Changes in Cognitive Functions in the Elderly Living in Temporary Housing after the Great East Japan Earthquake

On March 11, 2011, Japan experienced an earthquake of magnitude 9.0 and subsequent enormous tsunamis. This disaster destroyed many coastal cities and caused nearly 20,000 casualties. In the aftermath of the disaster, many tsunami survivors who lost their homes were forced to live in small temporary apartments. Although all tsunami survivors were at risk of deteriorating health, the elderly people were particularly at a great risk with regard to not only their physical health but also their mental health. In the present study, we performed a longitudinal cohort study to investigate and analyze health conditions and cognitive functions at 28, 32, and 42 months after the disaster in the elderly people who were forced to reside in temporary apartments in Kesennuma, a city severely damaged by the tsunamis. The ratio of people considered to be cognitively impaired significantly increased during the research period. On the other hand, the mean scores of the Kessler Psychological Distress Scale-6 and Athens Insomnia Scale improved based on the comparison between the data at 24 and 42 months. The multiple logistic regression analysis revealed that frequency of “out-of-home activities” and “walking duration” were independently associated with an increase in the ratio of people with cognitive impairment. We concluded that the elderly people living in temporary apartments were at a high risk of cognitive impairment and “out-of-home activities” and “walking” could possibly maintain the stability of cognitive functions.     

Analysis of Plasma Protein Concentrations and Enzyme Activities in Cattle within the Ex-Evacuation Zone of the Fukushima Daiichi Nuclear Plant Accident

The effect of the Fukushima Daiichi Nuclear Power Plant (FNPP) accident on humans and the environment is a global concern. We performed biochemical analyses of plasma from 49 Japanese Black cattle that were euthanized in the ex-evacuation zone set within a 20-km radius of FNPP. Among radionuclides attributable to the FNPP accident, germanium gamma-ray spectrometry detected photopeaks only from ¹³⁴Cs and ¹³⁷Cs (radiocesium) commonly in the organs and in soil examined. Radioactivity concentration of radiocesium was the highest in skeletal muscles. Assuming that the animal body was composed of only skeletal muscles, the median of internal dose rate from radiocesium was 12.5 μGy/day (ranging from 1.6 to 33.9 μGy/day). The median of external dose rate calculating from the place the cattle were caught was 18.8 μGy/day (6.0–133.4 μGy/day). The median of internal and external (total) dose rate of the individual cattle was 26.9 μGy/day (9.1–155.1 μGy/day). Plasma levels of malondialdehyde and superoxide dismutase activity were positively and glutathione peroxidase activity was negatively correlated with internal dose rate. Plasma alanine transaminase activity and percent activity of lactate dehydrogenase (LDH)-2, LDH-3 and LDH-4 were positively and LDH-1 was negatively correlated with both internal and total dose rate. These suggest that chronic exposure to low-dose rate of ionizing radiation induces slight stress resulting in modified plasma protein and enzyme levels.     

Design of an artificial light-harvesting unit by protein engineering: cytochrome b(562)-green fluorescent Protein chimera.

We have generated a novel model protein for an artificial light-harvesting complex composed of two proteins, cytochrome b(562) (cytb(562)) and enhanced green fluorescent protein (EGFP), in which two chromophores are fixed in each protein matrix. Cytb(562) was appended to the N-terminus of EGFP via a Gly-Ser linker and the resultant fusion protein was successfully expressed in Escherichia coli as a mixture of the apo- and the holo-forms as to the cytb(562) moiety. The fluorescence of EGFP was substantially quenched when the apo-form was reconstituted with hemin. Based on the fluorescence lifetime measurements, it appeared that light energy entrapped by EGFP is transferred to the heme of cytb(562) by resonance energy transfer (energy transfer yield: 65%). Spatial organization of two chromophores using small and stable protein matrices will be promising toward the construction of an artificial light-harvesting complex by protein engineering.     

A simple estimation of peroxisomal degradation with green fluorescent protein - an application for cell cycle analysis.

When nutrients are depleted from the environment, mammalian cells begin to degrade their own cytosol and organelles. This bulk protein degradation is mediated by autophagy. In this study, peroxisomes in living CHO-K1 cells were visualized by targeting the green fluorescent protein (GFP) tagged with a type 1 peroxisomal targeting signal. The nutrient-starved condition induced a decay of GFP fluorescence in the peroxisomes and autophagic inhibitors such as 3-methyladenine suppressed the decay of GFP fluorescence (13-60% of starvation). By double labeling the nuclear DNA and peroxisomal GFP, the autophagy specifically occurred at the G1 phase of the cell cycle and the autophagic inhibitors suppressed the G1 arrest. The vital stain technique with GFP is a very simple and useful marker to quantitatively estimate or to further study peroxisomal degradation.     

Taste Peptide Fractionation from a Fish Protein Hydrolysate

Various proteases were compared with each other for their ability of generating tastes from a fish protein concentrate (FPC), and Pronase was selected as an enzyme producing a large amount of brothy taste peptides. From the FPC hydrolysate obtained by treatment with this enzyme, an acidic fraction of mol. wt. lower than 1000 was prepared by ultrafiltration and subsequently by column treatments with activated charcoal and two different ion-exchangers. The acidic fraction was rechromatographed on Amberlite CG-120 to obtain a fraction containing neither free aspartic acid nor free glutamic acid. The resultant acidic, oligopeptide fraction was found to taste considerably brothy and have a favorable after-taste effect.     

Physiological Changes of Rhodotorula glutinis Induced by an Acid Protease Inhibitor (S–PI)

An acid protease inhibitor (S–PI) accelerated the growth of Rhodotorula glutinis. This acceleration of the growth was observed only when the pH of the culture fluid lowered during the cultivation, but was not observed when the pH of the culture fluid was adjusted to 2.8 with NaOH. The increase in number of cells was closely related to cell deaths. The cell deaths were observed in an active growing state but not in a resting state. S–PI increased the DNA, RNA and protein content in the cell and decreased the lipid, especially the phospholipid content. When the yeast was cultured in an acidic medium having an initial pH of 1.8 in the presence of S–PI, the decrease of the phospholipid in the cell preceded, followed by the leakage of potassium ion, UV absorbing materials and free pool amino acid from the cell which were accompanied with the cell death. On the basis of these results, physiological changes occuring in the yeast cell are discussed.     

Augmenting LTP-Like Plasticity in Human Motor Cortex by Spaced Paired Associative Stimulation

Paired associative stimulation (PAS_LTP) of the human primary motor cortex (M1) can induce LTP-like plasticity by increasing corticospinal excitability beyond the stimulation period. Previous studies showed that two consecutive PAS_LTP protocols interact by homeostatic metaplasticity, but animal experiments provided evidence that LTP can be augmented by repeated stimulation protocols spaced by ~30min. Here we tested in twelve healthy selected PAS_LTP responders the possibility that LTP-like plasticity can be augmented in the human M1 by systematically varying the interval between two consecutive PAS_LTP protocols. The first PAS_LTP protocol (PAS1) induced strong LTP-like plasticity lasting for 30-60min. The effect of a second identical PAS_LTP protocol (PAS₂) critically depended on the time between PAS₁ and PAS₂. At 10min, PAS₂ prolonged the PAS₁-induced LTP-like plasticity. At 30min, PAS₂ augmented the LTP-like plasticity induced by PAS₁, by increasing both magnitude and duration. At 60min and 180min, PAS₂ had no effect on corticospinal excitability. The cumulative LTP-like plasticity after PAS₁ and PAS₂ at 30min exceeded significantly the effect of PAS₁ alone, and the cumulative PAS₁ and PAS₂ effects at 60min and 180min. In summary, consecutive PAS_LTP protocols interact in human M1 in a time-dependent manner. If spaced by 30min, two consecutive PAS_LTP sessions can augment LTP-like plasticity in human M1. Findings may inspire further research on optimized therapeutic applications of non-invasive brain stimulation in neurological and psychiatric diseases.     

Decreased cytochrome oxidase activity in hepatic mitochondria after chronic ethanol consumption and the possible role of decreased cytochrome aa3 content and changes in phospholipids

In ethanol-fed baboons, hepatic mitochondrial cytochrome oxidase activity and cytochrome aa₃ content were significantly decreased by 58.3 and 50.5%, respectively, compared to their pair-fed controls. However, there was no significant correlation between the two, suggesting that other factors in addition to cytochrome aa₃ may be responsible for the depression in cytochrome oxidase activity. The total phospholipid content of the mitochondrial membranes was significantly decreased (0.24 ± 0.03 μmol of phospholipid phosphorus/mg of protein vs. 0.32 ± 0.04 in controls). This change was accounted for, in part, by the significant decrease in the levels of phosphatidylcholine and cardiolipin. In addition, the fatty acid pattern of the phospholipids was changed. There was a marked increase in the relative amounts of oleic and linoleic acid and a decrease in arachidonic acid. These changes were associated with an increase in the activity of phospholipase A₂. The reactivation rate of phospholipid-depleted cytochrome oxidase by endogenous phospholipids from ethanol-fed baboons was significantly lower than that by phospholipid from pair-fed controls, when measured at an optimal phospholipid to protein ratio. Thus, it appears that alterations in the phospholipid composition of the mitochondrial membranes are responsible, at least in part, for the depression of cytochrome oxidase activity produced by chronic ethanol consumption.