Association of Nonconcussive Repetitive Head Impacts and Intense Physical Activity With Levels of Phosphorylated Tau181 and Total Tau in Plasma of Young Elite Soccer Players.

Importance: Head impacts resulting in traumatic brain injury (TBI) lead to the elevation of phosphorylated tau protein (p-tau181) in plasma. To our knowledge, this study is the first to investigate dynamics of p-tau181 levels and the ratio of p-tau181 to total tau in individuals after nonconcussive head impacts. Objective: To determine the association of repetitive low-intensity head impacts on p-tau181 and total tau protein levels in the plasma of young adult elite soccer players and assess the possible association of head impacts with focused attention and cognitive flexibility. Design, Setting, and Participants: In this cohort study, young elite soccer players performed intense physical activity with and without heading the ball. The study was conducted at a university facility in Slovakia from October 1, 2021, to May 31, 2022. Eligible participants were selected based on similarities in demographic variables, excluding those with a history of TBI. Main Outcomes and Measures: The primary study outcomes were the levels of total tau protein and p-tau181 in plasma samples and the cognitive status of the study participants. Results: A total of 37 male athletes participated in the study (mean [SD] age: exercise group, 21.6 [1.6] years; heading group, 21.2 [1.5] years). We found significantly elevated levels of total tau and p-tau181 in the plasma of soccer players 1 hour after physical exercise (tau, 1.4-fold; 95% CI, 1.2-1.5; P < .001; p-tau181, 1.4-fold; 95% CI, 1.3-1.5, P < .001) and repetitive head impacts (tau, 1.3-fold; 95% CI, 1.2-1.4; P < .001; p-tau181, 1.5-fold; 95% CI, 1.4-1.7 P < .001). The ratio of p-tau181 to tau was significantly higher 1 hour after exercise and heading training, and remained elevated specifically in the heading group even after 24 hours (1.2-fold; 95% CI, 1.1-1.3; P = .002). Performance in cognitive tests revealed a significant decline in focused attention and cognitive flexibility after physical exercise and heading training; physical exercise of higher intensity without heading training was associated with a greater negative cognitive performance than heading only. Conclusions and Relevance: In this cohort study of young elite soccer players, the elevation of p-tau181 and tau was observed after acute intense physical activity and nonconcussive repetitive head impacts. The increase of p-tau181 levels relative to tau after 24 hours indicated an acute enrichment of phosphorylated tau fraction in the periphery when compared with preimpact levels; an imbalance of tau proteins may have long-lasting consequences in the brain of head-impacted individuals.

The Three-Level Model of Factors Contributing to High-Intensity Intermittent Performance in Male Soccer Players.

High-intensity intermittent performance in soccer is widely assessed using the yo-yo intermittent recovery level 2 test (YYIR2). This test is usually associated with aerobic-anaerobic performance. However, less is known about the direct or indirect contributions of abilities, including the anaerobic component. This study aims to propose a three-level model of factors contributing to YYIR2 performance, based on the investigation of relationships with aerobic endurance, repeated-sprint ability (RSA), and the linear and change-of-direction speed and power variables. Eighteen soccer players performed the YYIR2, with a 20-m shuttle run test (20mSR), an RSA test with change-of-direction, 5-m and 20-m sprints, and a 505 test, countermovement jump, squat jump, and drop jump. The results showed a significant relationship between the YYIR2 distance and the 20mSR distance (r = 0.721, p = 0.001), as well as with the RSA test mean time (r = -0.594, p = 0.009). In the second level, the 20mSR distance performance was not associated with any of the speed and power variables. However, the RSA test mean time correlated with the 5-m sprint (r = 0.587, p = 0.010), 20-m sprint (r = 0.702, p = 0.001), and 505 test (r = 0.585 p = 0.011) performance. In the third level, the 20-m sprint time was related to the squat jump (r = -0.577 p = 0.012) and countermovement jump (r = -0.768 p < 0.001) heights. In addition to aerobic endurance, this study highlights the importance of the anaerobic component in YYIR2 performance. More specifically, aerobic endurance (52%) and RSA (36%) are the main determinants of YYIR2 performance. Subsequently, the RSA performance is determined by the linear (34-49%) and change-of-direction speed (35%), while the explosive power of lower limbs contributes to sprinting performance (33-59%). Coaches should focus on the development of these abilities to improve the high-intensity intermittent performance of soccer players.

SELECTED ASPECTS OF TERAHERTZ SPECTROSCOPY IN PHARMACEUTICAL SCIENCES.

THz-TDS techniques are applied to investigate selected pharmaceutical samples. Investigations were performed on selected pharmaceutical samples with active pharmaceutical ingredients (API)--famotidine, ranitidine, fenofibrate, lovastatin, simvastatin, aspirin, ketoconazole, acyclovir (hydrated and non-hydrated), on excipients--lactose, glucose (hydrated and non-hydrated), Pluronic 127, and on mixtures of selected compounds. Pseudo-polymorphism effects are considered as well. Examples of the terahertz imaging technique are also given. APIs and excipients can be easily recognized in the terahertz band by their specific "fingerprints" as individual components and in mixtures. The hydration process as a variety of polymorphism can also be easily monitored using the THz technique. Moreover, terahertz light can be useful for the penetration of tablets, giving clear pictures of possible defects in tablet coatings.