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Investigation of MAGE D2 functions in cells stressed by camptothecin.
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Introduction: Mental fatigue is a pervasive problem affecting cognitive performance, but its underlying mechanisms and effective measurement methods remain insufficiently understood. This study aims to examine the effects of cognitive load (high vs. low) and task duration (16 minutes vs. 32 minutes) on mental fatigue in healthy young adults using the Time Load Dual Back (TLDB) task. Methods: Participants were divided into three groups based on task modality: Group 1 (low cognitive load, 16-minute task), Group 2 (low cognitive load, 32-minute task), and Group 3 (high cognitive load, 32-minute task). Objective performance measures (accuracy, reaction time, signal detection theory metrics) and subjective fatigue levels (measured via the Visual Analogue Scale of fatigue, VAS-f) were recorded before and after the task. The impact of task duration and cognitive load on these measures were analysed across groups using statistical methods. The deltas of the measurement scores were calculated to evaluate the impact of the time between the start and end of the task. Evaluation of task duration and workload were performed using t-tests for independent samples. Analyses for subjective measures (VAS-f) were performed using repeated measures ANOVA followed by post-hoc tests to analyse the differences between the groups. Pearson correlations were used to correlate objective and subjective measures. Results: Regarding the analysis of the effect of task duration modulation on performance, changes in reaction times during the task were significantly different between groups. The shorter task duration was associated with faster reaction times. For performance changes based on workload, significant differences were observed between the high and low workload. Lower accuracy, as well as lower sensitivity and liberal response, were associated with the high workload. Reaction time was more significant in the long-duration, low-workload group. Measurements using the VAS-f showed a significant increase in scores between before and after the task for duration and workload analyses, with a significant interaction between time and group for the high workload. However, there were no significant results regarding group conditions. Correlation analyses for task duration showed no significant correlation between cognitive performance and VAS-f. Significant negative correlations were found for high workload between changes in accuracy and VAS-f. Conclusion: The study confirms that cognitive load is a key determinant of mental fatigue, with a higher workload leading to more pronounced declines in cognitive performance and a correlation with task accuracy and fatigue sensation. Task duration did not show significant differences between short and long durations. The TLDB task is validated as an effective tool for inducing and measuring mental fatigue in healthy young adults, except for reaction time, which showed contradictory results. Future research should explore more physiological and subjective measures to elucidate the underlying mechanisms of cognitive fatigue.
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Mutations in extracellular matrix (ECM) related genes have been increasingly associated with hearing impairments in humans. By providing viscoelastic properties to the resonant structures of the inner ear, mechanical and trophic support to the cells and participating in cell signalling in response to environmental changes, the ECM is crucial for hearing function. In this work, we investigated some of its critical regulators namely, Cemip hyaluronidase, and the matrix metalloproteinases, MMP2 and MMP9. By using a mouse model invalidated for Cemip, we studied the hearing function at different ages to analyse whether hyaluronic acid (HA) accumulation could impair audition. Results from auditory brainstem recordings (ABR) reveal no obvious hearing decline in Cemip-deficient mice, up to 16 weeks of age. Future functional studies, up to 1 year of age, will allow us to know if age related hearing loss may be accelerated or exacerbated in the absence of Cemip. However, we can conclude that Cemip, which is defined as a deafness-causing gene in humans, is not essential for hearing in young adult mice. As noise overexposure has been reported to trigger ECM breakdown and remodelling, we characterized MMP2 and MMP9 gelatinases expression and localisation changes in a noise induced hearing loss mouse model. At the level of the whole cochlea, MMP2 transcript level tended to increase from 2 hours to 3 days following noise exposure, while MMP9 transcript tended to decrease progressively from 1 day to 7 days after trauma. Immunostainings revealed that MMP2 protein was upregulated throughout the cochlear tissue as soon as 2 hours following noise, particularly in the surrounding bony capsule but also at the level of the spiral ligament and auditory nerve fibres. In contrast, noise only induced a local accumulation of MMP9 in the spiral ligament. Altogether, our results suggest that MMP2 and MMP9 might be involved in local ECM remodelling after noise exposure, however, further studies are required to verify whether their presence translates into gelatinase activity.
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Medical sciences --- Sciences de la santé --- Medical sciences.
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Medical sciences --- Medicine --- Sciences de la santé --- Medicine - General
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"The Western Undergraduate Research Journal: Health and Natural Sciences (WURJHNS) launched in 2009. It is a student-run open access, peer-reviewed and Faculty-reviewed online journal that publishes original research, review articles and research progress reports."
Medical sciences --- Science --- Sciences de la santé --- Sciences
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Medicine --- Medical sciences --- Médecine --- Sciences de la santé --- India.
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Medical sciences --- Cardiology --- Cardiology. --- Sciences de la santé --- Cardiologie
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Medical sciences --- Sciences de la santé --- Medical sciences.
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