A288 ANAL SPHINCTER RELAXATION ASSOCIATED WITH THE DEFECATION REFLEX AND GAS EXPULSION, ASSESSED BY HIGH-RESOLUTION COLONIC MANOMETRY
Bibliographic record
Abstract
Continence and defecation require coordination between colonic motor patterns and internal anal sphincter relaxation, yet these relationships are not well understood. Our aim was to investigate the coordination between human colonic motor patterns and anal sphincter activity. High-Resolution Colonic Manometry (HRCM) was performed using an 84 sensor water-perfused catheter (1 cm spacing) in 14 healthy subjects. Colonic motor patterns and anorectal activity were recorded at baseline and provoking conditions (after a meal, balloon distensions, and luminal bisacodyl administration). A highly rhythmic alternation of contraction and relaxation of the internal AS in resting condition was observed in all subjects: a low-frequency rhythmicity at 1.2 ± 0.3 cpm with slowly developing and declining contraction, and a high-frequency rhythmicity at 15.0 ± 2.7 cpm superimposed on the slow rhythmicity. The High Amplitude Pressure Wave (HAPW) (Chen et al., 2017) was not routinely associated with IAS relaxation. However, 62.5% of HAPWs were associated with a brief transient relaxation at the onset of the HAPW in the proximal colon, which did not last for the duration of the HAPW. Gas expulsion was associated with Simultaneous Pressure Waves (SPWs), pan-colonic pressurizations that penetrated into the anal canal and were most often associated with strong relaxation of the IAS. Many HAPWs terminated in the mid or descending colon but were immediately followed by an SPW and this was accompanied by IAS relaxation. A total of 61 independent SPWs with a mean amplitude of 26.3 ± 7.9 mmHg, were associated with 50.2 ± 12.7% % IAS relaxation from 65.1 ± 15.6 mmHg to 31.5 ± 11.3 mmHg. Bisacodyl induced SPWs of highest amplitude (30.3 ± 4.7 mmHg), that were followed by 63.8 ± 9.0% IAS relaxation, compared to SPWs occurring at baseline of 23.8 ± 5.6 mmHg associated with 44.3 ± 12.4% IAS relaxation. Duration of relaxation was correlated neither with the amplitude of SPW nor the percentage of IAS relaxation. Out of 44 HAPWs analyzed, 27.2% were not associated with IAS relaxation, whereas 72.8% were accompanied by a transient IAS relaxation of 51.2 ± 17.3% at the onset of the HAPW which recovered during the progression of the HAPW. 45.4% of HAPWs (103.3 ± 24.0 mmHg) were immediately followed by SPWs (18.7 ± 6.5 mmHg), which were then associated with strong IAS relaxation of 66.9 ± 13.6%, going from 63.2 ± 19.4 mmHg to 20 ± 8.6 mmHg. The SPW, either in isolation and associated with gas expulsion or following an HAPW as part of the defection reflex, is consistently associated with internal anal sphincter relaxation. This relaxation reduces IAS tone which is maintained by rhythmic contractile activity. Chen JH, et al. (2017). Nature’s Scientific Reports doi:10.1038/srep41436. High-Resolution Colonic Manometry (HRCM) with 84 sensors, 1 cm apart. A simultaneous pressure wave (SPW), following a High Amplitude Pressure Wave (HAPW), penetrates into the anal canal and is associated with internal anal sphincter (IAS) relaxation. CIHRHamilton Academic Health Sciences Organization and the Canadian Foundation for Innovation
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 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 | 0.000 |
| 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".