Protective Role of Interleukin-10 in Ozone-Induced Pulmonary Inflammation

Background

The mechanisms underlying ozone (O₃)-induced pulmonary inflammation remain unclear. Interleukin-10 (IL-10) is an anti-inflammatory cytokine that is known to inhibit inflammatory mediators.

Objectives

We investigated the molecular mechanisms underlying interleuken-10 (IL-10)–mediated attenuation of O₃-induced pulmonary inflammation in mice.

Methods

Il10-deficient (Il10^−/−) and wild-type (Il10^+/+) mice were exposed to 0.3 ppm O₃ or filtered air for 24, 48, or 72 hr. Immediately after exposure, differential cell counts and total protein (a marker of lung permeability) were assessed from bronchoalveolar lavage fluid (BALF). mRNA and protein levels of cellular mediators were determined from lung homogenates. We also used global mRNA expression analyses of lung tissue with Ingenuity Pathway Analysis to identify patterns of gene expression through which IL-10 modifies O₃-induced inflammation.

Results

Mean numbers of BALF polymorphonuclear leukocytes (PMNs) were significantly greater in Il10^−/− mice than in Il10^+/+ mice after exposure to O₃ at all time points tested. O₃-enhanced nuclear NF-κB translocation was elevated in the lungs of Il10^−/− compared with Il10^+/+ mice. Gene expression analyses revealed several IL-10–dependent and O₃-dependent mediators, including macrophage inflammatory protein 2, cathepsin E, and serum amyloid A3.

Conclusions

Results indicate that IL-10 protects against O₃-induced pulmonary neutrophilic inflammation and cell proliferation. Moreover, gene expression analyses identified three response pathways and several genetic targets through which IL-10 may modulate the innate and adaptive immune response. These novel mechanisms of protection against the pathogenesis of O₃-induced pulmonary inflammation may also provide potential therapeutic targets to protect susceptible individuals.     

Exposure to ambient air fine particulate matter prevents VEGF-induced mobilization of endothelial progenitor cells from the bone marrow

Background: Exposure to ambient fine particulate matter air pollution (PM_2.5; < 2.5 µm in aerodynamic diameter) induces endothelial dysfunction and increases the risk for cardiovascular disease. Endothelial progenitor cells (EPCs) contribute to postnatal endothelial repair and regeneration. In humans and mice, EPC levels are decreased upon exposure to elevated levels of PM_2.5.Objective: We examined the mechanism by which PM_2.5 exposure suppresses circulating levels of EPCs.Methods: Mice were exposed to HEPA-filtered air or concentrated ambient fine particulate matter (CAP, 30–100 µg/m³) from downtown Louisville (Kentucky) air, and progenitor cells from peripheral blood or bone marrow were analyzed by flow cytometry or by culture ex vivo.Results: Exposure of the mice to CAP (6 hr/day) for 4–30 days progressively decreased circulating levels of EPCs positive for both Flk-1 and Sca-1 (Flk-1⁺/Sca-1⁺) without affecting stem cells positive for Sca-1 alone (Sca-1⁺). After 9 days of exposure, a 7-day exposure-free period led to complete recovery of the circulating levels of Flk-1⁺/Sca-1⁺ cells. CAP exposure decreased circulating levels of EPCs independent of apoptosis while simultaneously increasing Flk-1⁺/Sca-1⁺ cells in the bone marrow. We observed no change in tissue deposition of these cells. CAP exposure suppressed vascular endothelial growth factor (VEGF)-induced Akt and endothelial nitric oxide synthase (eNOS) phosphorylation in the aorta, and it prevented VEGF/AMD3100-induced mobilization of Flk-1⁺/Sca-1⁺ cells into the peripheral blood. Treatment with stem cell factor/AMD3100 led to a greater increase in circulating Flk-1⁺/Sca-1⁺ cells in CAP-exposed mice than in mice breathing filtered air.Conclusion: Exposure to PM_2.5 increases EPC levels in the bone marrow by preventing their mobilization to the peripheral blood via inhibition of signaling events triggered by VEGF-receptor stimulation that are upstream of c-kit activation. Suppression of EPC mobilization by PM_2.5 could induce deficits in vascular repair or regeneration.     

The role of the extracellular matrix protein mindin in airway response to environmental airways injury

Background: Our previous work demonstrated that the extracellular matrix protein mindin contributes to allergic airways disease. However, the role of mindin in nonallergic airways disease has not previously been explored.Objectives: We hypothesized that mindin would contribute to airways disease after inhalation of either lipopolysaccharide (LPS) or ozone.Methods: We exposed C57BL/6J and mindin-deficient (^–/–) mice to aerosolized LPS (0.9 μg/m³ for 2.5 hr), saline, ozone (1 ppm for 3 hr), or filtered air (FA). All mice were evaluated 4 hr after LPS/saline
exposure or 24 hr after ozone/FA exposure. We characterized the physiological and biological responses by analysis of airway hyperresponsiveness (AHR) with a computer-controlled small-animal ventilator (FlexiVent), inflammatory cellular recruitment, total protein in bronchoalveolar lavage fluid (BALF), proinflammatory cytokine profiling, and ex vivo bronchial ring studies.Results: After inhalation of LPS, mindin^–/– mice demonstrated significantly reduced total cell and neutrophil recruitment into the airspace compared with their wild-type counterparts. Mindin^–/– mice also exhibited reduced proinflammatory cytokine production and lower AHR to methacholine challenge by FlexiVent. After inhalation of ozone, mice had no detectible differences in cellular inflammation or total BALF protein dependent on mindin. However, mindin^–/– mice were protected from increased proinflammatory cytokine production and AHR compared with their C57BL/6J counterparts. After ozone exposure, bronchial rings derived from mindin^–/– mice demonstrated reduced constriction in response to carbachol.Conclusions: These data demonstrate that the extracellular matrix protein mindin modifies the airway response to both LPS and ozone. Our data support a conserved role of mindin in production of proinflammatory cytokines and the development of AHR in two divergent models of reactive airways disease, as well as a role of mindin in airway smooth muscle contractility after exposure to ozone.     

Innate immunity in DNA vaccine with Toxoplasma gondii-heat shock protein 70 gene that induces DC activation and Th1 polarization

Toxoplasma gondii-derived heat shock protein 70 (T.g.HSP70) is a tachyzoite-specific virulent molecule expressed before the death of hosts. We have already demonstrated the vaccine effects of T.g.HSP70 gene targeting peripheral epidermal or dermal dendritic cells (DC) to limit T. gondii loads in T. gondii-infected mice. In the present study, involvement of innate immunity in T.g.HSP70 gene vaccine-induced Th polarization at draining lymph nodes (dLN) of C57BL/6 (B6) mice and vaccine effects against toxoplasmosis have been evaluated. Compared to the mice unvaccinated or vaccinated with empty plasmid, CD11c⁺ cells at the dLN from naïve B6 mice expressed prominent IL-12 mRNA after the T.g.HSP70 gene vaccine. Also, CD4⁺ cells at the dLN from the mice expressed prominent interferon-γ, but not IL-4 or IL-17, mRNA at a maximum level at day 5 following vaccination. Thus, in vivo DC activation and successive early Th1 polarization were induced at the dLN of naïve mice by the T.g.HSP70 gene vaccine. The DC activation and Th1 polarization were observed at the dLN from wild type (WT) and Toll-like receptor (TLR) 2-deficient mice, but not TLR4-deficient mice with B6 background by the vaccine. This T.g.HSP70 gene vaccine-induced DC activation and Th1 polarization were also observed in TRIF-deficient mice, but not MyD88-deficient mice with B6 background indicating the involvement of TLR4/MyD88 signal transduction cascade in the vaccine effects with T.g.HSP70 gene. The T.g.HSP70 gene vaccine (twice at a 2-week interval) has been shown to limit T. gondii loads in the mesenteric LN of WT, TLR2-deficient and TRIF-deficient mice, but neither TLR4-deficient nor MyD88-deficient mice, at an acute phase of toxoplasmosis. The T.g.HSP70 gene vaccine also limited cyst number in the brains of WT, TLR2-deficient and TRIF-deficient mice, but not TLR4-deficient mice at a chronic phase of toxoplasmosis. Thus, innate immunity also has effects on the vaccine with T.g.HSP70 gene against acute and chronic phases of toxoplasmosis.     

Adverse cardiovascular effects with acute particulate matter and ozone exposures: interstrain variation in mice

OBJECTIVES: Increased ambient particulate matter (PM) levels are associated with cardiovascular morbidity and mortality, as shown by numerous epidemiology studies. Few studies have investigated the role of copollutants, such as ozone, in this association. Furthermore, the mechanisms by which PM affects cardiac function remain uncertain. We hypothesized that PM and O(3) induce adverse cardiovascular effects in mice and that these effects are strain dependent. STUDY DESIGN: After implanting radiotelemeters to measure heart rate (HR) and HR variability (HRV) parameters, we exposed C57Bl/6J (B6), C3H/HeJ (HeJ), and C3H/HeOuJ (OuJ) inbred mouse strains to three different daily exposures of filtered air (FA), carbon black particles (CB), or O(3) and CB sequentially [O(3)CB; for CB, 536 +/- 24 microg/m(3); for O(3), 584 +/- 35 ppb (mean +/- SE)]. RESULTS: We observed significant changes in HR and HRV in all strains due to O(3)CB exposure, but not due to sequential FA and CB exposure (FACB). The data suggest that primarily acute HR and HRV effects occur during O(3)CB exposure, especially in HeJ and OuJ mice. For example, HeJ and OuJ mice demonstrated dramatic increases in HRV parameters associated with marked brady-cardia during O(3)CB exposure. In contrast, depressed HR responses occurred in B6 mice without detectable changes in HRV parameters. CONCLUSIONS: These findings demonstrate that important interstrain differences exist with respect to PM- and O(3)-induced cardiac effects. This interstrain variation suggests that genetic factors may modulate HR regulation in response to and recuperation from acute copollutant exposures.     

A TLR2 agonist is a more effective adjuvant for a Chlamydia major outer membrane protein vaccine than ligands to other TLR and NOD receptors

Chlamydia trachomatis (Ct) is the most common sexually transmitted bacterial pathogen in the World and there is an urgent need for a vaccine to prevent these infections. To determine what type of adjuvant can better enhance the immunogenicity of a Chlamydia vaccine, we formulated the recombinant major outer membrane protein (Ct-rMOMP) with several ligands for Toll-like receptors (TLR) and the nucleotide-binding oligomerization domain (NOD) including Pam₂CSK₄ (TLR2/TLR6), Poly (I:C) (TLR3), monophosphoryl lipid A (TLR4), flagellin (TLR5), imiquimod R837 (TLR7), imidazoquinoline R848 (TRL7/8), CpG-1826 (TLR9), M-Tri-_DAP (NOD1/NOD2) and muramyldipeptide (NOD2). Groups of female BALB/c mice were immunized intramuscularly (i.m.) three times with the Ct-rMOMP and each one of those adjuvants. Four weeks after the last immunization the mice were challenged intranasally (i.n.) with 10⁴C. trachomatis mouse pneumonitis (MoPn) inclusion forming units (IFU). As negative antigen control, mice were immunized with the Neisseria gonorrhoeae recombinant porin B (Ng-rPorB) and the same adjuvants. As a positive vaccine control, mice were inoculated i.n. with 10⁴ IFU of MoPn. The humoral and cell mediated immune responses were determined the day before the challenge. Following the challenge the mice were weighed daily and, at 10 days post-challenge (p.c.), they were euthanized, their lungs weighted and the number of IFU in the lungs counted. As determined by the IgG2a/IgG1 ratio in the sera, mice immunized with Ct-rMOMP + Pam₂CSK₄ showed a strong Th2 biased humoral immune response. Furthermore, these mice developed a robust cellular immune response with high Chlamydia-specific T cell proliferation and levels of IFN-γ production. In addition, based on changes in body weight, weight of the lungs and number of IFU recovered from the lungs, the mice immunized with Ct-rMOMP + Pam₂CSK₄, were better protected against the i.n. challenge than any group of mice immunized with Ct-rMOMP and the other adjuvants. In conclusion, Pam₂CSK₄ should be evaluated as a candidate adjuvant for a C. trachomatis vaccine.     

Does Air Pollution Trigger Infant Mortality in Western Europe? A Case-Crossover Study

Background: Numerous studies show associations between fine particulate air pollutants [particulate matter with an aerodynamic diameter ≤ 10 μm (PM₁₀)] and mortality in adults.Objectives: We investigated short-term effects of elevated PM₁₀ levels on infant mortality in Flanders, Belgium, and studied whether the European Union (EU) limit value protects infants from the air pollution trigger.Methods: In a case-crossover analysis, we estimated the risk of dying from nontraumatic causes before 1 year of age in relation to outdoor PM₁₀ concentrations on the day of death. We matched control days on temperature to exclude confounding by variations in daily temperature.Results: During the study period (1998–2006), PM₁₀ concentration averaged 31.9 ± 13.8 μg/m³. In the entire study population (n = 2,382), the risk of death increased by 4% [95% confidence interval (CI), 0–8%; p = 0.045] for a 10-μg/m³ increase in daily mean PM₁₀. However, this association was significant only for late neonates (2–4 weeks of age; n = 372), in whom the risk of death increased by 11% (95% CI, 1–22%; p = 0.028) per 10-μg/m³ increase in PM₁₀. In this age class, infants were 1.74 (95% CI, 1.18–2.58; p = 0.006) times more likely to die on days with a mean PM₁₀ above the EU limit value of 50 μg/m³ than on days below this cutoff.Conclusions: Even in an affluent region in Western Europe, where infant mortality is low, days with higher PM air pollution are associated with an increased risk of infant mortality. Assuming causality, the current EU limit value for PM₁₀, which may be exceeded on 35 days/year, does not prevent PM₁₀ from triggering mortality in late neonates.     

Traffic-related air pollution and acute changes in heart rate variability and respiratory function in urban cyclists

Background: Few studies have examined the acute health effects of air pollution exposures experienced while cycling in traffic.Objectives: We conducted a crossover study to examine the relationship between traffic pollution and acute changes in heart rate variability. We also collected spirometry and exhaled nitric oxide measures.Methods: Forty-two healthy adults cycled for 1 hr on high- and low-traffic routes as well as indoors. Health measures were collected before cycling and 1–4 hr after the start of cycling. Ultrafine particles (UFPs; ≤ 0.1 μm in aerodynamic diameter), particulate matter ≤ 2.5 μm in aerodynamic diameter (PM_2.5), black carbon, and volatile organic compounds were measured along each cycling route, and ambient nitrogen dioxide (NO₂) and ozone (O₃) levels were recorded from a fixed-site monitor. Mixed-effects models were used to estimate associations between air pollutants and changes in health outcome measures relative to precycling baseline values.Results: An interquartile range increase in UFP levels (18,200/cm³) was associated with a significant decrease in high-frequency power 4 hr after the start of cycling [β = –224 msec²; 95% confidence interval (CI), –386 to –63 msec²]. Ambient NO₂ levels were inversely associated with the standard deviation of normal-to-normal (NN) intervals (β = –10 msec; 95% CI, –20 to –0.34 msec) and positively associated with the ratio of low-frequency to high-frequency power (β = 1.4; 95% CI, 0.35 to 2.5) 2 hr after the start of cycling. We also observed significant inverse associations between ambient O₃ levels and the root mean square of successive differences in adjacent NN intervals 3 hr after the start of cycling.Conclusions: Short-term exposures to traffic pollution may contribute to altered autonomic modulation of the heart in the hours immediately after cycling.     

Antioxidative effects of fermented sesame sauce against hydrogen peroxide-induced oxidative damage in LLC-PK1 porcine renal tubule cells

BACKGROUND/OBJECTIVES

This study was performed to investigate the in vitro antioxidant and cytoprotective effects of fermented sesame sauce (FSeS) against hydrogen peroxide (H₂O₂)-induced oxidative damage in renal proximal tubule LLC-PK1 cells.

MATERIALS/METHODS

1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical (^•OH), and H₂O₂ scavenging assay was used to evaluate the in vitro antioxidant activity of FSeS. To investigate the cytoprotective effect of FSeS against H₂O₂-induced oxidative damage in LLC-PK1 cells, the cellular levels of reactive oxygen species (ROS), lipid peroxidation, and endogenous antioxidant enzymes including catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-px) were measured.

RESULTS

The ability of FSeS to scavenge DPPH, ^•OH and H₂O₂ was greater than that of FSS and AHSS. FSeS also significantly inhibited H₂O₂-induced (500 µM) oxidative damage in the LLC-PK1 cells compared to FSS and AHSS (P < 0.05). Following treatment with 100 µg/mL of FSeS and FSS to prevent H₂O₂-induced oxidation, cell viability increased from 56.7% (control) to 83.7% and 75.6%, respectively. However, AHSS was not able to reduce H₂O₂-induced cell damage (viability of the AHSS-treated cells was 54.6%). FSeS more effectively suppressed H₂O₂-induced ROS generation and lipid peroxidation compared to FSS and AHSS (P < 0.05). Compared to the other sauces, FSeS also significantly increased cellular CAT, SOD, and GSH-px activities and mRNA expression (P < 0.05).

CONCULUSIONS

These results from the present study suggest that FSeS is an effective radical scavenger and protects against H₂O₂-induced oxidative damage in LLC-PK1 cells by reducing ROS levels, inhibiting lipid peroxidation, and stimulating antioxidant enzyme activity.     

Hsp70 vaccination-induced primary immune responses in efferent lymph of the draining lymph node

Bovine paratuberculosis is a highly prevalent chronic infection of the small intestine in cattle, caused by Mycobacterium avium subspecies paratuberculosis (MAP). In earlier studies we showed the protective effect of Hsp70/DDA subunit vaccination against paratuberculosis. In the current study we set out to measure primary immune responses generated at the site of Hsp70 vaccination. Lymph vessel cannulation was performed to obtain efferent lymph from the prescapular lymph node draining the neck area where the vaccine was applied. Hsp70 vaccination induced a significant increase of CD21⁺ B cells in efferent lymph, accounting for up to 40% of efferent cells post-vaccination. Proliferation (Ki67⁺) within the CD21⁺ B cell and CD4⁺ T cell populations peaked between day 3 and day 5 post-vaccination. From day 7, Hsp70-specific antibody secreting cells (ASCs) could be detected in efferent lymph. Hsp70-specific antibodies, mainly of the IgG1 isotype, were also detected from this time point onwards. However, post-vaccination IFN-γ production in efferent lymph was non-sustained. In conclusion, Hsp70-vaccination induces only limited Th1 type immune responsiveness as reflected in efferent lymph draining the vaccination site. This is in line with our previous observations in peripheral blood. The main primary immunological outcome of the Hsp70/DDA subunit vaccination is B cell activation and abundant Hsp70-specific IgG1 production. This warrants the question whether Hsp70-specific antibodies contribute to the observed protective effect of Hsp70 vaccination in calves.     

Arsenic Inhibits Myogenic Differentiation and Muscle Regeneration

Background

The incidence of low birth weights is increased in offspring of women who are exposed to high concentrations of arsenic in drinking water compared with other women. We hypothesized that effects of arsenic on birth weight may be related to effects on myogenic differentiation.

Objective

We investigated the effects of arsenic trioxide (As₂O₃) on the myogenic differentiation of myoblasts in vitro and muscle regeneration in vivo.

Methods

C2C12 myoblasts and primary mouse and human myoblasts were cultured in differentiation media with or without As₂O₃ (0.1–0.5 μM) for 4 days. Myogenic differentiation was assessed by myogenin and myosin heavy chain expression and multinucleated myotube formation in vitro; skeletal muscle regeneration was tested using an in vivo mouse model with experimental glycerol myopathy.

Results

A submicromolar concentration of As₂O₃ dose-dependently inhibited myogenic differentiation without apparent effects on cell viability. As₂O₃ significantly and dose-dependently decreased phosphorylation of Akt and p70s6k proteins during myogenic differentiation. As₂O₃-induced inhibition in myotube formation and muscle-specific protein expression was reversed by transfection with the constitutively active form of Akt. Sections of soleus muscles stained with hematoxylin and eosin showed typical changes of injury and regeneration after local glycerol injection in mice. Regeneration of glycerol-injured soleus muscles, myogenin expression, and Akt phosphorylation were suppressed in muscles isolated from As₂O₃-treated mice compared with untreated mice.

Conclusion

Our results suggest that As₂O₃ inhibits myogenic differentiation by inhibiting Akt-regulated signaling.     

Decontamination of room air and adjoining wall surfaces by nebulizing hydrogen peroxide

Aim: In 2010, the ASP GLOSAIR^TM 400 was introduced in Germany for nebulizing hydrogen peroxide (H₂O₂). Since there were no results of practical experience, the new method was to be checked under practical conditions for its effectiveness in decontaminating air in rooms, infested with mold after water damage and, at the same time, under experimentally controlled conditions, test surfaces, contaminated with Aspergillus brasiliensis.Method: After the nebulizer was used in two rooms with a massive mold infestation, the air colony count was determined (MAS-100^® Zinsser Analytik) and, at the same time, the mold infestation in samples of wall plaster.As part of this controlled study, test surfaces contaminated with Aspergillus brasiliensis were positioned vertically and horizontally in a test room. The effectiveness of the nebulization (5–6% H₂O₂ for 2 hours) was tested on these surfaces according to EN 13697.Results: In a massive mold infestation resulting from water damage (worst case), an approximately 9-fold decrease in the mold content and an approximately 13-fold decrease in the number of colony-forming units (sum of the bacteria + fungi) could be detected in the room air immediately after the nebulizing was finished. Even in samples of wall and joint plaster, the molds were reduced, although to a distinctly lesser extent. By indoor nebulization of 5–6% H₂O₂, A. brasiliensis was reduced >4 log on vertical and horizontal surfaces.Discussion: In rooms with a massive mold infestation, the ASP GLOSAIR^TM 400 system is suitable for attaining a clear reduction in the fungal and bacterial room air load, lasting for a week. On vertical and horizontal surfaces, contaminated experimentally with A. brasiliensis, a reduction of >4 lg is achieved. As a load of 10⁴ to 10⁵ fungal spores is unlikely to occur on pre-cleaned surfaces, the GLOSAIR^TM 400 can be considered a suitable complementary process for the substantial reduction of fungal contamination.     

Monitoring Intracellular Redox Changes in Ozone-Exposed Airway Epithelial Cells

Background: The toxicity of many xenobiotic compounds is believed to involve oxidative injury to cells. Direct assessment of mechanistic events involved in xenobiotic-induced oxidative stress is not easily achievable. Development of genetically encoded probes designed for monitoring intracellular redox changes represents a methodological advance with potential applications in toxicological studies.Objective: We tested the utility of redox-sensitive green fluorescent protein (roGFP)–based redox sensors for monitoring real-time intracellular redox changes induced by xenobiotics in toxicological studies.Methods: roGFP2, a reporter of the glutathione redox potential (E_GSH), was used to monitor E_GSH in cultured human airway epithelial cells (BEAS-2B cells) undergoing exposure to 0.15–1.0 ppm ozone (O₃). Cells were imaged in real time using a custom-built O₃ exposure system coupled to a confocal microscope.Results: O₃ exposure induced a dose- and time-dependent increase of the cytosolic E_GSH. Additional experiments confirmed that roGFP2 is not directly oxidized, but properly equilibrates with the glutathione redox couple: Inhibition of endogenous glutaredoxin 1 (Grx1) disrupted roGFP2 responses to O₃, and a Grx1-roGFP2 fusion protein responded more rapidly to O₃ exposure. Selenite-induced up-regulation of GPx (glutathione peroxidase) expression–enhanced roGFP2 responsiveness to O₃, suggesting that (hydro)peroxides are intermediates linking O₃ exposure to glutathione oxidation.Conclusion: Exposure to O₃ induces a profound increase in the cytosolic E_GSH of airway epithelial cells that is indicative of an oxidant-dependent impairment of glutathione redox homeostasis. These studies demonstrate the utility of using genetically encoded redox reporters in making reliable assessments of cells undergoing exposure to xenobiotics with strong oxidizing properties.     

Highly Pathogenic Avian Influenza Virus (H5N1) Infection in Red Foxes Fed Infected Bird Carcasses

Eating infected wild birds may put wild carnivores at high risk for infection with highly pathogenic avian influenza (HPAI) virus (H5N1). To determine whether red foxes (Vulpes vulpes) are susceptible to infection with HPAI virus (H5N1), we infected 3 foxes intratracheally. They excreted virus pharyngeally for 3–7 days at peak titers of 10^3.5–10^5.2 median tissue culture infective dose (TCID₅₀) per mL and had severe pneumonia, myocarditis, and encephalitis. To determine whether foxes can become infected by the presumed natural route, we fed infected bird carcasses to 3 other red foxes. These foxes excreted virus pharyngeally for 3–5 days at peak titers of 10^4.2–10^4.5 TCID₅₀/mL, but only mild or no pneumonia developed. This study demonstrates that red foxes fed bird carcasses infected with HPAI virus (H5N1) can excrete virus while remaining free of severe disease, thereby potentially playing a role in virus dispersal.     

Ozone and other air pollutants and the risk of oral clefts

Background

Air pollution influences the development of oral clefts in animals. There are few epidemiologic data on the relation of prenatal air pollution exposure and the risk of oral clefts.

Objectives

Our goal in this study was to assess the relations between exposure to ambient air pollution and the risk of cleft lip with or without cleft palate (CL/P).

Methods

We conducted a population-based case–control study of all 653 cases of CL/P and a random sample of 6,530 control subjects from 721,289 Taiwanese newborns in 2001–2003. We used geographic information systems to form exposure parameters for sulfur dioxide, nitrogen oxides, ozone, carbon monoxide, and particulate matter with an aerodynamic diameter ≤ 10 μm (PM₁₀) during the first 3 months of pregnancy using inverse distance weighting method. We present the effect estimates as odds ratios (ORs) per 10-ppb change for SO₂, NO_x, and O₃, 100-ppb change for CO, and 10-μg/m³ change for PM₁₀.

Results

The risk of CL/P was increased in relation to O₃ levels in the first gestational month [adjusted OR = 1.20; 95% confidence interval (CI), 1.02–1.39] and second gestational month (adjusted OR = 1.25; 95% CI, 1.03–1.52) in the range from 16.7 ppb to 45.1 ppb, but was not related to CO, NO_x, SO₂, or PM₁₀.

Conclusions

The study provides new evidence that exposure to outdoor air O₃ during the first and second month of pregnancy may increase the risk of CL/P. Similar levels of O₃ are encountered globally by large numbers of pregnant women.     

Saharan dust and associations between particulate matter and daily mortality in Rome, Italy

Background: Outbreaks of Saharan-Sahel dust over Euro-Mediterranean areas frequently induce exceedances of the Europen Union''s 24-hr standard of 50 μg/m³ for particulate matter (PM) with aerodynamic diameter ≤ than 10 μm (PM₁₀).Objectives: We evaluated the effect of Saharan dust on the association between different PM fractions and daily mortality in Rome, Italy.Methods: In a study of 80,423 adult residents who died in Rome between 2001 and 2004, we performed a time-series analysis to explore the effects of PM_2.5, PM_2.5–10, and PM₁₀ on natural, cardiac, cerebrovascular, and respiratory mortality. We defined Saharan dust days by combining light detection and ranging (LIDAR) observations and analyses from operational models. We tested a Saharan dust–PM interaction term to evaluate the hypothesis that the effects of PM, especially coarse PM (PM_2.5–10), on mortality would be enhanced on dust days.Results: Interquartile range increases in PM_2.5–10 (10.8 μg/m³) and PM₁₀ (19.8 μg/m³) were associated with increased mortality due to natural, cardiac, cerebrovascular, and respiratory causes, with estimated effects ranging from 2.64% to 12.65% [95% confidence interval (CI), 1.18–25.42%] for the association between PM_2.5–10 and respiratory mortality (0- to 5-day lag). Associations of PM_2.5–10 with cardiac mortality were stronger on Saharan dust days (9.73%; 95% CI, 4.25–15.49%) than on dust-free days (0.86%; 95% CI, –2.47% to 4.31%; p = 0.005). Saharan dust days also modified associations between PM₁₀ and cardiac mortality (9.55% increase; 95% CI, 3.81–15.61%; vs. dust-free days: 2.09%; 95% CI, –0.76% to 5.02%; p = 0.02).Conclusions: We found evidence of effects of PM_2.5–10 and PM₁₀ on natural and cause-specific mortality, with stronger estimated effects on cardiac mortality during Saharan dust outbreaks. Toxicological and biological effects of particles from desert sources need to be further investigated and taken into account in air quality standards.