Is urinary 1-hydroxypyrene a valid biomarker for exposure to air pollution in outdoor workers? A meta-analysis.

The aim of this study was to evaluate the usefulness and specificity of urinary 1-hydroxypyrene (1-OHPu) as a biomarker of the exposure from urban pollution to polycyclic aromatic hydrocarbons (PAHs) among outdoor workers in a meta-analysis. Our meta-analysis was performed according to standard methods, and the results show that the concentrations of 1-OHPu tend to be higher in exposed workers than in unexposed workers (if we exclude two highly heterogeneous articles), in exposed non-smokers than in unexposed non-smokers and in exposed than in unexposed workers who were carriers of the CYP1A1 genotype and in those with the glutathione-S-transferase M1 (-)genotype. These genotypes enhance the effect of exposure, particularly in non-smokers. Smoking reduces the differences between exposed and unexposed subjects. In conclusion, our results suggest that the use of the 1-OHPu biomarker appears to be reliable for studying occupational exposure to PAHs from urban pollution, as long as environmental and behavioural factors are considered.

Exposure to arsenic in urban and rural areas and effects on thyroid hormones.

CONTEXT: Arsenic is a ubiquitous element present in urban air as a pollutant, and it may interfere with thyroid hormones. OBJECTIVE: To evaluate the association between the personal exposure to arsenic and levels of TSH, fT4, fT3, and Tg in urban and rural workers. MATERIALS AND METHODS: Total urinary arsenic and thyroid markers were obtained from 108 non-smoking traffic policemen and 77 subjects working as roadmen in a rural area. Fifty subjects were monitored to evaluate airborne exposure to arsenic. RESULTS: The mean value of exposure to arsenic was 2.9 µg/m(3) in traffic policemen, while the mean value was less than 0.1 µg/m(3) in roadmen. The mean values of urinary arsenic (10.4 µg/g creatinine vs. 5.2 µg/g creatinine; p = 0.000), TSH (1.6 µlU/ml vs. 1.3 µlU/ml; p = 0.006), fT3 (3.5 pg/ml vs. 3.7 pg/ml; p = 0.000), fT4 (1.2 ng/dl vs. 1.3 ng/dl; p = 0.000) and Tg (42.8 ng/ml vs. 36.1 ng/ml; p = 0.04) were significantly different between traffic policemen and roadmen. In traffic policemen, urinary arsenic and arsenic in the air were correlated to the airborne arsenic and TSH values, respectively. Urinary arsenic was correlated to TSH, Tg, fT3, and fT4 values. The multiple linear regression models showed the following associations: i) among urinary arsenic, arsenic in the air and job title; ii) among TSH, fT3, Tg and urinary arsenic; and iii) between fT4 and both urinary arsenic and alcohol intake. CONCLUSION: These results provide information about the relationship between exposure to arsenic and thyroid markers and may be useful for other categories of outdoor workers who are similarly exposed.

Urban pollution.

Air pollution represents a health risk for people living in urban environment. Urban air consists in a complex mixture of chemicals and carcinogens and its effects on health can be summarized in acute respiratory effects, neoplastic nonneoplastic (e.g. chronic bronchitis) chronic respiratory effects, and effects on other organs and systems. Air pollution may be defined according to origin of the phenomena that determine it: natural causes (natural fumes, decomposition, volcanic ash) or anthropogenic causes which are the result of human activities (industrial and civil emissions). Transport is the sector that more than others contributes to the deterioration of air quality in cities. In this context, in recent years, governments of the territory were asked to advance policies aimed at solving problems related to pollution. In consideration of the many effects on health caused by pollution it becomes necessary to know the risks from exposure to various environmental pollutants and to limit and control their effects. Many are the categories of "outdoor" workers, who daily serve the in urban environment: police, drivers, newsagents, etc.

Assessment of occupational exposure to benzene, toluene and xylenes in urban and rural female workers.

OBJECTIVES: This is the first research study to compare among female, non-smoker workers: (a) the exposure to benzene, toluene and xylenes (BTXs) in urban air during work in the street (traffic policewomen, TP) vs. work in vehicles (police drivers, PD); (b) the exposure to BTXs in urban environments (in street and in car) vs. rural environments (roadwomen, RW); (c) the values of blood benzene, urinary trans, trans muconic acid (t,t-MA) and urinary S-phenylmercapturic acid (S-PMA) in urban areas (in street and in car) vs. rural areas. METHODS: Passive personal samplings and data acquired using fixed monitoring stations located in different areas of the city were used to measure environmental and occupational exposure to BTXs during the work shift in 48 TP, 21 PD and 22 RW. In the same study subjects, blood benzene, t,t-MA and S-PMA were measured at the end of each work shift. RESULTS: Personal exposure of urban workers to benzene seemed to be higher than the exposure measured by the fixed monitoring stations. Personal exposure to benzene and toluene was (a) similar among TP and PD and (b) higher among urban workers compared to rural workers. Personal exposure to xylenes was (a) higher in TP than in PD and (b) higher among urban workers compared to rural workers. Blood benzene, t,t-MA and S-PMA levels were similar among TP and PD, although the blood benzene level was significantly higher in urban workers compared to rural workers. In urban workers, airborne benzene and blood benzene levels were significantly correlated. CONCLUSIONS: Benzene is a human carcinogen, and BTXs are potential reproductive toxins at low dose exposures. Biological and environmental monitoring to assess exposure to BTXs represents a preliminary and necessary tool for the implementation of preventive measures for female subjects working in outdoor environments.

Long-distance energy transfer photosensitizers arising in hybrid nanoparticles leading to fluorescence emission and singlet oxygen luminescence quenching.

This paper presents energy transfer occurring in small organically modified core-shell nanoparticles (core lanthanide oxide, shell polysiloxane) (diameter < 10 nm) conjugated with photosensitizers designed for photodynamic therapy applications. These nanoparticles covalently encapsulate a photosensitizing PDT drug in different concentrations. Stable dispersions of the nanoparticles were prepared and the photophysical properties of the photosensitizers were studied and compared to those of the photosensitizers in solution. Increasing the photosensitizer concentration in the nanoparticles was not found to cause any changes in the absorption properties while fluorescence and singlet oxygen quantum yields decreased. As a possible explanation, we have suggested that both long distance energy transfer such as FRET and self-quenching could occur into the nanoparticles. A simple "trend" model of this kind of energy transfer complies with results of experiments on steady state fluorescence and singlet oxygen luminescence.