High-Resolution Capillary Gas Chromatography in Combination with Mass Spectrometry for Quantification of Three Major Polyamines in Postmortem Brain Cortex
Bibliographic record
Abstract
There is considerable evidence supporting a role of the polyamine system in the etiology and pathology of mental disorders. Changes in the expression and activity of polyamine anabolic/catabolic enzymes, as well as in the levels of individual polyamines, have been found in many psychiatric conditions, including schizophrenia, mood disorders, anxiety, and suicidal behavior. Recent microarray studies have found that spermidine/spermine-N¹-acetyltransferase (SAT1, SSAT), the key enzyme in charge of the polyamine catabolic pathway, is downregulated in brain tissue of individuals who were depressed and died by suicide. To provide further insight into the downstream effects of altered SAT1 expression, we developed a quantitative gas chromatography-mass spectrometry method for measurement of polyamine concentrations in postmortem human brain tissues. This protocol employs a conventional electron ionization method with total ion and selected ion monitoring. This method can accurately measure the levels of the polyamines putrescine, spermidine, and spermine from very small quantities (1-50 mg) of postmortem brain tissues, with quantitation limits down to 10 ng/g of wet tissue for putrescine and 100 ng/g for spermidine and spermine.
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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 | 0.001 | 0.000 |
| 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) | 0.000 | 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".