Oral cavity response to air pollutant exposure and association with pulmonary inflammation and symptoms in asthmatic children.

Exposure to fine particulate matter (PM2.5) and ozone (O3) may lead to inflammation and oxidative damage in the oral cavity, which is hypothesized to contribute to the worsening of airway inflammation and asthma symptoms. In this panel study of 43 asthmatic children aged 5-13 years old, each child had 4 clinic visits with a 2-week interval between two consecutive visits. At each visit, saliva samples were collected and subsequently analyzed for interleukin 6 (IL-6) and eosinophil cationic protein (ECP) as biomarkers of inflammation and malondialdehyde (MDA) as a biomarker of oxidative stress in the oral cavity. At each visit, children were measured for fractional exhaled nitric oxide (FeNO) as a marker of pulmonary inflammation. Asthma symptoms of these children were measured using the Childhood Asthma Control Test (C-ACT). We found that an interquartile range (IQR) increase in 24-h average personal exposure to PM2.5 measured 1 and 2 days prior was associated with increased salivary IL-6 concentration by 3.0% (95%CI: 0.2%-6.0%) and 4.2% (0.7%-8.0%), respectively. However, we did not find a clear association between personal O3 exposure and any of the salivary biomarkers, except for a negative association between salivary MDA and O3 exposure measured 1 day prior. An IQR increase in salivary IL-6 concentration was associated with significantly increased FeNO by 28.8% (4.3%-53.4%). In addition, we found that increasing salivary IL-6 concentrations were associated with decreased individual and total C-ACT scores, indicating the worsening of asthma symptoms. We estimated that 13.2%-22.2% of the associations of PM2.5 exposure measured 1 day prior with FeNO and C-ACT scores were mediated by salivary IL-6. These findings suggest that the induction of inflammation in the oral cavity may have played a role in linking air pollution exposure with the worsening of airway inflammation and asthma symptoms.

Personal Exposure to PM2.5 Oxidative Potential in Association with Pulmonary Pathophysiologic Outcomes in Children with Asthma.

Fine particulate matter (PM2.5) with a higher oxidative potential has been thought to be more detrimental to pulmonary health. We aim to investigate the associations between personal exposure to PM2.5 oxidative potential and pulmonary outcomes in asthmatic children. We measured each of the 43 asthmatic children 4 times for airway mechanics, lung function, airway inflammation, and asthma symptom scores. Coupling measured indoor and outdoor concentrations of PM2.5 mass, constituents, and oxidative potential with individual time-activity data, we calculated 24 h average personal exposures 0-3 days prior to a health outcome measurement. We found that increases in daily personal exposure to PM2.5 oxidative potential were significantly associated with increased small, large, and total airway resistance, increased airway impedance, decreased lung function, and worsened scores of individual asthma symptoms and the total symptom score. Among the PM2.5 constituents, organic matters largely of indoor origin contributed the greatest to PM2.5 oxidative potential. Given that the variability in PM2.5 oxidative potential was a stronger driver than PM2.5 mass for the variability in the respiratory health outcomes, it is suggested to reduce PM2.5 oxidative potential, particularly by reducing the organic matter constituent of indoor PM2.5, as a targeted source control strategy in asthma management.

Real-time measurements of PM2.5 and ozone to assess the effectiveness of residential indoor air filtration in Shanghai homes.

Portable air cleaners are increasingly used in polluted areas in an attempt to reduce human exposure; however, there has been limited work characterizing their effectiveness at reducing exposure. With this in mind, we recruited forty-three children with asthma from suburban Shanghai and deployed air cleaners (with HEPA and activated carbon filters) in their bedrooms. During both 2-week filtration and non-filtration periods, low-cost PM2.5 and O3 air monitors were used to measure pollutants indoors, outdoors, and for personal exposure. Indoor PM2.5 concentrations were reduced substantially with the use of air cleaners, from 34 ± 17 to 10 ± 8 µg/m3 , with roughly 80% of indoor PM2.5 estimated to come from outdoor sources. Personal exposure to PM2.5 was reduced from 40 ± 17 to 25 ± 14 µg/m3 . The more modest reductions in personal exposure and high contribution of outdoor PM2.5 to indoor concentrations highlight the need to reduce outdoor PM2.5 and/or to clean indoor air in multiple locations. Indoor O3 concentrations were generally low (mean = 8±4 ppb), and no significant difference was seen by filtration status. The concentrations of pollutants and the air cleaner effectiveness were highly variable over time and across homes, highlighting the usefulness of real-time air monitors for understanding individual exposure reduction strategies.

Malondialdehyde in Nasal Fluid: A Biomarker for Monitoring Asthma Control in Relation to Air Pollution Exposure.

Fine particulate matter (PM2.5) and ozone (O3) may exert oxidative damage in the nose, which is hypothesized to be associated with worsened asthma symptoms. This study, hence, is to explore whether an oxidative stress biomarker, malondialdehyde (MDA) in the nasal fluid, has the potential to aid personalized asthma control. In a panel study of 43 asthmatic children, 5-13 years old, each child was measured 4 times with a 2-week interval between consecutive clinic visits. At each visit, nasal fluid and urine samples were collected, and fractional exhaled nitric oxide (FeNO) was measured as a biomarker of pulmonary inflammation. In addition to nasal MDA, urinary MDA and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were measured as biomarkers of systemic oxidative stress. We also assessed asthma symptoms using the Childhood Asthma-Control Test (C-ACT). We found that interquartile range (IQR) increases in 24 h average personal PM2.5 exposure (22.2-33.5 µg/m3), estimated 0 to 5 days prior to a clinic visit, were associated with increased nasal MDA concentrations by 38.6-54.9%. Similarly, IQR increases in 24 h average personal O3 exposure (7.7-8.2 ppb) estimated 2 to 4 days prior were associated with increased nasal MDA by 22.1-69.4%. Only increased PM2.5 exposure was associated with increased FeNO. Increased nasal MDA concentration was associated with decreased total and individual C-ACT scores, indicating worsening of asthma symptoms. However, no significant associations were observed between urinary MDA or 8-OHdG and C-ACT scores. The results confirm that oxidative stress plays an important role in linking air pollution exposure and adverse respiratory health effects. These findings support that MDA in the nasal fluid may serve as a useful biomarker for monitoring asthma status, especially in relation to PM2.5 and O3 exposures, two known risk factors of asthma exacerbation.

The impact of household air cleaners on the oxidative potential of PM2.5 and the role of metals and sources associated with indoor and outdoor exposure.

The health effects associated with human exposure to airborne fine particulate matter (PM2.5) have been linked to the ability of PM2.5 to facilitate the production of excess cellular reactive oxygen species (oxidative potential). Concern about the adverse human health impacts of PM2.5 has led to the increased use of indoor air cleaners to improve indoor air quality, which can be an important environment for PM2.5 exposure. However, the degree to which the oxidative potential of indoor and personal PM2.5 can be influenced by an indoor air cleaner remains unclear. In this study we enrolled 43 children with physician diagnosed asthma in suburban Shanghai, China and collected two paired-sets of 48-h indoor, outdoor, and personal PM2.5 exposure samples. One set of samples was collected under "real filtration" during which a functioning air cleaner was installed in the child's bedroom, and the other ("false filtration") with an air cleaner without internal filters. The PM2.5 samples were characterized by inductively coupled plasma mass spectroscopy for elements, and by an alveolar macrophage assay for oxidative potential. The sources of metals contributing to our samples were determined by the EPA Positive Matrix Factorization model. The oxidative potential was lower under real filtration compared to sham for indoor (median real/sham ratio: 0.260) and personal exposure (0.813) samples. Additionally, the sources of elements in PM2.5 that were reduced indoors and personal exposure samples by the air cleaner (e.g. regional aerosol and roadway emissions) were found by univariate multiple regression models to be among those contributing to the oxidative potential of the samples. An IQR increase in the regional aerosol and roadway emissions sources was associated with a 107% (95% CI: 80.1-138%) and 38.1% (17.6-62.1%) increase in measured oxidative potential respectively. Our results indicate that indoor air cleaners can reduce the oxidative potential of indoor and personal exposure to PM2.5, which may lead to improved human health.

Factors associated with quality of life among married women in rural China: a cross-sectional study.

PURPOSE: Specific medical and living conditions in rural China may predispose people there to a poor quality of life. This study aimed to evaluate factors affecting the quality of life among married women in rural China. METHODS: This cross-sectional study was conducted in rural areas of Liaoning Province in China. Out of the 3900 married women, 3163 (81%) completed the questionnaire survey. Quality of life was assessed using the WHOQOL-BREF scale. Sociodemographic factors, such as monthly income, and living and health conditions, such as left-behind status, stress (quantified by the Perceived Stress Scale), and coping styles (assessed by the Simplified Coping Style Questionnaire) were collected through self-reported questionnaires. Hierarchical multiple regression was used to explore the factors related to quality of life. RESULTS: The mean scores of quality of life were 14.08 ± 2.27 for the domain of physical health, 11.78 ± 2.28 for psychological health, 13.07 ± 2.69 for social relationships, and 12.26 ± 2.67 for environmental conditions. Older age, having chronic diseases, being left-behind, sense of marriage insecurity, and stress were all negatively associated with quality of life scores, whereas a higher monthly income was associated with higher scores. Coping styles could be moderating factors in the relationship between stress and quality of life. CONCLUSIONS: Overall, married women living in rural China had relatively low scores for quality of life. Improving family income, providing access to affordable and high-quality medical care, facilitating couple communication, and promoting active coping styles could be intervention strategies to improve the quality of life of these rural residents.

[Effects of TiO2 nanoparticles on antioxidant function and element content of liver and kidney tissues in young and adult rats].

OBJECTIVE: To compare the effect of TiO2 nanoparticles on antioxidant function and element content of liver and kidney tissues in young and adult rats. METHODS: Forty-eight SD male rats, half in 4-week (youth) old and half in 9-week (adult) old rats, were randomly divided into 8 groups, which were exposed to TiO2 nanoparticles [(75 ± 15) nm, anatase] through intragastric administration at 0, 10, 50 and 200 mg/kg body weight every day for 30 days. The liver and kidney tissues were collected for antioxidant function and element content analysis. RESULTS: 200 mg/kg TiO2 nanoparticles exposure significantly increased the liver total superoxide dismutase (T-SOD) activity and the kidney reduced glutathione (GSH)/oxidized glutathione (GSSG) ratios in young rats, and significantly decreased the liver Mo, Co, Mn and P contents and the kidney Rb and Na contents in young rats. 200 mg/kg TiO2 nanoparticles exposure significantly increased GSH/GSSG ratios and Rb contents and decreased Na contents in the liver of adult rats. No significantly difference was found in antioxidant indexes and elements content in the kidney of adult rats between three experimental groups and control group. CONCLUSION: TiO2 nanoparticles can enhance the antioxidant capacity and decrease the elements content in rat liver and kidney tissues. The liver is the more sensitive target organ and the young animals are more susceptible to TiO2 nanoparticles toxicity by the oral routes.

Cardiovascular effects of pulmonary exposure to titanium dioxide nanoparticles in ApoE knockout mice.

Existing studies on the inhalation toxicology of titanium dioxide (TiO2) have focused on possible carcinogenic capacity; however researches on the cardiovascular effect are limited, particularly in terms of susceptible animal models. The present study examined the inhalation toxicology of nano-TiO2 in ApoE knockout mice (ApoE-/- mice), an atherosclerosis susceptible animal model. The nano-TiO2 particles used were anatase type and the diameter ranged from 5 to 10 nm. ApoE-/- mice were randomly divided into five groups (high dose group, median dose group, low dose group, PBS vehicle control group and the nontreatment control group), each of which were given tracheal instillation of nano-TiO2 at the dose of 100 microg, 50 microg and 10 microg and PBS solution per week respectively, totally for six weeks, while the nontreatment control group received no tracheal instillation. We measured various indicators of inflammation, endothelial dysfunction and lipid metabolism in serum, and determined plaque formation on the aorta. After six weeks of treatment, there was significant difference between the high dose group and PBS control group in terms of C reactive protein (CRP), nitric oxide (NO), endothelial nitric oxide synthases (eNOS), total cholesterol (TC) and high density lipoprotein cholesterol (HDL-C) in serum. The results also showed ratio of plaque area to luminal area and the ratio of the lipid-rich core area to plaque area in the median and high nano-TiO2 dose group significantly increased respectively in HE stained cross-sections. Our study showed that tracheal instillation of nano-TiO2 particles induced considerable systemic inflammation, endothelial dysfunction and lipid metabolism dysfunction, contributing to the progression of atherosclerosis.

Synthesis and evaluation of curcumin-related compounds containing benzyl piperidone for their effects on human cancer cells.

Eleven curcumin-related compounds containing a benzyl piperidone moiety were synthesized and evaluated for their effects on cultured prostate cancer PC-3 cells, pancreas cancer BxPC-3 cells, colon cancer HT-29 cells and lung cancer H1299 cells. Inhibitory effects of these compounds on the growth of PC-3, BxPC-3, HT-29 and H1299 cells were determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and trypan blue exclusion assay. Compounds benzyl piperidone 2 (P2), P4, P7, 4-bromo-2-fluoro-benzyl piperidone 2 (PFBr2), PFBr3 and PFBr4 (see syntheses and structures in Figs. 1, 2) exhibited potent inhibitory effects on the growth of cultured PC-3, BxPC-3, HT-29 and H1299 cells. The IC50 for these compounds was lower than 2 µM in all four cell lines. PFBr4 was 41-, 36-, 40- and 46-fold more active than curcumin for inhibiting the growth of PC-3, BxPC-3, HT-29 and H1299 cells, respectively. The benzyl piperidone-containing compounds studied also stimulated apoptosis in PC-3 cells. Mechanistic studies indicate that the effects of both curcumin and PFBr4 on PC-3 cells were associated with a decrease in phospho-Akt and phospho-extracellular signal-regulated kinase (Erk)1/2. The present study indicates that P2, P4, P7, PFBr2, PFBr3 and PFBr4 may have useful effects on human cancer cells.

Association between Childhood Asthma Control Test scores and lung pathophysiologic indicators in longitudinal measurements.

Background: Childhood Asthma Control Test (C-ACT) is a well-validated questionnaire for asthma controls among 4-11 years old children. This study aims to examine if longitudinal C-ACT score changes could also reflect lung pathophysiologic changes. Methods: Thirty-seven children (43% female) aged 5 to 10 years old with mild or moderate asthma were followed up for 6 weeks with bi-weekly assessments of C-ACT, airway mechanics, lung function and respiratory inflammation. Associations of longitudinal changes in C-ACT score with lung pathophysiologic indicators were evaluated using linear mixed-effects models. Results: A two-point worsening of total C-ACT score (sum of child and caregiver-reported) was associated with significant decreases in forced expiratory volume during the 1st second (FEV1) by 1.7% (P=0.04) and forced vital capacity (FVC) by 1.6% (P=0.01) and increased total airway resistance [airway resistance at 5 Hz (R5)] by 3.8% (P=0.05). A two-point worsening in child-reported score was significantly associated with 3.1% and 2.5% reductions in FEV1 and FVC, respectively, and with increases in R5 by 6.5% and large airway resistance [airway resistance at 20 Hz (R20)] by 5.5%. In contrast, a two-point worsening of caregiver-reported score was associated with none of the concurrent lung pathophysiologic measurements. Worsening of total C-ACT score was significantly associated with increased respiratory inflammation [fractional exhaled nitric oxide (FeNO)] in a subset (n=23) of children without eosinophilic airway inflammation. C-ACT scores were associated with none of the small airway measures. Conclusions: In children with mild or moderate asthma, longitudinal C-ACT score changes could reflect acute changes in large airway resistance and lung function. Measures of small airway physiology would provide valuable complementary information for asthma control. Asthma phenotype may affect whether C-ACT score could reflect respiratory inflammation.

Associations between personal apparent temperature exposures and asthma symptoms in children with asthma.

Ambient temperature and relative humidity can affect asthma symptoms. Apparent temperature is a measure of temperature perceived by humans that takes into account the effect of humidity. However, the potential link between personal exposures to apparent temperature and asthma symptoms has not been investigated. We conducted a panel study of 37 asthmatic children, aged 5-11 years, during an early spring season (average daily ambient temperature: 14°C, range: 7-18°C). Asthma symptoms were measured 4 times for each participant with a 2-week interval between consecutive measurements using the Childhood Asthma-Control Test (C-ACT). Average, minimum, and maximum personal apparent temperature exposures, apparent temperature exposure variability (TV), and average ambient temperature were calculated for the 12 hours, 24 hours, week, and 2 weeks prior to each visit. We found that a 10°C lower in 1-week and 2-week average & minimum personal apparent temperature exposures, TV, and average ambient temperature exposures were significantly associated with lower total C-ACT scores by up to 2.2, 1.4, 3.3, and 1.4 points, respectively, indicating worsened asthma symptoms. Our results support that personal apparent temperature exposure is potentially a stronger driver than ambient temperature exposures for the variability in asthma symptom scores. Maintaining a proper personal apparent temperature exposure could be an effective strategy for personalized asthma management.

Inhibition of progression of androgen-dependent prostate LNCaP tumors to androgen independence in SCID mice by oral caffeine and voluntary exercise.

The effect of oral caffeine or voluntary running wheel exercise (RW) alone or in combination on the progression of human androgen-dependent LNCaP prostate tumors to androgen independence in male severe combined immunodeficiency mice was determined. The mice were injected subcutaneously with LNCaP cells, and when the tumors reached a moderate size, the mice were surgically castrated and treated with caffeine (0.40 mg/ml drinking water) or RW alone or in combination for 42 days. We found that caffeine administration or RW inhibited the progression and growth of androgen-dependent LNCaP tumors to androgen independence, and a combination of the 2 regimens was more effective than the individual regimens alone. The ratios of the percent mitotic cells/caspase-3 positive cells in tumors from the caffeine-treated, RW-treated, or combination-treated mice were decreased by 34%, 38%, and 52%, respectively. Caffeine treatment increased the percentage of mitotic tumor cells undergoing apoptosis (lethal mitosis) whereas RW inhibited the increase in interleukin-6 that occurred during the progression of LNCaP tumors from androgen dependence to androgen independence. Our results indicate that oral administration of caffeine in combination with voluntary exercise may be an effective strategy for the prevention of prostate cancer progression from androgen dependence to androgen independence.

[Effect of titanium dioxide nanoparticles on hemogram in rats with gastric ulcer].

OBJECTIVE: To explore the effect of titanium dioxide (TiO2) nanoparticles on hemogram in rats with gastric ulcer. METHODS: Physicochemical properties of TiO2 nanoparticles were characterized. Twenty-four clear class SD male rats, aging 8 week-old, were randomly divided into 4 groups, 6 rats for each group. 20% acetic acid were injected into the rats' stomach on the border of gastric body and pyloric antrum, and hereby established the gastric ulcer model. The rats in 4 groups were exposed to TiO2 nanoparticles through intragastric administration at 0, 10, 50 and 200 mg/kg body weight respectively for 30 days. Afterwards, the rats were conducted blood routine test and blood coagulation test for analysis. RESULTS: TiO2 nanoparticles were anatase crystals, closely spherical shape, whose average grain diameter was (75 ± 15) nm. The levels of white blood cell (WBC) count ((8.48 ± 3.28)×109/L), lymphocyte (LYM) ((6.85 ± 2.53)×109/L), monocyte (MOD) ((0.27 ± 0.12)×109/L), granulocyte (GRN) ((1.37 ± 0.86)×109/L), red blood cell (RBC) ((8.20 ± 0.49)×109/L) and hematocrit (HCT) ((45.3 ± 1.4)%) in the 200 mg/kg dose group were significantly higher than those in the control group ((2.63 ± 0.34)×109/L, (2.25 ± 0.26)×109/L, (0.05 ± 0.06)×109/L, (0.33 ± 0.26)× 109/L, (4.87 ± 2.37)×109/L and (27.2 ± 13.3)%, respectively; t values were -3.449, -3.825, -3.554, -3.097, -2.972 and -2.936 respectively, P values all < 0.05). The levels of WBC ((6.88 ± 3.06)×109/L), MOD ((0.20 ± 0.07)×109/L), RBC ((7.79 ± 0.48)×109/L) and HCT ((42.7 ± 2.8)%) in 50 mg/kg dose group were also statistically higher than those in the control group (t values were -2.507, -2.367, -2.605 and -2.511 respectively, all P values < 0.05). There was no statistically difference found in other blood routine index and coagulation index between the three experimental groups and control group. CONCLUSION: The long term intake of TiO2 nanoparticles caused a statistically increase in the amount of WBC and RBC in rats with gastric ulcer; however, there was no obvious changes found in blood platelet and coagulation index.

Role of endogenous melatonin in pathophysiologic and oxidative stress responses to personal air pollutant exposures in asthmatic children.

BACKGROUND: Heightening oxidative stress and inflammation is an important pathophysiological mechanism underlying air pollution health effects in people with asthma. Melatonin can suppress oxidative stress and inflammation in pulmonary and circulatory systems. However, the role of melatonin in the oxidative stress and physiological responses to air pollution exposure has not been examined in children with asthma. METHODS: In this panel study of 43 asthmatic children (5-13 years old), each child had 4 clinic visits with a 2-week interval between two consecutive visits. At each visit, urine samples were collected and subsequently analyzed for 6-sulfatoxymelatonin (aMT6s) as a surrogate of circulating melatonin and for malondialdehyde (MDA) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) as two biomarkers of systemic oxidative stress. At each clinic visit, children were measured for pulmonary function and fractional exhaled nitric oxide (FeNO, a marker of pulmonary inflammation). None of the children reported to have taking melatonin supplementation. Concentrations of indoor and ambient PM2.5 and ozone (O3) were combined with individual time-activity data to calculate personal air pollutant exposures. RESULTS: We found that interquartile range increases in urinary MDA and 8-OHdG concentrations were associated with significantly increased urinary aMT6s concentrations by 73.4% (95% CI: 52.6% to 97.0%) and 41.7% (22.8% to 63.4%), respectively. Increases in daily personal exposure to O3 and to PM2.5 were each associated with increased urinary aMT6s concentrations. Increasing urinary aMT6s concentrations were associated with decreased FeNO and resonant frequency, indicating improved airway inflammation and lung elasticity, respectively. CONCLUSION: The results suggest that systemic oxidative stress heightened by air pollution exposure may stimulate melatonin excretion as a defense mechanism to alleviate the adverse effects.

Effects of personal air pollutant exposure on oxidative stress: Potential confounding by natural variation in melatonin levels.

Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) are commonly used biomarkers of oxidative stress. However, their associations with air pollutant exposure have not been consistent across studies. We hypothesize that the inconsistency is partly due to confounding of circulating melatonin. We analyzed urinary 6-sulfatoxymelatonin (aMT6s), a surrogate of circulating melatonin, along with 8-OHdG and MDA, in 159 healthy adults who had not taken melatonin supplementation. Within the natural range of endogenously-generated aMT6s (0.3-93.5 ng/mg creatinine) measured in this study, increasing aMT6s levels were significantly associated with increasing concentrations of 8-OHdG and MDA. Measurements of PM2.5, ozone (O3), and nitrogen dioxide (NO2), coupled with time-activity data, were used to calculate time-averaged personal exposures 12 -hour (12h) and 24-hour (24h) prior to urine collection. Without controlling for aMT6s, the relationships between pollutant exposure and 8-OHdG or MDA were not clear. After controlling for aMT6s, an interquartile range (IQR) increase in 12h PM2.5 and 12h NO2 exposure was associated with 6.1% [95%CI: 1.6%-10.8%] and 8.6% [1.3%-16.5%] increase in MDA, respectively. An IQR increase in 12h O3 exposure was associated with a 5.7% [1.9%-9.7%] in 8-OHdG. The findings suggest the need for controlling for aMT6s as a confounder in using urinary 8-OHdG and MDA as biomarkers of oxidative stress related to short-term air pollution exposure.

Children's microenvironmental exposure to PM2.5 and ozone and the impact of indoor air filtration.

BACKGROUND: In highly polluted urban areas, personal exposure to PM2.5 and O3 occur daily in various microenvironments. Identifying which microenvironments contribute most to exposure can pinpoint effective exposure reduction strategies and mitigate adverse health impacts. METHODS: This work uses real-time sensors to assess the exposures of children with asthma (N = 39) in Shanghai, quantifying microenvironmental exposure to PM2.5 and O3. An air cleaner was deployed in participants' bedrooms where we hypothesized exposure could be most efficiently reduced. Monitoring occurred for two 48-h periods: one with bedroom filtration (portable air cleaner with HEPA and activated carbon filters) and the other without. RESULTS: Children spent 91% of their time indoors with the majority spent in their bedroom (47%). Without filtration, the bedroom and classroom environments were the largest contributors to PM2.5 exposure. With filtration, bedroom PM2.5 exposure was reduced by 75% (45% of total exposure). Although filtration status did not impact O3, the largest contribution of O3 exposure also came from the bedroom. CONCLUSIONS: Actions taken to reduce bedroom PM2.5 and O3 concentrations can most efficiently reduce total exposure. As real-time pollutant monitors become more accessible, similar analyses can be used to evaluate new interventions and optimize exposure reductions for a variety of populations.

Effect of silver nanospheres and nanowires on human airway smooth muscle cells: role of sulfidation.

Background: The toxicity of inhaled silver nanoparticles on contractile and pro-inflammatory airway smooth muscle cells (ASMCs) that control airway calibre is unknown. We explored the oxidative activities and sulfidation processes of the toxic-inflammatory response. Method: Silver nanospheres (AgNSs) of 20 nm and 50 nm diameter and silver nanowires (AgNWs), short S-AgNWs, 1.5 µm and long L-AgNWs, 10 µm, both 72 nm in diameter were manufactured. We measured their effects on cell proliferation, mitochondrial reactive oxygen species (ROS) release and membrane potential, and also performed electron microscopic studies. Main results and findings: The greatest effects were observed for the smallest particles with the highest specific surface area and greatest solubility that were avidly internalised. ASMCs exposed to 20 nm AgNSs (25 µg mL-1) for 72 hours exhibited a significant decrease in DNA incorporation (-72.4%; p < 0.05), whereas neither the 50 nm AgNSs nor the s-AgNWs altered DNA synthesis or viability. There was a small reduction in ASMC proliferation for the smaller AgNS, although Ag+ at 25 µL mL-1 reduced DNA synthesis by 93.3% (p < 0.001). Mitochondrial potential was reduced by both Ag+ (25 µg mL-1) by 47.1% and 20 nm Ag NSs (25 µg mL-1) by 40.1% (*both at p < 0.05), but was not affected by 50 nm AgNSs and the AgNWs. None of the samples showed a change in ROS toxicity. However, malondialdehyde release, associated with greater total ROS, was observed for all AgNPs, to an extent following the geometric size (20 nm AgNS: 213%, p < 0.01; 50 nm AgNS: 179.5%, p < 0.01 and L-AgNWs by 156.2%, p < 0.05). The antioxidant, N-acetylcysteine, prevented the reduction in mitochondrial potential caused by 20 nm AgNSs. The smaller nanostructures were internalised and dissolved within the ASMCs with the formation of non-reactive silver sulphide (Ag2S) on their surface, but with very little uptake of L-AgNWs. When ASMCs were incubated with H2S-producing enzyme inhibitors, the spatial extent of Ag2S formation was much greater. Conclusion: The intracellular toxicity of AgNPs in ASMCs is determined by the solubility of Ag+ released and the sulfidation process, effects related to particle size and geometry. Passivation through sulfidation driven by biogenic H2S can outcompete dissolution, thus reducing the toxicity of the smaller intracellular Ag nanostructures.

Associations of personal exposure to air pollutants with airway mechanics in children with asthma.

BACKGROUND: The importance of airway mechanics has been increasingly recognized in pediatric asthma. However, no studies have examined responses of airway mechanics to air pollution exposure in asthmatic children. METHODS: In this panel study involving indoor air filtration manipulation that created a large gradient of personal exposure to PM2.5, the airway mechanics and lung function of 43 asthmatic children 5-13 years old in a suburb of Shanghai were measured four times within 3 consecutive months. Concentrations of indoor and outdoor PM2.5 and ozone were coupled with individual time-activity data to calculate personal exposures. Linear mixed effects models were used to examine the relationships of personal exposure with indicators of airway mechanics and lung function, respectively. RESULTS: An interquartile range (IQR) increase in 24-hour average PM2.5 personal exposure (30.3 µg/m3) in the prior day was associated with significant increases in small airway resistance (R5-R20) of 15.8%, total airway resistance (R5) of 6.3%, and airway inflammation (FeNO) of 9.6%. These associations were stronger in children with lower blood eosinophil counts (<450/µL). No significant associations were found between personal PM2.5 exposure and lung function. Low-level ozone exposure (daily maximum 8-hour exposure range 1.1-56.4 ppb) was not significantly associated with any of the outcomes. CONCLUSION: Changes in personal PM2.5 exposure, partly enhanced by air filtration, were associated with significant changes in airway resistance and inflammation in children with asthma. These findings suggest the importance of reducing PM2.5 exposure, via personal air quality management, in improving airflow limitation in the airways, especially the small airways.

Association Between Bedroom Particulate Matter Filtration and Changes in Airway Pathophysiology in Children With Asthma.

Importance: Fine particles (particulate matter 2.5 µm [PM2.5]), a ubiquitous air pollutant, can deposit in the small airways that play a vital role in asthma. It appears to be unknown whether the use of a PM2.5 filtration device can improve small airway physiology and respiratory inflammation in children with asthma. Objective: To discover what pathophysiological changes in the small airways are associated with using a PM2.5-removing device in the bedrooms of children with asthma. Design, Setting, and Participants: Children with mild or moderate asthma were enrolled in this double-blind, crossover study. The participants used a true filtration device and a sham filtration device in their bedrooms in a random order for 2 weeks each with a 2-week washout interval. The study was conducted in a suburb of Shanghai, China, during a low-ozone season. Exposures: Ozone and PM2.5 were measured inside bedrooms and outside a window. Main Outcomes and Measures: Impulse oscillometry, spirometry, and fractional exhaled nitric oxide were measured at the beginning and the end of each intervention. Peak expiratory flow was measured twice daily at home. Results: Forty-three children (5-13 years old; 26 boys [60%]) participated. Outdoor 24-hour mean PM2.5 concentrations were moderately high, ranging from 28.6 to 69.8 µg/m3 (median, 53 µg/m3). During true filtration, bedroom PM2.5 concentrations were a mean (SD) of 63.4% (35.9%) lower than during sham filtration. Compared with sham filtration, true filtration was significantly associated with improved airway mechanics, reflected in a 24.4% (95% CI, 11.8%-37.1%) reduction in total airway resistance, a 43.5% (95% CI, 13.7%-73.3%) reduction in small airway resistance, a 22.2% (95% CI, 2.2%-42.2%) reduction in resonant frequency, and a 73.1% (95% CI, 0.3%-145.8%) increase in airway reactance. True filtration was also associated with significant improvements in fractional exhaled nitric oxide (a 27.6% [95% CI, 8.9%-42.4%] reduction) and peak expiratory flow (a 1.6% [95% CI, 0.8%-2.5%] increase). These improvements were significantly associated with bedroom PM2.5 reduction. Improvements in small airway function were nonsignificant (8.4% [95% CI, -1.4% to 18.3%]) in all participants but significant (13.2% [95% CI, 1.2%-25.1%]) in participants without eosinophilic airway inflammation at baseline. No improvements were observed for forced vital capacity, forced expiratory volume during the first second, and the ratio of these in all participants or subgroups. Conclusions and Relevance: Per these results, indoor PM2.5 filtration can be a practical method to improve air flow in an asthmatic lung through improved airway mechanics and function as well as reduced inflammation. This warrants a clinical trial to confirm. Trial Registration: ClinicalTrials.gov Identifier: NCT03282864.

Effects of job conditions, occupational stress, and emotional intelligence on chronic fatigue among Chinese nurses: a cross-sectional study.

Purpose: Nurses are undertaking considerable emotional and physical work, which may lead to unrecoverable fatigue. This study aimed to evaluate the level of chronic fatigue and explore its associated factors among Chinese nurses in the hope of providing scientific evidence for fatigue-reduction strategies. Methods: This cross-sectional study was carried out in Liaoning Province, China in 2018. The study recruited 700 nurses and collected 566 effective respondents. Chronic fatigue, demographic factors, job conditions, and emotional intelligence were assessed through questionnaires. Chronic fatigue was assessed with the Fatigue Scale 11, occupational stress with the Effort-Reward Imbalance Questionnaire, and emotional intelligence with the Wong and Law Emotional Intelligence Scale. Hierarchical multiple regression was used to explore factors related to chronic fatigue and to test the moderating effect of emotional intelligence on the association between occupational stress and chronic fatigue. Simple slope analysis was conducted to visualize the interaction. Results: The mean score of chronic fatigue among the Chinese nurses was 17.14±6.16. Being married, having long weekly work time, working night shifts, and discontent with the nurse-patient relationship were positively associated with chronic fatigue. Effort:reward ratio, overcommitment, and emotional intelligence were important factors related to chronic fatigue. Emotional intelligence played a moderating role in the relationship between the effort:reward ratio and chronic fatigue. When emotional intelligence was higher, the effect of the effort:reward ratio on chronic fatigue became weaker. Conclusion: Most nurses surveyed in China might have relatively high levels of chronic fatigue. Our results highlight the importance of interventions on these factors for the reduction of fatigue among nurses in China. Providing more opportunities and support and developing emotional intelligence are crucial strategies to reduce chronic fatigue among nurses in China.