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Otsuka, M.

Publications and source records attributed to Otsuka, M..

2 recordsLinked to original sources

Cross-sectional and longitudinal research approaches: running pace and step characteristics of elite athletes in the 400-m hurdles

The aim of this study was to clarify the running pace and step characteristics among various competitive-level 400-m hurdlers through cross-sectional and longitudinal research approaches. We analysed spatiotemporal data for 13 male world-class and 14 male national-level 400-m hurdlers. We analysed 16.8 {+/-} 4.2 races for each world-class hurdler and 20.0 {+/-} 6.0 races for each national-level hurdler (the total number of analysed runs was 499) using publicly available television and internet broadcasts. Cross-sectional approach showed that positive relationships of finish time were highly obtained between both first- (r = 0.901) and latter-half split times (r = 0.914). In contrast, the first- and latter-half split times were not significantly correlated to SL and SF. A multiple single-subject approach showed that 14/27 hurdlers were identified as being latter-half speed reliant. In contrast, no hurdlers demonstrated first-half reliance. In the latter half of the race, 12/27 hurdlers were identified as being SF reliant; no hurdlers demonstrated SL reliance. In conclusions, important findings regarding high performance in a cross-sectional research approach do not always corresponded with those in a longitudinal research approach. Athletes and coaches should carefully improve performance in the first half of the race based on an individualization principle for training.

physiology

Identification of PTBP1 responsible for caspase dependent YRNA cleavage

Some RNAs such as 28S rRNA, U1 snRNA, and Y RNAs are known to be cleaved during apoptosis. As the underlying mechanism is yet unclear, the functions and biological significance of RNA degradation in apoptosis remain elusive. We previously identified novel, functional small RNAs named AGO-taxis small RNA (ASR) that are specifically bound to AGO1. Here, we investigated ASR biogenesis, which appears to be non-canonical. Y RNAs, non-coding RNAs degraded during apoptosis, were identified as the precursors of several ASRs. Cell-free analysis combined with fractionation methods revealed that the apoptosis-specific biogenesis of ASRs or Y RNA degradation was induced by PTBP1--an endoribonuclease inhibitor of Y RNAs. PTBP1, a splicing factor, was truncated by caspase 3, which subsequently activated endoribonuclease to induce biogenesis of ASRs and Y RNA cleavage.

molecular biology