Structural alterations of erythrocyte membrane components induced by exhaustive exercise
Bibliographic record
Abstract
Physical exercise was used as a model of the physiological modulator of free radical production to examine the effects of exercise-induced oxidative modifications on the physico-biochemical properties of erythrocyte membrane. The aim of our work was to investigate conformational changes of erythrocyte membrane proteins, membrane fluidity, and membrane susceptibility to disintegration. Venous blood was taken before, immediately after, and 1 h after an exhaustive incremental cycling test (30 W.min-1 ramp), performed by 11 healthy untrained males on balanced diets (mean age, 22 +/- 2 years; mean body mass index, 25 +/- 4.5 kg.m-2). In response to this exercise, individual maximum heart rate was 195 +/- 12 beats.min-1 and maximum wattage was 292 +/- 27 W. Electron paramagnetic resonance spectroscopy was used to investigate alterations in membrane proteins and membrane dynamics, and to measure production of radical species. The reducing potential of plasma (RPP) was measured using the reduction of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and the ferric-reducing ability of plasma. Exercise induced decreases in erythrocyte membrane fluidity in the polar region (p < 0.0001) and alterations in the conformational state of membrane proteins (p < 0.05). An increase in RPP was observed immediately after exercise (p < 0.001), with a further increase 1 h postexercise (p < 0.0001). Supporting measurements of lipid peroxidation showed an increase in thiobarbituric acid reactive substances immediately after exercise (p < 0.05) and at 1 h of recovery (p < 0.001); however, free radicals were not detected. Results indicate the existence of early postexercise mild oxidative stress after single-exercise performance, which induced structural changes in erythrocyte membrane components (protein aggregation) and in the membrane organization (lipids rigidization) that followed lipid peroxidation but did not lead to cellular hemolysis.
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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) | 0.001 | 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 | 0.000 |
| 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".