Antimicrobial peptides (AMPs) play an important role in innate immunity in human skin. It is known that AMPs mainly function in the stratum corneum. Therefore, AMP concentrations in the stratum corneum need to be precisely measured to clarify functional and physiological importance of AMPs in cutaneous defence. Tape stripping (TS) is a well-established method by which components in the stratum corneum can be collected. However, the usefulness of the TS method for measuring AMP concentration in human skin remains unclear. Therefore, we compared it with another popular method, skin rinsing, which had been established as a method for measuring AMP concentration in human skin. When investigated on healthy medial forearm using RNase 7, which is one of the typical AMPs, as an index, there was a significant positive correlation between RNase 7 concentrations measured by the TS method at adjacent forearm sites, demonstrating the reproducibility of the TS method. Next, a significant positive correlation was detected in RNase 7 concentrations measured using the TS and the skin rinsing method, indicating that the TS method is comparable to the skin rinsing method. Thus, we speculate that the TS method is useful for measuring AMP concentration in human skin.

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Background: The aim of this clinical study was to reveal the relationship between body dehydration and oral mucosa moisture measured by the use of a capacitance sensor for oral epithelial moisture. Methods: The following clinical parameters were recorded from each one of 19 athletes in a one-week period of high-intensity exercise at the U-23 Triathlon Training Camp in summer and winter; body weight, urine specific gravity, oral mucosa moisture, subjective oral thirst, and subjective throat thirst (within 30 min after waking and before breakfast at 7:00 a.m. on Day2 and Day6). Results: There were no significant differences in the mean values of body weight, urine specific gravity, oral mucosa moisture, oral thirst, and throat thirst between Day2 and Day6 in both measurements in summer and winter. The oral mucosa moisture had a moderate negative correlation with urine specific gravity (p < 0.05, r = −0.45). Conclusions: This study suggests that oral mucosal moisture determined using an oral moisture-checking device could be a potential index for assessing dehydration during sports activities.

The level of secretory immunoglobulin A (SIgA) in saliva is associated with the risk of upper respiratory infection and has been identified as a condition indicator for athletes and an indicator of mucosal immune function in the elderly. In addition, it has been suggested that non-specific polyreactive SIgA is present in human saliva and colostrum. The purpose of this study was to establish a new detection method of polyreactive salivary SIgA. Using saliva samples from eight healthy individuals, indirect ELISA was used to detect anti-LPS antibodies (LPS ELISA), and competitive ELISA was used to detect LPS antibodies after competition with DNA (LPS-DNA ELISA). The difference in SIgA concentration between LPS ELISA and LPS-DNA ELISA is thought to be the concentration of the polyreactive SIgA, which responds to both DNA and LPS. First, we determined the concentration for coating LPS and DNA as 10 μg/ml, and the saliva sample dilution was determined as 1/2. The concentration of anti-LPS antibody contained in the saliva sample, which is strongly reactive to LPS, was defined as the standard. Compared to the SIgA concentration determined by LPS ELISA, SIgA concentration of LPS-DNA ELISA did not decrease in two samples, but was reduced in 6 samples. The decrease in SIgA concentration is thought to be the concentration of polyreactive SIgA that reacts with both DNA and LPS. Notably, we found sample-to-sample differences in the concentration of polyreactive SIgA.

Choosing an appropriate pacing strategy is important for good triathlon performance. In the Japan Student Triathlon Championship held in 2020, the men's category was divided into two groups, which was a different racing style from the previous races that all athletes start at the same time. It is highly likely that the performance level will vary as grouping was performed according to the competence of each player. The aim of this study was to understand the relationship of the total time and time of each leg between the superior performance group and the inferior performance group, as well as the difference in pacing during running in participants of the 2020 Japan University Triathlon Championship Watarase Competition, which was held under unconventional conditions. We analyzed 153 male athletes (Group A: 77; Group B: 76) who completed the race. The total race time, leg time, and average speed in each leg and its variation coefficient were evaluated based on the official results of the competition and footage recorded during the race. The results showed that the total time and leg time for each leg were significantly shorter in Group A compared to those in Group B (p &lt; 0.05). In both groups, the Lap 4 run was significantly slower than those of Laps 1–3 (p &lt; 0.05), while there was no significant difference in the running speed to average speed ratio across all laps between the groups (p &lt; 0.05). Thus, there was a difference in running speed between the groups, but no significant difference in pacing. The results of this study serve as basic data for examining superior pacing strategies, although further studies on a wide range of competition levels are necessary.