[Concentrations of fine particulate matters and ultrafine particles and influenced factors during winter in an area of Beijing].

OBJECTIVE: To study the concentrations of fine particulate matters and ultrafine particles and influenced factors during winter in an area of Beijing. METHODS: Real-time monitoring of particles' mass and number concentrations were conducted in an area of Beijing from February 7(th) to 27(th), 2013. At the same time, the meteorological data were also collected from the Beijing meteorological website. Differences of the particles' mass and number concentrations during different periods were analyzed using Mann-Whitney U test. Meanwhile, the influenced factors were also analyzed. RESULTS: The mean concentrations of fine particulate matters and ultrafine particles were (157.2 ± 142.8) µg/m³ and (25 018 ± 9 309) particles/cm³, respectively. The particles' number and mass concentrations in haze days were 1.27 times and 2.91 times higher than those in non-haze days, respectively. The mass concentrations of fine particulate matters in the self-monitoring site were higher than those in the nearest central monitoring sites, and the hourly-average concentrations of particles were significantly consistent with those at the commuter times. Meanwhile, the setting off of fireworks/firecrackers during the Spring Festival could lead to short-term increases of the particles' number and mass concentrations. When the wind speed was low and the related humidity was high, the concentrations of particulate matters were relatively high, and the mass concentrations of fine particulate matters were lagged about 1-2 d. CONCLUSION: The level of the particulate matters in this area was high. Heavy traffic, setting off of fireworks/firecrackers and meteorological factors may be some of the main factors affecting the concentrations of the particulate matters in this area. Among those factors, the effect of setting off of fireworks/firecrackers didn't last long and the effect of the meteorological factors had a hysteresis effect.

[Effects of silver ion of silver nanoparticles on gap junctional intercellular communication of human skin cells].

OBJECTIVE: To further investigate the effects of silver ion (Ag+) dissolved from silver nanoparticles (AgNps) on gap junctional intercellular communication (GJIC) between HaCaT cells. METHODS: In this study, 20 000×g of 1 g/L AgNps suspension were centrifuged at 4 °C for 2 h, then the supernatant was collected as Ag(+) stock solution and measured by inductively coupled plasma mass spectrometry (ICP-MS); GJIC was detected by the scrape loading/dye transfer assay; connexin 43 (Cx43) protein and mRNA level were estimated by Western-blot and RT-PCR, respectively. RESULTS: Different concentrations of Ag(+) (0.01, 0.1 and 1.0 mg/L) did not affect the GJIC significantly. No notable changes were observed in expression of Cx43 protein and mRNA. CONCLUSION: The characteristics of Ag(+) and the effects on gap junctional intercellular communication between HaCaT cells may be different from those of AgNps.

[Systemic oxidative stress induced by intratracheal instilling with PM10 in rats].

OBJECTIVE: To observe the oxidative stress of serum, lung and heart tissues in rats caused by PM10. METHODS: In the study,24 male Wistar rats weighed 320-360 g were randomly divided into four groups, including one saline control group and three PM10 exposed groups. PM10 was administered to the exposed groups by intratracheal instillation at the doses of 3.75, 7.5, 15 mg/kg, respectively. The rats were sacrificed 24 hours after exposure. The levels of MDA and activities of SOD in the serum, lung and heart tissues were measured. In addition, the contents of protein carbonyl in lung and heart tissues were determined. RESULTS: The activities of SOD in the serum, lung and heart tissues decreased markedly in the 7.5 and 15 mg/kg groups. The levels of MDA in the lung tissues significantly increased in the 7.5 and 15 mg/kg groups, while those in the serum and heart tissues significantly increased only in the 15 mg/kg group. The contents of protein carbonyl in the lung tissues markedly increased in the 15 mg/kg group, but no significant change was found in the heart tissues. CONCLUSION: The study showed that PM10 can cause oxidative stress effects in rats. The lipids of cell membrane are more susceptible to oxidative stress than the proteins.

[Long-term effects of air pollution on the occurrence of respiratory symptoms in adults of Beijing].

OBJECTIVE: To investigate the long-term effects of air pollution on prevalence of respiratory symptoms in adults, in Beijing. METHODS: A cross-sectional study was conducted in an urban area and a suburban area with different levels of air pollution in October 2008, in Beijing. Respiratory symptoms were investigated by a standard questionnaire from the American Thoracic Society (ATS-DLD-78-A) in 9 052 adults who had lived there for at least two years. The concentrations of air pollutants for recent five years were obtained from Reports on the Quality of the Beijing Environment, Environmental Protection Bureau and Statistics Yearbook. The differences of the prevalence and standardized prevalence of respiratory symptoms in adults between the urban and suburban areas were analyzed by χ(2) test. RESULTS: The standardized prevalences of persistent phlegm and asthma in urban adults were significantly higher than those in suburban adults [(3.06% vs. 2.43%, P<0.05) and (0.65% vs. 0.31%, P<0.01), respectively], but lower than that of the breathless (0.75% vs. 1.12%, P<0.05). CONCLUSION: The study suggested that ambient air pollution had long-term effects on the prevalence of some respiratory symptoms in adults.

[The comparison of the indoor environmental factors associated with asthma and related allergies among school-child between urban and suburban areas in Beijing].

OBJECTIVE: To study the indoor environmental factors associated with the prevalence of asthma and related allergies among school children. METHODS: A cluster sampling method was used and the ISAAC questionnaire was conducted. A total of 4612 elementary students under Grade Five of 7 schools were enrolled in the survey for the impact of indoor environmental factors on the prevalence of asthma and related allergies in several urban and suburban schools of Beijing. RESULTS: A total of 4060 sample were finally analyzed including 1992 urban and 2068 suburban. The prevalence of wheeze, allergic rhinoconjunctivitis and atopic eczema in the past 12 months was 3.1% (61/1992), 5.3% (106/1992), 1.1% (22/1992) among urban children while 1.3% (27/2068), 3.1% (65/2068), 1.0% (22/2068) among suburban children respectively. The prevalence of wheeze and allergic rhinoconjunctivitis of the past 12 months in urban were both significantly higher than that in suburban (χ(2) = 14.77, 11.93, P < 0.01). The incidences of having asthma and eczema ever among urban children (5.3% (105/1992), 29.4% (586/1992)) were significantly (χ(2) = 39.03, 147.22, P < 0.01) higher than that among suburban (1.7% (35/2068), 13.8% (285/2068)). Although the distributions of indoor environmental factors were similar in both areas, passive smoking and interior decoration had different influence on the prevalence of asthma and related allergies among school children in the two areas. The significant impact of passive smoking on having asthma ever among suburban children was observed (OR = 2.70, 95%CI = 1.17 - 6.23) while no significant result in urban (OR = 1.06, 95%CI = 0.71 - 1.58); the percentage of interior decoration was 84.0% (1673/1992) among urban children and 80.0% (1655/2068) among suburban children, there was significant impact of interior decoration on the prevalence of having eczema ever among urban children (OR = 1.57, 95%CI = 1.17 - 2.10) but no significant results were found in suburban sample (OR = 1.06, 95%CI = 0.76 - 1.48). CONCLUSION: The prevalence of asthma and related allergies among school children is much higher in urban areas than that in suburban areas and the indoor environmental factors such as passive smoking and interior decoration may differently explain the prevalence of asthma and related allergies in the two areas.

[Short-time effects of inhalable particles and fine particles on children's lung function in a district in Beijing].

OBJECTIVE: To study short-term effects of PM10 (particulate matter of aerodynamic diameter <10 microm) and PM2.5 (particulate matter of aerodynamic diameter <2.5 microm) on children's lung function in one district in Beijing. METHODS: Two hundred and sixteen healthy students aged between 7 and 11 year-old were selected from two primary schools in Beijing in October 2008, and every subject was tested with eight lung function parameters. Levels of PM2.5 in the schoolyards were monitored. Temperature and relative humidity were also recorded. PM10 data was collected from the nearby monitoring sites. The association between children's lung function and PM10 and PM2.5 were analyzed by using ridge regression model. RESULTS: The decrements found in indicators reflecting large airway characteristics including slow vital capacity (SVC), forced vital capacity (FVC), forced expiratory volume in one second (FEV1.0), and in indicators reflecting small airway characteristics including forced expiratory flow between 25% and 75% of vital capacity (FEF25-75), forced expiratory flow after 25% of vital capacity has been expelled (FEF25), forced expiratory flow after 50% of vital capacity has been expelled (FEF50), were associated with accumulated 1-day lagged and 2-day lagged PM2.5 and PM10, while FVC and FEV1.0 decreased more significantly, and the declines of SVC, FVC and FEV1.0 in girls were slightly greater than that in boys. CONCLUSION: PM2.5 and PM10 had short-term adverse health effects on children's lung function. The effects on parameters reflecting large airway characteristics such as FVC and FEV1.0 were even more obvious. The large airways of girls might be more susceptible to ambient particulate matter.

[Pollutions of indoor fine particles in four types of public places and the influencing factors].

OBJECTIVE: To study the levels of pollutions caused by fine particulate matter (PM(2.5)) in the public places and investigate the possible influencing factors. METHODS: A total of 20 public places in four types such as rest room in bath center, restaurant, karaoke bars and cyber cafe in Tongzhou district in Beijing were chosen in this study; indoor and outdoor PM(2.5) was monitored by TSI sidepak AM510. Data under varying conditions were collected and analyzed, such as doors or windows or mechanical ventilation devices being opened, rooms cramped with people and smoking. RESULTS: The average concentration of indoor PM(2.5) in 20 public places was (334.6 +/- 386.3) microg/m(3), ranging from 6 microg/m(3) to 1956 microg/m(3); while in bath center, restaurant, karaoke bars and cyber cafe were (116.9 +/- 100.1)microg/m(3), (317.9 +/- 235.3) microg/m(3), (750.6 +/- 521.6)microg/m(3) and (157.5 +/- 98.5) microg/m(3) respectively. The concentrations of PM(2.5) in restaurant (compared with bath center: Z = -10.785, P < 0.01; compared with karaoke bars: Z = -10.488, P < 0.01; compared with cyber cafe: Z = -7.547, P < 0.01) and karaoke bars (compared with bath center: Z = -16.670, P < 0.01; compared with cyber cafe: Z = -15.682, P < 0.01) were much higher than those in other two places. Single-factor analysis revealed that the average concentration of indoor PM(2.5) in 20 public places was associated with the number of smokers per cube meters(9.13 x 10(-3); r = 0.772, F = 26.579, P < 0.01) and ventilation score [(2.5 +/- 1.5) points; r = 0.667, F = 14.442, P < 0.01], and there were significant correlation between the average indoor and outdoor levels in restaurant [(317.9 +/- 235.3) microg/m(3), (67.8 +/- 78.9) microg/m(3); r = 0.918, F = 16.013, P = 0.028] and cyber cafe [(157.5 +/- 98.5) microg/m(3), (67.7 +/- 43.7) microg/m(3); r = 0.955, F = 30.785, P = 0.012]. Furthermore, significant correlation was observed between the average concentration of indoor PM(2.5) [(157.5 +/- 98.5) microg/m(3)]and the number of people per cube meters (288.7 x 10(-3)) in cyber cafe (r = 0.891, F = 11.615, P = 0.042). Multiple regression analysis showed that smoking (b' = 0.581, t = 3.542, P = 0.003) and ventilation (b' = -0.348, t = -2.122, P = 0.049) were the major factors that may influence the concentration of indoor PM(2.5) in four public places. With cluster analysis, the results showed that the major factors that influence the concentration of indoor PM(2.5) was the outdoor PM(2.5) levels [(49.6 +/- 39.5) microg/m(3); b = 1.556, t = 3.760, P = 0.007] when ventilation (score > 2) was relatively good. The number of smokers per cube meters (14.7 x 10(-3)) became the major influence factor when the ventilation score

[Effects of nanoscale titanium dioxide on intercellular gap junction communication in human lung fibroblasts].

OBJECTIVE: To investigate the effects of nanoscale titanium dioxide (Nano-TiO(2)) on gap junctional intercellular communication (GJIC) between human lung fibroblasts. METHODS: Human lung fibroblasts were exposed to two different sizes Nano-TiO(2) (25 nm and 80 nm) for 24 hours at the concentrations of 0, 10, 20, 40 and 80 mg/L, respectively. The GJIC between cells was measured by using fluorescence redistribution after photobleaching (FRAP) assay. RESULTS: The results showed that GJIC between cells was significantly inhibited both by 25 nm and 80 nm Nano-TiO(2) in a dose-dependent manner. The fluorescence recovery rate was 20.81%+/-1.93% in control group, 7.26%+/-0.91% (P<0.05) in 25 nm 80 mg/L group and 9.94%+/-2.08% (P<0.05) in 80 nm 80 mg/L group. At the same concentration, the inhibitory effect of 25 nm Nano-TiO(2) on GJIC was slightly stronger than that of 80 nm Nano-TiO(2). CONCLUSION: Nano-TiO(2) with different sizes can inhibit GJIC between human lung fibroblasts.

[Relationship between 5,10-methylenetetrahydrofolate reductase genetic polymorphism and arsenic metabolism].

OBJECTIVE: To study the relationship between 5,10-methylenetetrahydrofolate reductase(MTHFR) genetic polymorphism and arsenic metabolism and the role of folate in it. METHODS: Forty-three individuals who were exposed to arsenic more than 0.05 mg/L in well water were chosen and the vein blood and morning urine was collected; The MTHFR C677 polymorphism was analyzed by PCR-RFLP method ; Urinary inorganic and methylated arsenic were speciated by high performance liquid chromatography combined with hydride-generation atomic fluorescence spectrometry; Microbiological assay was used to estimate serum folate. RESULTS: Subjects with the genotype of CT/TT had the increased percentage of urinary As3+ (r=27.17, P=0.029) and decreased percentage of urinary dimethylarsinic acid (r=26.57, P=0.033). No association was observed among serum folate, genetic polymorphisms of MTHFR C677 and the percentage of urinary arsenic (P>0.05). CONCLUSION: Genetic polymorphism of MTHFR C677 was significantly associated with arsenic methylation and this effect was not associated with the serum folate.

[Study on the relationship between methylene tetrahydrofolate reductase gene (677C-->T) mutation and skin lesions in endemic arsenic poisoning].

OBJECTIVE: Methylene tetrahydrofolate reductase (MTHFR) is the key enzyme in folate metabolism. We examined whether single nucleotide 677 C-->T mutation in the MTHFR gene could affect the occurrence of skin lesions in endemic arsenic poisoning. METHODS: Fifty individuals with arsenic-induced skin lesions were identified as cases, and 35 individuals without skin lesions from the same village were selected as controls. The MTHFR C677T polymorphism was analyzed by PCR-RFLP method, serum folic acid and Vitamin B12 were determined by microbiological assay and the electrochemiluminescence immunoassay, respectively. RESULTS: The frequencies of TT genotype and T allele in case group were 34.0% and 56.0%, respectively, and were not significantly different from those in controls. There was no significant difference between case and control group in the levels of folic acid and Vitamin B12 in serum. Compared to subjects carrying the CC genotype and having the level of folic acid above 10.5 nmol/L, other subjects were at elevated risk of skin lesions, but the 95% CI of both crude OR and adjusted OR (controlled for age, gender, smoking and arsenic level in drinking water) include 1. CONCLUSION: This study did not find the relationship between MTHFR gene (677C-->T) mutation and skin lesions in endemic arsenic poisoning.