In vitro Toxicological Study of Particulate Matter and the Relationship with Physicochemical Properties of Particles
Bibliographic record
Abstract
Numerous epidemiological and toxicological studies have reported substantial evidence linking airborne particulate matter (PM) exposure to adverse health effects. PM-initiated oxidative stress at the cellular level is considered a potential mechanism contributing the pathogenesis of cardiopulmonary diseases. However, there remain major gaps in knowledge about the relationship between toxicity and the physicochemical properties of PM. The main objective of this study was to investigate the effects of different source-related and size-fractionated ambient PM on cellular responses to identify relevant physicochemical properties (e.g., size, composition, and redox activity) of particles that could be responsible for the effects. Another objective was to evaluate whether progressive oxidative stress-induced cellular responses (i.e., activation of antioxidant defence at lower level of oxidative stress, followed by inflammatory response, and ultimately cell death as the stress level increases) represent a potential biological mechanism affecting cells in all size fractions. For this purpose, different source-related Standard Reference Materials (industrial, urban, and diesel PM), and size-fractionated ambient coarse, fine, and ultrafine PM (collected from Toronto, Canada) were tested. A549 cells were exposed to different PM doses for certain duration. After exposure, the cells were analyzed for different biological responses and the responses were then compared with available physicochemical properties of the PM. This study demonstrated that exposure to PM can initiate mass-dependent antioxidant, proinflammatory, and cytotoxic responses. Among the different source and size-related PM, transition metal-enriched industrial and coarse PM exhibited the greatest cytotoxic effect, whereas organic compound-enriched ultrafine PM caused significant induction of antioxidant defence. Correlation analyses with chemical constituents suggested transition metals and organic compounds were associated with the observed biological responses. However, the observed biological responses could not be explained by particle size or composition alone. Both of these properties should be considered when explaining the observed PM toxicity. This study also showed that ultrafine PM initiated the hypothesized progressive biological responses, whereas different biological pathways might be involved in coarse and fine PM. Overall, this study demonstrated that the cellular responses varied substantially after in vitro exposure to PM from different sources and ultrafine PM could be as potent as coarse and fine PM.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".