Prognosis of microscopic polyangiitis is well predictable in the first 2 weeks of treatment.

BACKGROUND: Kidney and life outcomes remain unsatisfactory in patients with microscopic polyangiitis (MPA). Appropriate treatment intensity must be provided to the appropriate patients. To identify severe cases early, we investigated the factors related to kidney and life outcomes. METHODS: We included patients diagnosed with MPA based on myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) positivity and kidney histopathology results after kidney biopsies between January 1, 2021, and May 11, 2023, at 10 affiliated centers, including our hospital. Death, maintenance dialysis, and estimated glomerular filtration rate (eGFR) < 15 after 6 months of treatment were defined as poor prognosis groups, and factors associated with these conditions were investigated. RESULTS: We included 84 (36 men and 48 women) patients in this study. Median age was 73.8 (interquartile range: 71-81) years. After 6 months of treatment, the proportion of patients in the poor prognosis group was 16.7 %, with a mortality of 7.1 % and a poor kidney prognosis rate of 9.5 %. Area under the receiver operating characteristic curve showed that eGFR at 2 weeks had a comparable prognostic performance equal as eGFR at 4 weeks (area under the curve: 0.875 and 0.896, respectively). After adjustment by various factors, eGFR at 2 weeks was related with prognosis significantly (p = 0.031). CONCLUSION: Kidney function 2 weeks after the start of treatment for MPA can predict prognosis.

Menthol alleviates post-race elevations in muscle soreness and metabolic and respiratory stress during running.

PURPOSE: We evaluated (1) whether participating in middle- and long-distance running races augments muscle soreness, oxygen cost, respiration, and exercise exertion during subsequent running, and (2) if post-race menthol application alleviates these responses in long-distance runners. METHODS: Eleven long-distance runners completed a 1500-m race on day 1 and a 3000-m race on day 2. On day 3 (post-race day), either a 4% menthol solution (Post-race menthol) or a placebo solution (Post-race placebo) serving as a vehicle control, was applied to their lower leg skin, and their perceptual and physiological responses were evaluated. The identical assessment with the placebo solution was also conducted without race participation (No-race placebo). RESULTS: The integrated muscle soreness index increased in the Post-race placebo compared to the No-race placebo (P < 0.001), but this response was absent in the Post-race menthol (P = 0.058). Oxygen uptake during treadmill running tended to be higher (4.3%) in the Post-race placebo vs. No-race placebo (P = 0.074). Oxygen uptake was 5.4% lower in the Post-race menthol compared to the Post-race placebo (P = 0.018). Minute ventilation during treadmill running was 6.7-7.6% higher in the Post-race placebo compared to No-race placebo, whereas it was 6.6-9.0% lower in the Post-race menthol vs. Post-race placebo (all P ≤ 0.001). The rate of perceived exertion was 7.0% lower in the Post-race menthol vs. Post-race placebo (P = 0.007). CONCLUSIONS: Middle- and long-distance races can subsequently elevate muscle soreness and induce respiratory and metabolic stress, but post-race menthol application to the lower legs can mitigate these responses and reduce exercise exertion in long-distance runners.