Modality-Specific Impairment of Hippocampal CA1 Neurons of Alzheimer’s Disease Model Mice

Impairment of episodic memory, a class of memory for spatiotemporal context of an event, is an early symptom of Alzheimer's disease. Both spatial and temporal information are encoded and represented in the hippocampal neurons, but how these representations are impaired under amyloid β (Aβ) pathology remains elusive. We performed chronic imaging of the hippocampus in awake male amyloid precursor protein (App) knock-in mice behaving in a virtual reality environment to simultaneously monitor spatiotemporal representations and the progression of Aβ depositions. We found that temporal representation is preserved, while spatial representation is significantly impaired in the App knock-in mice. This is due to the overall reduction of active place cells but not time cells, and compensatory hyperactivation of remaining place cells near Aβ aggregates. These results indicate the differential impact of Aβ aggregates on two major modalities of episodic memory, suggesting different mechanisms for forming and maintaining these two representations in hippocampus.SIGNIFICANCE STATEMENT:Spatiotemporal memory impairments are common at the early stage of Alzheimer's disease patients. We demonstrate the different impairment patterns of place and time cells in the dorsal hippocampus of head-fixed App knock-in mouse by in vivo two-photon calcium imaging over months under the virtual reality spatiotemporal tasks. These results highlight that place cells were preferentially and gradually damaged nearby Aβ aggregates, while time cells were less vulnerable. We further show these impairments were due to neuronal hyperactivity that occurs near the Aβ deposition. We suggest the differential and gradual impairment in two major modalities of episodic memory under Aβ pathology

Development of a Nursing Care Guideline to Support Families Face on Organ Donation as the Choice of Their Child’s End-of-Life

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Association between lifestyle, parental smoke, socioeconomic status, and academic performance in Japanese elementary school children: the Super Diet Education Project

Abstract Background Health and education are closely linked. However, few studies have explored the correlates of children’s academic performance in Japan. We aimed to investigate comprehensively the associations of low academic performance among school children with lifestyles, parental smoke, and socioeconomic status. Methods In 2016, children aged 6 to 13 years from the Super Diet Education School Project were surveyed using questionnaires. The survey explored the lifestyles and subjective academic performance of 1663 children and asked their parents about parental smoke and subjective socioeconomic status. Academic performance and socioeconomic status were divided into three levels. Then, we defined subjective academic performance in the lower two levels as low academic performance. The odds ratios (OR) were analyzed by logistic regression analysis. Results Among all participants, 299 (18.0%) children reported low academic performance. In general, low academic performance was significantly associated with late wakeup time (OR = 1.36 for 6:30 to < 7 a.m. and OR = 2.48 for ≥ 7 a.m.), screen time ≥ 2 h (OR = 1.35), studying at home < 1 h (OR = 1.82), paternal smoke (OR = 1.47), maternal smoke (OR = 1.87), and low socioeconomic status (OR = 1.48). Analyses stratified by grade showed stronger associations between academic performance and socioeconomic status in senior (OR = 1.62 for middle, OR = 1.52 for low in grades 4 to 6) than in junior children (OR = 1.15 for middle, OR = 1.38 for low in grades 1 to 3). Conclusions Children’s lifestyles, parental smoke, and socioeconomic status were significantly associated with low academic performance among Japanese children. Parents and health care providers should take these findings into consideration to prevent children from having low academic performance

Prevalence and associated factors of pathological Internet use and online risky behaviors among Japanese elementary school children

Background: Little is known about pathological Internet use (PIU) and online risky behaviors among elementary school children. We aimed to investigate the prevalence and factors associated with PIU and online risky behaviors. Methods: A school-based cross-sectional study was conducted in Toyama, Japan in 2018. The study included 13,413 children in the 4th–6th grades (mean, 10.5 years old) from 110 elementary schools (61.1% of elementary schools in Toyama). We assessed PIU using Young’s Diagnostic Questionnaire (YDQ) and risky behaviors. Poisson regression analysis was conducted. Results: Totally, 13,092 children returned questionnaires (response rate 97.6%). The prevalence of PIU was 4.2% and that of each risky behavior was as follows: 21.6% for spending money online, 6.6% for uploading personal movies, 5.2% for interpersonal issues, and 2.4% for having met strangers. PIU was significantly associated with boys (prevalence ratio [PR] 1.26; 95% confidence interval [CI], 1.04–1.52), skipping breakfast (PR 1.43; 95% CI, 1.14–1.79), Internet time (for 2∼3 h, PR 3.49; 95% CI, 2.63–4.65; for 3∼4 h, PR 4.45; 95% CI, 3.27–6.06; and for ≥4 h, PR 8.25; 95% CI, 6.45–10.55), physical inactivity (PR 2.63; 95% CI, 2.00–3.47), late bedtime (PR 1.86; 95% CI, 1.45–2.39 for ≥11 p.m.), no rules at home (PR 1.22; 95% CI, 1.01–1.46), no child-parent interaction (PR 1.37; 95% CI, 1.06–1.77), and no close friends in real life (PR 1.69; 95% CI, 1.30–2.19). Conclusions: PIU and risky behaviors were not rare among the elementary school children. Besides unhealthy lifestyles, social and family environments were associated with PIU. Having child-parent interaction and helping children develop close friendships in real life are effective deterrents to PIU

First observation of surface protonics on SrZrO3 perovskite under a H2 atmosphere

This is the first direct observation that surface proton hopping occurs on SrZrO3 perovskite even under a H2 (i.e. dry) atmosphere. Understanding proton conduction mechanisms on ceramic surfaces under a H2 atmosphere is necessary to investigate the role of proton hopping on the surface of heterogeneous catalysts in an electric field. In this work, surface protonics was investigated using electrochemical impedance spectroscopy (EIS). To extract the surface proton conduction, two pellets of different relative densities were prepared: a porous sample (R.D. = 60%) and a dense sample (R.D. = 90%). Comparison of conductivities with and without H2 revealed that only the porous sample showed a decrease in the apparent activation energy of conductivity by supplying H2. H/D isotope exchange tests revealed that the surface proton is the dominant conductive species over the porous sample with H2 supply. Such identification of a dominant conductive carrier facilitates consideration of the role of surface protonics in chemical reactions

Prevalence of molar incisor hypomineralization and regional differences throughout Japan

Abstract Background Molar incisor hypomineralization (MIH) frequently occurs in children worldwide. However, MIH prevalence throughout Japan has not yet been investigated. The purpose of this study was to clarify MIH prevalence rates and to consider potential regional differences throughout Japan. Methods A total of 4496 children aged 7–9 years throughout Japan were evaluated in this study. MIH prevalence rates among children were evaluated in eight regions throughout Japan. A child’s residence was defined as the mother’s residence during pregnancy. The localization of demarcated opacities and enamel breakdown was recorded on a standard code form using a guided record chart. Logistic regression analysis was used to evaluate whether MIH prevalence rates differed among age groups, sex, and regions. Results The overall prevalence of MIH in Japan was 19.8%. The prevalence of MIH was 14.0% in the Hokkaido region, 11.7% in the Tohoku region, 18.5% in the Kanto Shin-Etsu region, 19.3% in the Tokai Hokuriku region, 22.3% in the Kinki region, 19.8% in the Chugoku region, 28.1% in the Shikoku region, and 25.3% in the Kyushu region. These regional differences were statistically significant. Moreover, MIH prevalence rates decreased with age. No significant sex differences in MIH prevalence rates were demonstrated. Conclusions To our knowledge, this is the first MIH study carried out in several regions throughout Japan. Regional differences existed in MIH prevalence rates; particularly, MIH occurred more frequently in children residing in southwestern areas than those in northeastern areas of Japan