Transferability and reproducibility of exposed air-liquid interface co-culture lung models

Background The establishment of reliable and robust in vitro models for hazard assessment, a prerequisite for moving away from animal testing, requires the evaluation of model transferability and reproducibility. Lung models that can be exposed via the air, by means of an air-liquid interface (ALI) are promising in vitro models for evaluating the safety of nanomaterials (NMs) after inhalation exposure. We performed an inter-laboratory comparison study to evaluate the transferability and reproducibility of a lung model consisting of the human bronchial cell line Calu-3 as a monoculture and, to increase the physiologic relevance of the model, also as a co-culture with macrophages (either derived from the THP-1 monocyte cell line or from human blood monocytes). The lung model was exposed to NMs using the VITROCELL® Cloud12 system at physiologically relevant dose levels. Results Overall, the results of the 7 participating laboratories are quite similar. After exposing Calu-3 alone and Calu-3 co-cultures with macrophages, no effects of lipopolysaccharide (LPS), quartz (DQ12) or titanium dioxide (TiO2) NM-105 particles on the cell viability and barrier integrity were detected. LPS exposure induced moderate cytokine release in the Calu-3 monoculture, albeit not statistically significant in most labs. In the co-culture models, most laboratories showed that LPS can significantly induce cytokine release (IL-6, IL-8 and TNF-α). The exposure to quartz and TiO2 particles did not induce a statistically significant increase in cytokine release in both cell models probably due to our relatively low deposited doses, which were inspired by in vivo dose levels. The intra- and inter-laboratory comparison study indicated acceptable interlaboratory variation for cell viability/toxicity (WST-1, LDH) and transepithelial electrical resistance, and relatively high inter-laboratory variation for cytokine production. Conclusion The transferability and reproducibility of a lung co-culture model and its exposure to aerosolized particles at the ALI were evaluated and recommendations were provided for performing inter-laboratory comparison studies. Although the results are promising, optimizations of the lung model (including more sensitive read-outs) and/or selection of higher deposited doses are needed to enhance its predictive value before it may be taken further towards a possible OECD guideline

An inter-laboratory effort to harmonize the cell-delivered in vitro dose of aerosolized materials

Air-liquid interface (ALI) lung cell models cultured on permeable transwell inserts are increasingly used for respiratory hazard assessment requiring controlled aerosolization and deposition of any material on ALI cells. The approach presented herein aimed to assess the transwell insert-delivered dose of aerosolized materials using the VITROCELL® Cloud12 system, a commercially available aerosol-cell exposure system. An inter-laboratory comparison study was conducted with seven European partners having different levels of experience with the VITROCELL® Cloud12. A standard operating procedure (SOP) was developed and applied by all partners for aerosolized delivery of materials, i.e., a water-soluble molecular substance (fluorescence-spiked salt) and two poorly soluble particles, crystalline silica quartz (DQ12) and titanium dioxide nanoparticles (TiO2 NM-105). The material dose delivered to transwell inserts was quantified with spectrofluorometry (fluorescein) and with the quartz crystal microbalance (QCM) integrated in the VITROCELL® Cloud12 system. The shape and agglomeration state of the deposited particles were confirmed with transmission electron microscopy (TEM). Inter-laboratory comparison of the device-specific performance was conducted in two steps, first for molecular substances (fluorescein-spiked salt), and then for particles. Device- and/or handling-specific differences in aerosol deposition of VITROCELL® Cloud12 systems were characterized in terms of the so-called deposition factor (DF), which allows for prediction of the transwell insert-deposited particle dose from the particle concentration in the aerosolized suspension. Albeit DF varied between the different labs from 0.39 to 0.87 (mean (coefficient of variation (CV)): 0.64 (28%)), the QCM of each VITROCELL® Cloud 12 system accurately measured the respective transwell insert-deposited dose. Aerosolized delivery of DQ12 and TiO2 NM-105 particles showed good linearity (R2 > 0.95) between particle concentration of the aerosolized suspension and QCM-determined insert-delivered particle dose. The VITROCELL® Cloud 12 performance for DQ12 particles was identical to that for fluorescein-spiked salt, i.e., the ratio of measured and salt-predicted dose was 1.0 (29%). On the other hand, a ca. 2-fold reduced dose was observed for TiO2 NM-105 (0.54 (41%)), which was likely due to partial retention of TiO2 NM-105 agglomerates in the vibrating mesh nebulizer of the VITROCELL® Cloud12. This inter-laboratory comparison demonstrates that the QCM integrated in the VITROCELL® Cloud 12 is a reliable tool for dosimetry, which accounts for potential variations of the transwell insert-delivered dose due to device-, handling- and/or material-specific effects. With the detailed protocol presented herein, all seven partner laboratories were able to demonstrate dose-controlled aerosolization of material suspensions using the VITROCELL® Cloud12 exposure system at dose levels relevant for observing in vitro hazard responses. This is an important step towards regulatory approved implementation of ALI lung cell cultures for in vitro hazard assessment of aerosolized materials

Spontaneously formed porous and composite materials

In recent years, a number of routes to porous materials have been developed which do not involve the use of pre-formed templates or structure-directing agents. These routes are usually spontaneous, meaning they are thermodynamically downhill. Kinetic control, deriving from slow diffusion of certain species in the solid state, allows metastable porous morphologies rather than dense materials to be obtained. While the porous structures so formed are random, the average architectural features can be well-defined, and the porosity is usually highly interconnected. The routes are applicable to a broad range of functional inorganic materials. Consequently, the porous architectures have uses in energy transduction and storage, chemical sensing, catalysis, and photoelectrochemistry. This is in addition to more straightforward uses deriving from the pore structure, such as in filtration, as a structural material, or as a cell-growth scaffold. In this feature article, some of the methods for the creation of porous materials are described, including shape-conserving routes that lead to hierarchical macro/mesoporous architectures. In some of the preparations, the resulting mesopores are aligned locally with certain crystallographic directions. The coupling between morphology and crystallography provides a macroscopic handle on nanoscale structure. Extension of these routes to create biphasic composite materials are also described

Identification of Potential Environmentally Adapted Campylobacter jejuni Strain, United Kingdom

In a study of Campylobacter infection in northwestern England, 2003–2006, C. jejuni multilocus sequence type (ST)–45 was associated with early summer onset and was the most prevalent C. jejuni type in surface waters. ST-45 is likely more adapted to survival outside a host, making it a key driver of transmission between livestock, environmental, and human settings

Four-dimensional electrical resistivity imaging for monitoring pumping-induced saltwater intrusion in a coastal aquifer

Conventional views of saltwater intrusion (SWI), where a basal saline wedge extends inland below fresh groundwater, can be complicated by the influence of saltwater cells in the upper part of aquifers in areas affected by tidal cycles. Distinguishing the contribution of each saltwater source may prove fundamental for well design and resource management. Application of time-lapse electrical resistivity imaging (ERI) during a 32-h pumping test in a pristine unconfined coastal sand aquifer, affected by strong tidal ranges (>2 m), aimed to evaluate the potential of the method to characterize the source of induced SWI in four dimensions (three dimensions and time). Water level monitoring during the test revealed that at the end of pumping, the upper 2 m of the aquifer had dewatered in the vicinity of the well field, reversing hydraulic gradients between the aquifer and the sea. This induced SI, with mixing models of well head water quality suggesting that saline water contributions to total discharge rose from 4 % to 8 %. ERI results reflected dewatering through an increase in resistivity in the upper 2-6 m of the aquifer, while a decline in resistivity, relative to background conditions, occurred immediately below this, reflecting the migration of saline water through the upper layers of the aquifer to the pumping well. By contrast no change in resistivity occurred at depth, indicating no significant change in contribution from the basal saline water to discharge. Test findings suggest that future water resource development at the site should focus on close monitoring of shallow pumping, or pumping from deeper parts of the aquifer, while more generally demonstrating the value of time-lapse geophysical methods in informing coastal water resource management

Shocked monazite chronometry: integrating microstructural and in situ isotopic age data for determining precise impact ages

Monazite is a robust geochronometer and occurs in a wide range of rock types. Monazite also records shock deformation from meteorite impact but the effects of impact-related microstructures on the U–Th–Pb systematics remain poorly constrained. We have, therefore, analyzed shock-deformed monazite grains from the central uplift of the Vredefort impact structure, South Africa, and impact melt from the Araguainha impact structure, Brazil, using electron backscatter diffraction, electron microprobe elemental mapping, and secondary ion mass spectrometry (SIMS). Crystallographic orientation mapping of monazite grains from both impact structures reveals a similar combination of crystal-plastic deformation features, including shock twins, planar deformation bands and neoblasts. Shock twins were documented in up to four different orientations within individual monazite grains, occurring as compound and/or type one twins in (001), (100), (10 1 ¯) , {110}, { 212 } , and type two (irrational) twin planes with rational shear directions in [ 0 1 ¯ 1 ¯ ] and [ 1 ¯ 1 ¯ 0 ]. SIMS U–Th–Pb analyses of the plastically deformed parent domains reveal discordant age arrays, where discordance scales with increasing plastic strain. The correlation between discordance and strain is likely a result of the formation of fast diffusion pathways during the shock event. Neoblasts in granular monazite domains are strain-free, having grown during the impact events via consumption of strained parent grains. Neoblastic monazite from the Inlandsee leucogranofels at Vredefort records a 207Pb/206Pb age of 2010 ± 15 Ma (2σ, n = 9), consistent with previous impact age estimates of 2020 Ma. Neoblastic monazite from Araguainha impact melt yield a Concordia age of 259 ± 5 Ma (2σ, n = 7), which is consistent with previous impact age estimates of 255 ± 3 Ma. Our results demonstrate that targeting discrete microstructural domains in shocked monazite, as identified through orientation mapping, for in situ U–Th–Pb analysis can date impact-related deformation. Monazite is, therefore, one of the few high-temperature geochronometers that can be used for accurate and precise dating of meteorite impacts

An inter-laboratory effort to harmonize the cell-delivered in vitro dose of aerosolized materials

Air-liquid interface (ALI) lung cell models cultured on permeable transwell inserts are increasingly used for respiratory hazard assessment requiring controlled aerosolization and deposition of any material on ALI cells. The approach presented herein aimed to assess the transwell insert-delivered dose of aerosolized materials using the VITROCELL® Cloud12 system, a commercially available aerosol-cell exposure system. An inter-laboratory comparison study was conducted with seven European partners having different levels of experience with the VITROCELL® Cloud12. A standard operating procedure (SOP) was developed and applied by all partners for aerosolized delivery of materials, i.e., a water-soluble molecular substance (fluorescence-spiked salt) and two poorly soluble particles, crystalline silica quartz (DQ 12) and titanium dioxide nanoparticles (TiO 2 NM-105). The material dose delivered to transwell inserts was quantified with spectrofluorometry (fluorescein) and with the quartz crystal microbalance (QCM) integrated in the VITROCELL® Cloud12 system. The shape and agglomeration state of the deposited particles were confirmed with transmission electron microscopy (TEM). Inter-laboratory comparison of the device-specific performance was conducted in two steps, first for molecular substances (fluorescein-spiked salt), and then for particles. Device- and/or handling-specific differences in aerosol deposition of VITROCELL® Cloud12 systems were characterized in terms of the so-called deposition factor (DF), which allows for prediction of the transwell insert-deposited particle dose from the particle concentration in the aerosolized suspension. Albeit DF varied between the different labs from 0.39 to 0.87 (mean (coefficient of variation (CV)): 0.64 (28%)), the QCM of each VITROCELL® Cloud 12 system accurately measured the respective transwell insert-deposited dose. Aerosolized delivery of DQ 12 and TiO 2 NM-105 particles showed good linearity (R 2 > 0.95) between particle concentration of the aerosolized suspension and QCM-determined insert-delivered particle dose. The VITROCELL® Cloud 12 performance for DQ 12 particles was identical to that for fluorescein-spiked salt, i.e., the ratio of measured and salt-predicted dose was 1.0 (29%). On the other hand, a ca. 2-fold reduced dose was observed for TiO 2 NM-105 (0.54 (41%)), which was likely due to partial retention of TiO 2 NM-105 agglomerates in the vibrating mesh nebulizer of the VITROCELL® Cloud12. This inter-laboratory comparison demonstrates that the QCM integrated in the VITROCELL® Cloud 12 is a reliable tool for dosimetry, which accounts for potential variations of the transwell insert-delivered dose due to device-, handling- and/or material-specific effects. With the detailed protocol presented herein, all seven partner laboratories were able to demonstrate dose-controlled aerosolization of material suspensions using the VITROCELL® Cloud12 exposure system at dose levels relevant for observing in vitro hazard responses. This is an important step towards regulatory approved implementation of ALI lung cell cultures for in vitro hazard assessment of aerosolized materials

Institutional Engagement Practices as Barriers to Public Health Capacity in Climate Change Policy Discourse: Lessons from the Canadian Province of Ontario

Public health engagement in the communication, discussion, and development of climate change policies is essential for climate change policy decisions and discourse. This study examines how the existing governance approaches impact, enable, or constrain the inclusion, participation, and deliberation of public health stakeholders in the climate change policy discourse. Using the case study of the Canadian Province of Ontario, we conducted semi-structured, key informant interviews of public health (11) and non-public health (13) participants engaged in climate change policies in the province. The study results reveal that engagement and partnerships on climate change policies occurred within and across public health and non-public health organizations in Ontario. These engagements impacted public health’s roles, decisions, mandate, and capacities beyond the climate change discourse; enabled access to funds, expertise, and new stakeholders; built relationships for future engagements; supported knowledge sharing, generation, and creation; and advanced public health interests in political platforms and decision making. However, public health’s participation and deliberation were constrained by a fragmented sectoral approach, a lack of holistic inter-organizational structures and process, political and bureaucratic influences, irregular and unestablished communication channels for public health integration, and identities and culture focused on functions, mandates, biased ideologies, and a lack of clear commitment to engage public health. We conclude by providing practical approaches for integrating public health into climate change discourse and policymaking processes and advancing public health partnerships and collaborative opportunities

A pair of motion-sensitive neurons in the locust encode approaches of a looming object

Abstract Neurons in the locust visual system encode approaches of looming stimuli and are implicated in production of escape behaviours. The lobula giant movement detector (LGMD) and its postsynaptic partner, the descending contralateral movement detector (DCMD) compute characteristics of expanding edges across the locust eye during a loom and DCMD synapses onto motor elements associated with behaviour. We identified another descending interneuron within the locust ventral nerve cord. We named this neuron the late DCMD (LDCMD) as it responds later during an approach, with the firing rate peaking at about the time of collision. LDCMD produced lower amplitude, broader action potentials that were associated with an afterhyperpolarization, whereas DCMD action potentials showed a brief afterhyperpolarization often followed by an afterdepolarization. Within the mesothoracic ganglion, the primary LDCMD axon located adjacent to the DCMD axon, was thinner and lacked collateral projections to the lateral region of the neuropil. When compared with DCMD, LDCMD fired with fewer spikes during a loom and showed weaker habituation to repeated approaches. Coincidence of LDCMD and DCMD firing increased during object approach. Our findings indicate the presence of an additional motion-sensitive descending neuron in the locust that encodes temporally distinct properties of an approaching object