Dysbiosis of the gut microbiota as a susceptibility factor for Kawasaki disease

IntroductionGut microbial imbalance (dysbiosis) has been reported in patients with acute Kawasaki disease (KD). However, no studies have analyzed the gut microbiota while focusing on susceptibility to KD. This study aimed to evaluate whether dysbiosis elevates susceptibility to KD by assessing children with a history of KD. MethodsFecal DNA was extracted from 26 children with a history of KD approximately 1 year prior (KD group, 12 boys; median age, 32.5 months; median time from onset, 11.5 months) and 57 age-matched healthy controls (HC group, 35 boys; median age, 36.0 months). 16S rRNA gene analysis was conducted with the Illumina Miseq instrument. Sequence reads were analyzed using QIIME2.ResultsFor alpha diversity, Faith’s phylogenetic diversity was significantly higher in the KD group. Regarding beta diversity, the two groups formed significantly different clusters based on Bray–Curtis dissimilarity. Comparing microbial composition at the genus level, the KD and HC groups were significantly different in the abundance of two genera with abundance over 1% after Benjamini–Hochberg false discovery rate correction for multiple comparisons. Compared with the HC group, the KD group had higher relative abundance of Ruminococcus gnavus group and lower relative abundance of Blautia. Discussion and conclusionRuminococcus gnavus group reportedly includes pro-inflammatory bacteria. In contrast, Blautia suppresses inflammation via butyrate production. In the predictive functional analysis, the proportion of gut microbiota involved in several pathways was lower in the KD group. Therefore, dysbiosis characterized by distinct microbial diversity and decreased abundance of Blautia in parallel with increased abundance of Ruminococcus gnavus group might be a susceptibility factor for KD

Kinematics and Laxity of the Ankle Joint in Anatomic and Nonanatomic Anterior Talofibular Ligament Repair: A Biomechanical Cadaveric Study

足関節前距腓靭帯修復術における修復位置の違いが足関節のキネマティクスと制動性に及ぼす影響を検討した．解剖学的修復ではキネマティクス及び制動性は正常と差を認めなかった．非解剖学的修復ではキネマティクスは背屈時に内がえし方向，中間位で内旋方向への有意な変位を認め，制動性は底屈位で内旋の変位が有意に大きくなり，正常とは異なるキネマティクス及び制動性を示した

Factors influencing long-term survival after aortic valve replacement.

In the aortic stenosis group, the left ventricular (LV) muscle mass index was a good parameter for predicting the prognosis. Associated mitral valve disease had no influence on long term survival after aortic valve replacement. In the aortic insufficiency group, associated mitral valve disease had a marked influence on the results of aortic valve replacement. In general, the aortic insufficiency group had less clinical improvement postoperatively than the aortic stenosis group. In the annuloaortic ectasia group, left ventricular enddiastolic pressure (LVEDP) might be the predictor to the prognosis. This group had the worst prognosis, of the three groups. Early operation should be considered for patients who have no, or only mild symptoms of, aortic valve disease.</p

Effects of Initial Graft Tension during Anterior Talofibular Ligament Reconstruction on Ankle Kinematics, Laxity, and In-situ Forces of the Reconstructed Graft

前距腓靭帯は，足関節の安定性に関わる重要な靱帯である．前距腓靱帯の損傷後に慢性的な足関節の不安定性が残存した場合，前距腓靱帯再建手術が必要となるが，その際に再建靭帯にかける適切な張力について研究した報告はなかった．本論文では，再建靭帯にかける張力の違いが，足関節のキネマティクス，制動性，術後の靱帯張力に及ぼす影響と適切な再建靭帯初期固定張力を明らかにした

Off-equatorial Pi2 pulsations Inside and Outside the plasmapause observed by the Arase satellite

Using magnetic field and electron density data from the Arase satellite for the period from March 2017 to September 2019, we investigate the spatial properties of Pi2 pulsations in relation to the plasmapause over a wide latitudinal range (absolute magnetic latitude, |Mlat|, 0.7) with Pi2 pulsations in the north-south (H) component at low-latitude ground stations on the nightside, are dominantly identified from the magnetic fields in the radial (BR) and compressional (BP) components when the satellite is in the pre-midnight sector. In particular, high-coherence BP events are distributed over wide L-values and latitudinal ranges on the nightside in the pre-midnight sector. We identify the location of the plasmapause using the electron densities measured by Arase, and found that the BP-H power ratio and the cross phases of the high-coherence events show a gradual peak and a clear phase change from 0° to 180° in the vicinity of the plasmapause, respectively. These features indicate that mid- and low-latitude Pi2 pulsations on the nightside are excited by the plasmaspheric virtual resonance mode

A Statistical Study of the Solar Wind Dependence of Multi-Harmonic Toroidal ULF Waves Observed by the Arase Satellite

Toroidal standing Alfvén wave is one of the ultra-low frequency waves that are frequently observed in the terrestrial magnetosphere. They sometimes exhibit multi-harmonic frequency spectra, indicating wide energy range input in the magnetosphere. However, their energy source has not been fully understood due to the lack of statistical studies. Here we used the data of the Arase satellite observations for ∼3.5 years and conducted a statistical analysis of the solar wind dependence of the occurrence rate, wave power, and frequency of the multi-harmonic toroidal waves. We automatically detected the multi-harmonic waves and categorized them into four groups according to the solar wind velocity and the cone angle of the interplanetary magnetic field. We found that the occurrence rate and wave power of the multi-harmonic waves increase with the solar wind velocity on the flank sides. In the noon sector, the occurrence rate of the multi-harmonic waves increases with the decrease of the cone angle. The median frequency of the multi-harmonic waves on the dayside is positively correlated with the upstream wave frequency predicted by the theory of the ion beam instability for a small cone angle. The occurrence rate also increases with the solar wind dynamic pressure fluctuations. Therefore, we suggest that the Kelvin-Helmholtz instability, the upstream waves, and the dynamic pressure fluctuations are possible sources of the multi-harmonic waves. This study sheds light on the activity of the multi-harmonic waves which can affect radiation belt electrons under various solar wind conditions

Active auroral arc powered by accelerated electrons from very high altitudes

オーロラ粒子の加速領域が超高高度まで広がっていたことを解明 －オーロラ粒子の加速の定説を覆す発見－. 京都大学プレスリリース. 2021-01-20.Bright, discrete, thin auroral arcs are a typical form of auroras in nightside polar regions. Their light is produced by magnetospheric electrons, accelerated downward to obtain energies of several kilo electron volts by a quasi-static electric field. These electrons collide with and excite thermosphere atoms to higher energy states at altitude of ~ 100 km; relaxation from these states produces the auroral light. The electric potential accelerating the aurora-producing electrons has been reported to lie immediately above the ionosphere, at a few altitudes of thousand kilometres1. However, the highest altitude at which the precipitating electron is accelerated by the parallel potential drop is still unclear. Here, we show that active auroral arcs are powered by electrons accelerated at altitudes reaching greater than 30, 000 km. We employ high-angular resolution electron observations achieved by the Arase satellite in the magnetosphere and optical observations of the aurora from a ground-based all-sky imager. Our observations of electron properties and dynamics resemble those of electron potential acceleration reported from low-altitude satellites except that the acceleration region is much higher than previously assumed. This shows that the dominant auroral acceleration region can extend far above a few thousand kilometres, well within the magnetospheric plasma proper, suggesting formation of the acceleration region by some unknown magnetospheric mechanisms

Arase Observation of Simultaneous Electron Scatterings by Upper-Band and Lower-Band Chorus Emissions

This study reports a relation between electron flux modulations and chorus emissions by using correlation analysis. On April 18, 2017, Arase observed an enhancement of electron fluxes and intensification of banded chorus emissions at the same time. A result of the analysis shows that both the upper-band and lower-band chorus emissions have good correlations with field-aligned electron fluxes that satisfy their resonance conditions. This indicates simultaneous interactions with both the emission bands and electrons, resulting in electron pitch-angle scattering toward the magnetic field direction. In addition, low-energy electron fluxes in the perpendicular direction also show positive correlations with the chorus intensities, probably because the chorus emissions are modulated by a fluctuation of perpendicular low-energy electron fluxes

Energy Transfer Between Hot Protons and Electromagnetic Ion Cyclotron Waves in Compressional Pc5 Ultra-low Frequency Waves

The Magnetospheric Multiscale (MMS) spacecraft observed many enhancements of electromagnetic ion cyclotron (EMIC) waves in an event in the late afternoon outer magnetosphere. These enhancements occurred mainly in the troughs of magnetic field intensity associated with a compressional ultralow frequency (ULF) wave. The ULF wave had a period of ∼2–5 min (Pc5 frequency range) and was almost static in the plasma rest frame. The magnetic and ion pressures were in antiphase. They are consistent with mirror-mode type structures. We apply the Wave-Particle Interaction Analyzer method, which can quantitatively investigate the energy transfer between hot anisotropic protons and EMIC waves, to burst-mode data obtained by the four MMS spacecraft. The energy transfer near the cyclotron resonance velocity was identified in the vicinity of the center of troughs of magnetic field intensity, which corresponds to the maxima of ion pressure in the compressional ULF wave. This result is consistent with the idea that the EMIC wave generation is modulated by ULF waves, and preferential locations for the cyclotron resonant energy transfer are the troughs of magnetic field intensity. In these troughs, relatively low resonance velocity due to the lower magnetic field intensity and the enhanced hot proton flux likely contribute to the enhanced energy transfer from hot protons to the EMIC waves by cyclotron resonance. Due to the compressional ULF wave, regions of the cyclotron resonant energy transfer can be narrow (only a few times of the gyroradii of hot resonant protons) in magnetic local time