Radiolabeling proteins and hormones: The preparation and characterization of radiolabeled and fluorescent insulin probes
Bibliographic record
Abstract
1891 Objectives Molecular imaging agents derived from human insulin offer a valuable, non-invasive means to study insulin-related diseases in vivo and in vitro. The goal of this project is to develop novel insulin based probes that can be used for both SPECT and optical imaging. Methods A regioselective strategy was developed to synthesize a 99mTc labeled insulin analogue as a new SPECT tracer. The 99mTc-insulin compound was synthesized through a direct labeling method by complexing the [99mTc(CO)3]+ core to the protected insulin precursor using a robust bipyridyl derived chelating group, followed by deprotection with TFA containing anisole (r.c.y. 30 ± 11 %, n = 4). Results The non-radioactive iso-structural rhenium analogue was also prepared and screened in vivo, and it was determined that these chemical modifications resulted in no significant alteration of the biochemical properties of the hormone. A corresponding luminescent probe was also synthesized by using a bifunctional quinoline analog, in a similar manner as the bipyridyl system. In addition, a fluorescent insulin probe was synthesized by conjugating a fluorophore, such as a fluorescein dye, to insulin in an analogous manner to the bifunctional chelating systems. These probes can be used in fluorescence microscopy to study the distribution of the insulin conjugates in tissue samples, and provide a complementary tool for the in vivo imaging studies. Conclusions A novel SPECT tracer, 99mTc-insulin, was developed for monitoring the distribution and metabolism of insulin in vivo. Analogous fluorescent probes were also developed to serve as complimentary imaging tools.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 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".