1-(2-Deoxy-2-fluoro-β-D-arabinofuranosyl)-5-[36Cl]chlorouracil; Radiosynthesis and Preliminary Biodistribution Studies in an Experimental Murine Tumor Model
Bibliographic record
Abstract
The nucleoside to nucleic acids pathways are attractive targets for molecular imaging of cell proliferation, for radionuclide-based radiotherapy, for following molecular processes and for drug design, development and delivery. This paper describes the preparation of several radiolabelled nucleosides for comparitive study as markers of tumour cell proliferation. 1-(2-Deoxy-2-fluoro-β-D-arabinofuranosyl)-5-[ 36 Cl]chlorouracil (F[ 36 Cl]ClAU) 1 was synthesized by reaction of 1-(2-deoxy-2-fluoro-arabinofuranosyl)uracil (FAU) with Na 36 Cl in the presence of 2 M HNO 3 (32% radiochemical yield; 13.5 MBq/mmol). 1-(2-Deoxy-2-fluoroarabinofuranosyl)-5-fluoro/bromo/iodouracils radiolabelled with carbon-14 ([2- 14 C]FFAU; 1.5 GBq/mmol), bromine-82 (F[ 82 Br]BrAU; 167 MBq/mmol) and iodine-125 (F[ 125 I]IAU; 10.4 GBq/mmol) were synthesized according to literature methods. These radiolabelled halopyrimidine nucleosides were administered by i.v. injection into BDF 1 mice bearing transplanted Lewis Lung tumors. Uptake of test compounds by target (tumor) tissue was low, and not dissimilar to the reported uptake of their high-specific-activity 5-halopyrimidine nucleoside counterparts. Selected biodistribution data are presented. In general, clearance from blood was rapid, with less that one percent of the injected dose remaining in the blood within 1 h of injection. Tumor uptake was approximately 2% of the injected dose per g of tumor for F[ 36 Cl]ClAU and F[ 125 I]IAU, with [2- 14 C]FFAU showing less that 2% per g and F[ 82 Br]BrAU with over 3% per g at this time after injection. Data are compared to those for the respective high-specific-activity counterparts.
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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) | 0.000 | 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) | 0.000 | 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".