Carbon dioxide challenge enhances the sensitivity of whole body plethysmography (WBP) measurements of lung growth and ozone‐induced changes in juvenile Long‐Evans rats
Bibliographic record
Abstract
Background Risk factors associated with development of childhood disorders such as asthma and obesity include prematurity and intrauterine growth restriction. We recently demonstrated that exposure of Long Evans rats in early pregnancy to the air pollutant, ozone, resulted in reduced near‐term fetal growth. We propose to utilize this model of early life environmental stress to examine developmental origins of asthma later in life. Therefore, in this pilot study, we sought to improve the sensitivity of WBP to monitor lung volume growth in rats during development. Methods Subset A male and female offspring from air‐ or 0.8 ppm ozone‐exposed dams (4h/day on gestational day 5 and 6) (n ≅ 6/group) were monitored weekly from postnatal day (PND) 13 to PND70 for changes in body weight and spontaneous ventilatory parameters [i.e., breathing frequency ( f ), tidal volume (TV), minute volume (MV), EF50 and Penh]. Data were first obtained using mouse and later rat WBP chambers with EMKA iox 2 software (SCIREQ, Montreal, Canada). To enhance tidal breathing, Subset B male offspring (n = 7; ≥ PND50) were used to optimize a CO 2 challenge protocol (5–7.5% CO 2 ) for up to 10 minutes under control conditions, and then later (PND81) to assess whether the CO 2 challenge would also be tolerated acutely following exposure to ozone (0.4 or 0.8 ppm ×4h). Results Subset A offspring underwent rapid growth during the 8‐week study period with nearly 15‐fold increases in body weight in males and 10‐fold increases in females. Corresponding increases in TV (~0.2 to > 2.0 mL) were observed. In Subset B males, a 6% CO 2 challenge for 6 minutes appeared optimal. Likewise, in Subset A rats at PND67, this CO 2 challenge resulted in more uniform breathing, less movement‐related artifacts, and increased ventilatory effort (TV increased ~50%); although females were somewhat less responsive. Lastly, use of the 6% CO 2 challenge immediately following ozone exposure of Subset B males more readily distinguished the resultant breathing pattern alterations and lung volume deficits occurring. Conclusions Although the CO 2 ‐enhanced lung volume measurements obtained herein are not equivalent to maximal, expiratory maneuvers (i.e., FEV 1 ) as can be achieved in humans, this protocol was well tolerated and may provide a more sensitive, yet non‐invasive method of documenting differential lung growth trajectories in offspring— with or without prior in utero ozone exposure — as they undergo additional exposures during weanling and peri‐adolescent life stages. (Abstract does not reflect USEPA policy). This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 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".