Irradiance and light dose influence histological localization of photodamage induced by photodynamic therapy with aminolaevulinic acid
Bibliographic record
Abstract
BACKGROUND: Photodynamic therapy (PDT) with aminolaevulinic acid (ALA) is used in many countries for the treatment of actinic keratoses. OBJECTIVES: The objectives of the current study were to evaluate the influence of irradiance and light dose on the localization and extent of photodamage to mouse skin following ALA-PDT. METHODS: In this study we evaluated the influence of irradiance and light dose on epidermal photodamage following ALA-PDT. Groups of hairless mice received an intraperitoneal injection of ALA followed 2 h later by exposure to 12 J cm(-2), 24 J cm(-2) or 48 J cm(-2) of unfiltered light from a slide projector. For each of these fluences, groups of mice were exposed at the following irradiances: 5 mW cm(-2), 20 mW cm(-2) or 40 mW cm(-2). Skin biopsies were performed 24 h and 72 h later. RESULTS: Histological localization of photodamage was influenced by irradiance and light dose. At high irradiance and low fluence, PDT photodamaged cells were mostly located in the upper area of the epidermis whereas at lower irradiance and high fluence the complete epidermis was necrotic and often absent 24 h after light exposure. Protoporphyrin IX (PpIX) fluorescence intensity was similar in the upper and lower region of the epidermis 2 h after ALA injection. The decrease in PpIX fluorescence intensity immediately after light exposure was also similar in both regions of the epidermis. CONCLUSIONS: The localization of photodamage following ALA-PDT is influenced by irradiance and light dose. This phenomenon cannot be explained by differences in PpIX intensity in the epidermis either before or after light exposure.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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) | 0.000 | 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".