Alterations in carbohydrate levels in leaves of Populus due to ambient air pollution

Cuttings of Populus nigra L. cv. Loenen and Populus maximowiczii Henri × Populus nigra L. cv. Rochester were exposed for 6 weeks in open-top chambers to investigate effects of realistic mixtures of ozone, sulphur dioxide, and nitrogen oxides on carbohydrate levels. Whereas the total main nonstructural carbohydrates in the leaves were reduced, those in the roots were nearly not affected. The reduction in leaf carbohydrates was associated with a significant decrease in starch. In contrast, sucrose and especially glucose were increased, causing a shift in the starch to sucrose and the starch to glucose ratios. The effects were strongest in the older leaves of both cultivars, with cv. Loenen, especially, responding to ozonic mixtures. In the petioles, sucrose and glucose were unchanged or, in some cases, decreased. The alterations in carbohydrate levels were coupled to a reduction in both total fresh weight of leaves and total dry matter of roots, and were attributed to an air pollution-dependent demand for energy and carbon in leaves.     

Analysis of allergens in ambient aerosols: Comparison of areas subjected to different levels of air pollution

Recent studies describe interactions of pollen surfaces with aerosol particles; pollen surfaces undergo morphological changes and the release of allergens and allergenic fragments from the pollen can be enhanced. Thus allergens from pollen can be found in particle size fractions much smaller than undamaged pollen (<5 μm). This may explain allergic reactions in parts of the lungs which cannot be reached by undamaged pollen. In Switzerland the birch tree (betula verrucosa) major allergen Bet v 1 and the grass (phleum pratense) pollen major allergen Phl p 5 are of particular relevance for inducing pollinosis. In this study aerosols of different aerodynamic diameters were sampled by Andersen-Impactors over 18 months. Sampling areas are subjected to different levels of air pollution (Zürich, Switzerland, urban; Payerne, Switzerland, rural; Davos, Switzerland, alpine). Samples were scanned by electron microscopy and submitted to specific allergen assays (ELISA) for birch pollen major allergen Bet v 1 and grass pollen major allergen Phl p 5 respectively. Particle and major allergen concentrations were highest in Zürich, followed by Payerne and, significantly lower, Davos. Scanning electron microscopy investigations showed interactions of aerosols with pollen surfaces in Zürich and Payerne. The presence of Bet v 1 in smaller aerosol fractions was demonstrated in Zürich and Payerne some weeks before and after birch pollen was counted. An erratum to this article is available at .     

Analysis of allergens in ambient aerosols: Comparison of areas subjected to different levels of air pollution

Recent studies describe interactions of pollen surfaces with aerosol particles; pollen surfaces undergo morphological changes and the release of allergens and allergenic fragments from the pollen can be enhanced. Thus allergens from pollen can be found in particle size fractions much smaller than undamaged pollen (<5m). This may explain allergic reactions in parts of the lungs which cannot be reached by undamaged pollen. In Switzerland the birch tree (betula verrucosa) major allergen Bet v 1 and the grass (phleum pratense) pollen major allergen Phl p 5 are of particular relevance for inducing pollinosis. In this study aerosols of different aerodynamic diameters were sampled by Andersen-Impactors over 18 months. Sampling areas are subjected to different levels of air pollution (Zürich, Switzerland, urban; Payerne, Switzerland, rural: Davos, Switzerland, alpine). Samples were scanned by electron microscopy and submitted to specific allergen assays (ELISA) for birch pollen major allergen Bet v 1 and grass pollen major allergen Phl p 5 respectively. Particle and major allergen concentrations were highest in Zürich, followed by Payerne and, significantly lower, Davos. Scanning electron microscopy investigations showed interactions of aerosols with pollen surfaces in Zürich and Payerne. The presence of Bet v 1 in smaller aerosol fractions was demonstrated in Zürich and Payerne some weeks before and after birch pollen was counted.     

Metabolic syndrome is not a risk factor for kidney dysfunction in obese non-diabetic subjects

Objective: To investigate whether insulin resistance (IR) and the metabolic syndrome (MS) are associated with kidney dysfunction in obese non‐diabetic (OND) subjects. Methods and Procedures: Three‐hundred and eighty (113M/267F; age = 41 ± 14 years) OND subjects (BMI ≥ 30 kg/m²; range = 43 ± 8 kg/m²) were studied. Anthropometric measures, blood pressure, fasting glucose, insulin, lipid profile, and serum creatinine were evaluated. Glomerular filtration rate (GFR) was estimated (e‐GFR) with the Modification of Diet in Renal Disease equation. Chronic kidney disease (CKD) was defined as e‐GFR <60 ml/min/1.73 m². Results: e‐GFR was associated with gender (being lower in women) (P = 0.001) and age (P < 0.0001). CKD was present in 32 subjects (8.4%), who were older (P < 0.0001) and more frequently affected by hypertension (P = 0.04) as compared to subjects without CKD. MS was present in 212 (55.8%) subjects. They were older (P< 0.001), had lower e‐GFR (P = 0.02) and were more frequently affected by CKD (odds ratio (OR), 95% confidence interval (CI) = 2.3, 1.1–5.1) than those without MS. However, differences in e‐GFR values and in the risk of CKD were no longer statistically significant after adjusting for age (P = 0.99 for e‐GFR and OR, 95% CI = 1.2, 0.5–2.8 for the risk of CKD, respectively). Homeostasis model assessment of IR (HOMA_IR) index was neither higher in subject with CKD (P = 0.1) nor inversely correlated with e‐GFR (r = 0.1, P = 0.1). Discussion: In OND individuals the risk of CKD is independent of the MS and related abnormalities. This suggests that these individuals are not susceptible to a further deleterious role on kidney function on the top of that played by obesity itself.     

Rat lungs as affected by an acute exposure to an increased level of carbon dioxide in the ambient air

Changes in lung characteristics of healthy adult male rats were studied following a 24-hr exposure to 15% CO₂ in air. The animals were weighed before and after the exposure period. Following the CO₂-exposure, the lungs of the rats were removed and their weights were determined. Continuous pressurevolume curves including inflation and deflation first with air and then with 0.9% saline were recorded from the excised lungs. The average gain in body weight of the control rats during the 24-hr period was 9 g while the CO₂-exposed rats lost 24 g. The mean values for wet and dry lung weights and trapped gas volume in the lung were essentially the same in the two groups of rats. Similarly the lung tissue compliance both during inflation and deflation was not significantly different between the two groups of animals. One characteristic feature of the total lung compliance for 69% of the CO₂-exposed rats was a progressive decrease in compliance on successive runs associated with a decrease in the area described by the compliance curves. These would suggest instability of lung alveoli in these rats with a significant alteration of their surfactant activity.

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Zusammenfassung In gesunden, erwachsenen männlichen Ratten wurden die Lungeneigenschaften nach 24-Stunden Haltung in 15% CO₂ haltiger Luft untersucht. Die Tiere wurden vor und nach der Belastung gewogen. Anschliessend wurden die Lungen entfernt, gewogen und fortlaufende Druck-Volumen Kurven mit Aufblasen und Ablassen zuerst von Luft dann von 0.9% Kochsalzlösung aufgenommen. Die Kontrolltiere nahmen in Mittel 9 g zu, während die CO₂-belasteten Tiere 24 g abnahmen. Die Gewichte der feuchten und trockenen Lungen und der eingeschlossenen Luftmenge waren in beiden Gruppen gleich. Die Nachgiebigkeit der Lungen beim Aufblasen und Ausblasen war nicht signifikant verschieden. Die Lungen der CO₂-belasteten Tiere wiesen in 69% ein progressives Nachlassen der Nachgiebigkeit bei wiederholten Füllungen auf, die mit einer Verkleinerung der Fläche der Retraktions-Schleife verbunden war. Dies weist auf eine Schwäche der Alveolarauskleidung mit einer signifikanten Veränderung ihrer oberflächlichen Aktivität hin.

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Resume On a étudié les modifications survenues aux caractéristiques des poumons de rats mâles adultes placés durant 24 heures dans une atmosphère contenant 15% de CO₂. Les animaux furent pesés avant et après l'expérience. On a en outre extrait et pesé les poumons des animaux après qu'ils aient subi le traitement au CO₂. On a ensuite établi les courbes continues du rapport pression/volume (gonflement et vidange inclus) en utilisant d'abord de l'air, puis une solution de sel de cuisine à 0,9%. Le gain de poids des rats de contrôle a été de 9 g en 24 heures, alors que les animaux soumis au CO₂ perdaient 24 g en moyenne. Le poids des poumons humides ou secs ainsi que la quantité d'air qu'ils pouvaient contenir ont été égaux dans les 2 groupes. L'élasticité des poumons n'a pas présenté de différence significative lors de leur gonflement ou de leur vidange. Pourtant, un trait caractéristique des poumons de rats soumis au traitement par CO₂ a été, dans 69% des cas, une diminution progressive de l'élasticité après avoir été gonflés et dégonflés plusieurs fois. Cette diminution est en relation avec un rétrécissement de la surface de la boucle de rétractation. Ce résultat laisse à penser qu'on a affaire à une altération du revêtement alvéolaire accompagnée d'une modification significative de son activité superficielle.

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This study was supported by the Air Force Office of Scientific Research, Office of Aerospace Research, US Air Force (Contract F44620-68-C-0014).     

Association between long-term exposure to ambient air pollution and COVID-19 severity: a prospective cohort study

Background:The tremendous global health burden related to COVID-19 means that identifying determinants of COVID-19 severity is important for prevention and intervention. We aimed to explore long-term exposure to ambient air pollution as a potential contributor to COVID-19 severity, given its known impact on the respiratory system.Methods:We used a cohort of all people with confirmed SARS-CoV-2 infection, aged 20 years and older and not residing in a long-term care facility in Ontario, Canada, during 2020. We evaluated the association between long-term exposure to fine particulate matter (PM_2.5), nitrogen dioxide (NO₂) and ground-level ozone (O₃), and risk of COVID-19-related hospital admission, intensive care unit (ICU) admission and death. We ascertained individuals’ long-term exposures to each air pollutant based on their residence from 2015 to 2019. We used logistic regression and adjusted for confounders and selection bias using various individual and contextual covariates obtained through data linkage.Results:Among the 151 105 people with confirmed SARS-CoV-2 infection in Ontario in 2020, we observed 8630 hospital admissions, 1912 ICU admissions and 2137 deaths related to COVID-19. For each interquartile range increase in exposure to PM_2.5 (1.70 μg/m³), we estimated odds ratios of 1.06 (95% confidence interval [CI] 1.01–1.12), 1.09 (95% CI 0.98–1.21) and 1.00 (95% CI 0.90–1.11) for hospital admission, ICU admission and death, respectively. Estimates were smaller for NO₂. We also estimated odds ratios of 1.15 (95% CI 1.06–1.23), 1.30 (95% CI 1.12–1.50) and 1.18 (95% CI 1.02–1.36) per interquartile range increase of 5.14 ppb in O₃ for hospital admission, ICU admission and death, respectively.Interpretation:Chronic exposure to air pollution may contribute to severe outcomes after SARS-CoV-2 infection, particularly exposure to O₃.

By November 2021, COVID-19 had caused more than 5 million deaths globally¹ and more than 29 400 in Canada.² The clinical manifestations of SARS-CoV-2 infection range from being asymptomatic to multiple organ failure and death. Identifying risk factors for COVID-19 severity is important to better understand etiological mechanisms and identify populations to prioritize for screening, vaccination and medical treatment. Risk factors for severity of COVID-19 include male sex, older age, pre-existing medical conditions and being from racialized communities.^3–5 More recently, ambient air pollution has been implicated as a potential driver of COVID-19 severity.^6–10Long-term exposure to ambient air pollution, a major contributor to global disease burden,¹¹ could increase the risk of severe COVID-19 outcomes by several mechanisms. Air pollutants can reduce individuals’ pulmonary immune responses and antimicrobial activities, boosting viral loads.⁸ Air pollution can also induce chronic inflammation and overexpression of the alveolar angiotensin-converting enzyme 2 (ACE) receptor,⁷ the key receptor that facilitates SARS-CoV-2 entry into cells.^12,13 Exposure to air pollution contributes to chronic conditions, such as cardiovascular disease, that are associated with unfavourable COVID-19 prognosis, possibly owing to persistent immune activation and excessive amplification of cytokine development.¹⁰ Thus, greater exposure to long-term air pollution may lead to severe COVID-19 outcomes.Reports exist of positive associations between long-term exposure to particulate matter with diameters equal to or smaller than 2.5 or 10 μm (PM_2.5 and PM₁₀), ground-level ozone (O₃) and nitrogen dioxide (NO₂), and metrics of COVID-19 severity (e.g., mortality and case fatality rate).^8–10 However, most studies to date have used ecological and cross-sectional designs, owing to limited access to individual data, which leads to ambiguity in interpreting the results, thus hindering their influence on policy. ^6,14 Ecological designs do not allow for disentangling the relative impacts of air pollution on individual susceptibility to infection and disease severity.¹⁴ Residual confounding by factors such as population mobility and social interactions is also problematic. Therefore, a cohort study with data on individuals with SARS-CoV-2 is a more appropriate design.^6,14 Studies that have used individual data were conducted in specific subpopulations^15,16 or populations with few severe cases,¹⁷ or had limited data on individual exposure to air pollutants.¹⁸ In Canada, 1 ecological study found a positive association between long-term exposure to PM_2.5 and COVID-19 incidence,¹⁹ but no published study has explored the association between air pollution and COVID-19 severity.We aimed to examine the associations between long-term exposure to 3 common air pollutants (PM_2.5, NO₂ and O₃) and key indicators of COVID-19 severity, including hospital admission, intensive care unit (ICU) admission and death, using a large prospective cohort of people with confirmed SARS-CoV-2 infection in Ontario, Canada, in 2020. The air contaminants PM_2.5, NO₂ and O₃ are regularly monitored by the Canadian government, and are key pollutants that are considered when setting air-quality policies. They originate from varying sources (NO₂ is primarily emitted during combustion of fuel, O₃ is primarily formed in air by chemical reactions of nitrogen oxides and volatile organic compounds, and PM_2.5 can be emitted during combustion or formed by reactions of chemicals like sulphur dioxide and nitrogen oxides in air) and they may affect human health differently.^20,21,22     

Myostatin gene expression is reduced in humans with heavy-resistance strength training: a brief communication

This study examined changes in myostatin gene expression in response to strength training (ST). Fifteen young and older men (n = 7) and women (n = 8) completed a 9-week heavy-resistance unilateral knee extension ST program. Muscle biopsies were obtained from the dominant vastus lateralis before and after ST. In addition to myostatin mRNA levels, muscle volume and strength were measured. Total RNA was reverse transcribed into cDNA, and myostatin mRNA was quantified using quantitative PCR by standard fluorescent chemistries and was normalized to 18S rRNA levels. A 37% decrease in myostatin expression was observed in response to ST in all subjects combined (2.70 +/- 0.36 vs 1.69 +/- 0.18 U, arbitrary units; P < 0.05). Though the decline in myostatin expression was similar regardless of age or gender, the small number of subjects in these subgroups suggests that this observation needs to be confirmed. No significant correlations were observed between myostatin expression and any muscle strength or volume measure. Although further work is necessary to clarify the findings, these data demonstrate that myostatin mRNA levels are reduced in response to heavy-resistance ST in humans.     

Effects of particulate air pollution on cardiovascular health: a population health risk assessment

Particulate matter (PM) air pollution is increasingly recognized as an important and modifiable risk factor for adverse health outcomes including cardiovascular disease (CVD). However, there are still gaps regarding large population risk assessment. Results from the nationwide Behavioral Risk Factor Surveillance System (BRFSS) were used along with air quality monitoring measurements to implement a systematic evaluation of PM-related CVD risks at the national and regional scales. CVD status and individual-level risk factors were collected from more than 500,000 BRFSS respondents across 2,231 contiguous U.S. counties for 2007 and 2009. Chronic exposures to PM pollutants were estimated with spatial modeling from measurement data. CVD outcomes attributable to PM pollutants were assessed by mixed-effects logistic regression and latent class regression (LCR), with adjustment for multicausality. There were positive associations between CVD and PM after accounting for competing risk factors: the multivariable-adjusted odds for the multiplicity of CVD outcomes increased by 1.32 (95% confidence interval: 1.23-1.43) and 1.15 (1.07-1.22) times per 10 μg/m(3) increase in PM(2.5) and PM(10) respectively in the LCR analyses. After controlling for spatial confounding, there were moderate estimated effects of PM exposure on multiple cardiovascular manifestations. These results suggest that chronic exposures to ambient particulates are important environmental risk factors for cardiovascular morbidity.     

Influence of PAHs in ambient air on chromosomal aberrations in exposed subjects: international study - EXPAH

The aim of this study was to determine the influence of carcinogenic polycyclic aromatic hydrocarbons (c–PAHs) in complex mixtures in ambient air on DNA damage (chromosomal aberrations) in occupationally exposed subjects measured as percent of aberrant cells (% AB.C.).

There were in total 203 exposed subjects and 150 respective controls in the whole project, allocated in three different European cities – Kosice (Slovakia), Prague (Czech Republic) and Sofia (Bulgaria). The studied population from Kosice (Slovakia) consisted of 106 subjects. From these 51 were exposed policemen and 55 were controls. The Czech population comprised 52 exposed policemen and 50 controls. In Bulgaria, there were two equally numerous exposed groups: 50 policemen and 50 professional bus drivers together with 45 controls. According to personal monitoring, policemen and bus drivers in the Bulgarian capital Sofia were exposed to the highest levels of c-PAHs amongst the exposed subject groups in the cities (45.3 ± 25.9 ng/m³ in policemen resp. 36.1 ± 31.6 ng/m³ in bus drivers in Sofia, 26.8 ± 39.8 ng/m³ for policemen in Kosice and 11.9 ± 11.2 ng/m³ for policemen in Prague), compared to the respective controls (24.9 ± 17.7 ng/m³ for controls in Sofia, 7.9 ± 3.8 ng/m³ for controls in Kosice and 6.2 ± 3.6 ng/m³ for controls in Prague).

We observed the following frequency of % AB.C. scored by conventional method: 2.60 ± 2.64 in exposed policemen and 2.14 ± 1.61 in controls in Kosice (p = n.s.); 2.33 ± 1.53 in exposed policemen and 1.94 ± 1.28 in controls in Prague (p = n.s.); 3.04 ± 1.64 in exposed policemen, respectively, 3.60 ± 1.63 in exposed bus drivers and 1.79 ± 0.77 in the control group in Sofia (p < 0.05, respectively, p < 0.05).

According to data from multiple regression analysis, and group comparison of smokers versus nonsmokers in Sofia also cigarette smoking (p = 0.055) and the age (p = 0.020) seem to play an important role within the aberrant cell formation in addition to the occupational c-PAHs exposure (p = 0.000). Smoking status was the modifying factor for % AB.C. in Kosice (p = 0.020) after multiple regression approach was employed.

In summary, we can say that subjects occupationally exposed to higher levels of c-PAHs in ambient air in Sofia are at greater genotoxic risk compared to those working indoors.     

Aluminium and iron air pollution near an iron casting and aluminium foundry in Turin district (Italy)

This work reports the results of an environmental survey carried out in an industrial area in the Province of Turin: its main aim is to assess the levels of iron and aluminium in the outside air during the period from July to September to assess the influence of industrial activity (a cast-iron and aluminium foundry) which is interrupted during the month of August, on the level of metals present in the air. Conducting the analysis during this period of time made it possible to avoid the confounding effect of pollution due to domestic central heating. The measurements were taken from nine areas at different distances from the foundry in the area and according to the direction of the prevailing winds, as deduced from the historical data. The results of this survey show a statistically significant difference in iron and aluminium levels in the outside air in the geographic areas between the two main periods examined: during August (no foundry activity) v/s July-September (foundry activity). The values recorded are: Aluminium 0.4+/-0.45 microg/m(3) v/s 1.12+/-1.29 microg/m(3) (p<0.0001); Iron 0.95+/-0.56 microg/m(3) v/s 1.6+/-1.0 microg/m(3) (p<0.0001). There were no statistically significant differences between the nine sampling points from the point of view of the sampling sites, climate conditions and wind directions. We found no correlation with car traffic, in terms of the number of vehicles, and metals. The values of iron tended to be higher in the areas farther away from the foundry site in the areas located along the path of the prevailing winds.     

The sulphur: Nitrogen ratio of conifer foliage in relation to atmospheric pollution with sulphur dioxide

Summary The S : N ratio of the current foliage of two commonly planted conifers, Sitka spruce (Picea sitchensis (Bong.) Carr.) and Scots pine (Pinus sylvestris L.) was determined for areas known to have unpolluted atmospheres. The mean values of the ratio (0.034 and 0.028 respectively) were used to compare similar foliage from a) an industrialised area, and b) a series of transects radiating from a brickworks chimney. The established ratios were used to predict foliar S concentrations and the greater amounts found were ascribed to foliar absorption of atmospheric S. The ‘excess’ S was negatively related to distance from the supposed source, and also to needle weight which itself was positively related to distance. It is concluded that this measure derived from the S : N ratio is theoretically and practically a more sensitive indicator of the accumulation of S in conifer foliage exposed to atmospheric pollution than the analysis for elemental S or the SO₄-ion alone. re]19751115 Department of Forestry and Natural Resources University of Edinburgh     

Short term effects of a low-carbohydrate diet in overweight and obese subjects with low HDL-C levels

Background

The aim of this study was to evaluate short-term effects of a low-carbohydrate diet in overweight and obese subjects with low HDL-C levels.

Methods

Overweight (BMI between 25-30 kg/m²) or obese (BMI over 30 kg/m²) subjects with low HDL-C levels (men with HDL-C <1.03, women <1.29 mmol/l) were invited to the study. A 1400 kcal 75-gram carbohydrate (CHO) diet was given to women and an 1800 kcal 100-gram CHO diet was given to men for four weeks. The distribution of daily energy of the prescribed diet was 21-22% from CHO, 26-29% from protein and 49-53% from fat. Subjects completed a three-day dietary intake record before each visit. Anthropometric indices, body fat ratio, blood lipids, glucose and insulin were measured. Baseline and week-four results were compared with a Wilcoxon signed ranks test.

Results

Twenty-five women and 18 men participated. Basal median LDL-C level of men was 3.11 and basal median LDL-C level of women was 3.00 mmol/l. After four weeks of a low-carbohydrate diet, the median energy intake decreased from 1901 to 1307 kcal/day, daily energy from carbohydrate from 55% to 33%, body weight from 87.7 to 83.0 kg and HDL-C increased from 0.83 to 0.96 mmol/l in men (p < 0.002, for all). After four weeks of a low-carbohydrate diet, the median energy intake tended to decrease (from 1463 to 1243 kcal, p = 0.052), daily energy from carbohydrate decreased from 53% to 30% (p < 0.001) and body weight decreased from 73.2 to 70.8 kg (p < 0.001) in women, but HDL-C did not significantly change (from 1.03 to 1.01 mmol/l, p = 0.165). There were significant decreases in body mass index, waist circumference, body fat ratio, systolic blood pressure, total cholesterol, triglyceride and insulin levels in all subjects.

Conclusions

HDL-C levels increased significantly with energy restriction, carbohydrate restriction and weight loss in men. HDL-C levels didn't change in women in whom there was no significant energy restriction but a significant carbohydrate restriction and a relatively small but significant weight loss. Our results suggest that both energy and carbohydrate restriction should be considered in overweight and obese subjects with low HDL-C levels, especially when LDL-C levels are not elevated.     

Your attention please: increasing ambient noise levels elicits a change in communication behaviour in humpback whales (Megaptera novaeangliae)

High background noise is an important obstacle in successful signal detection and perception of an intended acoustic signal. To overcome this problem, many animals modify their acoustic signal by increasing the repetition rate, duration, amplitude or frequency range of the signal. An alternative method to ensure successful signal reception, yet to be tested in animals, involves the use of two different types of signal, where one signal type may enhance the other in periods of high background noise. Humpback whale communication signals comprise two different types: vocal signals, and surface-generated signals such as ‘breaching’ or ‘pectoral slapping’. We found that humpback whales gradually switched from primarily vocal to primarily surface-generated communication in increasing wind speeds and background noise levels, though kept both signal types in their repertoire. Vocal signals have the advantage of having higher information content but may have the disadvantage of loosing this information in a noisy environment. Surface-generated sounds have energy distributed over a greater frequency range and may be less likely to become confused in periods of high wind-generated noise but have less information content when compared with vocal sounds. Therefore, surface-generated sounds may improve detection or enhance the perception of vocal signals in a noisy environment.     

Increased plasma apoA-IV level is a marker of abnormal postprandial lipemia: a study in normoponderal and obese subjects.

Plasma apolipoprotein A-IV (apoA-IV) levels are found elevated in hypertriglyceridemic patients. However, the relationship between plasma apoA-IV level and postprandial lipemia is not well known and remains to be elucidated. Thus, our objective was to study the relationship between plasma apoA-IV and postprandial TG after an oral fat load test (OFLT). Plasma apoA-IV was measured at fast and during an OFLT in 16 normotriglyceridemic, normoglucose-tolerant android obese subjects (BMI = 34.6 +/- 2.9 kg/m(2)) and 30 normal weight controls (BMI = 22.2 +/- 2.3 kg/m(2)). In spite of not statistically different fasting plasma TG levels in controls and obese patients, the former group showed an altered TG response after OFLT, featuring increased nonchylomicron TG area under the curve (AUC) compared with controls (516 +/- 138 vs. 426 +/- 119 mmol/l x min, P < 0.05). As compared to controls, obese patients showed increased apoA-IV levels both at fast (138.5 +/- 22.4 vs. 124.0 +/- 22.8 mg/l, P < 0.05) and during the OFLT (apoA-IV AUC: 79,833 +/- 14,281 vs. 68,176 +/- 17,463 mg/l x min, P < 0.05). Among the whole population studied, as among the control and obese subgroups, fasting plasma apoA-IV correlated significantly with AUC of plasma TG (r = 0.60, P < 0.001), AUC of chymomicron TG (r = 0.45, P < 0.01), and AUC of nonchylomicron TG (r = 0.62, P < 0.001). In the multivariate analysis, fasting apoA-IV level constituted an independent and highly significant determinant of AUC of plasma TG, AUC of chymomicron TG, AUC of nonchylomicron TG, and incremental AUC of plasma TG. In conclusion, we show a strong link between fasting apoA-IV and postprandial TG metabolism. Plasma fasting apoA-IV is shown to be a good marker of TG response after an OFLT, providing additional information on post-load TG response in conjunction with other known factors such as fasting TGs.     

Effects of air pollution and habitual exercise on the risk of death: a longitudinal cohort study

Background:Exercise may exacerbate the adverse health effects of air pollution by increasing the inhalation of air pollutants. We investigated the combined effects of long-term exposure to fine particle matter (PM_2.5) and habitual exercise on deaths from natural causes in Taiwan.Methods:We recruited 384 130 adults (aged ≥ 18 yr) with 842 394 medical examination records between 2001 and 2016, and followed all participants until May 31, 2019. We obtained vital data from the National Death Registry of Taiwan. We estimated PM_2.5 exposure using a satellite-based spatiotemporal model, and collected information on exercise habits using a standard self-administered questionnaire. We analyzed the data using a Cox regression model with time-dependent covariates.Results:A higher level of habitual exercise was associated with a lower risk of death from natural causes, compared with inactivity (hazard ratio [HR] 0.84, 95% confidence interval [CI] 0.80–0.88 for the moderate exercise group; HR 0.65, 95% CI 0.62–0.68 for the high exercise groups), whereas a higher PM_2.5 exposure was associated with a higher risk of death from natural causes compared with lower exposure (HR 1.02, 95% CI 0.98–1.07, and HR 1.15, 95% CI 1.10–1.20, for the moderate and high PM_2.5 exposure groups, respectively). Compared with inactive adults with high PM_2.5 exposure, adults with high levels of habitual exercise and low PM_2.5 exposure had a substantially lower risk of death from natural causes. We found a minor, but statistically significant, interaction effect between exercise and PM_2.5 exposure on risk of death (HR 1.03 95% CI 1.01–1.06). Subgroup analyses, stratified by PM_2.5 categories, suggested that moderate and high levels of exercise were associated with a lower risk of death in each PM_2.5 stratum, compared with inactivity.Interpretation:Increased levels of exercise and reduced PM_2.5 exposure are associated with a lower risk of death from natural causes. Habitual exercise can reduce risk regardless of the levels of PM_2.5 exposure. Our results suggest that exercise is a safe health improvement strategy, even for people residing in relatively polluted regions.

Air pollution and physical inactivity are both major public health challenges worldwide.¹ Air pollution was the fifth leading cause of disability related to health and accounted for 4.9 million deaths worldwide in 2017.² More than 91% of the global population lives in areas where air quality does not meet the World Health Organization (WHO) guidelines.³ In addition, physical inactivity was the fourth leading risk factor for death globally, accounting for 5.3 million deaths worldwide in 2012.⁴ The WHO has challenged its member states to reduce physical inactivity by 15% by 2030.⁵As people exercise, their ventilation rate increases, which increases the volume of air pollutants they inhale. This may exacerbate the adverse health effects of air pollutants. Thus, the risk–benefit relation between air pollution and exercise needs to be assessed to understand whether it is safe to exercise regularly in polluted regions. Indeed, some studies have shown that acute exposure to air pollution when exercising may override the benefits of exercise.^6,7 It is possible that the effects of long-term exposure to air pollution may be irreversible and cause a much larger disease burden than short-term exposure. Limited information exists on the combined effects of long-term exposure to air pollution and habitual exercise on human health, and findings have been inconsistent depending on health outcome. Three cohort studies have explored the relation between air pollution, physical activity and risk of death in Hong Kong,⁸ Denmark and the United States,⁹ with relatively small sample sizes.¹⁰ Therefore, we sought to investigate the combined effects of habitual exercise and long-term exposure to fine particle matter (PM_2.5) on the risk of death from natural causes (i.e., deaths not attributable to accident, suicide or homicide) using a longitudinal cohort of adults in Taiwan, where the annual PM_2.5 concentrations are 1.6 times higher than the WHO-recommended limit. We hypothesized that the beneficial effects of habitual exercise on risk of death may outweigh the risk of high levels of air pollutants inhaled during exercise.     

Ambient air levels of Aspergillus fumigatus and thermophilic actinomycetes in a residential neighborhood near a yard-waste composting facility

Composting is a biological process that has thepotential to emit large quantities ofbioaerosols and, therefore, could adverselyaffect public health. Numerous previousstudies have demonstrated bioaerosol levelselevated above background adjacent tocomposting waste materials, but effects onoffsite bioaerosol levels due tocomposting-facility bioaerosol emissions havenot been extensively investigated. Of the fewsuch studies published, most have not foundelevated compost-related bioaerosols downwindfrom the composting operation. We investigatedviable Aspergillus fumigatus andthermophilic actinomycete levels upwind anddownwind of a large yard-waste compostingfacility and sought to determine whether levelsin a residential neighborhood near the facilitywere elevated above background levels due tofacility bioaerosol emissions. Mean bioaerosollevels at the composting facility weresignificantly higher than the mean backgroundlevels, exceeding the background means byroughly 20-fold. When a neighborhood samplingsite about 500 m from the facility was in thedownwind direction mean levels weresignificantly higher than for other winddirections, and excursions well abovebackground levels were significantly morefrequent than at background sites. There was asignificant temporal correlation betweenbioaerosol levels at the composting facilityand the downwind sampling site. The resultsindicate that bioaerosol emissions from a largeyard-waste composting facility cansignificantly increase bioaerosol exposurelevels at least 500 m downwind from thefacility.