129 research outputs found

    Selective loss of GABAB receptors in orexin/hypocretin-producing neurons results in disrupted sleep/wakefulness architecture

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    We generated mice with a selective loss of GABAB receptors in orexin neurons. Orexin neurons in these GABAB1<sup>-/-(orexin)</sup> mice showed reduced responsiveness to GABA<sub>A</sub> receptor agonists due to a compensatory increase in GABAA receptor-mediated inhibition. This increased GABA<sub>A</sub> receptor-mediated inhibition of orexin neurons is due to orexin-1 receptor-mediated activation of local GABAergic interneurons. Surprisingly, orexin neurons were also less responsive to glutamate, apparently because the augmented GABA<sub>A</sub> receptor-mediated inhibition increases the membrane conductance and shunts excitatory currents. These observations indicate that absence of GABA<sub>B</sub> receptors decreases the sensitivity of orexin neurons to both excitatory and inhibitory inputs. GABAB1<sup>-/-(orexin)</sup>mice exhibited severe fragmentation of sleep/wake states during both the light and dark periods without affecting total sleep time or inducing cataplexy, indicating that GABA<sub>B</sub> receptors are crucial regulators of orexin neurons and that "fine tuning" of orexin neurons by inhibitory and excitatory inputs is important for the stability of sleep/waking states

    Increase of nitrosative stress in patients with eosinophilic pneumonia

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    <p>Abstract</p> <p>Background</p> <p>Exhaled nitric oxide (NO) production is increased in asthma and reflects the degree of airway inflammation. The alveolar NO concentration (Calv) in interstitial pneumonia is reported to be increased. However, it remains unknown whether NO production is increased and nitrosative stress occurs in eosinophilic pneumonia (EP). We hypothesized that nitrosative stress markers including Calv, inducible type of NO synthase (iNOS), and 3-nitrotyrosine (3-NT), are upregulated in EP.</p> <p>Methods</p> <p>Exhaled NO including fractional exhaled NO (FE<sub>NO</sub>) and Calv was measured in ten healthy subjects, 13 patients with idiopathic pulmonary fibrosis (IPF), and 13 patients with EP. iNOS expression and 3-NT formation were assessed by immunocytochemistory in BALf cells. The exhaled NO, lung function, and systemic inflammatory markers of the EP patients were investigated after corticosteroid treatment for 4 weeks.</p> <p>Results</p> <p>The Calv levels in the EP group (14.4 ± 2.0 ppb) were significantly higher than those in the healthy subjects (5.1 ± 0.6 ppb, p < 0.01) and the IPF groups (6.3 ± 0.6 ppb, p < 0.01) as well as the FE<sub>NO </sub>and the corrected Calv levels (all p < 0.01). More iNOS and 3-NT positive cells were observed in the EP group compared to the healthy subject and IPF patient. The Calv levels had significant positive correlations with both iNOS (r = 0.858, p < 0.05) and 3-NT positive cells (r = 0.924, p < 0.01). Corticosteroid treatment significantly reduced both the FE<sub>NO </sub>(p < 0.05) and the Calv levels (p < 0.01). The magnitude of reduction in the Calv levels had a significant positive correlation with the peripheral blood eosinophil counts (r = 0.802, p < 0.05).</p> <p>Conclusions</p> <p>These results suggested that excessive nitrosative stress occurred in EP and that Calv could be a marker of the disease activity.</p

    Evaluating the Safety of Simultaneous Intracranial Electroencephalography and Functional Magnetic Resonance Imaging Acquisition Using a 3 Tesla Magnetic Resonance Imaging Scanner

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    Background: The unsurpassed sensitivity of intracranial electroencephalography (icEEG) and the growing interest in understanding human brain networks and ongoing activities in health and disease have make the simultaneous icEEG and functional magnetic resonance imaging acquisition (icEEG-fMRI) an attractive investigation tool. However, safety remains a crucial consideration, particularly due to the impact of the specific characteristics of icEEG and MRI technologies that were safe when used separately but may risk health when combined. Using a clinical 3-T scanner with body transmit and head-receive coils, we assessed the safety and feasibility of our icEEG-fMRI protocol. Methods: Using platinum and platinum-iridium grid and depth electrodes implanted in a custom-made acrylic-gel phantom, we assessed safety by focusing on three factors. First, we measured radio frequency (RF)-induced heating of the electrodes during fast spin echo (FSE, as a control) and the three sequences in our icEEG-fMRI protocol. Heating was evaluated with electrodes placed orthogonal or parallel to the static magnetic field. Using the configuration with the greatest heating observed, we then measured the total heating induced in our protocol, which is a continuous 70-min icEEG-fMRI session comprising localizer, echo-planar imaging (EPI), and magnetization-prepared rapid gradient-echo sequences. Second, we measured the gradient switching-induced voltage using configurations mimicking electrode implantation in the frontal and temporal lobes. Third, we assessed the gradient switching-induced electrode movement by direct visual detection and image analyses. Results: On average, RF-induced local heating on the icEEG electrode contacts tested were greater in the orthogonal than parallel configuration, with a maximum increase of 0.2°C during EPI and 1.9°C during FSE. The total local heating was below the 1°C safety limit across all contacts tested during the 70-min icEEG-fMRI session. The induced voltage was within the 100-mV safety limit regardless of the configuration. No gradient switching-induced electrode displacement was observed. Conclusion: We provide evidence that the additional health risks associated with heating, neuronal stimulation, or device movement are low when acquiring fMRI at 3 T in the presence of clinical icEEG electrodes under the conditions reported in this study. High specific absorption ratio sequences such as FSE should be avoided to prevent potential inadvertent tissue heating

    The E3 Ubiquitin Ligase Activity of Trip12 Is Essential for Mouse Embryogenesis

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    Protein ubiquitination is a post-translational protein modification that regulates many biological conditions [1], [2], [3], [4]. Trip12 is a HECT-type E3 ubiquitin ligase that ubiquitinates ARF and APP-BP1 [5], [6]. However, the significance of Trip12 in vivo is largely unknown. Here we show that the ubiquitin ligase activity of Trip12 is indispensable for mouse embryogenesis. A homozygous mutation in Trip12 (Trip12mt/mt) that disrupts the ubiquitin ligase activity resulted in embryonic lethality in the middle stage of development. Trip12mt/mt embryos exhibited growth arrest and increased expression of the negative cell cycle regulator p16 [7], [8], [9], [10]. In contrast, Trip12mt/mt ES cells were viable. They had decreased proliferation, but maintained both the undifferentiated state and the ability to differentiate. Trip12mt/mt ES cells had increased levels of the BAF57 protein (a component of the SWI/SNF chromatin remodeling complex) and altered gene expression patterns. These data suggest that Trip12 is involved in global gene expression and plays an important role in mouse development

    Physical inactivity is associated with decreased growth differentiation factor 11 in chronic obstructive pulmonary disease

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    Rie Tanaka,1 Hisatoshi Sugiura,1 Mitsuhiro Yamada,1 Tomohiro Ichikawa,1 Akira Koarai,1 Naoya Fujino,1 Satoru Yanagisawa,1 Katsuhiro Onodera,1 Tadahisa Numakura,1 Kei Sato,1 Yorihiko Kyogoku,1 Hirohito Sano,1 Shun Yamanaka,1 Tatsuma Okazaki,1 Tsutomu Tamada,1 Motohiko Miura,2 Tsuneyuki Takahashi,3 Masakazu Ichinose1 1Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai, Japan; 2Department of Respiratory Medicine, Tohoku Rosai Hospital, Aoba-ku, Sendai, Japan; 3Department of Internal Medicine, Tohoku Medical and Pharmaceutical University Wakabayashi Hospital, Wakabayashi-ku, Sendai, Japan Background: Growth differentiation factor 11 (GDF11) is reported to possess anti-aging and rejuvenating effects, including muscle regeneration and to be highly expressed in skeletal muscle. Recently, we demonstrated that the levels of plasma GDF11 were decreased in COPD. However, the effect of decreased circulating GDF11 in the pathophysiology of COPD remains unknown. The aim of this study is to investigate the association between the plasma GDF11 levels and various clinical parameters in patients with COPD. Patients and methods: Eighteen ex-smokers as control subjects and 70 COPD patients participated in the current study. We measured the levels of plasma GDF11 using immunoblotting, lung function, physical activity using a triaxial accelerometer, quadriceps strength, exercise capacity, and systemic inflammatory markers. We investigated the association between the levels of plasma GDF11 and these clinical parameters. Results: The levels of plasma GDF11 in the COPD patients had significant positive correlations with the data of lung function. Furthermore, the levels of plasma GDF11 were significantly correlated with the physical activity, quadriceps strength, and exercise capacity. Moreover, the levels of plasma GDF11 were significantly correlated with the data of inflammatory markers. Although various factors were related to GDF11, the multiple regression analysis showed that physical activity was significantly associated with the levels of plasma GDF11. Conclusion: Physical inactivity was significantly related to the decreased GDF11 levels in COPD, which might be useful for understanding the pathogenesis of COPD. Clarifying the relationships between the physical inactivity and GDF11 may reveal a potentially attractive therapeutic approach in COPD via increasing the plasma levels of GDF11. Keywords: physical activity, muscle strength, rejuvenating factor, COP

    Working report of the combined exercise program for geological and seismological surveys

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    海洋研究開発機構では高校を始めとする教育機関向けに地質学実習であるSand for Students(S4S)を2005年より実施してきた。一方で、近年推進している地震発生帯研究の成果についても教育機関や中高生向けにわかりやすく伝える機会や方法について模索してきた。そして、新たに地震探査実習を考案し(桑野他、本大会地殻構造セッションにてポスター発表)、今年度S4Sとともに実施することとした。本実習は、(独)科学技術振興機構が理科教育を推進するために運営しているサイエンス・パートナーシップ・プログラムの採択校である横浜高等学校向けに実施したものである。本発表では実際の実習内容とともにその教育的効果、および課題や今後の計画についても紹介する。  実習プログラムは7月29日(月)?8月2日(金)に実施した。それぞれ2日間の地震学実習と地質学実習を経て、最終日に生徒のとりまとめたプレゼンテーション発表までの全5日間構成となっている。地震学実習では、1日目に屈折法地震探査の実験および実習を行い、2日目に「日本列島の形成」および「海洋プレート沈み込みに伴う海溝型地震研究」をテーマとした特別セミナー、様々な海洋調査機器の見学、実際に研究で使用されている地震計の原理を紹介し、地震計や海底地震計に触れてみる体験を盛り込んだ内容とした。地質学実習は、1日目に酒匂川(丹沢)周辺で地層の観察と鉱物の採取を行い、2日目に採取した鉱物を顕微鏡で観察する内容である。  地震探査実習では、通常、地面に震動を与えることによって生じる地下を伝わる波を地震計で計測し、記録した後、研究室などに持ち帰りデータ処理、解析をすることが一般的であり、実際の研究で実施している作業プロセスと同じ内容を行うことが多い。今回の地震探査実習では、地震波計測により地下構造が明らかにできることを直感的に理解しやすくすることをねらいとし、地殻を模した寒天2層構造を用いた実験を考えた。この実験では模擬地殻物質が透明であるため光弾性を利用することで、弾性波の伝わる様子を可視化できる。さらに寒天の横波の伝播速度は数m/sと充分遅いため観察が容易になる。この実習では、地震波が伝わる様子をその場で一目で容易に観察でき、さらに観察の様子を録画し、そのデータを画像処理することで寒天模擬地殻表面の各点での振動波形を得ることもできる。この波形データは実際の屈折法地震探査データと同様に解析できるので、これを用いて寒天2層構造の速度構造を推定する演習を行う。演習を行いながら、地震探査を実施して地殻構造を推定することが、地震の発生メカニズムの解明にとって重要であることについて理解を促す。  地質学実習では、身近な河川の砂を採取して観察することで河川流域の地質を把握するとともに、河川流域の地質の成り立ちを学ぶことで、日本列島形成の重要なメカニズムである付加体形成についての理解を促している。これは同時に、河川を通じて深海底に運ばれる陸源物質を探す作業でもあり、いわば地殻を構成する物質循環の基礎調査に相当する。  本実習全体のねらいは、地震および地質調査研究に関する基礎的な科学知識・技能を普及させることである。特に、地震国である日本の地で生活する上で、身につけておいてほしい知識や技能の向上、問題の認識を目的としている。今回の実習では、講義、実験、演習、地質巡検を通じて、日本列島の形成や地震研究には地質学、地震学ともに必要であること、さらには様々な学問分野の知識が地球科学にとって重要であることを実感できるような構成とした。今回2日間で実施した地震学実習全体については、今後も実習プログラムの内容の改良、発展を加える上、地震探査実習については、実験レシピを作成して公開することも目指す。P1-36ポスター要旨, 日本地震学会2013年度秋季大会(2013年10月7日~9日, 神奈川県横浜市

    Seed-specific expression of truncated OsGAD2 produces GABA-enriched rice grains that influence a decrease in blood pressure in spontaneously hypertensive rats

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    Gamma-aminobutyric acid (GABA) is a four-carbon amino acid that is commonly present in living organisms and functions as a major inhibitory neurotransmitter in mammals. It is understood to have a potentially anti-hypertensive effect in mammals. GABA is synthesized from glutamate by glutamate decarboxylase (GAD). In plants, GAD is regulated via its calmodulin-binding domain (CaMBD) by Ca2+/CaM. We have previously reported that a C-terminal truncated version of one of the five rice GAD isoforms, GAD2ΔC, revealed higher enzymatic activity in vitro and that its over-expression resulted in exceptionally high GABA accumulation (Akama and Takaiwa, J Exp Bot 58:2699–2607, 2007). In this study, GAD2ΔC, under the control of the rice glutelin promoter (GluB-1), was introduced into rice cells via Agrobacterium-mediated transformation to produce transgenic rice lines. Analysis of the free amino acid content of rice grains revealed up to about a 30-fold higher level of GABA than in non-transformed rice grains. There were also very high levels of various free protein amino acids in the seeds. GABA-enriched rice grains were milled to a fine powder for oral administration to spontaneously hypertensive rats (SHRs) and normotensive Wistar-Kyoto rats (WKYs). Six weeks of administration showed that transgenic rice brings about a 20 mmHg decrease in blood pressure in two different kinds of SHRs, while there was no significant hypotensive effect in WKYs. These results suggest an alternative way to control and/or cure hypertension in humans with GABA-enriched rice as part of a common daily diet

    Definition and diagnosis of asthma–COPD overlap (ACO)

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    It is now widely recognized that asthma and COPD can coexist as asthma–COPD overlap (ACO), but the preliminary attempts at providing universal guidelines for the diagnosis of ACO still need to be improved. We believe that a case can be made for devising guidelines for the diagnosis of this increasingly common disease that are specific to Japan. In this paper, we present our consensus-based description of ACO which we believe is realistic for use in our country. In addition, we cite the scientific evidence for our own “objective” features used to develop the criteria for COPD and asthma diagnosis. We acknowledge that they will need to be validated and updated over time, but hope the results will encourage further research on the characteristics and treatment of this commonly encountered clinical problem. Keywords: Airway responsiveness, Allergic rhinitis, CT, Eosinophil, Exhaled N
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