Low doses of ionizing radiation can prevent radiation-induced colonic epithelial hyporesponsiveness to muscarinic agonists
Bibliographic record
Abstract
PURPOSE: Colonic epithelium hyporesponsiveness to different secretagogues occurs after exposure to ionizing radiation, increasing susceptibility to bacterial translocation and intraluminal toxins. Growing evidence suggests that the biological effects of radiation might be hormetic in nature. We investigated if exposure to low doses of ionizing radiation (LDR) can prevent colon hyposecretion due to subsequent larger doses. METHODS: Rats were exposed to LDR (0.05 Gy) 24 h prior to 6 Gy, high dose radiation (HDR). The cyclic adenosine monophosphate (cAMP)-mediated pathway was explored using forskolin (FSK) and the intracellular Ca2+-mediated pathway through cholinergic stimulation. Changes in the colonic epithelium at the ultrastructural level were also explored. RESULTS: Maximal short circuit current (Isc) response to carbachol was significantly reduced in the group exposed to 6 Gy HDR and this was completely prevented by prior exposure to LDR. Responses to both FSK and electrical field stimulation (EFS) were significantly reduced after HDR but they were not prevented by prior adaption of LDR. Hyposecretion was not prevented by the inducible nitric oxide synthase (iNOS) inhibitor L-N6-(l-iminoethyl)lysine (L-NIL) ruling out a role for iNOS-derived nitric oxide (NO) in the colonic hyposecretion associated with whole body radiation. Prior exposure to LDR diminished the deleterious effect of full HDR on the ultrastructure of colonic epithelium as colonocytes vacuolization, microvilli lost and separation between neighboring cells were less evident. CONCLUSIONS: Previous exposure to LDR can prevent intracellular Ca2+-mediated colonic hyposecretion associated with exposure to HDR but fails to modify cAMP-mediated hyposecretion. Morphological damage at the ultrastructural level is less evident after prior LDR.
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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) | 0.000 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".