Neuropathology of bouncer Long Evans, a novel dysmyelinated rat.
Bibliographic record
Abstract
BACKGROUND AND PURPOSE: Spontaneous animal mutants affected by abnormal formation of myelin in the central nervous system (CNS) are useful in studies on myelinogenesis and remyelination leading to better understanding of cellular and molecular interactions involved in myelin repair. A novel rat mutant, Bouncer Long Evans (LE-bo) is severely dysmyelinated, but with exceptional longevity, and its clinical and pathologic phenotype are described. METHODS: Clinical observations, genetic studies, and determination of longevity were performed in a colony of rats, including carriers of LE-bo phenotype producing the mutant animals. Comprehensive histologic studies were performed on all perfusion-fixed tissues, and ultrastructural examination of the optic nerve and thoracic part of the spinal cord also was done in rats 1 to 14 weeks old. RESULTS: The LE-bo phenotype is characterized by whole body tremor, progressively severe ataxia, and severe seizure activity. The LE-bo phenotype is transferred as an autosomal recessive trait and is stable. The LE-bo rat can survive in good health beyond 45 weeks. Neuropathologic changes include severe global dysmyelination, with thin uncompacted myelin sheaths in young rats forming no major dense line, whereas the myelin sheaths of the peripheral nervous system appear normal. Oligodendrocytes degenerate with apparently progressing accumulation of membranous material in the perikaryon. Large numbers of immature glial cells were detected in the CNS of LE-bo rats at 4 to 14 weeks. CONCLUSION: The LE-bo rat is severely dysmyelinated due to inability of its oligodendrocytes to form myelin sheaths. Similarities of the LE-bo rat and Long Evans Shaker (les) rat neuropathologic features, such as severe dysmyelination, lack of major dense line in uncompacted myelin sheaths, apparent proliferation of oligodendroglial cells, and considerable longevity, are striking and suggest that a LE-bo mutation may functionally affect the myelin basic protein gene.
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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 | 0.001 |
| 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".