Search

Introduction Bright light therapy (BLT) has been used for treating seasonal affective disorder, depression and bipolar depression. However, it's precise mechanism remains unclear. Bright light exposure (BL) induces neurogenesis in the adult rat hippocampal dentate gyrus (DG). We hypothesized that BL may induce neurogenesis in the human DG as well. Method A 4-week randomized controlled trial study was conducted, where healthy participants were randomly assigned to a BL group (10,000 lux) or dim light exposure group (DL group; 50 lux). Magnetic resonance imaging was performed at baseline and after 4 weeks. Longitudinal hippocampal subfield segmentation was generated via the FreeSurfer 7.1.1 hippocampal subfields module to evaluate volume of bilateral granule cell and molecular layer of the DG-head and -body. Results Our final sample size was 20, which consisted of BL group (n = 10) and DL group (n = 10). After age and sex adjustment, significant effects of time and group were detected in the left DG-head volume (p = 0.04). In the BL group, the left DG-head volume significantly increased (p = 0.004), whereas no significant volumetric change was observed in the DL group. Conclusions This study revealed that 4-week BL significantly increased left DG-head volume in healthy participants. Thus, neurogenesis might be induced by BL in the human DG, which is a completely new mechanism of BLT.

我が国では東電福島第一原子力発電所事故の前までは、主にグローバルフォールアウトの分析や室内トレーサー実験により環境挙動研究が行われてきた。また、長期平衡状態を想定した場合には、安定元素を使った研究も行われてきた。しかし2011年3月に発生した福島第一原発事故以降は事態が一変し、放射性ヨウ素や放射性セシウム（Cs）の実環境試料を使った研究が可能となった。これらの研究結果を、これまでの知識やチェルノブイリ原発事故後の事象と比較検討することは、放射性核種による被ばく線量評価のために重要である。まだ事故から十分時間が経過していない期間、実際の環境試料測定データは、将来原発事故が発生した時の備えとするためにも極めて貴重である。 我々はそれらのデータを後世に残し、世界で広く活用してもらうため、IAEA研究プログラムMODARIA II（MOdelling and DAta for Radiological Impact Assessments II、期間：2016-2019）での活動を通じてIAEAの公式技術書であるTechnical Documentを発行した（Tecdoc-1927）4。データをまとめるにあたり、Fig. 1に示したような海洋、森林、農業関連、河川を含む集水域等の区分に分類し、それぞれにおいて重要な環境移行パラメータの収集を国内の研究者と協力してデータの信頼性向上に努めた。得られたデータの整理の仕方については、海外の専門家らとディスカッションを重ねて、これまでのIAEAの技術書と整合性がとれるように工夫をした。対象核種は主に放射性セシウムである。本研究協力を通して得られた成果について、下記にいくつか紹介する。

We measured the concentrations of cesium isotopes (

In the working population, bipolar disorder can have a significant negative effect on professional relationships, attendance, functioning, and loss of productivity. In Japan, workers who take a leave due to depressive episodes receive a work-focused intervention program called the "return to work program" during their leave. A 39-year-old Japanese woman with bipolar II disorder took a third sick leave of absence. We recommended her the return to work program of our university hospital. At the beginning of the program, she had a rigid thought process toward her perceptions of her duties in the workplace and at home. Through the program, mindfulness might identify rigidity, group cognitive-behavioral therapy might correct rigidity, and self-analysis might have regained flexibility. In conclusion, a variety of effects of our return to work program might have enabled her thought process to evolve from rigid to flexible, and she showed successful reinstatement.

A large amount of radiocaesium (137Cs + 134Cs) was released into the atmosphere and diffused mainly in the Tohoku and Kanto regions after the TEPCO’s Fukushima Daiichi Nuclear Power Plant accident in March 2011. Fallout radiocaesium flows into rivers and lakes over time and have been taken up by living organisms. Although as of September 2019, more than 8 years have passed since the accident, freshwater fish contamination with radiocaesium is still serious issue in some area because shipping restrictions and restraint have continued. Internal radiation exposure through the consumption of contaminated fish is of the public concerns. Therefore, it is important to understand the current contamination state in freshwater fish and to predict the trend of the contamination in future. Freshwater fishes have been captured from September 2015 in Lake Inba, Chiba Prefecture. Activity concentrations of 137Cs in the muscle of funa remained constant after November 2016. The similar trends were found for catfish, snakehead, largemouth bass, bluegill and so on. In addition, effective half-life of 137Cs in muscle tissues of funa from Lake Inba was calculated about 9,900 days. These results suggest that the same concentration level of 137Cs in 2018 will be seen for those fishes in the future. It is still important to monitor 137Cs in freshwater fish to provide information for predicting future concentration changes.

Despite the unavailability of essential anti-dementia drugs, lithium may inhibit glycogen synthase kinase-3 (GSK-3) and decrease beta-amyloid and hyper-phosphorylated tau. In this review, we hypothesized that trace to standard levels of lithium (i.e., corresponding to the therapeutic levels for bipolar disorder) may be effective for dementia prevention. Excluding three insufficient level studies, we obtained two and one excellent clinical studies on standard and trace lithium levels, respectively, all of which supported the effects of lithium for dementia prevention. In addition, we identified good clinical and epidemiological studies (four each) on standard lithium levels, of which six studies supported the effects of lithium. Moreover, of three good epidemiological studies on trace lithium levels, two supported the aforementioned effects of lithium. The number of studies were substantially small, particularly those on trace lithium levels. Moreover, studies on standard lithium levels were insufficient to establish the efficacy of lithium for dementia prevention. This necessitates accumulating good or excellent clinical evidence for the effects of trace to standard lithium levels on dementia prevention.

Aim We aimed to investigate the hypotheses that hyperthymic temperament may be positively associated with self-directedness and self-transcendence with adjustment for relevant factors. Methods Using the database of our previous studies, the data from 111 healthy subjects with scores for both the Temperament and Character Inventory and the Temperament Evaluation of Memphis, Pisa, Paris, and San Diego Autoquestionnaire were secondarily used for the present study. Results Hyperthymic Temperament scores were significantly and positively associated with Self-Transcendence scores, but not with Self-Directedness scores, following adjustment for relevant factors. Despite the lack of association between self-transcendence and self-directedness, cooperativeness was significantly and positively associated with self-transcendence and self-directedness, but not with hyperthymic temperament. Moreover, despite the lack of association between hyperthymic temperament and self-directedness, harm avoidance was significantly and negatively associated with hyperthymic temperament and self-directedness, but not with self-transcendence. Conclusion The present findings suggest that hyperthymic temperament may be positively associated with self-transcendence, but not with self-directedness. Moreover, hyperthymic temperament may be, a selfish and reckless trait, self-transcendence may be altruistic and not reckless, and self-directedness may be altruistic but reckless.

A large amount of radiocesium (137Cs + 134Cs) was released into the atmosphere and diffused mainly in the Tohoku and Kanto regions after the TEPCO’s Fukushima Daiichi Nuclear Power Plant accident in March 2011. Fallout radiocesium flows into rivers and lakes over time and has been taken up by living organisms. Although as of September 2019, more than 8 years have passed since the accident, freshwater fish contamination with radiocesium is still serious issue in some area because shipping restrictions and restraint have continued. Internal radiation exposure through the consumption of contaminated fish is of the public concerns. Therefore, it is important to understand the current contamination state in freshwater fish and to predict the trend of the contamination in future. Freshwater fishes have been captured from September 2015 in Lake Inba, Chiba Prefecture. Activity concentrations of 137Cs in the muscle of funa remained constant after November 2016. The similar trends were found for catfish, snakehead, largemouth bass, bluegill, and so on. In addition, effective half-life of 137Cs in muscle tissues of funa from Lake Inba was calculated about 9900 days. These results suggest that the same concentration level of 137Cs in 2018 will be seen for those fishes in the future. It is still important to monitor 137Cs in freshwater fish to provide information for predicting future concentration changes.

Contamination of freshwater fishes with 137Cs remains as a serious problem in Japan, nearly 10 years after the Fukushima nuclear power plant accident, but there is limited information on the distribution of 137Cs contamination in fish bodies. The 137Cs distribution can be used for the estimation of internal radiation exposure through the consumption of fish and for the dose estimation of fish themselves. In this study, the 137Cs distribution in the bodies of 8 freshwater fish species was investigated as percentages of total body burden for fish inhabiting Lake Inba. Fish samples were caught in stake nets placed close to the shore approximately once a month. After the measurement of body length and fresh weight, the radioactivities of 137Cs in muscle, internal organs, spawn, milt and bone were assayed using high-purity germanium detectors. Analysis of all fish samples showed that the 137Cs distribution was highest in muscle (54 ± 12%), followed by internal organs (7.8 ± 4.6%), spawn (7.4 ± 5.4%), milt (3.2 ± 2.1%) and bone (1.2 ± 0.58%). Among fish species, the highest proportion of 137Cs in muscle was detected in largemouth bass (71 ± 1 3%), followed by snakehead (69 ± 14%), channel catfish (63 ± 17%), common carp (62 ± 14%), barbel steed (58 ± 6.5%), silver carp (57 ± 7.7%), bluegill (53 ± 4.7%), and crucian carp (50 ± 10%). These results suggested that the 137Cs in muscle was likely to be high in piscivorous fishes compared to omnivorous fishes, especially crucian carp. The proportion of 137Cs in muscle of crucian carp was not explained either by body length or fresh weight. However, a positive correlation was found between the proportion of 137Cs in muscle and the condition factor which was an indicator of nutritional status calculated from a length–weight relationship. This correlation implied that more 137Cs accumulated in muscle tissue of a fish species with high nutritional status. This is the first study to show that condition factor is more important than body length and wet weight in explaining the high proportion of 137Cs in muscle tissues, at least for crucian carp.

Objectives The aims of the present study thus were (a) to further investigate the association between lithium levels in drinking water and suicide rates by adjusting relevant factors using the so far largest available dataset in Japan, (b) to confirm sex differences, (c) to estimate the effects of long-term exposure to trace lithium, (d) to investigate the effects of drinking bottled instead of tap water, and (e) to exploratorily investigate which lithium levels may be associated with lower suicide rates. Methods Mean lithium levels in drinking water of all 808 cities and wards (ie, 785 cities of 46 prefectures and 23 wards of Tokyo) in Japan were examined in relation to mean suicide standardized mortality ratios (SMRs) during the 7 years from 2010 to 2016. Multiple regression analyses adjusted for the size of each population were used to investigate the association of lithium levels with suicide SMRs with adjustments for relevant factors. Results The adjusted model showed significant inverse associations of lithium levels with total and male SMRs, but not with female SMRs. Neither the proportion of residents who continued to live in the same city nor the consumption of bottled water changed the association between lithium levels and suicide SMRs. Finally, it was 30 μg/L or more that was associated with lower suicide SMRs. Conclusions The present findings reconfirm the inverse association between lithium levels in drinking water and suicide rates particularly in the male population.

A dose-response curve is a plot of drug efficacy versus dose. Interestingly, some antidepressants show a bell-shaped dose-response curve where increasing dose leads to increasing efficacy only up to a point, whereupon further increases lead to decreasing efficacy. Here, we propose that the first part of the curve reflects the basic, uncomplicated dose-response relationship of these antidepressants whereas the second, decreasing part remains to be explained. Our hypothesis is that a negative feedback pathway through 5-HT

Objective Previous studies have investigated the effects of omega-3, omega-6 and lithium on suicide-related behaviors separately. This study was performed to comprehensively investigate the effects of naturally absorbed EPA, DHA, arachidonic acid and lithium in relation to suicide attempt and deliberate self-harm, with adjustment for each other. Methods We analyzed plasma EPA, DHA, arachidonic acid levels and serum lithium levels of 197 patients including 33 patients with suicide attempts, 18 patients with deliberate self-harm, and 146 control patients. Results Multivariate logistic regression analysis with adjustment for age, gender, EPA, DHA, arachidonic acid and log-transformed lithium levels revealed that the negative associations with EPA levels (adjusted OR 0.972, 95% CI 0.947–0.997, p = 0.031) and log-transformed lithium levels (adjusted OR 0.156, 95% CI 0.038–0.644, p = 0.01) and the positive association with DHA levels (adjusted OR 1.026, 95% CI 1.010–1.043, p = 0.002) were significant in patients with suicide attempts than in control patients. The analysis also demonstrated that the positive association with arachidonic acid levels (adjusted OR 1.015, 95% CI 1.005–1.025, p = 0.004) was significant in patients with deliberate self-harm than in control patients. Limitations The limitations are relatively small number of patients and the effects of demographics of individual patients could not be adjusted for the analyses. Conclusions The present findings suggest that, as naturally absorbed nutrients, higher EPA and lithium levels may be associated with less suicide attempt, and that higher arachidonic acid levels may be associated with more deliberate self-harm.

The effects of the Japanese horned beetle larvae on the transfer of 137Cs from a contaminated leaf litter to the leaf vegetable, komatsuna (Brassica rapa var. perviridis) was studied. Feces of the larvae which were fed 137Cs-contaminated leaf litter were added to a potting mix in which komatsuna plants were cultivated. The presence of feces increased the harvest yield of komatsuna, suggesting that feces provided nutrients for the plant growth. In addition, the amount of exchangeable 137Cs in leaf litter was experimentally confirmed to be enhanced by the presence of feces which were excreted by larvae feeding. However, there was no difference in the soil-to-plant transfer factor of 137Cs for the presence and absence of feces. Interactions between clay minerals and exchangeable 137Cs in the soil beneath the litter layer may diminish the root uptake of 137Cs. From these results, it was concluded that the effect of exchangeable 137Cs released from feces was limited for the transfer of 137Cs to plants if plant roots were not present in litter layers.

Aim In order to resolve the equivocal relationship between anxious temperament rated by the Temperament Evaluation of Memphis, Pisa, Paris, and San Diego-Autoquestionnaire (TEMPS-A) and harm avoidance rated by the Temperament and Character Inventory (TCI), the present study aimed to investigate whether the anxious temperament scale and the harm avoidance scale are significantly associated with adjustment of relevant factors. Our hypothesis was that anxious temperament might be associated with harm avoidance. Methods From the database of our previous studies, the data of 111 healthy subjects who had both TCI and TEMPS-A scores were extracted for the present study. Two multiple regression analyses were performed: one to predict variance in anxious temperament scores without and with harm avoidance scores, and relevant factors; and another to predict variance in harm avoidance scores without and with anxious temperament scores, and relevant factors. Results Anxious temperament was significantly and positively associated with depressive temperament, irritable temperament, and Hamilton Rating Scale for Depression whereas harm avoidance was significantly and negatively associated with hyperthymic temperament, novelty seeking, persistence, and self-directedness, although both were significantly and positively associated with each other. Conclusion These findings support our hypothesis and suggest that anxious temperament may have 'depressive proneness' whereas harm avoidance may have 'passive proneness.'

Cyclothymic temperament possesses a central dimension that includes rapid fluctuations in mood and emotional instability, and it is regarded as a prodromal state of bipolar disorder. The aim of the present study is to explore the neural correlates of cyclothymic temperament. We used the data of 55 healthy participants in our previous study and analyzed the association between cyclothymic temperament scores rated by the Temperament Evaluation of Memphis, Pisa, Paris and San Diego-Autoquestionnaire (TEMPS-A) and the uptake of [18F]-FDG measured by positron emission tomography (PET). A whole brain analysis revealed a cluster of [18F]-FDG uptake significantly and positively associated with cyclothymic temperament scores, located in the right superior parietal lobule (SPL). Even after adjustment for relevant factors, there remained a significant cluster of [18F]-FDG uptake with cyclothymic temperament scores in the right SPL. In ROI analyses, there were similar significant peaks in the right SPL in association with cyclothymic temperament scores. These findings suggest that the right superior parietal lobule may be one of the neural correlates of cyclothymic temperament.

Several epidemiological studies have shown the inverse association of lithium levels in drinking water and suicide rates; however, it is necessary to perform a clinical study dealing with individual patients. We analyzed 199 patients including 31 patients with suicide attempts, 21 patients with self-harm, and 147 control patients. All were transferred to a university emergency department suffering from intoxication or injury, were aged 20 or more years, and were alive at the start of the study. The exclusion criteria consisted of suffering from schizophrenia and a past or present history of lithium therapy. These exclusions were applied because it is difficult to determine whether their suicide attempt was induced by the intent to end their life or by psychotic symptoms such as auditory hallucinations, and if the patient had received lithium therapy, the association between the small amount of lithium taken from drinking water and food and serum lithium levels cannot be detected. There was a significant difference (p = 0.043) between the three groups whereby patients with suicide attempts had significantly lower lithium levels than control patients (p = 0.012) in males but not females. Multivariate logistic regression analysis with adjustment for age and gender revealed that patients with suicide attempts had significantly lower lithium levels than control patients (p = 0.032, odds ratio 0.228, 95% CI 0.059–0.883). The limitations of the present study are the nature of observational research which cannot reveal a causal relationship and the relatively small number of subjects. The present findings suggest that higher serum lithium levels may be protective against suicide attempts in lithium therapy-naive individuals.

Radiocesium isotopes were released into the environment in the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, which resulted from the massive Tohoku earthquake in March 2011. Lake Inba is located in Chiba Prefecture about 200 km from the FDNPP site and the lake was contaminated by radioactivity from the accident. The present work was carried out in order to investigate the vertical distributions and accumulations of radiocesium and Pu in sediment cores collected during 2011–2015, and to study the migration behaviors of radiocesium and Pu isotopes in the sediments. The observed 134Cs/137Cs activity ratios in the core samples were approximately 1 (decay-corrected to 15 March, 2011), suggesting that sediment samples were contaminated by the FDNPP-released radiocesium. Compared with radiocesium inventories in soil in the area surrounding the Lake Inba, the calculated higher radiocesium inventories of the collected sediment cores indicated that most of the radiocesium was subsequently accumulated in the lake, and that the radiocesium input by atmospheric deposition and input from surrounding soil were greater than the output of the radiocesium. The 239+240Pu activities in the sediments were all within the background level seen before the accident. The atom ratios of 240Pu/239Pu ranged from 0.175 to 0.210, suggesting that Pu originated from global stratospheric fallout rather than from the FDNPP accident.

Objectives: Mindfulness is a method of training the regulation of attention with non-judgmental acceptance that is linked to beneficial effects on health. The existential approach supports the uniqueness of each individual and helps to provide meaning to their lives. In this randomized controlled trial, we examined whether mindfulness-based intervention (MBI) and the existential approach could be combined sequentially and whether they operated antagonistically or cooperatively. Methods: One hundred thirty-seven participants aged 20 years or older without any severe mental disorders were randomly assigned (1:1), via an envelope method, to receive either 8-week MBI (N = 68) or 4-week MBI followed by 4-week existential approach (EXMIND) (N = 69). Participants were first allocated to a waiting-list group and subsequently randomized to the MBI group or EXMIND group. The primary outcome was self-compassion scale (SCS) total scores at 0, 4, and 8 weeks during intervention or waiting. The analyses were performed by linear mixed models for both primary and secondary outcomes following the intention-to-treat principle. Results: Both MBI and EXMIND groups had significantly increased SCS total scores compared to those of the waiting group, with mean SCS total scores of 2.3 (SD 3.0) in the MBI group and 2.1 (2.9) in the EXMIND group versus 0.3 (2.2) in the waiting group. Conclusions: Our findings suggest that MBI followed by existential approach are not antagonistic and may have cooperative effects, suggesting that EXMIND may be a useful treatment.

We have investigated the redistribution dynamics of radiocesium deposited after the nuclear power station accident in March 2011 in a forested catchment located in North Fukushima over a four-year period (2012–2015). At the catchment scale, 137 Cs accumulation decreased drastically by 50% of the estimated initial accumulation during the first 2 years. Cs-137 accumulation in the forest floor occurred in the litter layers and the surface part of mineral soils and have accounted for about 90% of the total catchment scale accumulation. The internal 137Cs cycle among the soil-plant system was also identified as a retention mechanism and was biologically dynamic. Monitoring the decreasing and retaining mechanisms of radioactivity at the ecosystem scale will be required for effective forest and water resource management.

Radiocesium (134 Cs and 137 Cs) in mushrooms has been a matter of public concern after the accident at Fukushima Daiichi Nuclear Power Plant. To minimize the internal dose by ingestion of cultivated mushrooms, the Japanese government set a guideline level with respect to the radiocesium concentration in bed-logs and mushroom beds; however, the effects of indoor and outdoor cultivation methods on radiocesium concentrations in cultivated mushrooms were not clear.; Results: The effects of indoor and outdoor cultivation on the radiocesium concentrations in mushroom were examined using published food monitoring data. 137 Cs concentration data in Lentinula edodes from the Aizu area in Fukushima Prefecture and seven prefectures outside Fukushima were used for the analysis. No statistically significant 137 Cs concentration differences were found between these two cultivation methods. Using detected 137 Cs data in shiitake, the geometric means from each prefecture were less than one-quarter of the standard limit (100 Bq kg-1 ) for total radiocesium under both cultivation conditions.; Conclusion: It was suspected that re-suspended radiocesium might have been taken up by mushrooms or that radiocesium might have been absorbed into the mushrooms from the soil in the outdoor cultures. However, neither effect was significant for cultivated mushrooms in the areas examined. © 2016 Society of Chemical Industry.; © 2016 Society of Chemical Industry.