Preventive Effect of Betaine Against Cognitive Impairments in Amyloid ß Peptide-Injected Mice Through Sirtuin1 in Hippocampus.

In the pathophysiology of Alzheimer's disease, the deposition of amyloid ß peptide (Aß) is associated with oxidative stress, leading to cognitive impairment and neurodegeneration. We have already reported that betaine (glycine betaine), an osmolyte and methyl donor in cells, prevents the development of cognitive impairment in mice with intracerebroventricular injection of Aß25-35, an active fragment of Aß, associated with oxidative stress in the hippocampus, but molecular mechanisms of betaine remain to be determined. Here, to investigate a key molecule underlying the preventive effect of betaine against cognitive impairments in Aß25-35-injected mice, cognitive tests and qPCR assays were performed in Aß25-35-injected mice with continuous betaine intake, in which intake was started a day before Aß25-35 injection, and then continued for 8 days. The Aß25-35 injection impaired short-term and object recognition memories in the Y-maze and object recognition tests, respectively. PCR assays revealed the down-regulation of Sirtuin1 (SIRT1), a NAD+-dependent deacetylase that mediates metabolic responses, in the hippocampus of Aß25-35-injected mice, whereas betaine intake prevented memory deficits as well as the decrease of hippocampal SIRT1 expression in Aß25-35-injected mice. Further, sirtinol, an inhibitor of the Sirtuin family, blocked the preventive effect of betaine against memory deficits. On the other hand, resveratrol, the potent compound that activates SIRT1, also prevented memory impairments in Aß25-35-injected mice, suggesting that SIRT1 plays a causative role in the preventive effect of betaine against memory deficits caused by Aß exposure.

Impact of Microporous Layer on Heat and Mass Transfer in a Single Cell of Polymer Electrolyte Fuel Cell Using a Thin Polymer Electrolyte Membrane and a Thin Gas Diffusion Layer Operated at a High-Temperature Range.

The impact of microporous layer (MPL) on the heat- and mass-transfer characteristics and power generation performance of a polymer electrolyte fuel cell using a thin polymer electrolyte membrane (PEM) and a thin gas diffusion layer (GDL) is investigated in this paper. The power generation is investigated at the operational temperatures of 90 and 100 °C which are the target temperatures from year 2020 to 2025 according to the New Energy and Industrial Technology Development Organization's road map in Japan. The in-plane temperature distributions on the separator back at the anode and the cathode are also measured by a thermograph. As a result, it is found that the voltage drop with the MPL at a high current density is larger compared to that without the MPL irrespective of the initial temperature of the cell and relative humidity conditions. The study also revealed from the anode side observation that the in-plane temperature distribution with the MPL is wider compared to that without the MPL, especially at the initial temperature of 90 °C of the cell . Similarly, from the cathode side observation, the in-plane temperature distributions with the MPL were found to be wider compared to that without the MPL. This study has concluded that the MPL is not effective in obtaining a high performance and even an in-plane temperature distribution for a polymer electrolyte fuel cell with the thin PEM and the thin GDL at a high operational temperature range.

Preventive Effects of Continuous Betaine Intake on Cognitive Impairment and Aberrant Gene Expression in Hippocampus of 3xTg Mouse Model of Alzheimer's Disease.

BACKGROUND: The deposition of amyloid-ß (Aß) and hyperphosphorylation of tau are well-known as the pathophysiological features of Alzheimer's disease (AD), leading to oxidative stress and synaptic deficits followed by cognitive symptoms. We already demonstrated that betaine (glycine betaine) prevented cognitive impairment and hippocampal oxidative stress in mice intracerebroventricularly injected with an active fragment of Aß, whereas the effect of betaine in chronic models of AD remains unknown. OBJECTIVE: Our objective was to investigate the effects of chronic betaine intake on cognitive impairment and aberrant expression of genes involved in synapse and antioxidant activity in the hippocampus of a genetic AD model. METHODS: We performed cognitive tests and RT-PCR in the hippocampus in 3xTg mice, a genetic AD model. RESULTS: Cognitive impairment in the Y-maze and novel object recognition tests became evident in 3xTg mice at 9 months old, and not earlier, indicating that cognitive impairment in 3xTg mice developed age-dependently. To examine the preventive effect of betaine on such cognitive impairment, 3xTg mice were fed betaine-containing water for 3 months from 6 to 9 months old, and subsequently subjected to behavioral tests, in which betaine intake prevented the development of cognitive impairment in 3xTg mice. Additionally, the expression levels of genes involved in synapse and antioxidant activity were downregulated in hippocampus of 3xTg mice at 9 months old compared with age-matched wild-type mice, which were suppressed by betaine intake. CONCLUSION: Betaine may be applicable as an agent preventing the progression of AD by improving the synaptic structure/function and/or antioxidant activity.

214Bi/214Pb radioactivity ratio in rainwater for residence time estimation of cloud droplets and raindrops.

Continuous observation of radioactivity ratio of (214)Bi to (214)Pb as tracers in rainwater was carried out with 15-min cyclic measurement at Nagoya, Japan, from August 2011 to July 2012 to characterise wet deposition. The ratio ranged from 0.55 to 3.82. Based on the observation and a simplified time evolution model of (214)Pb and (214)Bi radioactivities during rainwater formation, the 'age' of raindrops ranged from sub-10 to several 100 min. The age would have negative correlation to rainfall intensity, but its variation for lower rainfall intensities was quite large. Secular equilibrium of (214)Pb and (214)Bi radioactivities in cloud water with airborne radon did not hold for some rainfall events.