Development of a new surgical technique to infuse kynurenic acid to optic nerves in chickens for studying loss of myelination
Bibliographic record
Abstract
Prolonged infusion of a high dose of kynurenic acid (KYNA) reduces the myelin content in the rat spinal cord with preservation of the axonal integrity and without inducing an inflammatory response. We hypothesized that subdural infusion of a high concentration of KYNA can induce myelin loss in the optic nerves (ONs) of chickens. However, existing methods to deliver agents to the ON are inefficient, unlocalized and provide only acute exposure. Thus, we developed a surgical approach for sustained delivery of KYNA to the chicken ON. In brief, the novel surgical technique, which does not include excision of the extraocular muscles, involves incision of the skin and underlying fascial sheath to access the optic nerve within the muscle cone, implantation of a catheter in the dura of the optic nerve, the other end of which exits the orbit under the skin. The catheter runs under the skin near the lateral canthus, over the ears to the back of the neck, where a second incision is made to both implant the osmotic pump and to attach the catheter to the osmotic pump. India ink was used to confirm prolonged sustained administration to the optic nerves and across the chiasm. This surgical model was used to investigate KYNA's effect(s) on myelin loss in the ON. ONs of 7-day old chickens were infused with 50 mM KYNA or phosphate buffered saline (PBS) for seven days. Analysis of KYNA-infused contralateral ON g-ratios and protein levels indicated a reduction in myelin. These findings demonstrate the utility of our surgical approach for sustained delivery of KYNA into the ON and suggest a role for KYNA in modulating CNS myelination.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| 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 | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".