Centralized Blood Processing for the Selenium and Vitamin E Cancer Prevention Trial: Effects of Delayed Processing on Carotenoids, Tocopherols, Insulin-Like Growth Factor-I, Insulin-Like Growth Factor Binding Protein 3, Steroid Hormones, and Lymphocyte Viability
Bibliographic record
Abstract
This experiment examined the effects of delays in separation and freezing of whole blood components on analytes of interest in studies of prostate cancer prevention, in order to evaluate the feasibility of centralized processing of blood for the multisite Selenium and Vitamin E Cancer Prevention Trial. Blood from 40 healthy men was subjected to four treatment protocols, allowing the contrast of immediate processing to delays of 32, 72, and 144 hours. At 32 hours, simulating refrigerated storage and overnight shipping, there was a 2.9% decrease (95% confidence interval, 0.7-5.1) in insulin-like growth factor-I (IGF-I) but no significant change in carotenoids, tocopherols, testosterone, 3alpha-androstanediol glucuronide (AAG), sex hormone-binding globulin (SHBG) or insulin-like growth factor binding protein 3 (IGFBP3). A 144-hour processing delay, simulating weekend blood collection or shipping delay, resulted in significant changes in gamma-tocopherol (-1.5%), IGF-I (-5.7%), IGFBP3 (-2.9%), SHBG (-4.0%), testosterone (+4.7%), and AAG (+5.5%). The rank-order and intraclass correlations between analytes from blood processed immediately and those subjected to delayed processing were 0.96 or higher for carotenoids, tocopherols, AAG, and SHBG, and between 0.87 and 0.95 for IGF-I, IGFBP3, and testosterone. A 32-hour delay decreased lymphocyte viability from 82.5% to 75.0% (P = 0.45), but a 72-hour delay decreased viability to 36.8% (P < 0.001). Overnight shipping and centralized processing is an acceptable approach to blood collection in large multisite trials examining the cancer-related measures proposed in the Selenium and Vitamin E Cancer Prevention Trial. Longer processing delays, however, have small but statistically significant effects on many analytes and substantially decrease lymphocyte viability.
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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 | 0.003 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".