Low visual information-processing speed and attention are predictors of fatigue in elementary and junior high school students

Background: Fatigue is a common complaint among elementary and junior high school students, and is known to be associated with reduced academic performance. Recently, we demonstrated that fatigue was correlated with decreased cognitive function in these students. However, no studies have identified cognitive predictors of fatigue. Therefore, we attempted to determine independent cognitive predictors of fatigue in these students.Methods: We performed a prospective cohort study. One hundred and forty-two elementary and junior high school students without fatigue participated. They completed a variety of paper-and-pencil tests, including list learning and list recall tests, kana pick-out test, semantic fluency test, figure copying test, digit span forward test, and symbol digit modalities test. The participants also completed computerized cognitive tests (tasks A to E on the modified advanced trail making test). These cognitive tests were used to evaluate motor-and information-processing speed, immediate and delayed memory function, auditory and visual attention, divided and switching attention, retrieval of learned material, and spatial construction. One year after the tests, a questionnaire about fatigue (Japanese version of the Chalder Fatigue Scale) was administered to all the participants.Results: After the follow-up period, we confirmed 40 cases of fatigue among 118 students. In multivariate logistic regression analyses adjusted for grades and gender, poorer performance on visual information-processing speed and attention tasks was associated with increased risk of fatigue.Conclusions: Reduced visual information-processing speed and poor attention are independent predictors of fatigue in elementary and junior high school students

Index markers of chronic fatigue syndrome with dysfunction of TCA and urea cycles

Chronic fatigue syndrome (CFS) is a persistent and unexplained pathological state characterized by exertional and severely debilitating fatigue, with/without infectious or neuropsychiatric symptoms, lasting at least 6 consecutive months. Its pathogenesis remains incompletely understood. Here, we performed comprehensive metabolomic analyses of 133 plasma samples obtained from CFS patients and healthy controls to establish an objective diagnosis of CFS. CFS patients exhibited significant differences in intermediate metabolite concentrations in the tricarboxylic acid (TCA) and urea cycles. The combination of ornithine/citrulline and pyruvate/isocitrate ratios discriminated CFS patients from healthy controls, yielding area under the receiver operating characteristic curve values of 0.801 (95% confidential interval [CI]: 0.711–0.890, P < 0.0001) and 0.750 (95% CI: 0.584–0.916, P = 0.0069) for training (n = 93) and validation (n = 40) datasets, respectively. These findings provide compelling evidence that a clinical diagnostic tool could be developed for CFS based on the ratios of metabolites in plasma

日本の児童生徒における疲労関連症状出現の予測因子としての気質・性格の検討 - 1年間の追跡調査

京都大学0048新制・課程博士博士(社会健康医学)甲第15278号社医博第31号新制||社医||6(附属図書館)27756京都大学大学院医学研究科社会健康医学系専攻(主査)教授 川村 孝, 教授 佐藤 俊哉, 教授 松林 公蔵学位規則第4条第1項該当Doctor of Public HealthKyoto UniversityDA

Isolation and characterization of mutants defective in the localization of LCIB, an essential factor for the carbon-concentrating mechanism in Chlamydomonas reinhardtii.

The unicellular green alga Chlamydomonas reinhardtii acclimates to low-CO2 (LC) conditions by actively transporting inorganic carbon (Ci) into the cell, resulting in an increase in photosynthetic efficiency. This mechanism is called the carbon-concentrating mechanism (CCM), and soluble protein LCIB is essential for the CCM. LCIB is localized in the vicinity of pyrenoid, a prominent structure in the chloroplast, under LC conditions in the light. In contrast, in the dark or in high-CO2 conditions, where the CCM is inactive, LCIB diffuses away from the pyrenoid. Although the functional importance of LCIB for the CCM has been shown, the significance and mechanism of the change in suborganellar localization of LCIB remain to be elucidated. In this study, we screened 13, 000 DNA-tagged mutants and isolated twelve aberrant LCIB localization (abl) mutants under LC conditions. abl-1 and abl-3 with dispersed and speckled localization of LCIB in the chloroplast showed significant decreases in Ci affinity, Ci accumulation, and CO2 fixation. Ten abl mutants (abl-1, abl-3, abl-4, abl-5, abl-6, abl-7, abl-8, abl-9, abl-11, and abl-12) showed not only aberrant LCIB localization but also reduced pyrenoid sizes. Moreover, three abl mutants (abl-10, abl-11, and abl-12) showed the increased numbers of pyrenoids per cell. These results suggested that the specific LCIB localization could be related to pyrenoid development

Characterization of cooperative bicarbonate uptake into chloroplast stroma in the green alga Chlamydomonas reinhardtii.

藻類の光合成を支える二酸化炭素濃縮システムを解明. 京都大学プレスリリース. 2015-05-27.The supply of inorganic carbon (Ci; CO2 and HCO3 (-)) is an environmental rate-limiting factor in aquatic photosynthetic organisms. To overcome the difficulty in acquiring Ci in limiting-CO2 conditions, an active Ci uptake system called the CO2-concentrating mechanism (CCM) is induced to increase CO2 concentrations in the chloroplast stroma. An ATP-binding cassette transporter, HLA3, and a formate/nitrite transporter homolog, LCIA, are reported to be associated with HCO3 (-) uptake [Wang and Spalding (2014) Plant Physiol 166(4):2040-2050]. However, direct evidence of the route of HCO3 (-) uptake from the outside of cells to the chloroplast stroma remains elusive owing to a lack of information on HLA3 localization and comparative analyses of the contribution of HLA3 and LCIA to the CCM. In this study, we revealed that HLA3 and LCIA are localized to the plasma membrane and chloroplast envelope, respectively. Insertion mutants of HLA3 and/or LCIA showed decreased Ci affinities/accumulation, especially in alkaline conditions where HCO3 (-) is the predominant form of Ci. HLA3 and LCIA formed protein complexes independently, and the absence of LCIA decreased HLA3 mRNA accumulation, suggesting the presence of unidentified retrograde signals from the chloroplast to the nucleus to maintain HLA3 mRNA expression. Furthermore, although single overexpression of HLA3 or LCIA in high CO2 conditions did not affect Ci affinity, simultaneous overexpression of HLA3 with LCIA significantly increased Ci affinity/accumulation. These results highlight the HLA3/LCIA-driven cooperative uptake of HCO3 (-) and a key role of LCIA in the maintenance of HLA3 stability as well as Ci affinity/accumulation in the CCM

The neural mechanisms of re-experiencing mental fatigue sensation: a magnetoencephalography study.

There have been several studies which have tried to clarify the neural mechanisms of fatigue sensation; however fatigue sensation has multiple aspects. We hypothesized that past experience related to fatigue sensation is an important factor which contributes to future formation of fatigue sensation through the transfer to memories that are located within specific brain structures. Therefore, we aimed to investigate the neural mechanisms of fatigue sensation related to memory. In the present study, we investigated the neural activity caused by re-experiencing the fatigue sensation that had been experienced during a fatigue-inducing session. Thirteen healthy volunteers participated in fatigue and non-fatigue experiments in a crossover fashion. In the fatigue experiment, they performed a 2-back test session for 40 min to induce fatigue sensation, a rest session for 15 min to recover from fatigue, and a magnetoencephalography (MEG) session in which they were asked to re-experience the state of their body with fatigue that they had experienced in the 2-back test session. In the non-fatigue experiment, the participants performed a free session for 15 min, a rest session for 15 min, and an MEG session in which they were asked to re-experience the state of their body without fatigue that they had experienced in the free session. Spatial filtering analyses of oscillatory brain activity showed that the delta band power in the left Brodmann's area (BA) 39, alpha band power in the right pulvinar nucleus and the left BA 40, and beta band power in the left BA 40 were lower when they re-experienced the fatigue sensation than when they re-experienced the fatigue-free sensation, indicating that these brain regions are related to re-experiencing the fatigue sensation. Our findings may help clarify the neural mechanisms underlying fatigue sensation

Involvement of the olfactory system in the induction of anti-fatigue effects by odorants

<div><p>Some components of the neural circuits underlying innate odor-evoked responses have recently been elucidated. Odor information detected by the olfactory receptors is transmitted from the olfactory bulb to the cortical amygdala, where physiological and emotional states such as attraction or avoidance are controlled. Thus, activation of specific olfactory receptors can elicit changes in physiological and/or psychological state. Here, we examined on the odorant Hex-Hex Mix, which has been reported to induce anti-fatigue effects. Fatigue is a prevalent condition that is often related to overwork and psychological stress. Various anti-fatigue treatments have been developed, including supplements and odorants. However, the mechanisms underlying the anti-fatigue effects of these substances are currently unclear. In the present study, we analyzed the involvement of the olfactory system in the mechanisms underlying this effect. We identified the human olfactory receptors activated by Hex-Hex Mix, and evaluated whether activation of these olfactory receptors by a newly developed odorant elicited a similar anti-fatigue effect to Hex-Hex Mix. We assessed anti-fatigue effects with behavioral tests, and 17 healthy males performed the 2-back test as a fatigue-inducing task with or without exposure to the new odorant. Immediately before and after the task, participants performed a cognitive task to evaluate their level of mental fatigue. We found that the difference value of the correct response rate on the cognitive task in the evaluation session was significantly different between in the odorant condition and in the without-odorant condition during the fatigue-inducing session suggesting that the new odorant may improve performance in the fatigue-inducing condition. The results indicated that the new odorant activates the same olfactory receptors as Hex-Hex Mix, which has been reported to induce anti-fatigue effects. Our findings suggest that the olfactory receptors in the olfactory system may be involved in the attenuation of fatigue.</p></div