Association of self-rated health with type and frequency of social interaction during the declaration of COVID-19 state of emergency among Japanese community-dwelling oldest-old adults.

AIM: To investigate whether the type and frequency of social interaction during the state of emergency due to coronavirus disease were associated with self-rated health (SRH) after the state of emergency. METHODS: Data from a cross-sectional study were collected for 889 oldest-old adults in Bibai City, Hokkaido, Japan. In total, 612 participants (mean age: 83.0 ± 4.3 years; women: 51.8%) were included in the analysis, taking biological sex into account. The self-reported questionnaire included questions about demographic variables, SRH (July 2020, after the emergency), and the type and frequency of social interaction (March 2020, during the state of emergency). RESULTS: There was no significant association between social interaction and SRH in men (P > 0.05). Women who had social interactions (both face-to-face and non-face-to-face) more than once a week during the state of emergency reported higher SRH after the emergency than those who did not (odds ratio 2.17, 95% confidence interval 1.07-4.41). CONCLUSIONS: Having both types of interaction more than once a week during the state of emergency was related to higher SRH after the emergency among oldest-old women. It is suggested that having opportunities for both types of interaction at least once a week would potentially be beneficial for high SRH in women, even in situations where the declaration of a state of emergency restricts face-to-face interaction. Geriatr Gerontol Int 2022; 22: 405-411.

Association between cognitive frailty and higher-level competence among community-dwelling older adults.

OBJECTIVES: The purpose of this cross-sectional study was to examine the association between cognitive frailty (CF) and higher-level competence among community-dwelling older adults. METHODS: Data from 871 older adults (aged ≥ 65 years, mean age 74.3 years, 61.5% women) who had participated in a community-based health check survey (Tarumizu Study 2018-2019) were analyzed. CF was defined as comorbid physical frailty and mild cognitive impairment (MCI). We defined physical frailty as either slow walking speed or poor grip strength. MCI was defined as values below the age- and education-adjusted reference threshold in several tests. Participants were categorized into four groups: robust, physical frailty, MCI, and CF. Higher-level competence was assessed using the Japan Science and Technology Agency Index of Competence (JST-IC). The JST-IC consists of 16 items and four subscales (technology usage, information practice, life management and social engagement). The bottom 20-30% score of the JST-IC and each subscale corresponded to poor higher-level competence. RESULTS: The prevalence of CF was 14.4%. Multivariate logistic regression analysis showed that, CF was significantly associated with poor higher-level competence (odds ratio 1.92, 95% confidence interval 1.18-3.13) after adjusting for covariates. Using a similar analysis to assess the JST-IC subscales, CF was associated with limitations on technology usage (odds ratio 2.29, 95% confidence interval 1.36-3.85) and low social engagement (odds ratio 1.62, 95% confidence interval 1.00-2.61). CONCLUSIONS: This study suggests that CF is associated with poor higher-level competence, especially limitations on technology usage and low social engagement.

Associations of alpha-actinin-3 genotype with thigh muscle volume and physical performance in older adults with sarcopenia or pre-sarcopenia.

BACKGROUND: This cross-sectional study aimed to investigate the relationship of the ACTN3 genotype with thigh muscle volume and physical performance in older adults with sarcopenia or pre-sarcopenia. METHODS: Data from 64 older Japanese adults (mean age 74.4 ± 6.9 years, women 71.9%) with sarcopenia or pre-sarcopenia were analyzed. Sarcopenia and pre-sarcopenia were defined using the Asian Working Group for Sarcopenia. We collected oral mucosa samples to determine the ACTN3 genotype. Thigh muscle volumes were measured using magnetic resonance imaging. Physical performance was assessed using the usual and maximum gait speed, timed up and go test, and five-repetition sit-to-stand test. Muscle strength was assessed using grip strength. RESULT: The ACTN3 genotype proportions were 20.3% for RR, 51.6% for RX, and 28.1% for XX. Participants with the RR genotype showed greater thigh muscle volume/ht2 compared to those with the RX and XX ACTN3 genotypes (p < 0.05). The multiple linear regression analysis revealed that RX (p < 0.01) and XX (p < 0.01) ACTN3 genotypes, compared to RR, were associated with lower thigh muscle volume/ht2 and with age, sex (reference; men), weight and maximum walking speed. There was no significant difference between physical performance and muscle strength between the ACTN3 genotypes. CONCLUSION: The ACTN3 genotype of the X allele was associated with decreased thigh muscle volume compared to the ACTN3 genotype of RR in older adults with sarcopenia or pre-sarcopenia.

Effects of a Multicomponent Exercise Program in Physical Function and Muscle Mass in Sarcopenic/Pre-Sarcopenic Adults.

This study aimed to assess the effects of a multicomponent exercise program on physical function and muscle mass in older adults with sarcopenia or pre-sarcopenia. Moreover, we aim to standardize the exercise program for easy incorporation in the daily life of community-dwelling older adults as a secondary outcome. A single-blind randomized controlled trial was conducted with individuals (≥60 years) who had sarcopenia or pre-sarcopenia (n = 72). Participants were randomly assigned to the exercise and control groups. The exercise program consisted of 12 weekly 60-minute sessions that included resistance, balance, flexibility, and aerobic training. Outcome measures were physical function and muscle mass. Assessments were conducted before and immediately after the intervention. Among the 72 participants (mean age: 75.0 ± 6.9 years; 70.8% women), 67 (93.1%) completed the trial. Group-by-time interactions on the chair stand (p = 0.02) and timed "up and go" (p = 0.01) tests increased significantly in the exercise group. Although the exercise group showed a tendency to prevent loss of muscle mass, no significant interaction effects were observed for cross-sectional muscle area and muscle volume. The 12-week exercise program improved physical function in the intervention group. Although it is unclear whether the program is effective in increasing muscle mass, a multicomponent exercise program would be an effective treatment for physical function among older adults with sarcopenia.

Comparative analysis of strategies to prepare electron sinks in aquatic photoautotrophs.

While subject to illumination, photosystem I (PSI) has the potential to produce reactive oxygen species (ROS) that can cause photo-oxidative damage in oxygenic photoautotrophs. The reaction center chlorophyll in PSI (P700) is kept oxidized in excess light conditions to limit over-excitation of PSI and alleviate the production of ROS. Oxidation of P700 requires a sufficient electron sink for PSI, which is responsible for flavodiiron proteins (FLV) safely dissipating electrons to O2 in cyanobacteria, green algae, and land plants except for angiosperms during short-pulse light (SP) illumination under which photosynthesis and photorespiration do not occur. This fact implies that O2 usage is essential for P700 oxidation but also raises the question why angiosperms lost FLV. Here, we first found that aquatic photoautotrophs in red plastid lineage, in which no gene for FLV has been found, could keep P700 oxidized during SP illumination alleviating the photo-oxidative damage in PSI even without O2 usage. We comprehensively assessed P700 oxidation during SP illumination in the presence and absence of O2 in cyanobacteria (Cyanophyta), green algae (Chlorophyta), angiosperms (Streptophyta), red algae (Rhodophyta), and secondary algae (Cryptophyta, Haptophyta, and Heterokontophyta). A variety of dependencies of P700 oxidation on O2 among these photoautotrophs clearly suggest that O2 usage and FLV are not universally required to oxidize P700 for protecting PSI against ROS damage. Our results expand the understanding of the diverse strategies taken by oxygenic photoautotrophs to oxidize P700 and mitigate the risks of ROS.

Diversity in photosynthetic electron transport under [CO2]-limitation: the cyanobacterium Synechococcus sp. PCC 7002 and green alga Chlamydomonas reinhardtii drive an O2-dependent alternative electron flow and non-photochemical quenching of chlorophyll fluorescence during CO2-limited photosynthesis.

Some cyanobacteria, but not all, experience an induction of alternative electron flow (AEF) during CO2-limited photosynthesis. For example, Synechocystis sp. PCC 6803 (S. 6803) exhibits AEF, but Synechococcus elongatus sp. PCC 7942 does not. This difference is due to the presence of flavodiiron 2 and 4 proteins (FLV2/4) in S. 6803, which catalyze electron donation to O2. In this study, we observed a low-[CO2] induced AEF in the marine cyanobacterium Synechococcus sp. PCC 7002 that lacks FLV2/4. The AEF shows high affinity for O2, compared with AEF mediated by FLV2/4 in S. 6803, and can proceed under extreme low [O2] (about a few µM O2). Further, the transition from CO2-saturated to CO2-limited photosynthesis leads a preferential excitation of PSI to PSII and increased non-photochemical quenching of chlorophyll fluorescence. We found that the model green alga Chlamydomonas reinhardtii also has an O2-dependent AEF showing the same affinity for O2 as that in S. 7002. These data represent the diverse molecular mechanisms to drive AEF in cyanobacteria and green algae. In this paper, we further discuss the diversity, the evolution, and the physiological function of strategy to CO2-limitation in cyanobacterial and green algal photosynthesis.

A novel aqueous lithium-oxygen cell based on the oxygen-peroxide redox couple.

The electrochemical process of an aqueous Li-O2 cell is investigated. Li2O2 is detected as a discharge product of an aqueous Li-O2 cell using a catalyst-free carbon-based electrode. The electrolyte solution saturated with lithium hydroxide prevents hydrolysis of the Li2O2. Since the electron transfer process is based on the oxygen-peroxide redox couple, the galvanostatic charging-discharging profile shows stable cycling with an extremely low charging overpotential of <0.1 V at 1.0 mA cm(-2).

A rapid and efficient method for neuronal induction of the P19 embryonic carcinoma cell line.

BACKGROUND: P19 mouse embryonic carcinoma cells are conventionally induced to differentiate into neural cells by suspension culture in the presence of retinoic acid to form cell aggregates, followed by adhesion culture in a poly-l-lysine-coated dish. Drawbacks of this procedure include it taking more than 10 days to obtain mature neurons, and non-neuronal proliferating cells occupying the majority of the cell population with time. NEW METHOD: Here, we show a novel method for the rapid and efficient neurogenesis of P19 cells, without aggregate formation in a suspension culture. The new approach is based on an adherent serum-free culture in a laminin-coated dish in the presence of FGF8, a γ-secretase inhibitor, and cytosine arabinoside. RESULTS: The new method efficiently induced P19 cells to differentiate into neurons within 4 days, and subsequently into mature neurons that were responsive to several neurotransmitters, giving spontaneous neuronal network activity within 6 days. COMPARISON WITH EXISTING METHOD: The novel method accelerated neuritogenesis and enhanced population of neuron selectively compared to the conventional method. Proliferating non-neuronal cells were eliminated by adding cytosine arabinoside during neuronal maturation. CONCLUSIONS: The method is useful for studying neuronal differentiation or activities.