Stage-dependent localization of F-actin and Na+ /K+ -ATPase in zebrafish embryos detected using optimized cryosectioning immunostaining protocol.

The increasing use of the zebrafish model in biomedical and (eco)toxicological studies aimed at understanding the function of various proteins highlight the importance of optimizing existing methods to study gene and protein expression and localization in this model. In this context, zebrafish cryosections are still underutilized compared with whole-mount preparations. In this study, we used zebrafish embryos (24-120 hpf) to determine key factors for the preparation of high-quality zebrafish cryosections and to determine the optimal protocol for (immuno)fluorescence analyses of Na+ /K+ -ATPase and F-actin, across developmental stages from 1 to 5 dpf. The results showed that the highest quality zebrafish cryosections were obtained after the samples were fixed in 4% paraformaldehyde (PFA) for 1 h, incubated in 2.5% bovine gelatin/25% sucrose mixture, embedded in OCT, and then sectioned to 8 µm thickness at -20°C. Fluorescence microscopy analysis of phalloidin-labeled zebrafish skeletal muscle revealed that 1-h-4% PFA-fixed samples allowed optimal binding of phalloidin to F-actin. Further immunofluorescence analyses revealed detailed localization of F-actin and Na+ /K+ -ATPase in various tissues of the zebrafish and a stage-dependent increase in their respective expression in the somitic muscles and pronephros. Finally, staining of zebrafish cryosections and whole-mount samples revealed organ-specific and zone-dependent localizations of the Na+ /K+ -ATPase α1-subunit. RESEARCH HIGHLIGHTS: This study brings optimization of existing protocols for preparation and use of zebrafish embryos cryosections in (immuno)histological analyses. It reveals stage-dependent localization/expression of F-actin and Na+ /K+ -ATPase in zebrafish embryos.

Developing a smartphone-based ecological momentary assessment protocol to collect biopsychosocial data with community-dwelling late-middle-aged and older adults.

Although ecological momentary assessment (EMA) has been used in youth and adult populations, very few of the studies provided evidence of the feasibility and utility of smartphone-based EMA protocols to collect biopsychosocial data from aging populations. This study aimed to describe the design and implementation of a smartphone-based EMA protocol, and to evaluate the feasibility and utility of this EMA protocol among community-dwelling late-middle-aged and older Chinese. A sample of 78 community-dwelling Chinese aged between 50 and 70 years was trained to participate in a 1-week EMA data collection, during which each participant carried an Android smartphone loaded with a researcher-developed EMA application and a smartphone-based electrocardiogram (ECG) monitor to provide psychosocial (e.g., daily activities, social interaction, affect) data and ECG recordings six times daily. Adherence was demonstrated with a total response rate of 91.5% of all scheduled assessments (n = 3,822) and a moderately high level of perceived feasibility. Female participants reported higher compliance to the study and rated the overall experience as more pleasant and interesting than male participants. Our study provided the first evidence of the feasibility and utility of smartphone-based EMA protocols among late-middle-aged and older Chinese. Key areas for improvement in future design and implementation of mobile-based EMA include the incorporation of usable technology, adequate and training, and timely assistance.

Using a Smartphone-Based Ecological Momentary Assessment Protocol With Community Dwelling Older African Americans.

OBJECTIVES: Little is known about the feasibility of smartphone-based Ecological Momentary Assessment (EMA) approaches to collect psychosocial data from older populations, especially disadvantaged older populations. In response to this gap, this report provides evidence of the feasibility and utility of a smartphone-based EMA approach for real-time assessment with older African Americans. In addition, we share lessons learned about how to improve utility. METHODS: Ninety-seven older African Americans ages 55 and older (range: 55-95 years) used an Android smartphone loaded with an EMA application to provide data about their everyday activities and stress four times per day for seven consecutive days. RESULTS: Exit interviews early in the study suggested enhancements to the EMA interface. Adherence was demonstrated with response completion rates of 92-98% on EMA measures and no participant attrition based on the EMA protocol. DISCUSSION: Our findings suggest using a smartphone-based EMA approach for data collection is feasible and has utility with older African Americans. We most likely enhanced adherence by testing, training, monitoring, and adapting the EMA protocol using input from older adults early in the EMA design process.