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Research demonstrates that the novel single kringle-containing fragment termed p22 is derived from plasminogen that binds to bovine capillary endothelial or human fibrosarcoma cells. Results show that the p22 fragment is a potent antiangiogenic protein and that it is a derivative of plasmin N-terminal region.

Purpose: The use of daytime napping as a recovery tool following exercise is virtually unexplored. The objective of this study was to assess the quality of daytime nap sleep following endurance training in an athletic population, and to appraise the optimal circadian timing of the nap and the time interval between training and the nap. Methods: Six physically trained male subjects (22.5 ± 2.4 y) performed four separate standardized 90-min endurance training sessions followed by a 90-min daytime nap either 1 or 2 h after training (time interval), commencing at either 10:30 or 11:30 (circadian timing). During the nap, sleep was monitored using polysomnography. Subjective measurements of sleep quality, alertness and preparedness to train following a nap were recorded using a visual analog scale. Results: The duration of slow wave sleep (SWS) was significantly greater during the 11:30 naps (13.7 ± 9.0 min) compared with the 10:30 naps (6.9 ± 8.8 min) (P = .049). There was no significant difference in SWS duration between a 1-h (10.6 ± 10.2 min) or 2-h (10.0 ± 9.0 min) time interval between training and the nap (P = .82). No other sleep variables differed significantly according to circadian timing or time interval. Conclusion: Recovery naps commenced later in the morning contain more SWS than earlier naps. The data imply that daytime naps have a potential role as a valuable recovery tool following endurance exercise, given the suggested energy restorative functions of SWS. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the acute effects of different environmental oxygen conditions on shuttle repeated sprint performance in futsal players. Using a counterbalanced design, 16 male university-level futsal players performed 3 sets of shuttle repeated sprints (6 × 10 s) over a 5m distance with 20 s active rest between reps and 5 min active rest between sets. Participants completed 4 trials in a random order over 4 weeks with different inspired oxygen fractions for each trial (FIO2 = 20.9%, 14.5%, 13.5% and 12.5%). Electromyography (RMSEMG) data was recorded from the vastus lateralis muscle during sprinting. The number of completed shuttles in each 10 s period, blood lactate concentration, rating of perceived exertion, oxygen saturation (SpO2), and cardiorespiratory variables were recorded after each set. We found that after set3, blood lactate concentration was substantially higher (p <0.05) in the 12.5% FIO2 (10.4 ± 2.1 mmol/L) compared to normoxia, 14.5% or 13.5% condition (5.0 ± 1.6, 7.8 ± 1.5, and 9.4 ± 1.9 mmol/L, respectively). Compared to normoxia, the RMSEMG signal was 34.1% lower in the 12.5% condition, 14.1% and 18.6% lower in the 14.5% and 13.5% oxygen condition respectively. Moreover, SpO2 after set3 was substantially lower (p <0.05) in 12.5% (73.7 ± 3.4%) compared to normoxia, 14.5% or 13.5% condition (95.1 ± 1.8, 81.1 ± 2.1, and 79.1 ± 2.4%, respectively). Overall the lower FIO2 conditions produced lower in number of sprints, and highest heart rate, ventilation and rating of perceived exertion levels. In conclusion, FIO2 13.5% is an appropriate choice for shuttle repeated sprint training in hypoxia. Although, FIO2 13.5% was lower in benefitcial responses than FIO2 12.5% but FIO2 12.5% might produce unnecessary and unwanted fatigue from insufficient oxygen to athletes. [ABSTRACT FROM AUTHOR]

Protein glycation is a common, normally innocuous, post-translational modification in therapeutic monoclonal antibodies. However, when glycation occurs on complementarity-determining regions (CDRs) of a therapeutic monoclonal antibody, its biological activities (e.g., potency) may be impacted. Here, we present a comprehensive approach to understanding the mechanism of protein glycation using a bispecific antibody. Cation exchange chromatography and liquid chromatography-mass spectrometry were used to characterize glycation at a lysine residue within a heavy chain (HC) CDR (HC-CDR3-Lys98) of a bispecific antibody. Thermodynamic analysis revealed that this reaction is reversible and can occur under physiological conditions with an apparent affinity of 8-10 mM for a glucose binding to HC-CDR3-Lys98. Results from kinetic analysis demonstrated that this reaction follows Arrhenius behavior in the temperature range of 5°C-45°C and can be well predicted in vitro and in a non-human primate. In addition, this glycation reaction was found to be driven by an unusually low pK a on the ε-amino group of HC-CDR3-Lys98. Van't Hoff analysis and homology modeling suggested that this reaction is enthalpically driven, with this lysine residue surrounded by a microenvironment with low polarity. This study provides, to our knowledge, new insights toward a mechanistic understanding of protein glycation and strategies to mitigate the impact of protein glycation during pharmaceutical development., (Copyright © 2022 Biophysical Society. All rights reserved.)