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Purpose: This study aims to investigate the listening effort made by young children in real classrooms during a prolonged speech reception task in the presence of background noise. Method: The experiment was proposed to 117 typically developing kindergarten and primary school pupils, aged 5-7 years old. An ecological experimental approach was followed, and speech-in-noise tests were presented in the classrooms to groups made up of the whole class. The speech material of the Word Intelligibility by Picture Identification Test in the Italian language (Arslan, Genovese, Orzan, & Turrini, 1997) was presented in 2 listening conditions (quiet classroom [no noise added] and working classroom [with stationary noise]) and was repeated twice during the experiment. Data on the number of correctly recognized words and the single-task response time (RT) were collected; the quantity of the latter was considered informative on listening effort. Results: It was found that when background noise was present, the pupils' performance decreased, and greater RTs were required compared to the "quiet classroom" condition. When the RTs were analyzed over the course of the experiment, there were no changes in the quiet condition, whereas in the working classroom, a significant increase was found for the 6- and 7-year-old pupils. On the contrary, the youngest pupils (5-year-olds) showed a decrease in the RT results over the test repetitions. Conclusions: The RT measured with a single-task paradigm was found to be a viable approach for investigating the listening effort in 6- to 7-year-old pupils. For this age range, the metric was sensitive to changes both in the listening conditions and within the same listening condition across the time of exposure. More research is needed to assess the feasibility of the experimental paradigm with the 5-year-old children.

Author(s): Damiano Girardi[sup.1] , Alessandra Falco[sup.1] , Alessandro De Carlo[sup.2] , Paula Benevene[sup.2] , Manola Comar[sup.3] [sup.4] , Enrico Tongiorgi[sup.5] , Giovanni Battista Bartolucci[sup.6] Author Affiliations: (1) FISPPA Section of [...]

The purpose of the study is to evaluate the urinary levels of free 2,5-hexanedione (2,5-HD) in Italian subjects non-occupationally exposed to n-hexane, in order to define background values in non-occupational settings. The study was carried out on 99 subjects of the general population. The analysis of free 2,5-HD was performed by gas chromatography-mass spectrometry. Personal information about the subjects was ascertained by means of a self-administered questionnaire. The urinary levels of free 2,5-HD were in the range of <12.0–77.9 µg/L (5th–95th percentiles). The urinary excretion of the metabolite did not seem to be influenced by gender, age, smoking habit or area of residence. Statistically significant differences (p = 0.03) were found between the free 2,5-HD urinary levels according to the vehicular traffic intensity within the area of residence and to body mass index of subjects. The background levels of free 2,5-HD found in this study could contribute to the definition of reference values of general population non-occupationally exposed and could be useful to the toxicologists and industrial hygienists to determine whether workers have been exposed to higher levels of n-hexane than the general population. [ABSTRACT FROM AUTHOR]

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Aims: The goal of the present study was to establish the efficacy of the measles vaccine and the validity of the vaccination schedule adopted in Italy. Materials & methods: The following procedures are adopted: analyze the compliance to the vaccination schedule; assess the seroprevalence of measles antibodies according to the year of birth and the number of doses; and investigate the persistence of positive antibodies post-vaccination. We gathered and elaborated data of both vaccination history and seroprevalence against measles in a large population of students (4195) belonging to the Medical School of Padua University (Italy). Results: Our results reveal a requirement for a two-dose vaccination schedule to ensure protection from the disease. Nevertheless, these results clearly indicate that the percentage of seropositivity reached using the two-dose strategy is below the percentage (95%) that ensures optimal population immunity. Conclusion: It is uncertain whether immune coverage persists when circulating antibodies vanish, but two vaccine doses should prevent disease outbreaks. [ABSTRACT FROM AUTHOR]

ABSTRACT The present research investigates the occurrence of hyaline droplet (HD) accumulation related to age, dose and time after treatment in male Wistar rats given a single i.p. injection of hexachloro-1:3-butadiene (HCBD). In the study on age, rats from 1 to 12 months of age were treated with 100 mg kg−1 body weight (b.w.) HCBD dose. Rats treated at 2 months of age showed a greater accumulation of HD than the other age groups; HD accumulation was not observed in 1-month-old rats. In the dose-response study, the treatment with 25, 50 and 100 mg kg−1 b.w. at 2 months of age caused HD accumulation in the proximal convoluted tubule at all doses, with the 100 mg kg−1 b.w. group slightly more affected. Finally, in the time-course study, rats treated with a 100 mg kg−1 b.w. dose at 2 months of age and sacrificed at 6, 12, 24, 48, 72 and 96 h post-dosing showed a time-related HD accumulation in terms of incidence and severity, after 6 h, with a peak at 24 and 48 h and decreasing at 72 and 96 h. The present results show that HD accumulation is an early finding, and is unrelated to dose level and particularly evident in rats of 2 month of age. These findings in male rats treated with HCBD emphasize the importance of considering the age of rats at the start of a study. The more sensitive model was used in the detection of nephrotoxic effects of chemicals. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: The environmental and biological monitoring of benzene exposure is crucial to prevent the toxic effects of this solvent in workers. The degree of correlation, however, between the two and of different biomarkers among them varies, particularly at low levels of exposure, depending on various factors, including variability in metabolizing enzymes and smoking habits. To investigate these further, a cohort of 28 petrochemical workers (6 smokers and 22 non smokers) was monitored throughout ten consecutive days, on two occasions, two years apart, by collecting in total 173 environmental and biological samples. The airborne benzene levels, the urinary t,t-muconic acid (t,t-MA) and S-phenylmercapturic acid (S-PMA) concentrations, and the glutathione S-transferases (GST) M1 and T1 genotypes were measured. S-PMA was the only metabolite statistically correlated with airborne benzene levels (r =0.447, P <0.0001), particularly in non smokers (r =0.667, P <0.0001), the smoking habit being the only variable influencing metabolite excretion. Finally, a reduced S-PMA excretion was found to be associated with the GSTT1, but not the GSTM1, null genotype. In conclusion, the results show that S-PMA, but not t,t-MA, is able to monitor exposure to low benzene concentrations and confirm that the GSTT1 null genotype has a significant influence on metabolite excretion. The influence of the GSTT1 null genotype, however, was low, even when studying each subject with several urine samples. [Copyright &y& Elsevier]

In order to ascertain whether the urinary excretion of D-glucaric acid (DGA) might be a suitable biomarker of effect in monitoring workers exposed to anaesthetic gases, we measured DGA before and after an operating session (and, in some workers, before and after a 2-week vacation) in 229 workers of surgical units and in 229 controls. In the former, we also measured urinary levels of nitrous oxide (N[sub 2]O) and isofiurane after at least 4 h of exposure. For all subjects, information on age, smoking habits, daily intake of alcohol, coffee, and drugs, history of liver or kidney disease was collected. Study subjects were ranked according to: exposure (class 0: subjects not exposed; class 1: N[sub 2]O < 27 μg l[sup -1] and isofiurane < 1 μg l-1; class 2: N[sub 2]O < 27 μg l[sup -1] and isofiurane > 1 μg l[sup -1]; class 3: N[sub 2]O > 27 μg l-1and isofiurane < 1 μg l-1; class 4: N[sub 2]O > 27 μg l[sup -1] and isofiurane > 1 μg l[sup -1]); general habits; and DGA (two groups, below and above the arbitrary cut-off value of 3.5 mmol mol[sup -1] creatinine). The relative risk of presenting high DGA excretion was estimated through the Odds Ratio (OR) and 95% Confidence Intervals (CI). In univariate analysis, ORs increased from class 1 (lowest exposure) to class 4 (highest exposure) and with increases in coffee and cigarette consumption. The ORs adjusted for sex, age, creatinine, and alcohol and coffee intake, conventionally 1.0 in the control group, were 0.68 (CI = 0.33-1.38), 2.68 (CI= 1.36-5.27), 2.68 (CI = 1.21-4.90) and 3.73 (CI = 1.51-9.18) respectively in exposure classes 1, 2, 3 and 4. By contrast, individual levels of DGA did not correlate with urinary concentrations of anaesthetic gases. Moreover, no significant differences in DGA levels were observed between urine samples taken before and immediately after a workshift, nor between samples collected before and after at least 2 weeks vacation. In conclusion, DGA excretion cannot be used as an individual biomarker of effect in workers exposed to anaesthetic gases. Since effects on hepatic function were not found at lower concentrations (exposure class 1), the currently adopted threshold limits (isofiurane: 1 μg l[sup -1]; and N[sub 2]O: 27 μg l-1) appear sufficiently protective. [ABSTRACT FROM AUTHOR]

Objective: Spot urine samples were investigated to determine correlations between urinary creatinine and specific gravity, and intra- and inter-day variations other than gender- and age-dependence of urinary concentrations. Methods: Urinary creatinine concentrations and specific gravity were determined in 534 spot samples (385 from men and 149 from women). Subjects' ages ranged between 18 and 68 years. Spot urine samples were also collected from 14 male subjects before and after a 1-week work-shift for the evaluation of intra- and inter-day variations of creatinine and specific gravity. Results: In spot samples, creatinine concentrations ranged between 0.16 and 4.36 g/l and specific gravity between 1.002 and 1.037. A high correlation (r=0.82, P < 0.001) was observed between creatinine and specific gravity; male subjects showed significantly higher values of creatinine (P < 0.001) than did female subjects (1.90 ± 0.74 and 1.41 ± 0.72 g/l, respectively) and specific gravity (1.023 ± 0.006 and 1.020 ± 0.007, respectively). In addition, creatinine but not specific gravity significantly decreased (P < 0.02) in subjects older than 50 years, compared with those under 40. Conclusions: Results confirm the gender-dependence of creatinine concentrations in spot specimens and also show age-dependence, indicating the need for these aspects to be considered when the range of acceptable samples is to be set. No significant intra- or inter-day variations were observed for the two parameters. Lastly, the possibility of a comparison of differently adjusted values was indicated by a conversion formula derived from adjustments to creatinine and the corresponding specific gravity of a hypothetical urinary value, as follows: specific gravity adjusted values= 1.48 × creatinine adjusted values. [ABSTRACT FROM AUTHOR]

Blood and urine perchloroethylene and urine trichloroacetic acid, as markers of exposure, and serum AST, ALT, GGT and creatinine, urine total solutes and proteins, angiotensin converting enzyme, N-acetyl-ß-D-glucosaminidase and glutamine synthetase, as markers of effect, were measured in 40 dry-cleaning and 45 ironing-shop female workers. Average perchloroethylene air level in the dry-cleaning shops was 59.7 mg m[sup -3], i.e. three-fold lower than the current A.C.G.I.H. TLV-TWA (170 mg [sup m-3]). No statistically significant difference in the mean values of any of the effect markers was observed between the two groups, except for AST which was significantly higher in drycleaners. In addition, a statistically significant correlation was observed in dry-cleaners between environmental perchloroethylene and total urinary solutes (r = 0.308, p < 0.05) or urine glutamine synthetase (r= 0.469, p < 0 .01), between glutamine synthetase and blood perchloroethylene in post-shift (r= 0.406, p < 0.01) or urinary perchloroethylene in post(r= 0.571, p < 0.001) or pre-shift (r= 0.586, p < 0.001), and between urinary perchloroethylene in pre-shift and GGT (r= 0.407, p < 0.05). Interestingly, some statistically significant correlations between exposure and effect indices were found in ironing-shop workers alone, as in all subjects. Finally, transaminases, GGT and total urinary proteins were influenced by age and alcohol consumption which were significantly higher in dry-cleaners, thus providing an explanation for some of the correlations observed. In conclusion, our results show a dose-related increase of glutamine synthetase activity,a marker of damage of the pars recta of the kidney proximal tubule, in the urine of female subjects exposed to perchloroethylene concentrations in the work environment lower than current A.C.G.I.H. TLV-TWA. [ABSTRACT FROM AUTHOR]

Abstract: This study was aimed to identify useful biomarkers of exposure and effect in workers exposed to low levels of benzene, and to evaluate any correlations existing between these parameters. Benzene exposure was measured in 33 petrochemical industry operators (PIO), 28 service station attendants (SSA), 21 gasoline pump maintenance workers (GPMW) and 51 non-exposed controls by GC-FID analysis. Samples were collected with personal passive samplers (Radiello®). End-shift urine samples were collected for t,t-muconic acid (t,t-MA) determination by HPLC and for S-phenylmercapturic acid (S-PMA) measurement by HPLC–MS/MS. The alkaline version of the comet assay and, in a subgroup of 19 SSA and 16 control subjects, chromosomal aberrations (CA) and glutathione (GSH) levels were measured in peripheral blood lymphocytes. Personal benzene exposure was significantly higher in PIO, SSA and GPMW as compared to controls. The urinary excretion of the two metabolites showed a significant increase in SSA (p =0.0258 and p =0.0001, for t,t-MA and S-PMA, respectively) and in PIO (p =0.0013 and p =0.0001, for t,t-MA and S-PMA, respectively) as compared with the control group, while no such increase was observed for GPMW, for whom occupational exposure was not continuous and occurred on specific working days only. Significant increases of DNA damage were found by the comet assay for tail moment (TM) and tail length (TL) in SSA (p <0.0001 and p =0.008, for TM and TL, respectively) and PIO (p <0.0001 and p <0.0001, for TM and TL, respectively) when compared with controls. The PIO group also displayed a significant increase in the number of cells with comet (p <0.0001). Smoking habits did not appear to interfere with these results in any of the groups. No difference was found in percentage of CA between exposed workers and controls. Significant correlations were found, in all groups, between benzene exposure and the more representative comet parameter TM (r =0.509, p =0.007; r =0.525, p =0.017 and r =0.420, p =0.046 in SSA, GPMW, and PIO, respectively). A trend of negative correlation was observed between DNA damage and either GSH or urine S-PMA for exposed workers. In summary, in present study urinary S-PMA and DNA damage by the comet assay were both sensitive to exposure to low levels of benzene, and GSH seems to play an important defence role against benzene-dependent DNA damage. [Copyright &y& Elsevier]

Highlights • SPMA was confirmed as the best biomarker of benzene, even at very low levels of exposure. • Cigarette smoking was confirmed as an important confounding factor for the benzene biomarkers. • The GSTT1 but not GSTM1 genotype significantly modulates the urinary levels of SPMA. • Toluene exposure, even at low concentrations, inhibits benzene metabolism to SPMA. Abstract The aim of the study was to investigate the effect of various factors that modulate the metabolism of benzene, including smoking habits, metabolic genotype of GST and co-exposure to toluene, on the levels of three biomarkers, i.e. urinary benzene (UB), S-phenylmercapturic acid (SPMA) and t,t -muconic acid (t,t -MA), in 146 refinery workers exposed to low levels of air benzene (AB) in the range <1.5–529.2 μg/m3 (mean value 32.6 μg/m3). The study confirmed the validity of SPMA as a good biomarker of benzene exposure even at low levels of exposure. It was also confirmed that cigarette smoking is the main confounding factor when assessing biological monitoring data of occupational exposure to AB. Our data indicate that the GSTT1, but not the GSTM1 genotype, significantly increases the urinary levels of SPMA, even at low levels of exposure. It is not known, though, whether subjects with a GSTT1 "null" genotype may be more susceptible to the effects of benzene. Finally, environmental toluene appears to inhibit the metabolism of benzene to SPMA even at low concentrations, also resulting in an underestimation by SPMA levels of the actual exposure of workers to benzene. [ABSTRACT FROM AUTHOR]

This study aimed to correlate environmental sevoflurane levels with urinary concentrations of sevoflurane (Sev-U) or its metabolite hexafluoroisopropanol (HFIP) in order to assess and discuss the main issues relating to which biomarker of sevoflurane exposure is best, and possibly suggest the corresponding biological equivalent exposure limit values. Individual sevoflurane exposure was measured in 100 healthcare operators at five hospitals in north-east Italy using the passive air sampling device Radiello ® , and assaying Sev-U and HFIP concentrations in their urine collected at the end of the operating room session. All analyses were performed by gas chromatography-mass spectrometry. Environmental sevoflurane levels in the operating rooms were also monitored continuously using an infrared photoacoustic analyzer. Our results showed very low individual sevoflurane exposure levels, generally below 0.5 ppm (mean 0.116 ppm; range 0.007–0.940 ppm). Sev-U and HFIP concentrations were in the range of 0.1–17.28 μg/L and 5–550 μg/L, respectively. Both biomarkers showed a statistically significant correlation with the environmental exposure levels (Sev-U, r = 0.49; HFIP, r = 0.52), albeit showing fairly scattered values. Sev-U values seem to be influenced by peaks of exposure, especially at the end of the operating-room session, whereas HFIP levels by exposure on the previous day, the data being consistent with the biomarkers’ very different half-lives (2.8 and 19 h, respectively). According to our results, both Sev-U and HFIP are appropriate biomarkers for assessing sevoflurane exposure at low levels, although with some differences in times/patterns of exposure. More work is needed to identify the best biomarker of sevoflurane exposure and the corresponding biological equivalent exposure limit values. [ABSTRACT FROM AUTHOR]

Abstract: The need to evaluate personal exposure to aerosol instead of simply measuring outdoor concentrations is now evident. In this connection, Personal Cascade Impactor Samplers (PCIS) and Optical Particle Counters (OPC) are likely to be widely deployed in the near future because their characteristic light weight and low cost make them suitable for the purpose by minimizing interferences in human activities. The study here presented assesses the performances of the two aforementioned instruments by making a comparison with CEN-EU standardized procedures in 24h concurrent measurements of urban PM10, PM2.5 and PM1. The comparison between PM concentrations measured by OPC and CEN-UE standard procedure showed an unsatisfactory agreement: systematic differences, dependent on PM concentration, were evidenced with an underestimation of PM by OPC in the days with low concentrations and an overestimation at higher levels of PM concentration. On the contrary, PCIS can be considered statistically equivalent to CEN-EU standard methods for the determination of PM10, PM2.5 and PM1 with 95% confidence level except that systematic errors in the determination of water soluble inorganic ions (ion chromatography) and some relevant metals (ICP-MS) were evidenced, which could be mainly attributed to a different size cut-off and particle bouncing-off phenomena inside the multi-stage sampler. However, the seasonal mean concentrations of those species measured with PCIS and CEN-EU standard methods were substantially comparables. Thus, PCIS can be considered reliable in studies of PM characterization focused on personal exposure and effects of urban aerosol. [Copyright &y& Elsevier]

Abstract: CYP2E1, an inducible enzyme present in different human tissues, metabolizes several potentially toxic substances including many volatile organic compounds (VOCs). One indirect way to monitor exposure to VOCs may be, therefore, the assessment of CYP2E1 activity in vivo using the chlorzoxazone (CHZ) test. Goal: To compare CYP2E1 activity in two groups of workers: one with a known occupational exposure to VOCs (exposed group) and the other employed in administrative tasks at two universities (control group) from the city of León, Guanajuato, México. Material and methods: (1) Passive diffusion monitors were used to evaluate individual levels of exposure to toluene, benzene and ethylbenzene in 48 persons (24 tannery workers and 24 administrative controls) during a 8h work shift; (2) after 12h fasting 500mg CHZ, a selective probe for assessing CYP2E1 activity, was orally administered and, after 2h, a venous blood sample was collected for HPLC plasmatic quantitative determination of CHZ and its mean metabolite 6-hydroxychlorzoxazone. Results: Toluene mean exposure levels were higher in the exposed group (2.86±2ppm vs. 0.05±0.005ppm; p <0.001). Also, in this group CYP2E1 activity was lower (p <0.05) and it decreased as the accumulated months of labor exposure increased (negative correlation, p <0.05). These results are in line with previous findings obtained from shoemakers exposed to various solvents but, interestingly, they are partly in contrast with those of another study in printers. Conclusion: In spite of the relatively low levels of toluene exposure found for tannery workers, an effect on CYP2E1 activity was evident. Although the mechanism of this interaction is still unknown, the decrease in CYP2E1 activity per se might represent a health risk, considering that these workers may be less protected against other CYP2E1 substrates present in the labor setting or derived from an intentional exposure. [Copyright &y& Elsevier]

Abstract: Personal exposure to PM10 measured in different seasons in a sample of asthmatic subjects living in Padova (Northern Italy) was compared with simultaneously measured outdoor PM10 concentrations. The specific contribution of ambient PM10 and other factors to individual exposure was evaluated in one of the areas of Europe with the worst air pollution. Thirty-one asthmatic subjects (21 non-smokers and 10 smokers) carried personal PM10 monitors for six 24-hr sessions, in different seasons of the year. Concomitant daily 24-hr ambient PM10 concentrations were measured by air quality monitoring networks. A multivariate analysis was performed to identify factors explaining personal exposure to PM10, using a random effect model. The analysis on the 31 subjects referred to a total of 155 observations. The mean personal PM10 exposure was higher (range 79.3–126.1μg/m3) than the outdoor concentrations (range 37.3–85.4μg/m3) in all seasons; and personal exposures varied less than outdoor PM10 levels from one season to another. Smokers had significantly higher personal PM10 concentrations than non-smokers (127.99 vs 78.8μg/m3; T=−5.70; p<0.001). Moderate correlations emerged between outdoor and personal PM10 concentrations. The correlation improved after excluding subjects exposed to active or passive smoking (median Pearson''s R 0.41 vs 0.26). Considering all the subjects, smoking was the main factor affecting personal exposure, contributing to 41% of the variability. Outdoor PM10 concentrations (25%), temperature (12%) and season (15%) also contributed to personal PM10 exposure. Outdoor PM10 (46%), temperature (20%), season (19%) and time spent indoors (6%) were significantly associated with personal exposure in non-smokers. We concluded that it is crucial to perform personal monitoring and to evaluate the complexity of factors that contribute to individual PM exposure. While tobacco smoke was the primary source of PM10 in all subjects, the contribution of ambient components was particularly relevant for the personal exposure levels of our non-smokers living in a highly-polluted environment. [Copyright &y& Elsevier]

Abstract: Occupational exposure to styrene was studied in 34 workers employed in the production of fiberglass-reinforced plastic sheets and compared to 29 unexposed healthy controls. We evaluated genotoxic effects induced by occupational styrene exposure in lymphocytes by alkaline version of the comet assay to detect single-strand breaks (SSBs), DNA oxidation products (formamido pyrimidine glycosilase (Fpg)- and endonuclease (Endo III)-sensitive sites) and DNA repair kinetics studies, as well as the neutral version of comet assay for DNA double-strand breaks (DSBs). An innovative aspect of this study was the use of immuno-comet assay, a new technique that recognizes DSBs with specific antibody by DAPI/FITC method. The battery of parameters included markers of external and internal exposure. Exposed workers showed significant high levels of SSBs (p < 0.0001) and DSBs (p < 0.0001) in neutral- and immuno-comet assay. A drastic decrease in DNA repair activity as compared to controls was observed (180min vs. 35min). Styrene workplace concentration significantly correlated with alkaline comet parameters (TM, p =0.013; TI, p =0.008), in negative with TL (p =0.022), and with DNA-base oxidation (TM Endo III, p =0.048 and TI Endo III, p =0.028). There was a significant negative correlation between urinary metabolites (MA+PGA) and TM Endo III (p =0.032) and TI Endo III (p =0.017). [Copyright &y& Elsevier]

Abstract: The aim of this study was to assess gasoline filling-station attendants’ exposure to benzene and to determine which biological exposure index (BEI), trans,trans-muconic acid (t,t-MA) or S-phenylmercapturic acid (S-PMA), shows better correlation with environmental exposure. Exposure to benzene was measured using passive samplers (Radiello) attached to the collar of the overalls of subjects (n =33) just before the work-shift (approximately 8h); analysis was performed by GC-FID. S-PMA and t,t-MA were determined, respectively, by an immunochemiluminescent assay based on specific monoclonal antibodies and by HPLC–UV at 264nm. Both methods of biological monitoring were performed on beginning and end-shift urine samples, and expected t,t-MA and S-PMA values were calculated. Smoking habits and life-style were ascertained by means of a questionnaire. Both environmental and biological monitoring data showed that benzene exposure for gasoline filling-station attendants was low when compared with the respective ACGIH limit values (means—benzene: 0.044mg/m3; t,t-MA: 171μg/g creatinine; S-PMA: 2.7μg/g creatinine). No significant correlation was found between exposure to benzene and t,t-MA or S-PMA excretion data. The use of expected values was also experimented for S-PMA and t,t-MA. This consists of calculating, on the basis of the known half-life of the benzene metabolite, the concentration of that metabolite that a worker should present at the end of the work-shift, the difference between this value and the value actually found is a measure of benzene exposure during work. The use of expected values in biological monitoring did not improve correlations. At these low benzene levels, environmental monitoring seems to be the best method of evaluating individual exposure. However, biological monitoring remains useful, as a mean of assessing group exposure. [Copyright &y& Elsevier]