Abstract 1317: The 2-phenylbenzimidazole-5-sulfonic acid sunscreen agent photosensitizes oxidized guanines following UVA or UVB exposure
Bibliographic record
Abstract
Abstract The 2-phenylbenzimidazole-5-sulfonic acid (PBSA) is a sunscreen agent widely used in the cosmetic industry because it absorbs strongly at UVB wavelengths providing a good protection against the cyclobutane pyrimidine dimer (CPD) generation. Previous studies have shown that PBSA oxidize guanine bases in vitro (isolated DNA). Due to its potential phototoxic effect, it is of great interest to determine whether PBSA can play the role of a photosensitizer in cellulo. For this purpose, we investigated in vitro and in cellulo (in fibroblasts) the effect of 0 to 4 mM PBSA on DNA damage formation after UVA or UVB irradiation. In order to monitor oxidized bases and CPD formation, DNA was digested with either endonuclease III and FaPy-DNA glycosylase or T4 endonuclease V and photolyase, then analyzed by means of glyoxal gel electrophoresis and ligation-mediated polymerase chain reaction (LMPCR). We found that in cellulo and in vitro, PBSA provided a good protection against CPD formation, but induced oxidative damage and DNA-strand breaks. Moreover, with the LMPCR technology we were able to determine that oxidative damage were preferentially formed at guanine sites. Our results indicate that PBSA has the potential to act as a double-edged sword toward DNA, on one hand it blocks the formation of CPDs after UVB and on the other hand increase the formation of oxidized guanines upon UVA and UVB irradiation. This raises major concern regarding its suitability for sunscreen applications. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1317.
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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 | 0.002 | 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 | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 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".