ALA dendrimers to improve diagnostic specificity of fluorescence guided diagnosis of bladder cancer
Bibliographic record
Abstract
Background: Fluorescence guided cystoscopy with 5-aminolevulinic acid (ALA) or its hexyl derivative (h-ALA, Hexvix®) has been shown to increase bladder cancer diagnosis and offer the possibility to perform a more complete resection, thereby reducing the recurrence and progression rate. The fast photobleaching of the fluorophore protoporphyrin IX (PpIX) limits the visualization during cystoscopy and the specificity is low. Methods: To overcome these drawbacks, dendrimers containing 18 ALA molecules (18-ALA) were synthesized. We investigated the in vitro hydrolysis of ALA, the PpIX synthesis as well as the photobleaching of equimolar concentrations of ALA, h-ALA and 18-ALA. We instilled 18-ALA intravesically in rats, bearing orthotopic bladder tumors to study the specificity on frozen sections by fluorescence microscopy. Results: A slow mono-exponential hydrolysis of the dendrimers probably attributed to steric hindrance and limited access to esterases is observed, as opposed to the rather fast liberation of free ALA from Hexvix®. The continuous synthesis of PpIX and the slower photobleaching of dendrimer induced PpIX, would thus ensure a prolonged presence of fluorescence during cystoscopy. In vivo, 1h instillation is sufficient to enable endocytosis of dendrimers but a minimum of 3h resting time is required to observe PpIX fluorescence with a better specificty towards the tumor as opposed to h-ALA. Conclusion: The prolonged and sustained PpIX synthesis with a reduced photobleaching and the improved specificity are primary indicators that ALA dendrimers could possibly overcome drawbacks of ALA/h-ALA fluorescence guided cystoscopy.
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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 | 0.000 |
| 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".