Association between Traffic-Related Air Pollution,Subclinical Inflammation and Impaired Glucose Metabolism: Results from the SALIA Study

Background

Environmental and lifestyle factors regulate the expression and release of immune mediators. It has been hypothesised that ambient air pollution may be such an external factor and that the association between air pollution and impaired glucose metabolism may be attributable to inflammatory processes. Therefore, we assessed the associations between air pollution, circulating immune mediators and impaired glucose metabolism.

Methods

We analysed concentrations of 14 pro- and anti-inflammatory immune mediators as well as fasting glucose and insulin levels in plasma of 363 women from the Study on the influence of Air pollution on Lung function, Inflammation and Aging (SALIA, Germany). Exposure data for a group of pollutants such as nitrogen oxides (NO₂, NO_x) and different fractions of particulate matter were available for the participants'' residences. We calculated the association between the pollutants and impaired glucose metabolism by multiple regression models.

Results

The study participants had a mean age of 74.1 (SD 2.6) years and 48% showed impaired glucose metabolism based on impaired fasting glucose or previously diagnosed type 2 diabetes. Only long-term exposure NO₂ and NO_x concentrations showed positive associations (NO₂: OR 1.465, 95% CI 1.049-2.046, NO_x: OR 1.409, 95% CI 1.010-1.967) per increased interquartile range of NO₂ (14.65 µg/m³) or NO_x (43.16 µg/m³), respectively, but statistical significance was lost after correction for multiple comparisons. Additional adjustment for circulating immune mediators or the use of anti-inflammatory medication had hardly any impact on the observed ORs.

Conclusions

Our results suggest that exposure to nitrogen oxides may contribute to impaired glucose metabolism, but the associations did not reach statistical significance so that further studies with larger sample sizes are required to substantiate our findings. Our data do not preclude a role of inflammatory mechanisms in adipose or other tissues which may not be reflected by immune mediators in plasma.     

Air travel and incidence of pneumothorax in lymphangioleiomyomatosis

Background

Pulmonary lymphangioleiomyomatosis (LAM) is a rare disease of women characterized by multiple lung cysts leading to respiratory insufficiency and frequent pneumothorax (PT). Air travel (AT) could increase the risk of PT in LAM through rupture of subpleural cysts induced by atmospheric pressure changes in aircraft cabin. To determine whether AT increases the risk of PT in LAM, we performed a retrospective survey of members of European LAM patient associations. A flight-related PT was defined as occurring ≤30?days after AT.

Results

145 women reported 207 PT. In 128 patients with available data, the annual incidence of PT was 8% since the first symptoms of LAM and 5% since LAM diagnosis, compared to 0.006% in the general female population. Following surgical or chemical pleurodesis, the probability of remaining free of PT recurrence was respectively 82, 68, and 59% after 1, 5 and 10?years, as compared to only 55, 46 and 39% without pleurodesis (p?=?0.026). 70 patients with available data performed 178 AT. 6 flight-related PT occurred in 5 patients. PT incidence since first symptoms of LAM was significantly higher ≤30?days after AT as compared to non-flight periods (22 versus 6%, risk ratio 3.58, confidence interval 1.40–7.45).

Conclusions

The incidence of PT in LAM is about 1000 times higher than in the general female population, and is further increased threefold after AT. Chemical or surgical pleurodesis partly reduces the risk of PT recurrence in LAM.

     

Association between Air Pollutants and Asthma Emergency Room Visits and Hospital Admissions in Time Series Studies: A Systematic Review and Meta-Analysis

Background

Air pollution constitutes a significant stimulus of asthma exacerbations; however, the impacts of exposure to major air pollutants on asthma-related hospital admissions and emergency room visits (ERVs) have not been fully determined.

Objective

We sought to quantify the associations between short-term exposure to air pollutants [ozone (O₃), carbon monoxide (CO), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and particulate matter ≤10μm (PM₁₀) and PM_2.5] and the asthma-related emergency room visits (ERV) and hospitalizations.

Methods

Systematic computerized searches without language limitation were performed. Pooled relative risks (RRs) and 95% confidence intervals (95%CIs) were estimated using the random-effect models. Sensitivity analyses and subgroup analyses were also performed.

Results

After screening of 246 studies, 87 were included in our analyses. Air pollutants were associated with significantly increased risks of asthma ERVs and hospitalizations [O₃: RR(95%CI), 1.009 (1.006, 1.011); I² = 87.8%, population-attributable fraction (PAF) (95%CI): 0.8 (0.6, 1.1); CO: RR(95%CI), 1.045 (1.029, 1.061); I² = 85.7%, PAF (95%CI): 4.3 (2.8, 5.7); NO₂: RR(95%CI), 1.018 (1.014, 1.022); I² = 87.6%, PAF (95%CI): 1.8 (1.4, 2.2); SO₂: RR(95%CI), 1.011 (1.007, 1.015); I² = 77.1%, PAF (95%CI): 1.1 (0.7, 1.5); PM₁₀: RR(95%CI), 1.010 (1.008, 1.013); I² = 69.1%, PAF (95%CI): 1.1 (0.8, 1.3); PM_2.5: RR(95%CI), 1.023 (1.015, 1.031); I² = 82.8%, PAF (95%CI): 2.3 (1.5, 3.1)]. Sensitivity analyses yielded compatible findings as compared with the overall analyses without publication bias. Stronger associations were found in hospitalized males, children and elderly patients in warm seasons with lag of 2 days or greater.

Conclusion

Short-term exposures to air pollutants account for increased risks of asthma-related ERVs and hospitalizations that constitute a considerable healthcare utilization and socioeconomic burden.     

Novel RING finger proteins, Air1p and Air2p, interact with Hmt1p and inhibit the arginine methylation of Npl3p

Heterogeneous nuclear ribonucleoproteins (hnRNPs) are involved in the mRNA processing and export and are post-translationally modified by methylation at arginine residues in their arginine-glycine-rich (RGG) domains. We screened the factors that can interact with the RGG domain of Npl3p only in the presence of Hmt1p with the two-hybrid system in Saccharomyces cerevisiae. An isolated clone, YIL079, encodes a novel RING finger protein that was not directly bound to Npl3p but associated with the N terminus of Hmt1p. Thus, we designated the gene product Air1p (arginine methyltransferase-interacting RING finger protein). Air1p inhibited the Hmt1p-mediated methylation of Npl3p in vitro. Overexpression of Air1p repressed the Hmt1p-dependent growth of cells. Since homology searches indicate that the YDL175 gene product has significant identity (45%) with Air1p, we designated the gene AIR2. Air2p also has a RING finger domain and was bound to Hmt1p. Although single disruption of either gene gave no effect on the cell growth, cells lacking Air1p and Air2p grew at an extremely slow rate with accumulated poly(A)(+) RNA in the nucleus. Thus, Air1p and Air2p may affect mRNA transport by regulating the arginine methylation state of heterogeneous nuclear ribonucleoproteins.     

The pressure exerted on the tracheal wall by two endotracheal tube cuffs: A prospective observational bench-top, clinical and radiological study

Background

Recent studies have questioned our previous understanding on the effect of nitrous oxide on muscle relaxants, since nitrous oxide has been shown to potentiate the action of bolus doses of mivacurium, rocuronium and vecuronium. This study was aimed to investigate the possible effect of nitrous oxide on the infusion requirements of cisatracurium.

Methods

70 ASA physical status I-III patients aged 18-75 years were enrolled in this randomized trial. The patients were undergoing elective surgery requiring general anesthesia with a duration of at least 90 minutes. Patients were randomized to receive propofol and remifentanil by target controlled infusion in combination with either a mixture of oxygen and nitrous oxide (Nitrous oxide/TIVA group) or oxygen in air (Air/TIVA group). A 0.1 mg/kg initial bolus of cisatracurium was administered before tracheal intubation, followed by a closed-loop computer controlled infusion of cisatracurium to produce and maintain a 90% neuromuscular block. Cumulative dose requirements of cisatracurium during the 90-min study period after bolus administration were measured and the asymptotic steady state rate of infusion to produce a constant 90% block was determined by applying nonlinear curve fitting to the data on the cumulative dose requirement during the study period.

Results

Controller performance, i.e. the ability of the controller to maintain neuromuscular block constant at the setpoint and patient characteristics were similar in both groups. The administration of nitrous oxide did not affect cisatracurium infusion requirements. The mean steady-state rates of infusion were 0.072 +/- 0.018 and 0.066 +/- 0.017 mg * kg-1 * h-1 in Air/TIVA and Nitrous oxide/TIVA groups, respectively.

Conclusions

Nitrous oxide does not affect the infusion requirements of cisatracurium.

Trial registration

ClinicalTrials.gov NCT01152905; European Clinical Trials Database at http://eudract.emea.eu.int/2006-006037-41.     

Ambient Air Pollution and Birth Defects in Brisbane,Australia

Background

Birth defects are a major public health concern as they are the leading cause of neonatal and infant mortality. Observational studies have linked environmental pollution to adverse birth outcomes, including congenital anomalies. This study examined potential associations between ambient air pollution and congenital heart defects and cleft lip or palate among births in Brisbane, Australia (1998–2004).

Methods

Ambient air pollution levels were averaged over weeks 3–8 of pregnancy among 150,308 births. Using a case–control design, we used conditional logistic regression and matched cases to 5 controls. Analyses were conducted using all births, and then births where the mother resided within 6 and 12 kilometers of an ambient air quality monitor.

Findings

When analyzing all births there was no indication that ambient air pollution in Brisbane was associated with a higher risk of cardiac defects. Among births where the mother resided within 6 kilometers of an ambient air quality monitor, a 5 ppb increase in O₃ was associated with an increased risk of pulmonary artery and valve defects (OR 2.96, 95% CI: 1.34, 7.52) while a 0.6 ppb increase in SO₂ was associated with an increased risk of aortic artery and valve defects (OR 10.76, 95% CI: 1.50, 179.8). For oral cleft defects among all births, the only adverse association was between SO₂ and cleft lip with or without cleft palate (OR 1.27, 95% CI: 1.01, 1.62). However, various significant inverse associations were also found between air pollutants and birth defects.

Conclusions

This study found mixed results and it is difficult to conclude whether ambient air pollution in Brisbane has an adverse association with the birth defects examined. Studies using more detailed estimates of air pollution exposure are needed.     

The Cost of Simplifying Air Travel When Modeling Disease Spread

Background

Air travel plays a key role in the spread of many pathogens. Modeling the long distance spread of infectious disease in these cases requires an air travel model. Highly detailed air transportation models can be over determined and computationally problematic. We compared the predictions of a simplified air transport model with those of a model of all routes and assessed the impact of differences on models of infectious disease.

Methodology/Principal Findings

Using U.S. ticket data from 2007, we compared a simplified “pipe” model, in which individuals flow in and out of the air transport system based on the number of arrivals and departures from a given airport, to a fully saturated model where all routes are modeled individually. We also compared the pipe model to a “gravity” model where the probability of travel is scaled by physical distance; the gravity model did not differ significantly from the pipe model. The pipe model roughly approximated actual air travel, but tended to overestimate the number of trips between small airports and underestimate travel between major east and west coast airports. For most routes, the maximum number of false (or missed) introductions of disease is small (<1 per day) but for a few routes this rate is greatly underestimated by the pipe model.

Conclusions/Significance

If our interest is in large scale regional and national effects of disease, the simplified pipe model may be adequate. If we are interested in specific effects of interventions on particular air routes or the time for the disease to reach a particular location, a more complex point-to-point model will be more accurate. For many problems a hybrid model that independently models some frequently traveled routes may be the best choice. Regardless of the model used, the effect of simplifications and sensitivity to errors in parameter estimation should be analyzed.     

Air sampling of its pheromone to monitor the occurrence of Osmoderma eremita, a threatened beetle inhabiting hollow trees

Osmoderma eremita is a threatened scarab beetle living in the hollows of old deciduous trees and is regarded as an umbrella species of the beetle fauna associated with this habitat. Several methods like pitfall trapping and wood mould sampling have been used to monitor the occurrence of O. eremita, but these methods cannot be applied for trees with certain characteristics. Recently, (R)-(+)--decalactone was identified as a male-produced sex pheromone of the species. Here, we show that -decalactone can be detected in hollow trees by air sampling and that the presence of the compound is strongly correlated with the occurrence of living male beetles in the same trees. Air was sampled from tree cavities and extracts analysed using gas chromatography–and mass spectrometry. There was a 89% match between the detection of -decalactone in extracts and the occurrence of male O. eremita±2 days from the sampling event. In the absence of males, samples never contained -decalactone, and the presence of this compound in a tree cavity appears to be a good predictor of O. eremita occupancy. Air sampling can be a useful complement to other methods when trying to detect as many trees housing this beetle as possible, which is crucial when estimating populations sizes and developing conservation strategies for this species.     

Some results in graph theory and their application to abstract relational biology

It has been shown in earlier work that one approach to what Rashevsky has called “abstract biology” is through the study of the class of ( )-systems that can be formed in an arbitrary subcategory of the category of sets. The concept of the ( )-system, however, depends on the availability of mappings that contain other mappings in their range. It is shown that, by introducing an appropriate measure for this property, the problem of characterizing those categories suitable for a rich theory of ( )-systems reduces to a problem familiar from the general theory of graphs. Some new results in these directions are obtained, and it is then shown that any category with mappings that possess properties we might expect to hold in the physical world will also admit a rich theory of ( )-systems. In particular, it is shown that a sufficiently large family of mappings drawn at random from such a category will with overwhelming probability contain an ( )-system. This research was supported by the United States Air Force through the Air Force Office of Scientific Research of the Air Research and Development Command, under Grant No. AF-AFOSR-9-63.     

Investigation of Elements Sufficient To Imprint the Mouse Air Promoter

Imprinted maternal-allele-specific expression of the mouse insulin-like growth-factor type 2 receptor (Igf2r) gene depends on a 3.7-kb element named region 2, located in the second intron of the gene. Region 2 carries a maternal-allele-specific methylation imprint and contains an imprinted CpG island promoter (Air) that expresses a noncoding antisense RNA from the paternal inherited allele only. Here, we use transgenes to test the minimal requirements for imprinting of Air and to test if the action of region 2 is restricted to Igf2r. Transgenes up to 9 kb with Air as a single promoter are expressed but not imprinted. When coupled to the Igf2r CpG island promoter on a 44-kb transgene, Air was imprinted in one of three lines. However, Air on a 4.6-kb fragment is also imprinted in 2 of 14 lines when inserted in an intron of an adenine phosphoribosyltransferase (Aprt) transgene, and in one line, the imprinted methylation and expression of Air have been transferred onto the Aprt CpG island promoter. These data suggest that a dual CpG island promoter setting may facilitate Air imprinting as a short transgene and also show that Air can transfer imprinting onto other genes. However, for reliable Air imprinting, elements are necessary that are located outside a 44-kb region spanning the Air-Igf2r promoters.     

Lacrimal Cytokines Assessment in Subjects Exposed to Different Levels of Ambient Air Pollution in a Large Metropolitan Area

Background

Air pollution is one of the most environmental health concerns in the world and has serious impact on human health, particularly in the mucous membranes of the respiratory tract and eyes. However, ocular hazardous effects to air pollutants are scarcely found in the literature.

Design

Panel study to evaluate the effect of different levels of ambient air pollution on lacrimal film cytokine levels of outdoor workers from a large metropolitan area.

Methods

Thirty healthy male workers, among them nineteen professionals who work on streets (taxi drivers and traffic controllers, high pollutants exposure, Group 1) and eleven workers of a Forest Institute (Group 2, lower pollutants exposure compared to group 1) were evaluated twice, 15 days apart. Exposure to ambient PM_2.5 (particulate matter equal or smaller than 2.5 μm) was 24 hour individually collected and the collection of tears was performed to measure interleukins (IL) 2, 4, 5 and 10 and interferon gamma (IFN-γ) levels. Data from both groups were compared using Student’s t test or Mann- Whitney test for cytokines. Individual PM_2.5 levels were categorized in tertiles (lower, middle and upper) and compared using one-way ANOVA. Relationship between PM_2.5 and cytokine levels was evaluated using generalized estimating equations (GEE).

Results

PM_2.5 levels in the three categories differed significantly (lower: ≤22 μg/m³; middle: 23–37.5 μg/m³; upper: >37.5 μg/m³; p<0.001). The subjects from the two groups were distributed unevenly in the lower category (Group 1 = 8%; Group 2 = 92%), the middle category (Group 1 = 89%; Group 2 = 11%) and the upper category (Group 1 = 100%). A significant relationship was found between IL-5 and IL-10 and PM_2.5 levels of the group 1, with an average decrease of 1.65 pg/mL of IL-5 level and of 0.78 pg/mL of IL-10 level in tear samples for each increment of 50 μg/m3 of PM_2.5 (p = 0.01 and p = 0.003, respectively).

Conclusion

High levels of PM_2.5 exposure is associated with decrease of IL-5 and IL-10 levels suggesting a possible modulatory action of ambient air pollution on ocular surface immune response.     

Protien purification: Principles,high resolution methods,and applications

Book Review

Protien purification: Principles, high resolution methods, and applicationsJan-Christer janson and Lars Ryden (Eds.), Weinheim: Verlag Chemie, 1989. xi + 502 pages. DM124.00; £44.45. ISBN 3-527-261-84-2     

Stomatal regulation in a changing climate: a field study using Free Air Temperature Increase (FATI) and Free Air CO2 Enrichment (FACE)

This study investigates effects of climate warming (+ 2.5°C ubove ambient) and elevated CO₂ concentration (600 μmol mol^?1) on the stomatal functioning and the water relations of Lolium perenne, using Free Air Temperature Increase (FATI) and Free Air CO₂ Enrichment (FACE). Compared to growth at ambient temperature, whole-season temperature increase reduced leaf stomatal conductance, but only at the top of the canopy (-14.6 and -8.8% at ambient and elevated CO₂, respectively). However, because higher canopy temperature raised the leaf-to-air vapour pressure difference, leaf transpiration rate increased (+28% at ambient and +48% at elevated CO₂) and instantaneous leaf water use efficiency, derived from short-term measurements of assimilation and transpiration rate, declined (-11% at ambient and -13% at elevated CO₂). Nevertheless, at the stand level, growth at + 2.5°C reduced transpiration due to fewer tillers per plant and a smaller leaf area per tiller. This sparser vegetation was also more closely coupled to the atmosphere and maintained a drier internal microclimate. To assess whether the stomatal behaviour observed in this experiment could be explained by prevailing concepts of stomatal functioning, three models were applied (Cowan 1977; Ball, Woodrow & Berry 1987; Leuning 1995). The latter model accounted for the highest proportion of variability in the data (58%) and was insensitive to CO₂ and temperature regime, which suggests that the principles of stomatal regulation are not affected by changes in CO₂ or climate.     

Association between Traffic-Related Air Pollution in Schools and Cognitive Development in Primary School Children: A Prospective Cohort Study

Background

Air pollution is a suspected developmental neurotoxicant. Many schools are located in close proximity to busy roads, and traffic air pollution peaks when children are at school. We aimed to assess whether exposure of children in primary school to traffic-related air pollutants is associated with impaired cognitive development.

Methods and Findings

We conducted a prospective study of children (n = 2,715, aged 7 to 10 y) from 39 schools in Barcelona (Catalonia, Spain) exposed to high and low traffic-related air pollution, paired by school socioeconomic index; children were tested four times (i.e., to assess the 12-mo developmental trajectories) via computerized tests (n = 10,112). Chronic traffic air pollution (elemental carbon [EC], nitrogen dioxide [NO2], and ultrafine particle number [UFP; 10–700 nm]) was measured twice during 1-wk campaigns both in the courtyard (outdoor) and inside the classroom (indoor) simultaneously in each school pair. Cognitive development was assessed with the n-back and the attentional network tests, in particular, working memory (two-back detectability), superior working memory (three-back detectability), and inattentiveness (hit reaction time standard error). Linear mixed effects models were adjusted for age, sex, maternal education, socioeconomic status, and air pollution exposure at home.Children from highly polluted schools had a smaller growth in cognitive development than children from the paired lowly polluted schools, both in crude and adjusted models (e.g., 7.4% [95% CI 5.6%–8.8%] versus 11.5% [95% CI 8.9%–12.5%] improvement in working memory, p = 0.0024). Cogently, children attending schools with higher levels of EC, NO2, and UFP both indoors and outdoors experienced substantially smaller growth in all the cognitive measurements; for example, a change from the first to the fourth quartile in indoor EC reduced the gain in working memory by 13.0% (95% CI 4.2%–23.1%). Residual confounding for social class could not be discarded completely; however, the associations remained in stratified analyses (e.g., for type of school or high-/low-polluted area) and after additional adjustments (e.g., for commuting, educational quality, or smoking at home), contradicting a potential residual confounding explanation.

Conclusions

Children attending schools with higher traffic-related air pollution had a smaller improvement in cognitive development.     

Indoor Air as a Source of VOC Contamination in Shallow Soils Below Buildings

US EPA and many state regulatory agency guidance documents recommend below-foundation vapor sampling as a key element of site investigations to determine if vapor migration from underlying soil into buildings is a completed exposure pathway (USEPA, 2002 US EPA (U.S. Environmental Protection Agency). Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils (Subsurface Vapor Intrusion Guidance). November2002.  [Google Scholar]; WIDHFS, 2003 WIDHFS (Wisconsin Department of Health and Family Services). Chemical Vapor Intrusion and Residential Indoor Air, Guidance for Environmental Consultants and Contractors. June202004. Available at http://dhfs.wisconsin.gov/eh/Air/fs/VI_prof.htm (accessed) [Google Scholar]; San Diego County, 2004 San Diego County Department of Environmental Health. Site Assessment and Mitigation (SAM) Manual. June202004. http://www.sdcounty.ca.gov/deh/lwq/sam/vapor_risk_assessment_2000.html (accessed) [Google Scholar]; PADEP, 2004 PADEP (Pennsylvania Department of Environmental Protection). Land Recycling Program Technical Guidance Manual-Section IV.A.4. June202004. Vapor Intrusion into Buildings from Groundwater and Soil under Act 2 Statewide Health Standard. Document Number 253-0300-100. http://www.dep.state.pa.us/eps/default.asp (accessed) [Google Scholar]). If volatile organic compounds (VOCs) are detected below the building foundation, then VOC migration from the subsurface is assumed to be occurring, and further investigation is needed to determine the extent of the VOC impact. These guidance documents are predicated on the assumption that VOCs detected in below-foundation samples have originated from deeper within the subsurface. However, detection of VOCs in below-foundation vapor samples alone is not sufficient to conclude that the VOCs are migrating from the subsurface upward towards a building. VOCs detected in below-foundation vapor samples can originate from indoor sources, migrating down through the slab by diffusion or advection. Commonly referenced conceptual models for vapor intrusion address VOC migration from the subsurface into buildings but do not consider the potential for VOC migration from buildings into the subsurface (USEPA, 2002 US EPA (U.S. Environmental Protection Agency). Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils (Subsurface Vapor Intrusion Guidance). November2002.  [Google Scholar]; Johnson and Ettinger, 1991 Johnson, P. C. and Ettinger, R. A. 1991. Heuristic model for the intrusion rate of contaminant vapors into buildings. Environ. Sci. Technol., 25(8): 1445–1452. [CSA][CROSSREF][Crossref], [Web of Science ®] [Google Scholar]; Parker, 2003 Parker, J. C. 2003. Modeling volatile chemical transport, biodecay, and emission to indoor air. Ground Water Mon. Remed., 23(1): 107–120. [CSA][Crossref], [Web of Science ®] [Google Scholar]). The advective and diffusive forces that lead to the migration of VOCs from the subsurface into buildings are equally likely to result in the migration of VOCs from buildings into the subsurface when pressure or concentration gradients support such migration. In this paper we present: i) pressure gradient measurements indicating bi-directional advective flow across building foundations, ii) simple modeling indicating that indoor sources of VOCs may cause subsurface impacts through advection across the building foundation, and iii) field data from a site where indoor sources rather than subsurface contamination were the source of VOCs detected in below-foundation vapor samples.     

Quantification of Shared Air: A Social and Environmental Determinant of Airborne Disease Transmission

Background

Tuberculosis is endemic in Cape Town, South Africa where a majority of the population become tuberculosis infected before adulthood. While social contact patterns impacting tuberculosis and other respiratory disease spread have been studied, the environmental determinants driving airborne transmission have not been quantified.

Methods

Indoor carbon dioxide levels above outdoor levels reflect the balance of exhaled breath by room occupants and ventilation. We developed a portable monitor to continuously sample carbon dioxide levels, which were combined with social contact diary records to estimate daily rebreathed litres. A pilot study established the practicality of monitor use up to 48-hours. We then estimated the daily volumes of air rebreathed by adolescents living in a crowded township.

Results

One hundred eight daily records were obtained from 63 adolescents aged between 12- and 20-years. Forty-five lived in wooden shacks and 18 in brick-built homes with a median household of 4 members (range 2–9). Mean daily volume of rebreathed air was 120.6 (standard error: 8.0) litres/day, with location contributions from household (48%), school (44%), visited households (4%), transport (0.5%) and other locations (3.4%). Independent predictors of daily rebreathed volumes included household type (p = 0.002), number of household occupants (p = 0.021), number of sleeping space occupants (p = 0.022) and winter season (p<0.001).

Conclusions

We demonstrated the practical measurement of carbon dioxide levels to which individuals are exposed in a sequence of non-steady state indoor environments. A novel metric of rebreathed air volume reflects social and environmental factors associated with airborne infection and can identify locations with high transmission potential.     

Long-Term Exposure to Ambient Air Pollution and Metabolic Syndrome in Adults

Air pollutants (AP) play a role in subclinical inflammation, and are associated with cardiovascular morbidity and mortality. Metabolic syndrome (MetS) is inflammatory and precedes cardiovascular morbidity and type 2 diabetes. Thus, a positive association between AP and MetS may be hypothesized. We explored this association, (taking into account, pathway-specific MetS definitions), and its potential modifiers in Swiss adults. We studied 3769 participants of the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults, reporting at least four-hour fasting time before venepuncture. AP exposures were 10-year mean residential PM₁₀ (particulate matter <10μm in diameter) and NO₂ (nitrogen dioxide). Outcomes included MetS defined by World Health Organization (MetS-W), International Diabetes Federation (MetS-I) and Adult Treatment Panel-III (MetS-A) using four- and eight-hour fasting time limits. We also explored associations with individual components of MetS. We applied mixed logistic regression models to explore these associations. The prevalence of MetS-W, MetS-I and MetS-A were 10%, 22% and 18% respectively. Odds of MetS-W, MetS-I and MetS-A increased by 72% (51-102%), 31% (11-54%) and 18% (4-34%) per 10μg/m³ increase in 10-year mean PM₁₀. We observed weaker associations with NO₂. Associations were stronger among physically-active, ever-smokers and non-diabetic participants especially with PM₁₀ (p<0.05). Associations remained robust across various sensitivity analyses including ten imputations of missing observations and exclusion of diabetes cases. The observed associations between AP exposure and MetS were sensitive to MetS definitions. Regarding the MetS components, we observed strongest associations with impaired fasting glycemia, and positive but weaker associations with hypertension and waist-circumference-based obesity. Cardio-metabolic effects of AP may be majorly driven by impairment of glucose homeostasis, and to a less-strong extent, visceral adiposity. Well-designed prospective studies are needed to confirm these findings.     

Experimental technique for growth of Trichophyton mentagrophytes on fabric

Various techniques were used to develop a method for the growth ofTrichophyton mentagrophytes on fabrics. Air Force sock samples composed of wool, nylon and cotton mixtures were used as test materials. Growth of the organism on sock samples was obtained at 23°C and 70% relative humidity after seeding with horsehair spraying with yeast extract.Contribution no. 162. Department of Infectious Diseases, College of Veterinary Medicine, Kansas Agricultural Experiment Station, Manhattan, 66502.This study was supported under the Project Themis Program (USAFORSR Contract F 44620-68-C-0020 sponsored by the United States Air Force).