PLASMA MALONDIALDEHYDE CONCENTRATIONS INCREASE TRANSIENTLY FOLLOWING ISCHEMIC FOREARM EXERCISE
Bibliographic record
Abstract
Studies have demonstrated that exercise and ischemia-reperfusion (I-R) induce oxidative stress in skeletal muscle and that 17-β-estradiol may have antioxidant properties. Malondialdehyde (MDA) has been used as a marker of oxidative stress with varying conclusions regarding free radical generation during exercise. PURPOSE To determine whether the forearm ischemic test (FIT), a model of exercise and I-R, induces oxidative stress and secondly, whether females show attenuated oxidative stress due to the antioxidant properties of 17-β-estradiol. METHODS 8 males and 7 females performed a FIT: blood flow was occluded to the forearm and 6 cycles of maximal isometric handgrip exercise were executed using a 9:1, duty: rest cycle, for 60 seconds. Blood samples were collected pre, immediately (imm.) post, 1, 3, and 10 min post-FIT. Females were tested in both the follicular and luteal phases of their menstrual cycle. The samples were analyzed for MDA, acetaldehyde and methyl ethyl ketone by high performance liquid chromatography, 17-β-estradiol, testosterone, progesterone, and lactate. RESULTS Menstrual cycle phase did not influence any outcome variable and the data was collapsed across both phases. Plasma MDA increased by 188% and 104% in males (0.024 ± 0.023 mmol/L to 0.069 ± 0.025 mmol/L to 0.049 ± 0.017 mmol/L, p < 0.05) and 175% and 150% in females (0.016 ± 0.028 mmol/L to 0.044 ± 0.038 mmol/L to 0.040 ± 0.030 mmol/L, p < 0.05) from baseline to imm. post and 1 min post-FIT, respectively. Plasma MDA concentrations returned to baseline levels by 3 min post-FIT. Lactate concentrations increased imm. post, 1, 3 and 10 min post-FIT (p < 0.05) for both males and females, and males had significantly higher lactate concentrations compared to females imm. post, 1 and 3 min post-FIT (p < 0.05). CONCLUSION Plasma MDA increased only transiently following a FIT in both males and females. Future studies must take care to sample immediately following the administration of a stressor, such as exercise, in order to quantify any change in MDA concentration. Supported by NSERC Canada.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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 | 0.001 |
| 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".