the lab blank scan from a given session (Method 2), the average of all pre-sample filter scans (Method 3), and the average of all lab blank filter scans (Method 4). We assessed the agreement between Method 1 and the alternative methods using Bland-Altman analysis. We also assessed the relationship between Method 1 and the alternative methods across the complete measurement range and after stratifying exposure data into quartiles according to Method 1 eBC exposures. The mean (SD) personal eBC exposure for Method 1 was 7.8 μg/m3 (5.9), and exposures ranged from 1.3 to 46.8 μg/m3. Compared to Method 1, eBC using Methods 2, 3, and 4 were higher by 0.7 μg/m3, 0.1 μg/m3, and 0.7 μg/m3, respectively. The performances of linear regression models between Method 1 and all other methods were moderate to strong (R2 range: 0.42-0.93) in the second, third, and fourth quartiles; however, the models in the first quartile (eBC range: 1.3-2.9 μg/m3) performed poorly (R2 = 0.25-0.26), with error approximately 25% of the mean. Our findings suggest that, in most instances, conventional methods for obtaining I0 values can be used to sufficiently characterize eBC; however, analyzing filters before sampling adds appreciably to the accuracy of eBC estimations in lower concentration settings.Implications: Filter-based optical techniques compare light transmission intensities between loaded (I) and unloaded (I0) filters as a measure of light-absorbing mass for subsequent estimations of equivalent black carbon (eBC). To assess the influence that different methods of I0 estimations have on eBC measures, we analyzed 5,379 15 mm Teflon filters from the Household Air Pollution Intervention Network (HAPIN) trial. Our findings suggest that, in most instances, conventional methods for obtaining I0 values can be used to sufficiently characterize eBC; however, analyzing filters before sampling adds appreciably to the accuracy of eBC estimations in lower concentration settings.

Soot↗
PubMed2006

The case of Sarno River (Southern Italy): effects of geomorphology on the environmental impacts.

BACKGROUND, AIM AND SCOPE: Analysis of the morphological, geological and environmental characteristics of the Sarno River basin has shown the present degraded condition of the area. Over the past thirty years, the supply of untreated effluent of domestic, agricultural and industrial origin has ensured the presence of high concentrations of pollutants, including heavy metals. The geological context of the catchment area has played a major part in determining the current ecological conditions and public health problems: while human activity has modified the landscape, the natural order has indirectly contributed to increasing the environmental impact. RESULTS AND DISCUSSION: The health situation is precarious as the basin's inhabitants feed on agricultural and animal products, and use polluted water directly or indirectly. The hazard of contracting degenerative illnesses of the digestive or respiratory apparatus, bacterial infections or some neoplasia has gradually increased, especially in the last five years. Moreover, polluted basin waters flowing into the Bay of Naples increase sea water contamination, thereby damaging tourism, public health and degrading the local littoral quality. CONCLUSION: The overview presented shows how the environmental state of the Sarno River basin gives considerable cause for concern. The basin's complex geomorphologic setting has a direct bearing on local environmental and health conditions. The analysis of the available data demonstrates how the physical aspects of the area are closely linked to the diffusion and concentration of the pollutants, and how the latter ones have a large influence on the hygienic-sanitary conditions of the local population. RECOMMENDATION AND PERSPECTIVE: Specific interventions need to be undertaken to monitor and improve the chemical, physical and microbiological conditions of water and sediments, especially in light of the geomorphological vulnerability of the river basin.

Ecosystem↗
PubMed2004

Acute ex vivo effects of dimethylbenz[a]anthracene and heat shock on rat tail artery.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants that are known to increase oxidative stress, proteotoxicity, and cytotoxicity in many cell types, but the acute effects of PAHs on vascular contractility are not known. The 70-kDa heat shock protein (HSP70) is known to protect cells against proteotoxicity and cellular apoptosis. Thus, increased HSP70 may be hypothesized to prevent any negative effects of PAHs on vascular smooth muscle. Heat shock treatment is a method used to increase expression of HSPs. Therefore, the objective of this study was to examine the acute (<24-h) ex vivo effects of a PAH (dimethylbenz[a]anthracene; DMBA), heat shock, or a combination of the two treatments on arterial contractility. The results of the present study suggest that acute ex vivo exposure of rat tail arteries to DMBA caused a transient impairment (at 6 h but not 12 h) in contractile response to norepinephrine (NE), but not to depolarization with excess KCl. The DMBA-induced impairment in NE contraction was not explained by a change in 20-kDa myosin light chain (LC20) phosphorylation. Heat shock alone impaired excess KCl-induced contraction and LC20 phosphorylation. Moreover, heat treatment failed to mitigate the effects of DMBA, suggesting that cytotoxicity was not the mechanism of DMBA effect on NE-induced contractility. Therefore, both acute ex vivo PAH exposure and heat shock impaired contractility of isolated rat tail arteries in the current study but in independent, noninteracting manners.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1990

[Evaluation of the effects of various fluoride concentrations in drinking water and atmospheric air on permanent teeth eruption in children aged 12 years].

Dental age was evaluated in 382 children aged 12 +/- 6 years in four Silesian localities differing in the content of fluorine in drinking water and air: in Milicz--without fluoride, in Wroclaw where artificial Fluoridation of drinking water is conducted to levels regarded as optimal--from 0.8 to 1.2 mg/l, in Gryfów where the mean annual pollution of atmospheric air with fluorides was from 0.044 to 0.059 mg/m3 in Nysa where drinking water contains an excess of fluorides 4.0 to 7.0 mg/l. In the light of these studies fluoride was found to retard teeth age. The greater dose of fluorine is taken up by the organism in the period of development the longer is the retardation of dental age.

Air Pollutants↗
PubMed2005

[Eutrophication and pollution level of microcystin in Dianshan Lake].

A survey was conducted in Dianshan Lake to study the eutrophication indexes including total phosphorus (TP), total nitrogen (TN), pH, temperature, diaphaneity and chlorophyll-a level and dominant algae in seasons. The impacts of temperature, light, nitrogen and phosphorus on growth of and microcystin LR production by Microcystis aeraginosa strain under laboratory conditions were studied. Relationship between algal cell density and concentration of microcystin LR were studied. Results suggest that water in Dianshan Lake was eutrophicated. The suitable seasons for algae growth are the end of spring and summer. The annual average of TP and TN were 1.93 mg/L and 0.18 mg/L respectively. And 93.5 and 92.2 percent of TP and TN were higher than the criteria for the third class water body. Significant impact from agriculture was indicated since the peak of algae laged one month after the maxium use of fertilizer. The dominant algae in Dianshan Lake were cyanobacteria, bacillariophyta, cryptophyta and euglenophyta. Microcystis, anabaena and synedra, which excrete toxins and indicate water pollution, and are dominant algae species in summer. M. aeraginosa strain had a biggest growth rate at temperature of 25 degrees C and light intensity of 3 0001x, while microcystin LR production contents reached maximum at 20 degrees C and 5000lx respectively. The optimum TP and TN concentrations for growth of and toxin production by M. aeraginosa were found to be 650 micromol/L and 6.5 micromol/L respectively. TP is suspected to be the limiting factor for the growth of algae both in field and laboratory conditions. Positive correlations between total microcystin LR concentrations and algae cell density or M. aeraginosa cell densities are found. The algae cell density can be used to predict the level of algal toxins in water.

China↗
PubMed2000

Daily deaths are associated with combustion particles rather than SO(2) in Philadelphia.

OBJECTIVES: To assess whether the association between SO(2) and daily deaths in Philadelphia during the years 1974-88 is due to its correlation with airborne particles, and vice versa. METHODS: There is a significant variation in the relation between total suspended particulate (TSP) and SO(2) in Philadelphia by year and season. Firstly, 30 separate regressions were fitted for each pollutant in the warm and cold season of each year. These regressions controlled for weather, long term temporal patterns, and day of the week. Then a meta-regression was performed to find whether the effect of SO(2) was due to TSP, or vice versa. RESULTS: Controlling for TSP, there was no significant association between SO(2) and daily deaths. By contrast, in periods when TSP was less correlated with SO(2), its association with daily deaths was higher. However, all of the association between TSP and daily deaths was explained by its correlation with extinction coefficient, a measurement of the scattering of light by fine particles, which has been shown to be highly correlated with fine combustion particles in Philadelphia. CONCLUSIONS: The association between air pollution and daily deaths in Philadelphia is due to fine combustion particles, and not to SO(2).

Air Pollutants↗
PubMed2002

Agrochemical and nutrient impacts on estuaries and other aquatic systems.

This paper summarizes the "Agrochemical and Nutrient Impacts on Estuaries" symposium held at the 220th National Meeting of the American Chemical Society. The focus of the symposium was to highlight ongoing research efforts to understand estuarine function and pollutant fate in these important ecosystems. Expanding urbanization and agricultural activity can result in increased particulate and chemical loads, resulting in decreased light penetration and degraded aquatic habitats. Legislative and regulatory protections, such as the Clean Water Act and Total Maximum Daily Loads (TMDLs), are considered here. Measurement of nutrient and pesticide loads and their ecotoxicological impacts are explored, as well as potential mitigation practices. The complexity and high visibility of estuarine ecosystem health will require continued examination to develop more effective agricultural and land management strategies and sound science-based regulations.

Agrochemicals↗