Social detachment due to coronavirus disease (COVID-19) has caused a decline in physical activity, leading to sarcopenia and frailty in older adults. This study aimed to compare muscle mass, strength, and function values in older women before and after the first wave of the COVID-19 pandemic (April−May 2020). Furthermore, changes in muscle measures across women who experienced different levels of impact on their social participation due to the COVID-19 pandemic were examined. Muscle mass (total, trunk, and appendicular muscle), grip strength, oral motor skills, social interactions (social network and participation), and social support were assessed in 46 Japanese community-dwelling older women (mean, 77.5 y; range 66−93 y) before and after the first wave of the COVID-19 pandemic. Trunk muscle mass significantly decreased after the first wave of the pandemic. When comparing changed values between the enhanced/maintained and reduced group during the pandemic, significant group difference was observed in trunk muscular mass, grip strength, and oral motor skills. Intriguingly, those who enhanced social participation had a positive change of grip strength values, showing that social participation might influence muscle function during the COVID-19 pandemic.

Background Restrictions on outdoor movements due to the coronavirus disease (COVID‐19) pandemic have led to a decreased physical activity; this can lead to sarcopenia and frailty in older adults. Our recent study has demonstrated a significant decrease in the trunk muscle mass immediately after the pandemic's first wave (April–May 2020) among Japanese community‐dwelling older women. In the present study, we further examined whether muscle mass recovery or deterioration occurs after 1 year of the pandemic's first wave by comparing physical measurements among the following assessment periods: before the first wave, immediately after the first wave, and at 1‐year follow‐up thereafter. Methods This study included 77 women (78.0 ± 5.7 years) who underwent physical measurements for muscle mass, grip strength, one‐leg stand‐up ability (3 s), and oral motor skills and answered questionnaires on sociality (social network, participation, and support) in the three assessment periods. Results The frequency of going out and the subjective vitality were significantly decreased immediately after the first wave; these recovered at the 1‐year follow‐up (P < 0.001). When comparing muscular measures, the trunk muscle mass index preferentially decreased immediately after the first wave but recovered significantly at the 1‐year follow‐up (P < 0.001). Conversely, the appendicular skeletal muscle mass index (ASMI) and grip strength continued to decrease until the 1‐year follow‐up (P < 0.001 and P = 0.03, respectively). The ability to perform a one‐leg stand‐up for 3 s and the oral motor skills did not change significantly across the assessment periods. The prevalence of pre‐sarcopenia and sarcopenia tended to increase during these periods (P = 0.068). The reduction and subsequent recovery patterns for sociality were similar to those observed for the trunk muscle mass. Conclusions Our findings demonstrated differences in the reversibility of skeletal muscle mass and strength at 1 year after the first wave of the COVID‐19 pandemic: the trunk muscle mass declined acutely and recovered rapidly, whereas the ASMI and grip strength declined continuously. These differences in the skeletal muscle recovery and deterioration might help formulate short‐term or long‐term strategies for COVID‐19‐related sarcopenia prevention in community‐dwelling older adults.

Nuclear morphology of carcinoma cells is critical for the pathological diagnosis of papillary thyroid carcinoma (PTC). However, three‐dimensional architecture of PTC nuclei is still elusive. In this study, we analyzed the three‐dimensional ultrastructure of PTC nuclei using serial block‐face scanning electron microscopy which takes advantage of the high‐throughput acquisition of serial electron microscopic images and three‐dimensional reconstruction of subcellular structures. En bloc‐stained and resin‐embedded specimens were prepared from surgically removed PTCs and normal thyroid tissues. We acquired two‐dimensional images from serial block‐face scanning electron microscopy and reconstructed three‐dimensional nuclear structures. Quantitative comparisons showed that the nuclei of carcinoma cells were larger and more complex than those of normal follicular cells. The three‐dimensional reconstruction of carcinoma nuclei divided intranuclear cytoplasmic inclusions into “open intranuclear cytoplasmic inclusions” connecting to cytoplasm outside the nucleus and “closed intranuclear cytoplasmic inclusions” without that connection. Cytoplasm with abundant organelles was observed in open inclusions, but closed inclusions contained fewer organelles with or without degeneration. Granules with a dense core were only observed in closed inclusions. Our observations suggested that open inclusions originate from nuclear invaginations, and disconnection from cytoplasm leads to closed inclusions.