Large Interactive Touchscreens as an Opportunity for Synchronous Hybrid Teaching during the COVID-19 Pandemic and Beyond.

The year 2020 will be remembered as the year of COVID-19 and its subsequent lockdowns. The time to return to face-to-face teaching has arrived, but the shadow of the disease still hangs over teachers, students, and society. Disruption in teaching can still occur for students, or even teachers, if they are either diagnosed as COVID-19 positive or as a contact case and forced to self-isolate. In order to limit the impact of self-isolation on learning, synchronous hybrid teaching (i.e., teaching face to face to students in a classroom and to students online at the same time) was successfully implemented owing to the combination of video conference software and a large interactive touchscreen. The setup presented in this paper allows courses to be broadcast to students at home (i.e., voice, visual pedagogic support, and, more interestingly, indications handwritten by the teacher) as well as simultaneously teaching to students in the classroom face-to-face. It also allows self-isolated teachers to teach tutorials from their home to students in the classroom. This paper focuses on the use of large interactive touchscreens for synchronous hybrid teaching and its evaluation by students using a questionnaire. The key findings of this study are that students prefer synchronous hybrid teaching rather than missing a course and that synchronous hybrid teaching should only be used in case of absolute necessity.

Toxicological responses of BEAS-2B cells to repeated exposures to benzene, toluene, m-xylene, and mesitylene using air-liquid interface method.

In order to reduce exposure to toxic chemicals, the European REACH regulation (1907/2006) recommends substituting toxic molecules with compounds that are less harmful to human health and the environment. Toluene is one of the most frequently used solvents in industries despite its toxicity. The objective of this study is to better understand and compare the toxicity of toluene and its homologues in a bronchial cell model. Thus, human bronchial BEAS-2B cells were exposed to steams of toluene, m-xylene, mesitylene (1,3,5-trimethylbenzene), and benzene (20 and 100 ppm). Exposure was carried out using an air-liquid interface (ALI) system (Vitrocell) during 1 h/day for 1, 3, or 5 days. Cytotoxicity, xenobiotic metabolism enzyme gene expression, and inflammatory response were evaluated following cell exposures. BEAS-2B cell exposure to toluene and its homologues revealed the involvement of major (CYP2E1) and minor metabolic pathways (CYP1A1). A late induction of genes (EPHX1, DHDH, ALDH2, and ALDH3B1) was measured from Day 3 and can be linked to the formation of metabolites. An increase in the secretion level of inflammatory markers (TNF-α, IL-6, IL-8, MCP-1, and GM-CSF) was also observed. In parallel, regulation between inflammatory mediators and the expression of transmembrane glycoprotein mucin MUC1 was also studied. This in vitro approach with ALI system points out the relevance of conducting repeated exposures to detect potential late effects. The difference recorded after cell exposure to toluene and its homologues highlights the importance of substitution principle.

Extracellular vesicles as actors in the air pollution related cardiopulmonary diseases.

Many associations were reported between air pollution and daily mortality rates for cardiopulmonary diseases. Humans are exposed to a mixture of oxidizing gases and particles, both anthropogenic and natural. Exposure to air toxics causes or exacerbates cardiovascular damages and respiratory diseases. Numerous studies have identified the induction of oxidative stress and sustained inflammatory response as among the main known underlying pathophysiological mechanisms of air pollutants. More recently, the relationship between these mechanisms of action and the secretion of extracellular vesicles (EVs) by lung cells has been revealed. EVs have been shown to be important mediators of cellular communication in the body. The purpose of this review is to first recall the main air pollutants. Then, the cardiopulmonary diseases caused by exposure to air pollution and the pathophysiological mechanisms are presented before showing, through an exhaustive review of the literature, the involvement of EVs in the toxicity of air pollutants and the initiation of cardiopulmonary diseases.

A prospective pilot study of the T-lymphocyte response to fine particulate matter exposure.

Exposure to air pollution is associated with increased morbidity and mortality. Once the fine atmospheric particulate matter (FP) is inhaled, some of its compounds can pass through the lungs and reach the bloodstream where they can come into contact with immune cells. Exposure to FP particularly affects sensitive populations such as the elderly. Aging affects the immune system, making the elderly more vulnerable. The project aims to determine the effects of FP exposure on human T cells while looking for biomarkers associated with exposure. Blood samples from 95 healthy subjects in three different age groups (20-30, 45-55 and 70-85 years) were collected to determine a potential age effect. T lymphocytes were isolated to be exposed ex vivo for 72 hours to 45 µg/mL of FP collected in Dunkirk and chemically characterized. Overexpression of the CYP1A1, CYP1B1 and CYP2S1 genes was therefore measured after exposure of the T cells to FP. These genes code for enzymes known to be involved in the metabolic activation of organic compounds such as polycyclic aromatic hydrocarbons detected in the FP sample. T-cell profiling allowed us to suggest a mixed T-helper 1/2 profile caused by exposure to FP. With regard to the influence of age, we have observed differences in the expression of certain genes, as well as an increase in interleukin-4 and -13 concentrations in the elderly. These results showed that exposure of T lymphocytes to FP causes effects on both transcriptomic and cytokine secretion levels.

Chemical characterization of fine and ultrafine PM, direct and indirect genotoxicity of PM and their organic extracts on pulmonary cells.

Particulate matter in ambient air constitutes a complex mixture of fine and ultrafine particles composed of various chemical compounds including metals, ions, and organics. A multidisciplinary approach was developed by studying physico-chemical characteristics and mechanisms involved in the toxicity of particulate atmospheric pollution. PM0.3-2.5 and PM2.5 including ultrafine particles were sampled in Dunkerque, a French industrialized seaside city. PM samples were characterized from a chemical and toxicological point of view. Physico-chemical characterization evidenced that PM2.5 comes from several sources: natural ones, such as soil resuspension and marine sea-salt emissions, as well as anthropogenic ones, such as shipping traffic, road traffic, and industrial activities. Human BEAS-2B lung cells were exposed to PM0.3-2.5, or to the Extractable Organic Matter (EOM) of PM0.3-2.5 and PM2.5. These exposures induced several mechanisms of action implied in the genotoxicity, such as oxidative DNA adducts and DNA Damage Response. The toxicity of PM-EOM was higher for the sample including the ultrafine fraction (PM2.5) containing also higher concentrations of polycyclic aromatic hydrocarbons. These results evidenced the major role of organic compounds in the toxicity of PM.

Usefulness of toxicological validation of VOCs catalytic degradation by air-liquid interface exposure system.

Toluene is one of the most used Volatile Organic Compounds (VOCs) in the industry despite its major health impacts. Catalytic oxidation represents an efficient remediation technique in order to reduce its emission directly at the source, but it can release by-products. To complete the classical performance assessment using dedicated analytical chemistry methods, we propose to perform an untargeted toxicological validation on two efficient catalysts. Using biological system allows integrating synergy and antagonism in toxic effects of emitted VOCs and by-products, often described in case of multi-exposure condition. Catalysts Pd/α-Al2O3 and Pd/γ-Al2O3 developed for the oxidation of toluene were both coupled to a Vitrocell® Air-Liquid Interface (ALI) system, for exposure of human A549 lung cells during 1h to toluene or to catalysts exhaust before quantification of xenobiotics metabolizing enzymes. This study validated initially the Vitrocell® as an innovative, direct and dynamic model of ALI exposure in the assessment of the performances of new catalysts, showing the presence of chemically undetected by-products. The comparison of the two catalysts showed then that fewer organic compounds metabolizing genes were induced by Pd/γ-Al2O3 in comparison to Pd/α-Al2O3, suggesting that Pd/γ-Al2O3 is more efficient for toluene total oxidation from a toxicological point of view.

Characterisation and seasonal variations of particles in the atmosphere of rural, urban and industrial areas: Organic compounds.

Atmospheric aerosol samples (PM2.5-0.3, i.e., atmospheric particles ranging from 0.3 to 2.5µm) were collected during two periods: spring-summer 2008 and autumn-winter 2008-2009, using high volume samplers equipped with cascade impactors. Two sites located in the Northern France were compared in this study: a highly industrialised city (Dunkirk) and a rural site (Rubrouck). Physicochemical analysis of particulate matter (PM) was undertaken to propose parameters that could be used to distinguish the various sources and to exhibit seasonal variations but also to provide knowledge of chemical element composition for the interpretation of future toxicological studies. The study showed that PM2.5-0.3 concentration in the atmosphere of the rural area remains stable along the year and was significantly lower than in the urban or industrial ones, for which concentrations increase during winter. High concentrations of polycyclic aromatic hydrocarbons (PAHs), dioxins, furans and dioxin like polychlorinated biphenyls (DL-PCBs), generated by industrial activities, traffic and municipal wastes incineration were detected in the samples. Specific criteria like Carbon Preference Index (CPI) and Combustion PAHs/Total PAHs ratio (CPAHs/TPAHs) were used to identify the possible sources of atmospheric pollution. They revealed that paraffins are mainly emitted by biogenic sources in spring-summer whereas as in the case of PAHs, they have numerous anthropogenic emission sources in autumn-winter (mainly from traffic and domestic heating).

Temporal-spatial variations of the physicochemical characteristics of air pollution Particulate Matter (PM2.5-0.3) and toxicological effects in human bronchial epithelial cells (BEAS-2B).

While the evidence for the health adverse effects of air pollution Particulate Matter (PM) has been growing, there is still uncertainty as to which constituents within PM are most harmful. Hence, to contribute to fulfill this gap of knowledge, some physicochemical characteristics and toxicological endpoints (i.e. cytotoxicity, oxidative damage, cytokine secretion) of PM2.5-0.3 samples produced during two different seasons (i.e. spring/summer or autumn/winter) in three different surroundings (i.e. rural, urban, or industrial) were studied, thereby expecting to differentiate their respective adverse effects in human bronchial epithelial cells (BEAS-2B). Physicochemical characteristics were closely related to respective origins and seasons of the six PM2.5-0.3 samples, highlighting the respective contributions of industrial and heavy motor vehicle traffic sources. Space- and season-dependent differences in cytotoxicity of the six PM2.5-0.3 samples could only be supported by considering both the physicochemical properties and the variance in air PM concentrations. Whatever spaces and seasons, dose- and even time-dependent increases in oxidative damage and cytokine secretion were reported in PM2.5-0.3-exposed BEAS-2B cells. However, the relationship between the chemical composition of each of the six PM2.5-0.3 samples and their oxidative or inflammatory potentials seemed to be very complex. These results supported the role of inorganic, ionic and organic components as exogenous source of Reactive Oxygen Species and, thereafter, cytokine secretion. Nevertheless, one of the most striking observation was that some inorganic, ionic and organic chemical components were preferentially associated with early oxidative events whereas others in the later oxidative damage and/or cytokine secretion. Taken together, these results indicated that PM mass concentration alone might not be able to explain the health outcomes, because PM is chemically nonspecific, and supported growing evidence that PM-size, composition and emission source, together with sampling season, interact in a complex manner to produce PM2.5-0.3-induced human adverse health effects.

Xenobiotic metabolism induction and bulky DNA adducts generated by particulate matter pollution in BEAS-2B cell line: geographical and seasonal influence.

Airborne particulate matter (PM) toxicity is of growing interest as diesel exhaust particles have been classified as carcinogenic to humans. However, PM is a mixture of chemicals, and respective contribution of organic and inorganic fractions to PM toxicity remains unclear. Thus, we analysed the link between chemical composition of PM samples and bulky DNA adduct formation supported by CYP1A1 and 1B1 genes induction and catalytic activities. We used six native PM samples, collected in industrial, rural or urban areas, either during the summer or winter, and carried out our experiments on the human bronchial epithelial cell line BEAS-2B. Cell exposure to PM resulted in CYP1A1 and CYP1B1 genes induction. This was followed by an increase in EROD activity, leading to bulky DNA adduct formation in exposed cells. Bulky DNA adduct intensity was associated to global EROD activity, but this activity was poorly correlated with CYPs mRNA levels. However, EROD activity was correlated with both metal and polycyclic aromatic hydrocarbon (PAH) content. Finally, principal components analysis revealed three clusters for PM chemicals, and suggested synergistic effects of metals and PAHs on bulky DNA adduct levels. This study showed the ability of PM samples from various origins to generate bulky DNA adducts in BEAS-2B cells. This formation was promoted by increased expression and activity of CYPs involved in PAHs activation into reactive metabolites. However, our data highlight that bulky DNA adduct formation is only partly explained by PM content in PAHs, and suggest that inorganic compounds, such as iron, may promote bulky DNA adduct formation by supporting CYP activity.

Polycyclic aromatic hydrocarbons within airborne particulate matter (PM(2.5)) produced DNA bulky stable adducts in a human lung cell coculture model.

To extend current knowledge on the underlying mechanisms of air pollution particulate matter (PM(2.5))-induced human lung toxicity, the metabolic activation of polycyclic aromatic hydrocarbons (PAH) within PM(2.5) and PAH-DNA bulky stable adduct patterns in human alveolar macrophage (AM) and/or human lung epithelial L132 cells in mono- and cocultures were studied. In the coculture system, only human AM were exposed to air pollution PM(2.5), unlike L132 cells. Particles, inorganic fraction and positive controls [i.e. TiO(2), thermally desorbed PM (dPM) and benzo[a]pyrene, B[a]P, respectively] were included in the experimental design. Cytochrome P450 (CYP) 1A1 gene expression, CYP1A1 catalytic activity and PAH-DNA bulky stable adducts were studied after 24, 48 and/or 72 h. Relatively low doses of PAH within PM(2.5) induced CYP1A1 gene expression and CYP1A1 catalytic activity in human AM and, thereafter, PAH-DNA bulky stable adduct formation. Adduct spots in PM(2.5) -exposed human AM were higher than those in dPM-exposed ones, thereby showing the incomplete removal of PAH by thermal desorption. PAH within air pollution PM(2.5) induced CYP1A1 gene expression but not CYP1A1 catalytic activity in L132 cells. However, despite the absence of PAH-DNA bulky stable adduct in L132 cells from human AM/L132 cell cocultures exposed to dPM(2.5) or PM(2.5), reliable quantifiable PAH-DNA bulky stable adducts were observed in L132 cells from human AM/L132 cell coculture exposed to B[a]P. Taken together, these results support the exertion of genotoxicity of highly reactive B[a]P-derived metabolites produced within human AM not only in primary target human AM, but also in secondary target L132 cells.

Prooxidant and proinflammatory potency of air pollution particulate matter (PM2.5₋0.3) produced in rural, urban, or industrial surroundings in human bronchial epithelial cells (BEAS-2B).

Compelling evidence indicates that exposure to air pollution particulate matter (PM) affects human health. However, how PM composition interacts with PM-size to cause adverse health effects needs elucidation. In this study, we were also interested in the physicochemical characteristics and toxicological end points of PM2.5₋0.3 samples produced in rural, urban, or industrial surroundings, thereby expecting to differentiate their respective in vitro adverse health effects in human bronchial epithelial cells (BEAS-2B). Physicochemical characteristics of the three PM2.5₋0.3 samples, notably their inorganic and organic components, were closely related to their respective emission sources. Referring also to the dose/response relationships of the three PM2.5₋0.3 samples, the most toxicologically relevant exposure times (i.e., 24, 48, and 72 h) and doses (i.e., 3.75 µg PM/cm² and 15 µg PM/cm²) to use to study the underlying mechanisms of action involved in PM-induced lung toxicity were chosen. Organic chemicals adsorbed on the three PM2.5₋0.3 samples (i.e., polycyclic aromatic hydrocarbons) were able to induce the gene expression of xenobiotic-metabolizing enzymes (i.e., Cytochrome P4501A1 and 1B1, and, to a lesser extent, NADPH-quinone oxidoreductase-1). Moreover, intracellular reactive oxygen species within BEAS-2B cells exposed to the three PM2.5₋0.3 samples induced oxidative damage (i.e., 8-hydroxy-2'-deoxyguanosine formation, malondialdehyde production and/or glutathione status alteration). There were also statistically significant increases of the gene expression and/or protein secretion of inflammatory mediators (i.e., notably IL-6 and IL-8) in BEAS-2B cells after their exposure to the three PM2.5₋0.3 samples. Taken together, the present findings indicated that oxidative damage and inflammatory response preceeded cytotoxicity in air pollution PM2.5₋0.3-exposed BEAS-2B cells and supported the idea that PM-size, composition, and origin could interact in a complex manner to determine the in vitro responsiveness to PM.

Relationship between physicochemical characterization and toxicity of fine particulate matter (PM2.5) collected in Dakar city (Senegal).

The massive increase in emissions of air pollutants due to economic and industrial growth in developing countries has made air quality a crucial health problem in this continent. Hence, it is somewhat critical to have a better knowledge on the air pollution in Sub-Saharan Africa countries. Three air pollution PM2.5 samples were also collected in two urban sites (i.e., Fann and Faidherbe) in Dakar (Senegal) and in a rural site near Dakar (i.e., Ngaparu). The two urban sites mainly differ in the type of used vehicles: in Fann, most of the traffic is made of buses, which are absent, in Faidherbe. The physicochemical characteristics of the three PM2.5 samples revealed their high heterogeneities and complexities, related to the multiple natural and anthropogenic emission sources. Results from 5-bromodeoxyuridine incorporation into DNA, mitochondrial dehydrogenase activity, and extracellular lactate dehydrogenase activity in PM2.5-exposed BEAS-2B cells suggested the exposure conditions (i.e., 3 and 12 µg PM/cm² during 24, 48, and 72 h) to further consider. The organic fractions (i.e., mainly PAHs) of the PM(2.5) samples were able to induce a time and/or concentration-dependent gene expression of CYP1A1 and CYP1B1, and, to a lesser extent, NQO1. There was a time and/or dose-dependent increase of both the gene expression and/or protein secretion of inflammatory mediators (i.e., TNF-α, IL-1ß, IL-6, and/or IL-8) in PM(2.5)-exposed BEAS-2B cells. In agreement with the physicochemical characterization, urban PM(2.5) samples caused greater biological responses in BEAS-2B cells than the rural one. Variable concentrations of transition metals (i.e., Fe, Al, Pb, Mn, Zn) and organic compounds (i.e., PAHs) founded in the three PM2.5 samples might be firmly involved in a time- and/or dose-dependent toxicity, relying on inflammatory processes.

The toxicity of SiO2 NPs on cell proliferation and cellular uptake of human lung fibroblastic cell line during the variation of calcination temperature and its modeling by artificial neural network.

Less attention had been paid to cell toxicity of the various synthesis methods of nanoparticles, this study investigated the effect of the calcination temperature(CT) on the crystallization of SiO2 nanoparticles(NPs), cell proliferation(CP), and cellular uptake(CU) in MRC-5. In this study, parameters were adjusted as CT(70-1000 °C), calcination time(2, 12, and 24 h), and catalyst feed rate(0.01, 0.05, and 0.1 mL.min1). CP was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) test after a 24-h exposure. The CU was achieved using ICP-MS. Results were analyzed using MATLAB2018. Results revealed that the size of synthesized particles was lower than 50 nm and, the XRD peak varied from 21 to 30° during the increase in CT. FTIR spectra confirmed the existence of Si-O and Si-Cl bonds. The maximum level of crystallization was at 1000 °C. CP decreased with the rise in the concentration of NPs(p < 0.05), as well as an increase in feed rate. A positive relationship between increased crystallization and decreased CP(R = 0.78) was seen, while such a trend was not observed in calcination time. The suggested structure in this study was 4:10:1 with Rall = 0.97, Rtest = 0.97, RMSE = 0.25, and MSE = 0.003. Furthermore, the CU rate increased with the rise in CT and calcination time. The maximum and minimum CU levels were related to NPs calcinated in 1000 °C-24 h and 350 °C-2 h, respectively. As a consequence, the most toxicity of SiO2 NPs was related to the crystalline NP. Therefore, the increase in CT and the calcination time were significant factors affecting on crystallization of SiO2 NPs, CP of lung cell, as well as CU of SiO2. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40201-021-00663-4.

Benzene-induced mutational pattern in the tumour suppressor gene TP53 analysed by use of a functional assay, the functional analysis of separated alleles in yeast, in human lung cells.

Recent concern has centred on the effects of continuous exposure to low concentrations of benzene, both occupationally and environmentally. Although benzene has for a long time been recognised as a carcinogen for humans, its mechanistic pathway remains unclear. Since mutations in the tumour suppressor gene TP53 are the most common genetic alterations involved in human cancer, our objective was to establish the first mutational pattern induced by benzene on the TP53 gene in human type II-like alveolar epithelial A549 cells by using the Functional Analysis of Separated Alleles in Yeast (FASAY). Seventeen mutations linked to benzene exposure were found: 3 one- or two-base deletions, and 14 single nucleotide substitutions (1 nonsense and 13 missense mutations). A>G and G>A transitions were the most prevalent (23.5% for both). Other mutations included A>C transversions and deletions (3/17, 17.6% for both), G>T transversions (2/17, 11.8%) and A>T transversions (1/17, 5.9%). Data arising from this benzene-induced mutational pattern affecting TP53, a critical target gene in human carcinogenesis, have been compared with those reported in human acute myeloid leukaemia, the aetiology of which is clearly linked to benzene exposure, and in experimental benzene-induced carcinoma. This comparison suggests that A>G transition could be a fingerprint of benzene exposure in tumours. Furthermore, our results demonstrate that FASAY is a promising tool for the study of the carcinogenic potency of benzene in the human lung.

Oxidative damage induced in A549 cells by physically and chemically characterized air particulate matter (PM2.5) collected in Abidjan, Côte d'Ivoire.

Exposure to high levels of air pollution particulate matter (PM) is strongly associated with increased pulmonary morbidity and mortality. However, the underlying mechanisms of action whereby PM cause adverse health effects are still unclear. In developing countries, like in the sub-Saharian region of Africa, people are often exposed to high PM levels. Hence, three PM(2.5) samples were collected in the District of Abidjan (Côte d'Ivoire), under rural, urban or industrial influences. Their most toxicologically relevant physical and chemical characteristics were determined--thereby showing that most of them were equal or smaller than 2.5 microm--and the influence of both natural (Ca, Na, Mg, Ti, etc.) and anthropic (Al, Fe, Mn, Cr, Pb, Zn, Cu, Ni, benzene and its derivatives, paraffins, etc.) emission sources. The toxicity induced by the three PM samples was studied through 5-bromodeoxyuridine incorporation to DNA, mitochondrial dehydrogenase activity and extracellular lactate dehydrogenase activity. Hence, effect concentrations at 10 and 50% (EC(10) and EC(50), respectively) were as follows: (i) rural PM--EC(10) = 5.91 microg cm(-2) and EC(50) = 29.55 microg cm(-2); (ii) urban PM--EC(10) = 5.45 microg cm(-2) and EC(50) = 27.23 microg cm(-2); and (iii) industrial PM--EC(10) = 6.86 microg cm(-2) and EC(50) = 34.29 microg cm(-2). Moreover, PM-induced oxidative damage in A549 cells was observed through the induction of lipid peroxidation, the alteration of superoxide dismutase activity, and the disruption of glutathione status. Both the transition metals and the organic chemicals within the three collected PM samples under study might be involved in the oxidative damage and, therefore, the toxicity they induced in A549 cells.

Air pollution particulate matter (PM2.5)-induced gene expression of volatile organic compound and/or polycyclic aromatic hydrocarbon-metabolizing enzymes in an in vitro coculture lung model.

The overarching goals were: (i) to develop an in vitro coculture model, including two relevant lung target cells: human alveolar macrophage (AM) isolated from bronchoalveolar lavage fluid, and immortalized cells originated from the normal lung tissue of a human embryo (L132 cell line), as a future strategy for near-realistic exposures to air pollution particulate matter (PM), and (ii) to study the gene expression of volatile organic compound (VOC) and/or polycyclic aromatic hydrocarbons (PAH)-metabolizing enzymes in this in vitro coculture model. Human AM and/or L132 cells in mono- and coculture were exposed for 24, 48 and 72h to Dunkerque City's PM2.5 at its lethal concentrations at 10% and 50% (i.e. AM: LC10=14.93 microgPM/mL and LC50=74.63 microgPM/mL; L132: LC10=18.84 microgPM/mL and LC50=75.36 microgPM/mL), and the gene expression (i.e. Cytochrome P450 1A1, CYP1A1; CYP2E1; CYP2F1; microsomal Epoxide Hydrolase; NADPH Quinone Oxydo-Reductase-1, NQO1; and Glutathione S-Transferase pi-1 and mu-3, GST-pi1 and GST-mu3) was studied. In human AM in mono- and coculture, and in L132 cells in monoculture, VOC and/or PAH-coated onto PM induced the gene expression of CYP1A1, CYP2E1, NQO1, GST-pi1, and/or GST-mu3. However, there were quiet different outcomes based on the use of L132 cells in mono- vs. coculture: the pattern of VOC and/or PAH-metabolizing enzymes induced by PM in L132 cells in monoculture remained almost unaffected when in coculture with AM. Taken together, these results reinforced the key role of PM-exposed target human AM in the defenses of the human lung from external injuries, notably through their higher capacity to retain PM, and indicated that carbonaceous cores of PM, as physical vector of the penetration and retention of coated-VOC and/or PAH into cells, enabled them to exert a longer toxicity. The use of such a near realistic exposure system could also be a very useful and powerful tool to identify the mechanisms by which air pollution PM induced adverse health effects.

In vitro toxicological evaluation of emissions from catalytic oxidation removal of industrial VOCs by air/liquid interface (ALI) exposure system in repeated mode.

Toxicity of toluene and by-products formed during its catalytic oxidative degradation was studied in human bronchial BEAS-2B cells repeatedly exposed. BEAS-2B cells were exposed using an Air-Liquid Interface (ALI) System (Vitrocell®) for 1 h per day during 1, 3 or 5 days to gaseous flows: toluene vapors (100 and 1000 ppm) and outflow after catalytic oxidation of toluene (10 and 100%). After exposure to gaseous flow, cytotoxicity, inflammatory response and Xenobiotic Metabolism Enzymes (XME) gene expression were investigated. No significant cytotoxicity was found after 5 days for every condition of exposure. After cells exposure to catalytic oxidation flow, IL-6 level increased no significantly in a time- and dose-dependent way, while an inverted U-shaped profile of IL-8 secretion was observed. XME genes induction, notably CYP2E1 and CYP2F1 results were in line with the presence of unconverted toluene and benzene formed as a by-product, detected by analytical methods. Exposure to pure toluene also demonstrated the activation of these XMEs involved in its metabolism. Repeated exposure permits to show CYP1A1, CYP1B1 and CY2S1 expression, probably related to the formation of other by-products, as PAHs, not detected by standard analytical methods used for the development of catalysts.

Gene expression induction of volatile organic compound and/or polycyclic aromatic hydrocarbon-metabolizing enzymes in isolated human alveolar macrophages in response to airborne particulate matter (PM2.5).

To contribute to improve the knowledge of the underlying mechanisms of action involved in air pollution particulate matter (PM)-induced cytotoxicity, we were interested in the metabolic activation of volatile organic compounds (VOC) and/or polycyclic aromatic hydrocarbons (PAH) coated onto Dunkerque City's PM2.5 in human alveolar macrophages (AM) isolated from bronchoalveolar lavage fluid (BALF). This in vitro cell lung model is closer to the normal in vivo situation than other lung cell lines, notably in the characteristics that AM display in terms of gene expression of phase I and phase II-metabolizing enzymes. The bronchoscopic examinations and BAL procedures were carried out without any complications. After 24, 48 and 72h of incubation, calculated lethal concentrations at 10% and 50% of collected airborne PM were 14.93microg PM/mL and 74.63microg PM/mL, respectively, and indicated the higher sensibility of such target lung cells. Moreover, VOC and/or PAH coated onto PM induced gene expression of cytochrome P450 (cyp) 1a1, cyp2e1, nadph quinone oxydo-reductase-1, and glutathione S-transferase-pi 1 and mu 3, versus controls, suggesting thereby the formation of biologically reactive metabolites. In addition, these results suggested the role of physical carrier of carbonaceous core of PM, which can, therefore, increase both the penetration and the retention of attached-VOC into the cells, thereby enabling them to exert a longer induction. Hence, we concluded that the metabolic activation of the very low doses of VOC and/or PAH coated onto Dunkerque City's PM2.5 is one of the underlying mechanisms of action closely involved in its cytotoxicity in isolated human AM in culture.

A new approach for safe planning transfer using semi-automatically adjustable instrument guides.

Accurate planning transfer is a prerequisite for successful operative care. For different applications, diverse computer-assisted systems have been developed and clinically evaluated. This paper presents the implementation and evaluation of a new modular concept. The approach is based on passive application specific kinematics that are semi-automatically adjusted using a universal hand-held computer controlled Smart Screw Driver. The system was realized for pedicle screw instrumentation and evaluated according to IEC 60601-1-6 (usability engineering). The accuracies of the drill holes achieved were comparable with robotic approaches, while operation time and radiation were reduced compared with conventional operation techniques. The adjustment procedure has proven high learnability and user satisfaction. The next step will be optimization of the kinematic structure and fixation to the patient in order to increase accuracies of planning transfer as well as evaluation of the overall system by medical staff in preclinical and clinical studies.

Influence of aging in the modulation of epigenetic biomarkers of carcinogenesis after exposure to air pollution.

BACKGROUND: Classified as carcinogenic to humans by the IARC in 2013, fine air particulate matter (PM2.5) can be inhaled and retained into the lung or reach the systemic circulation. This can cause or exacerbate numerous pathologies to which the elderly are often more sensitive. METHODS: In order to estimate the influence of age on the development of early cellular epigenetic alterations involved in carcinogenesis, peripheral blood mononuclear cells sampled from 90 patients from three age classes (25-30, 50-55 and 75-80 years old) were ex vivo exposed to urban PM2.5. RESULTS: Particles exposure led to variations in telomerase activity and telomeres length in all age groups without any influence of age. Conversely, P16INK4A gene expression increased significantly with age after exposure to PM2.5. Age could enhance MGMT gene expression after exposure to particles, by decreasing the level of promoter methylation in the oldest people. CONCLUSION: Hence, our results demonstrated several tendencies in cells modification depending on age, even if all epigenetic assays were carried out after a limited exposure time allowing only one or two cell cycles. Since lung cancer symptoms appear only at an advanced stage, our results underline the needs for further investigation on the studied biomarkers for early diagnosis of carcinogenesis to improve survival.