Increased Serum Levels of 8-Hydroxy-2′-Deoxyguanosine in Clinical Depression
Bibliographic record
Abstract
Objective: We sought to understand the pathophysiological effects of depression by examining group differences in serum levels of 8-hydroxy-2′-deoxyguanosine (8-OHdG), a biomarker of oxidative damage. Methods: Our sample consisted of 169 participants. Eight-four of these participants met diagnostic criteria for clinical depression. The 85 participants in our comparison group were matched on age, gender, and ethnicity to the depressed group. 8-OHdG was measured by enzyme-linked immunosorbent assay. Results: After adjusting for age, gender, race/ethnicity, years of education, daily smoking, average number of alcoholic drinks per week, average amount of physical activity per week, and body mass index, participants in the depressed group had significantly higher levels of oxidative DNA damage compared with participants in the control group. Pairwise comparisons showed that participants with major depression had significantly higher levels of 8-OHdG than control subjects and marginally higher levels of 8-OHdG compared with those with minor depression. Furthermore, participants with recurrent episodes of depression had more oxidative damage than participants with single episodes, who in turn had more damage than healthy control subjects. Finally, participants with recurrent episodes of major depression had more DNA damage than other depressed participants, who in turn had more damage than healthy control subjects. Conclusions: Our findings suggest that increased oxidative damage may represent a common pathophysiological mechanism, whereby depressed individuals become vulnerable to comorbid medical illness. 8-OHdG = 8-hydroxy-2′-deoxyguanosine; DSM-IV= Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition; DISH = Depression Interview and Structured Hamilton Interview; ELISA = enzyme-linked immunosorbent assay; HPLC-EC = high-performance liquid chromatography with electrochemical detection; GC-MS= gas chromatography–mass spectrometry; BMI= body mass index.
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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 | 0.000 |
| 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) | 0.001 | 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".