The role of domestic factors and day-care attendance on lung function of primary school children.
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The results of studies examining the relationship of domestic factors to lung function are contradictory. We therefore examined the independent effects of maternal smoking during pregnancy, exposure to environmental tobacco smoke (ETS), the presence of a cat, type of heating and cooking used in the home and day-care attendance on lung function after controlling for socioeconomic status (SES). Nine hundred and eighty-nine children from 18 Montreal schools were studied between April 1990 and November 1992. Information on the child's health and exposure to domestic factors was collected by questionnaire. Spirometry was performed at school. The data were analysed by multiple linear regression with percent predicted FEV1, FVC, and FEV1/FVC as dependent variables. In the overall sample (both sexes combined), cat in the home (regression coefficient, beta = -1.15, 95% confidence interval, CI: -2.26-(-)0.05) and electric baseboard units (beta = -1.26, 95% CI: -2.39-(-)0.13) were independently associated with a lower FEV1/FVC, while day-care attendance (beta = -2.05, 95% CI: -3.71-(-)0.40) significantly reduced FEV1. Household ETS was significantly associated with increasing level of FVC (beta = 2.86, 95% CI: +0.55 to +5.17). In boys but not girls, household ETS (beta = -2.13, 95% CI: -4.07-(-)0.19) and the presence of a cat (beta = -2.19, 95% CI: -3.94-(-)0.45) were associated with lower FEV1/FVC. By contrast, day-care attendance was associated with lower FEV1 (beta = -2.92, 95% CI: -5.27-(-)0.56) and FEV1/FVC (beta = -1.53, 95% CI: -2.73-(-)0.33) in girls only. In conclusion, the results provide evidence that domestic factors and day-care attendance primarily affected airway caliber and gender differences were apparent in the effects of these factors. (+info)
Stimulation of IL-8 release from epithelial cells by gas cooker PM(10): a pilot study.
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OBJECTIVE: To measure the effect of matter collected by a method that has a 50% efficiency for particles with an aerodynamic diameter of 10 microm (PM10), generated by gas and electric cooking, on A549 epithelial cells with and without nitrogen dioxide (NO2). METHOD: Multiple indoor PM10 samples were collected on Teflon filters during the use of gas or electric cookers. Interleukin-8 (IL-8) concentrations were measured with a sandwich enzyme linked immunosorbent assay (ELISA) system. RESULTS: Treatment of A549 cells with PM10 generated from gas cooking resulted in increased concentrations of IL-8 compared with untreated cells; particles from the electric cooker had no effect. NO2 did not alter the concentration of IL-8. CONCLUSION: PM10 generated by gas cooking has the potential to cause proinflammatory effects in lung cells. This may have implications for susceptible people. (+info)
Interrelations of lead levels in bone, venous blood, and umbilical cord blood with exogenous lead exposure through maternal plasma lead in peripartum women.
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Recent research has raised the possibility that fetal lead exposure is not estimated adequately by measuring lead content in maternal whole blood lead because of the variable partitioning of lead in whole blood between plasma and red blood cells. Lead in maternal plasma may derive in large part from maternal bone lead stores. In this study we aimed to estimate the contribution of maternal whole blood lead, maternal bone lead levels, and environmental lead to umbilical cord blood lead levels (as a measure of fetal lead exposure). In the model, we assumed that lead from all of these sources reaches the fetus through the maternal plasma lead pathway. In 1994-1995, we recruited 615 pregnant women for a study of lead exposure and reproductive outcomes in Mexico City. We gathered maternal and umbilical cord blood samples within 12 hr of each infant's delivery and measured maternal lead levels in cortical bone and trabecular bone by a K-X-ray fluorescence (K-XRF) instrument within 1 month after delivery. We administered a questionnaire to assess use of lead-glazed ceramics (LGC) to cook food and we obtained data on regional air lead levels during the 2 months before delivery. We used structural equation models (SEMs) to estimate plasma lead as the unmeasured (latent) variable and to quantify the interrelations of plasma lead, the other lead biomarkers, and environmental lead exposure. In the SEM analysis, a model that allowed plasma lead to vary freely from whole blood lead explained the variance of cord blood lead (as reflected by a total model R(2); R(2) = 0.79) better than did a model without plasma lead (r(2) = 0.67). Cortical bone lead, trabecular bone lead, use of LGC, and mean air lead level contributed significantly to plasma lead. The exchange of lead between plasma and red blood cells was mostly in the direction of plasma to cells. According to the final model, an increase in trabecular bone lead and cortical bone lead was associated with increases in cord blood lead of 0.65 and 0.25 microg/dL, respectively. An increase of 0.1 microg/m(3) in air lead was associated with an increase in the mean level of fetal cord blood lead by 0.67 microg/dL. With one additional day of LCG use per week in the peripartum period, the mean fetal blood lead level increased by 0.27 microg/dL. Our analyses suggested that maternal plasma lead varies independently from maternal whole blood lead and that the greatest influences on maternal plasma lead are maternal bone lead stores, air lead exposures, and recent cooking with LGC. The contributions from endogenous (bone) and exogenous (environmental) sources were relatively equal. Measurement of plasma and bone lead may be important in accurately assessing fetal lead exposure and its major sources, particularly if exogenous exposures decline. (+info)
Ultrafine particles and nitrogen oxides generated by gas and electric cooking.
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OBJECTIVES: To measure the concentrations of particles less than 100 nm diameter and of oxides of nitrogen generated by cooking with gas and electricity, to comment on possible hazards to health in poorly ventilated kitchens. METHODS: Experiments with gas and electric rings, grills, and ovens were used to compare different cooking procedures. Nitrogen oxides (NO(x)) were measured by a chemiluminescent ML9841A NO(x) analyser. A TSI 3934 scanning mobility particle sizer was used to measure average number concentration and size distribution of aerosols in the size range 10-500 nm. RESULTS: High concentrations of particles are generated by gas combustion, by frying, and by cooking of fatty foods. Electric rings and grills may also generate particles from their surfaces. In experiments where gas burning was the most important source of particles, most particles were in the size range 15-40 nm. When bacon was fried on the gas or electric rings the particles were of larger diameter, in the size range 50-100 nm. The smaller particles generated during experiments grew in size with time because of coagulation. Substantial concentrations of NO(X) were generated during cooking on gas; four rings for 15 minutes produced 5 minute peaks of about 1000 ppb nitrogen dioxide and about 2000 ppb nitric oxide. CONCLUSIONS: Cooking in a poorly ventilated kitchen may give rise to potentially toxic concentrations of numbers of particles. Very high concentrations of oxides of nitrogen may also be generated by gas cooking, and with no extraction and poor ventilation, may reach concentrations at which adverse health effects may be expected. Although respiratory effects of exposure to NO(x) might be anticipated, recent epidemiology suggests that cardiac effects cannot be excluded, and further investigation of this is desirable. (+info)
Nitrogen dioxide exposure from domestic gas cooking and airway response in asthmatic women.
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BACKGROUND: Previous studies have not found a consistent association between exposure to domestic cooking using gas appliances and exacerbation of asthma. We investigated the immediate airflow response to acute exposure from single episodes of gas cooking, and peak airflow variability from continued exposure to repeated episodes of gas cooking in a group of non-smoking asthmatic women. METHODS: Sixteen adult non-smoking women with mild to severe persistent asthma were studied. The acute short term level of nitrogen dioxide (NO2) during gas cooking episodes and the mean exposure to NO2 from repeated gas cooking episodes were measured over a 2 week period, as well as proxy measures of frequency of cooking on each day and the length of time spent cooking each day. Their asthma status was monitored using peak expiratory flow rates (PEFR) before and after cooking, 2 week self-recorded serial readings of PEFR, respiratory symptom severity score, and use of rescue bronchodilators for acute asthma attacks. RESULTS: Cooking was significantly associated with an immediate mean fall in PEFR of 3.4% (p=0.015, paired t test). The acute short term NO2 level during cooking was significantly correlated with the fall in PEFR (r=-0.579; p=0.019). The frequency of cooking over a 2 week period was positively correlated with the mean exposure to NO2 (r=0.529; p=0.042). Continued exposure to NO2 over a 2 week period was associated significantly with increased frequency of rescue bronchodilator usage for asthma attacks (r=0.597; p=0.031). However, it was negatively associated with PEFR variability (r=-0.512; p=0.051) and respiratory symptom severity score (r= -0.567; p=0.043), probably due to the masking effects of bronchodilator treatment. CONCLUSIONS: Acute short term exposure to NO2 from single episodes of gas cooking is associated with immediate airflow limitation. Continued exposure from repeated episodes of gas cooking in asthmatic women is associated with greater use of rescue bronchodilators. (+info)
Potential role of fomites in the vehicular transmission of human astroviruses.
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The persistence of human astroviruses dried on representative porous (paper) and nonporous (china) surfaces was investigated. Long-term astrovirus survival on fomites was monitored by an integrated cell culture-reverse transcription-PCR procedure. Viruses were applied to inanimate surfaces in the presence and absence of fecal material, and their survival was assayed at 4 and 20 degrees C with high relative humidity. Astroviruses exhibited a notable persistence when dried on porous and nonporous materials, particularly at low temperature. Short-term survival of astroviruses on fomites was compared to that of other enteric viruses significant for health, such as rotavirus, adenovirus, poliovirus, and hepatitis A virus. Overall, astroviruses persisted better than poliovirus and adenovirus, although they exhibited a shorter survival than rotavirus and hepatitis A virus. Astroviruses show a high level of persistence at the desiccation step, which is of major significance in determining the chance of subsequent virus survival dried on fomites. Astroviruses are able to survive on inert surfaces long enough to suggest that fomites may play a relevant role in the secondary transmission of astrovirus diarrhea. (+info)
An industrial approach to evaluation of pyrolysis and combustion hazards.
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In addition to the usual toxicology studies necessary for the safe manufacture and use of polymers at room temperature, special studies are needed for polymers which will be used at elevated temperatures. This paper discusses various areas to be investigated and principles for deciding on test materials, tests, and test conditions, polytetrafluoroethylene (PTFE) and fluorinated polyethylene-propylene (PFEP) pyrolysis studies being used as an illustrative case history. Some limitations of animal testing also are mentioned. A toxicological spectrum relating toxicological determinants to PTFE temperature is developed. (+info)
Effects of seasoning and heating device on mutagenicity and heterocyclic amines in cooked beef.
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Pan-roasted beef showed a lower mutagenicity after various degrees of cooking than charcoaled one. The high mutagenicity of charcoaled beef was due to the formation of more heterocyclic amines, especially AalphaC (2-amino-9H-pyrido- [2,3-b]indole) and PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine) because of rapid and direct heating on the surface of the meat at a high temperature. Seasoning decreased mutagenicity of pan-roasted beef except the very well done sample with unchanged heterocyclic amine contents, but increased mutagenicity of charcoaled beef with decreased levels of AalphaC and PhIP, probably due to the change of heterocyclic amine precursors or alternatively to the occurrence of other mutagens. (+info)