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We evaluated the reliability of 8-hydroxy-2'-deoxyguanosine (8-OHdG), and determined its ability to predict functional outcomes in stroke survivors. The rehabilitation effect on 8-OHdG and functional outcomes were also assessed. Sixty-one stroke patients received a 4-week rehabilitation. Urinary 8-OHdG levels were determined by liquid chromatography-tandem mass spectrometry. The test-retest reliability of 8-OHdG was good (interclass correlation coefficient = 0.76). Upper-limb motor function and muscle power determined by the Fugl-Meyer Assessment (FMA) and Medical Research Council (MRC) scales before rehabilitation showed significant negative correlation with 8-OHdG (r = -0.38, r = -0.30; p < 0.05). After rehabilitation, we found a fair and significant correlation between 8-OHdG and FMA (r = -0.34) and 8-OHdG and pain (r = 0.26, p < 0.05). Baseline 8-OHdG was significantly correlated with post-treatment FMA, MRC, and pain scores (r = -0.34, -0.31, and 0.25; p < 0.05), indicating its ability to predict functional outcomes. 8-OHdG levels were significantly decreased, and functional outcomes were improved after rehabilitation. The exploratory study findings conclude that 8-OHdG is a reliable and promising biomarker of oxidative stress and could be a valid predictor of functional outcomes in patients. Monitoring of behavioral indicators along with biomarkers may have crucial benefits in translational stroke research. [ABSTRACT FROM AUTHOR]

A point source for environmental pollution may be identified by the spatial association of samples collected in the vicinity of the emission source. In this study, we used a simple permutation test to explore the spatial correlations between the ambient air and soil polychlorinated dibenzo- p-dioxin/dibenzofuran (PCDD/F) congener profile concentrations and their distances to a municipal solid waste incinerator (MSWI) in northern Taiwan. Kendall's τ was applied for the correlation between the PCDD/F concentrations of a total of 9 airborne and 12 soil sampling sites and their distances to the incinerator. The results showed that the correlation was highly negatively associated for soil PCDD/Fs (τ = −0.515, p-value = 0.011) and was marginal for airborne PCDD/Fs (τ = −0.667, p-value = 0.055), conditional on the seasonal wind attributions. For the 17 individual congener profiles, most of the air and soil samples had a negative association, with 7 and 10 reaching statistical significance ( p-value < 0.05) or borderline significance ( p-value < 0.10), respectively. The permutation test provides a simple and robust statistical method for the identification of a potential pollution source from a limited sample size. Our analytical results show that dioxin emissions from the investigated MSWI had a definite environmental impact on the surrounding area. [ABSTRACT FROM AUTHOR]

Background and Objectives. Robot-assisted therapy (RT) is a current promising intervention in stroke rehabilitation, but more research is warranted for examining its efficacy and the dose–benefit relation. The authors investigated the effects of higher intensity versus lower intensity RT on movements of forearm pronation–supination and wrist flexion–extension relative to conventional rehabilitation (CR) in patients poststroke for a mean of 21 months. Methods. In this pilot study, 18 patients with initial mean Fugl-Meyer Assessment (FMA) of 37 to 44 for the upper extremity were randomized to higher intensity RT, lower intensity RT, or CR intervention for 4 weeks. The dose of the higher intensity RT was twice the number of repetitions in the lower intensity RT. Outcome measures at pretreatment and posttreatment were administered to patients to evaluate beneficial and adverse effects of interventions. Primary outcomes were the FMA and Medical Research Council scale. Results. There were significant differences in motor function (P = .04) and daily performance (P = .03) among the 3 groups. The higher intensity RT group showed better improvement in motor function, muscle strength, performance of daily activities, and bimanual ability than the other 2 groups. The intensive RT intervention did not induce higher levels of an oxidative DNA biomarker. Conclusions. Higher intensity of RT that assists forearm and wrist movements may lead to greater improvement in motor ability and functional performance in stroke patients. A sample size of only 20 to 25 in each arm of a larger randomized controlled trial is needed to confirm the findings for similar subjects. [ABSTRACT FROM PUBLISHER]

Objective: We conducted a repeated-measurement study to (1) investigate the correlation between occupational exposure to airborne acrylamide (AA) and the time-dependent behavior of urinary AAMA, GAMA2, and GAMA3 and (2) calculate the estimated biological exposure index at the permissible exposure limit (PEL) level of 30 μg/m. Methods: Forty-four workers were recruited-8 were AA-exposed and 36 were controls. Pre- and post-shift urine samples were collected from the exposed group in parallel with personal sampling for 8 consecutive days and only 1 day for the control group and analyzed using liquid chromatography-electrospray ionization/tandem mass spectrometry (LC-ESI-MS/MS). Results: Post-shift urinary AAMA level was significantly associated with personal AA exposure ( p < 0.001), indicating that urinary AAMA was a better AA exposure biomarker. The estimated urinary excretion of AAMA was 3.0 mg/g creatinine for nonsmoking workers exposed to the PEL of 30 μg/m. The median GAMA (the sum of GAMA2 and GAMA3)/AAMA ratio for exposed workers was 0.03 (range, 0.005-0.14), relatively lower than that of the nonoccupational group. Conclusions: Although sample size in this study was small, the repeated-measurement data provide useful reference for future studies related to biological monitoring of occupational exposure to AA. [ABSTRACT FROM AUTHOR]

Introduction: Maternal environmental tobacco smoke (ETS) has been identified as a key risk factor for problem behavior in children, but the role of genetic susceptibility is not clear. The purpose of this study was to examine the metabolic genetic modification effect of exposure to ETS in nonsmoking mothers on child behavior at 2 years of age. Methods: A prospective cohort study was conducted among 191 mothers who gave births between 2004 and 2005 and their infants in Taiwan. The mothers completed a questionnaire before delivery in which they provided information on exposure to ETS during pregnancy. Four metabolic genes, CYP1A1 MspI, CYP1A1 Ile462Val, GSTT1, and GSTM1 were isolated from both maternal and infant DNA samples. Children’s behavior problems at 2 years of age were reported by their mothers using the Child Behavior Checklist/1.5–5. Multiple linear models were used to estimate the effects of ETS and genotype on child behavior. Results: Maternal ETS exposure was associated with the anxious score. The ETS-exposed group with both the CYP1A1 MspI and the CYP1A1 Ile462Val variants had higher scores, as reflected in total CBCL score as well as scores on the internalizing scale and its emotional subdomain, the anxious scale, and the externalizing scale and its aggressive subdomain. Conclusions: Child behavioral problems may be associated with prenatal ETS exposure, and this effect may be modified by infant CYP1A1 MspI and CYP1A1 Ile462Val genes. [ABSTRACT FROM PUBLISHER]

Objectives: To develop a highly sensitive analytical method for very low acrylamide (AA) exposure and to conduct an occupational exposure assessment by the developed method. [ABSTRACT FROM PUBLISHER]

Physiologically based toxicokinetic (PBTK) modeling has been well established to study the distributions of chemicals in target tissues. In addition, the hierarchical Bayesian statistical approach using Markov Chain Monte Carlo (MCMC) simulations has been applied successfully for parameter estimation. The aim was to estimate the constant inhalation exposure concentration (assumed) using a PBTK model based on repeated measurements in venous blood, so that exposures could be estimated. By treating the constant exterior exposure as an unknown parameter of a four-compartment PBTK model, we applied MCMC simulations to estimate the exposure based on a hierarchical Bayesian approach. The dataset on 16 volunteers exposed to 100 ppm (≅0.538 mg/L) trichloroethylene vapors for 4 h was reanalyzed as an illustration. Cases of time-dependent exposures with a constant mean were also studied via 100 simulated datasets. The posterior geometric mean of 0.571, with narrow 95% posterior confidence interval (CI) (0.506, 0.645), estimated the true trichloroethylene inhalation concentration (0.538 mg/L) with very high precision. Also, the proposed method estimated the overall constant mean of the simulated time-dependent exposure scenarios well with slightly wider 95% CIs. The proposed method justifies the accuracy of exposure estimation from biomonitoring data using PBTK model and MCMC simulations from a real dataset and simulation studies numerically, which provides a starting point for future applications in occupational exposure assessment. [ABSTRACT FROM AUTHOR]

Background: Cigarette smoking cannot fully explain the epidemiologic characteristics of chronic obstructive pulmonary disease (COPD) in women, particularly for those who rarely smoke, but COPD risk is not less than men. The aim of our study is to investigate the relationship between second-hand smoke (SHS) exposure and chronic bronchitis in Taiwanese women.Methods: We used Taiwan's National Health Insurance Bureau claims data in 1999, and cross-checked using criteria set by the American Thoracic Society; there were 33 women with chronic bronchitis, 182 with probable chronic bronchitis, and 205 with no chronic bronchitis during our interview time between 2000 and 2005. We measured second-hand smoke (SHS) exposure by self-reported measures (household users and duration of exposure), and validated this by measuring urinary cotinine levels of a subset subjects. Classification of chronic bronchitis was also based on spirometry defined according to the GOLD guidelines to get the severity of COPD.Results: Women who smoked and women who had been exposed to a lifetime of SHS were 24.81-fold (95% CI: 5.78-106.38) and 3.65-fold (95% CI: 1.19-11.26) more likely to have chronic bronchitis, respectively, than those who had not been exposed to SHS. In addition, there was a significant increasing trend between the severity of COPD and exposure years of SHS (p < 0.01). The population attributable risk percentages of chronic bronchitis for smokers and those exposed to SHS were 23.2 and 47.3% respectively.Conclusions: These findings indicate that, besides cigarette smoking, exposure to SHS is a major risk factor for chronic bronchitis in Taiwanese women. [ABSTRACT FROM AUTHOR]

Uptake of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in laying ducks was determined at different degree of feed contamination. To observe the extent of the transfer of 17 PCDD/Fs from feed to the duck eggs and duck meat, 18 ducks were divided into 3 groups (6 in each group) and fed feed with two different levels of PCDD/Fs. As a control, one group of ducks was fed with the non-contaminated feed for comparison, while the other 2 groups were exposed to the feed doped with EAF dusts (fly ash). The experiment lasted for 60 days, with an exposure duration of 41 days and the subsequent non-contaminated feed being given for an additional 19 days. PCDD/F levels in the eggs of the all 3 groups were observed to increase significantly on the 15th day. For the low contaminated group, PCDD/F levels reached 2.61 pg WHO-TEQ/g lipid at day 41, whereas those of the high contaminated group accounted exceeded 3 pg/g lipid on the 15th day. Furthermore, PCDD/Fs levels in the duck meat were analyzed before and after exposure duration, and at the end of the experiment. The results showed that the level of PCDD/F in the duck eggs and the duck meat may reach unacceptable levels due to the effect of accumulation, although the PCDD/Fs in the duck feed were at acceptable levels. [ABSTRACT FROM AUTHOR]

Abstract  Exposure assessment of individuals exposed to certain chemicals plays an important role in the analysis of occupational—as well as environmental-health problems. Biological monitoring, as an alternative to direct environmental measurements, may be applied to relate the exterior exposure with the amount of individual intake. In this paper, we estimate individuals’ (inhalation) exposure retrospectively from their blood concentrations via a simplified one-compartment toxicokinetic model. Considering stochastic variations to the toxicokinetic model, the solution to the resultant stochastic differential equation (SDE), together with measurement error, is transformed into a dynamic linear state-space model. The unknown model parameters and the mean inhalation concentration are then estimated via Markov Chain Monte Carlo (MCMC) simulations. The proposed method is used in the analysis of the styrene data (Wang et al. in Occup Environ Med 53:601–605, 1996) to backward estimate the inhalation concentration, assuming it is unknown. The data analysis showed that the internal stochastic variations, often ignored in toxicokinetic model analysis, outweighed in standard deviation almost twice that of the measurement error. Also, the simulation results showed that the method performed relatively well to the approach considering measurement error only. [ABSTRACT FROM AUTHOR]

To determine whether urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG), an in vivo parameter of oxidative stress, is correlated with the outcome of critically septic patients. Clinical outcome study in an adult medical ICU. Eighty-five consecutive septic patients: 59 men and 26 women. Urinary 8-OHdG was analyzed using isotope-dilution liquid chromatography with tandem mass spectrometry (LC/MS/MS). ICU mortality in these 85 septic patients was 25.9% ( n = 22) and hospital mortality 38.8% ( n = 33). APACHE II scores of survivors on day 1, on day 3, and the difference between them differed significantly from those of nonsurvivors (day 1, 21.0 ± 7.1 vs. 25.9 ± 8.0; day 3, 15.0 ± 5.8 vs. 23.2 ± 8.3; difference, 6.0 ± 5.5 vs. 1.7 ± 6.6). Urinary 8-OHdG was significantly lower in survivors than in nonsurvivors on day 1 (1.8 ± 2.4 vs. 3.0 ± 2.4). The area under receiver operating characteristic curve analysis for the association between day 1 urinary 8-OHdG and ICU mortality was 0.71. The comparison performed upon discharge from hospital revealed similar results. This is a preliminary study. The excretion of the urinary 8-OHdG, as measured using isotope-dilution LC/MS/MS, as the APACHE II score, were correlated with the outcome of critically septic patients in medical ICU. [ABSTRACT FROM AUTHOR]

To determine whether urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG), an in vivo parameter of oxidative stress, is correlated with the outcome of critically septic patients. Clinical outcome study in an adult medical intensive care unit (ICU). 85 consecutive septic patients (59 men, 26 women). Patient characteristics and the clinical course were examined. Urinary 8-OHdG was analyzed using isotope-dilution liquid chromatography with tandem mass spectrometry (LC/MS/MS). ICU mortality was 25.9% (22/85) and hospital mortality 38.8% (33/85). Survivors' APACHE II scores on days 1 and 3 and the difference between them differed significantly from those of nonsurvivors (day 1, 21.0 ± 7.1 vs. 25.9 ± 8.0; day 3, 15.0 ± 5.8 vs. 23.2 ± 8.3; difference, 6.0 ± 5.5 vs. 1.7 ± 6.6). Urinary 8-OHdG was significantly lower in survivors than in nonsurvivors on day 1 (1.8 ± 2.4 vs. 3.0 ± 2.4). The area under receiver operating characteristic curve analysis for the association between day 1 urinary 8-OHdG and ICU mortality was 0.71. The comparison performed upon discharge from hospital revealed similar results. This is a preliminary study. Excretion of urinary 8-OHdG, as measured using isotope-dilution LC/MS/MS, and the APACHE II score were correlated with the outcome of critically septic patients in medical ICU. [ABSTRACT FROM AUTHOR]

Objectives: The aim was to determine whether occupational exposure to polycyclic aromatic hydrocarbons (PAHs) in men has adverse effect on semen quality. Methods: Forty-eight coke-oven workers, including 16 topside-oven (TO) workers and 32 sideoven (SO) workers, were studied. Ambient PAHs exposure, urinary 1-hydroxypyrene (1-OHP) levels, and parameters of semen quality were determined. Results: TO workers had significantly higher ambient PAHs exposure (3,436.1±3,411.0 vs. 1,123.1±1,829.3 ng/m3, P<0.01), urinary 1-OHP levels (207.8±176.4 vs. 54.0±44.8 μg/g, P<0.001), frequency of oligospermia (18.8 vs. 0%, P<0.05), and morphological abnormality in sperm (32.3 vs. 14.6%, P<0.01) than SO workers. Among cigarette smokers, TO workers had significantly higher rates of DNA denaturation in spermatozoa (αT) and percentage of sperm with increased DNA denaturation (COMP αT) levels than SO workers (246.2±49.5 vs. 198.1±30.3 for αT; 34.8±14.4 vs. 19.3±13.9% for COMP αT, P<0.05). There was a positive correlation between urinary 1-OHP and αT, COMP αT, and abnormal sperm morphology and a tenfold increase in urinary 1-OHP associated with a 2.35-fold increase in αT, as well as a 1.07-fold increase in percentage of sperm with abnormal morphology. Conclusions: A potential risk of sperm dysfunction should be considered for workers occupationally exposed to high levels of PAHs. Cigarette smoking may aggravate this risk. Urinary 1-OHP can be used as a biomarker predicting sperm dysfunction. [ABSTRACT FROM AUTHOR]

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Statistical analysis procedure in two-sample treatment difference, as well as alternative hypothesis, may play a central role in statistical inference, especially in small sample size case. In this paper, simple non-parametric two-sample permutation tests for scale difference based on the Hodges–Lehmann estimator are reformulated, and are applied to a study examining whether previous styrene exposure increases (thus a one-sided alternative hypothesis rather than a two-sided one) the human liver's metabolic ability to convert styrene into styrene oxide, in which a three-compartment physiologically based pharmacokinetic (PBPK) model was used to compare the estimated metabolic constant κamong the previously exposed and unexposed groups. Contrary to the previous conclusion, the proposed tests for scale difference identified from a mixed-effects model showed a significant result. Copyright © 2004 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Background A new engineering intervention measure, an embracing air curtain device (EACD), was used to increase the capture efficiency of cooker hoods and reduce cooking oil fume (COF) exposure in Chinese restaurants. Methods An EACD was installed in six Chinese restaurants where the cooks complained of COF exposure. Before- and after-installation measurements were taken to compare changes in particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) in kitchen air, and changes in levels of urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) and malondialdehyde (MDA). The association between PM and PAHs in air and 8-OHdG and MDA in urine was evaluated by linear mixed-effects regression analysis. Results Results showed that geometric mean kitchen air levels of PM10, PM2.5, PM1.0 and total particulate PAHs were significantly reduced after the EACDs were introduced. Urinary levels of 8-OHdG and MDA in cooks were also significantly lower after EACD instalment. PM2.5, PM1.0 and benzo(a)pyrene (BaP) levels were positively associated with urinary 8-OHdG levels after adjusting for key personal covariates. Urinary MDA levels in cooks were also positively associated with BaP levels after adjusting for key personal covariates. Conclusion This study demonstrates that the EACD is effective for reducing COF and oxidative stress levels in cooks working in Chinese kitchens. [ABSTRACT FROM AUTHOR]

Objectives: Occupational exposure assessment is a major task in industrial hygiene studies. Although statistical analyses for magnitudes and variations of exposures to various types of working populations based on existing data sets are extensive, relatively few discussions on study designs appear in the literature, especially for sample size determination and number of repeated measurements. Methods: In this paper, we propose a general framework of sampling strategies on sample size requirement together with the number of repeated measurements using the mixed-effects generalized linear model (GLM). As illustrative examples, we discuss sampling strategies separately under the log-normal assumption for hypotheses testing on (i) mean exposure differences of multiple worker groups and (ii) presence of a long-term exposure trend. Results: Given a specified alternative hypothesis, the desired significance level and statistical power, the number of repeated measurements, within-worker and between-worker variances, and a correlation structure, we have derived and tabulated an explicit sample size requirement of the two hypothetical cases under log-normal distribution assumption. Conclusions: On the basis of the tabulated outcomes, the sample size requirement is much more dominant than the number of repeated measurements for a group exposure comparison. Thus, in this case, recruiting more workers with fewer repeated measurements may be more economical than the opposite approach. For testing the presence of a long-term exposure trend, the sample size required decreases substantially with the number of repeated measurements. Also, equally spaced sampling times would be optimal because the effect of between-worker variance is algebraically cancelled out in sample size calculations. [ABSTRACT FROM AUTHOR]

A correction to the article "Urinary biomarker of oxidative stress correlating with outcome in critically septic patients" that was published in the July 2007 issue is presented.