Comparisons of the factors influencing intrinsic radiosensitivity between two isogenic human ovarian carcinoma cell lines.
Bibliographic record
Abstract
The human ovarian carcinoma cell line, A2780s, and its variant, A2780cp, provide an isogenic tumour model for examining factors which determine intrinsic radiosensitivity. A2780s demonstrates sensitivity to ionization radiation while A2780cp is relatively radioresistant (surviving fraction following a 2 Gy dose is 0.083 and 0.43, respectively). The increased radioresistance of A2780cp can not be explained by greater cellular recovery, neither from sublethal nor potentially lethal damage. Moreover, A2780s demonstrates significantly greater (P < 0.05) sublethal and potentially lethal damage recovery than A2780cp. The induction of double strand breaks (dsb), as measured by asymmetric field inversion gel electrophoresis (AFIGE), is identical in these cell lines. Dsb rejoining efficiency is similar between A2780s and A2780cp. Initially, rejoining kinetic experiments reveal that A2780s is deficient in the slow phase of rejoining, while A2780cp is not (80% of dsb remain for A2780s vs 29% A2780cp) (P < 0.01). This deficiency however, is not reproduced in residual dsb experiments and further analysis reveals that it may be an artifact of the normalization process. When the level of residual dsb as a function of dose is examined, the slopes are similar for both cell lines and the only significant difference is seen for the highest dose used, 150 Gy (50% for A2780s and 33% for A2780cp) (P < 0.05). Finally, the cell-free fidelity assay demonstrates that for blunt-cut plasmid, no differences exist in the rejoining efficiency of nuclear extracts. The ligation infidelity of blunt-cut plasmid however, is significantly less (P < 0.05) in A2780cp extracts (0.021 for A2780s vs 0.0030 for A2780cp). Therefore, neither the induction of dsb, nor the efficiency of dsb repair can explain observed differences in radiosensitivity. The fidelity of rejoining however, is significantly greater in the resistant variant and may, in part, explain these differences.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.001 | 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".