【背景】近年、歯周炎や歯肉炎に関連する嫌気性グラム桿菌であるFusobacterium nucleatum (F. nucleatum) は大腸がんの発生や進行に関与することが報告されている。この菌の制御が大腸がんの予防につながる可能性があると考え、深紫外線発光ダイオード (DUV-LED) によるF. nucleatumの殺菌効果を検討した。【方法】DUV-LEDのF. nucleatumに対する殺菌効果を定性的、定量的に評価した。ピーク波長が265nmと280nmの2種類のDUV-LEDを使用した。F. nucleatumのDNAに対するダメージは、シクロブタンピリミジン二量体(CPD)とピリミジンピリミドン光生成物 (6-4PP) の生成で評価した。【結果】DUV-LEDでの265nmまたは280nmの波長を3分間照射したところ、コロニーの成長は観察されなかった。265nmのDUV-LED光照射下におけるF. nucleatumの生存率は10秒照射で0.0014%、20秒照射で0%に低下した。同様に、280nmのDUV-LED光照射では，10秒照射で0.00044%、20秒照射で0%に低下した。DUV-LEDから35mmの距離での放射照度は、265nmのLEDで0.265mW/cm^2、280nmのLEDでは0.415mW/cm^2であった。従って、致死量を示す放射エネルギーは265nm LEDは5.3mJ/cm^2、280nm LEDは8.3mJ/cm^2であった。265nmと280nmのDUV-LED光をF. nucleatumに照射した際のCPDと6-4PPの量はそれぞれ6.548ng/μg、1.333ng/μgであった。【結論】DUV-LED光は、F. nucleatumに対して、ピリミジン二量体を形成することにより殺菌効果を発揮した。

前身に投与された治療薬が脳組織実質に到達するには、神経組織の血管により形成される血液脳関門を通過する必要がある。そのため、組織への損傷を最小限に抑えて血液脳関門を開くことができれば、難治性神経疾患の治療法開発に大きな進展をもたらすことが期待される。本研究では、血液脳関門を形成する血管内皮細胞に発現するBasiginに着目し、その内因性リガンドであるCyclophilin A (CypA) を用いて、血液脳関門機能を人為的に制御することを目的とした。マウス脳血管内皮細胞株を用いたin vivo解析により、CypAの投与がBasiginを介して血液脳関門機能を低下させること、それにより脳実質へ効率的に薬物を送達できることを示した。単層培養された血管内皮細胞において、CypAはタイト結合構成分子の一つであるClaudin-5を一過性かつ可逆的に細胞膜から消失させて、バリアー機能を低下させることを見出した。また、マウスへのCypAの単回静脈内投与では血液脳関門が一定期間開いた後、自発的に元の状態へ回復することが示され、そしてその限定された機関において、全身投与された水溶性薬物Doxorubicinが脳組織実質へ送達されることが明らかとなった。本研究の結果は、CypAの静脈内投与によって、脳実質への薬物送達を自在にコントロールできることを示しており、難治性神経疾患に対する治療法確立に向けた重要な成果であると考えられる。

The hippocampal dentate gyrus has been identified to play a critical role in maintaining contextual memory in many mammalian species. To evaluate learning-induced synaptic plasticity of granule cells, we subjected male rats to an inhibitory avoidance (IA) task and prepared acute hippocampal slices. In the presence of 0.5 µM tetrodotoxin, we recorded miniature EPSCs in male rats experiencing four groups: untrained, IA-trained, unpaired, and walk-through. Compared with the untrained, IA-trained, unpaired, and walk-through groups, the unpaired group significantly enhanced mean mEPSC amplitudes, suggesting the experience-induced plasticity at AMPA receptor-mediated excitatory synapses. For inhibitory synapses, both unpaired and walk-through groups significantly decreased mean mIPSC amplitudes, showing the experience-induced reduction of postsynaptic GABA_A receptor-mediated currents. Unlike the plasticity at CA1 synapses, it was difficult to explain the learning-specific plasticity at the synapses. However, overall multivariate analysis using four variables of mE(I)PSC responses revealed experience-specific changes in the diversity, suggesting that the diversity of excitatory/inhibitory synapses onto granule cells differs among the past experience of animals include the learning. In comparison with CA1 pyramidal neurons, granule cells consistently showed greater amplitude and frequency of mE(I)PSCs. Fluctuation analysis further revealed that granule cells provide more postsynaptic AMPA receptor channels and greater single-channel current of GABA_A receptors of than CA1 pyramidal neurons. These findings show functional differences between two types of principal cells in the hippocampus.

Cardiovascular diseases are the leading cause of mortality and disability worldwide. We have previously found that sphingosylphorsphorylcholine (SPC) is the key molecule leading to vasospasm. We have also identified the SPC/Src family protein tyrosine kinase Fyn/Rho-kinase (ROK) pathway as a novel signaling pathway for Ca^{2+}-sensitization of vascular smooth muscle (VSM) contraction. The present study aimed to investigate whether hesperetin can inhibit the SPC-induced contraction with little effect on 40 mM K^+-induced Ca^{2+}-dependent contraction and to elucidate the underlying mechanisms. Hesperetin significantly inhibited the SPC-induced contraction of porcine coronary artery smooth muscle strips with little effect on 40 mM K^+-induced contraction. Hesperetin blocked the SPC-induced translocation of Fyn and ROK from the cytosol to the membrane in human coronary artery smooth muscle cells (HCASMCs). SPC decreased the phosphorylation level of Fyn at Y531 in both VSMs and HCASMCs and increased the phosphorylation levels of Fyn at Y420, myosin phosphatase target subunit 1 (MYPT1) at T853 and myosin light chain (MLC) at S19 in both VSMs and HCASMCs, which were significantly suppressed by hesperetin. Our results indicate that hesperetin inhibits the SPC-induced contraction at least in part by suppressing the Fyn/ROK pathway, suggesting that hesperetin can be novel drug to prevent and treat vasospasm.

　本研究では、小児期（幼児期、学童期、青年期）の生活習慣、遺伝要因と肥満との関連を調査し、肥満予防のための公衆衛生的アプローチを検討した。食物繊維摂取が学童期の子どもの肥満および血圧、血中脂質パラメーターに及ぼす影響を明らかにすること（調査1：10～11歳の横断研究）、FT0遺伝子多型が幼児期から青年期の体格変化に及ぼす影響を明らかにすること（調査2：3歳、10歳、13歳に渡る縦断研究）、さらに、学童期から青年期にかけて身体活動がFT0遺伝子多型と体格変化に及ぼす影響を明らかにすること（調査3：13歳、18歳に渡る縦断研究）、を本研究の目的とした。 　調査1では、学童期の食物繊維摂取は肥満およびコレステロール高値のリスク低減に有効であることが示唆された。 　調査2では、幼児期から学童期にかけてFT0遺伝子の影響が強く表れ、中学生の年代になるとこの影響は逆に減弱し、部活動等が始まるこの時期の身体活動の影響が関連している可能性があることが推測された。 　調査3では、青年期で、身体活動量が多いほどBMIの増加を弱め、FT0遺伝子多型の影響を減弱させた。 　本論文の構成は5章からなる。 第1章では、緒言として、研究の背景と本研究の目的を述べる。 第2章では、食物繊維摂取が学童期の子どもの肥満および血圧、血中脂質パラメーターに及ぼす影響を検討した。 第3章では、FT0遺伝子多型が幼児期から青年期の体格変化に及ぼす影響を検討した。 第4章では、身体活動がFT0遺伝子多型と体格変化に及ぼす影響について検討した。 第5章では、結言として、本研究のまとめと今後の研究の方向性、今後の展望を述べた。

With the deterioration of bridges as social infrastructure, appropriate maintenance and life extension are required. However, aging degradation of individual bridges is not the same. Since traffic volume and bridge environment are different for each bridge, the degree of deterioration of the bridge is also different. Therefore, it is necessary to identify and eliminate the cause of individual deterioration and to take appropriate measures. This paper focuses on weathering steel bridge that the formation of dense rust is greatly influenced by the environment. The purpose of this study is to clarify the effect of anticorrosion by the environmental improvement which covers the whole steel girder with the metal sandwich panel for weathering steel bridge. Since the space in the girder covered with the metal sandwich panel cannot be expected to have the effect of washing by rainwater or drying and wetting by the flow of wind, the adoption of the metal sandwich panel for weatherproof steel bridge has not been judged until now. In this thesis, the corrosion behavior of weathering steel and the effectiveness of corrosion protection are shown by exposure test, and the corrosion protection effect of environmental improvement by metal sandwich panel is clarified. In addition, this study examines the economical advantages by the metal sandwich panel installation by calculating the life cycle cost. This paper consists of six chapters. Chapter 1 describes the background and purpose of this research. Chapter 2 summarizes previous studies on corrosion protection methods used in steel bridges. In Chapter 3, exposure tests were conducted inside and outside the metal sandwich panel and the following finding were obtained. 1) In the girder covered with the metal sandwich panel, fluctuation range of temperature and humidity is small throughout the year, and it does not follow the sudden weather change of outside of the panel. Since the difference between the temperature and dew point in the panel is large, the wet time in the panel is suppressed to 1/5 or less of the wet time of outside the panel. 2) At the structure which has thin floor slab and low height girder, the temperature rise in the panel may be unavoidable depending on season. However, since the humidity in the panel is low and the wet time is also greatly reduced, the anticorrosive effect can be expected in the steel bridge including the weathering steel bridge. 3) Amount of air born salt into the panel after the metal sandwich panel installation was not detected. In Chapter 4, a small test specimen was placed in the inside space of the steel girder, and the transition of corrosion, anticorrosion effect by environmental improvement and inner surface painting were examined. 1) The untreated steel and the uncoated steel in the ingrown rust region evaluated by the ion permeation resistance method are kept almost same condition after five years. 2) It is also conceivable that the initial salinity of the steel material subjected to the substrate adjustment by blasting exists even after the substrate adjustment, and that the adhering salinity penetrates into the inside of the steel plate at the time of rust formation. However, the increase rate of rust thickness due to aging is slow, and a method of installing a metal sandwich panel after blasting is also effective. 3) Although the effect of environmental isolation from outside the girder was confirmed, it became clear that it was difficult to completely suppress the progress of rust. Chapter 5 examined the economic effects of installing metal sandwich panels on new girders from the beginning and installing them on overbridges 50 years after the star of service. 1) If repainting is required even 1 time during the during the design service period of 100 years, the anticorrosion method by environmental improvement of the metal sandwich panel is economically superior. 2) Accumulating the cost of close visual inspection (for 50 years) of the overbridge that has been in service for 50 years increases the maintenance cost. Chapter 6 summarizes this research and describes future issues.

ダイアモンド・ブラックファン貧血 (Diamond–Blackfan anemia : DBA) は, リボゾーム蛋白異常によって生じる赤芽球癆で, 新生児期の貧血および一部で身体奇形を合併する. 臨床的特徴が多様で, 原因となるリボゾーム蛋白遺伝子も多数存在するため, 新生児期にDBAと確定診断し, 適切な治療を行うことが困難である. 本研究では, 全エクソーム解析 (whole-exome sequencing; WES) を用いて最終診断した3組の母子例について報告する. 貧血の重症度や治療反応性は各母子間で異なり, 低身長, 翼状頸, 母指球形成不全などの特徴的な身体奇形を認めた症例は, 母1名のみだった. この母はRPL11 (exon 2, c.58_59del) のフレームシフト変異があり, 子は一過性の新生児貧血を認めたがリボゾーム蛋白遺伝子の変異はなかった. 他の2組の母子では, それぞれRPS19 (exon 4, c.185G>A) のミスセンス変異とRPS7のスプライシング変異 (exon 3, c.76-1G>T) を同定した. それぞれの変異と別に, 貧血を来し得る遺伝子変異はなかった. 本研究は, WESがヒトリボゾーム病の迅速かつ正確な診断を得るために有用であることを示唆した.

The reduction of excessive discharge of phosphate into water bodies is a dominant theme to combat the critical eutrophication issue and requires the development of high-performance materials for effective phosphate treatment. In this study, rice straw was used as a raw material for the synthesis of biochar functionalized with layered double hydroxides (BC-LDHs) as efficacious phosphate adsorbents, and their successful synthesis was corroborated via characterization analysis. Experimental investigations, including pH, coexisting anion, reaction time, and initial phosphate concentration effects were systematically performed with selected BC-LDHs 6 and pure LDHs. An optimum pH of 3.0 was observed in both samples. Kinetic and isotherm studies indicated that phosphate adsorption on these samples was controlled by the pseudo-second-order model and the Freundlich model. Comparative kinetic tests also demonstrated that BC-LDHs 6 and pure LDHs reached the equilibrium within 24 h and 3 h, respectively. Nonetheless, the maximum adsorption capacity of the composite was 192 mg/g, which was higher than that of pure LDHs (166 mg/g). The coexistence of various anions negligibly affected the removal efficiency of the composite; however, fluoride was the most competitive anion for adsorption on pure LDHs. The adsorption mechanisms of the composite involved electrostatic interaction, inner-sphere complexation, pore diffusion, precipitation, and reconstruction. Furthermore, phosphate adsorbed on both materials could be easily recovered by 0.1 M NaOH solution owing to the displacement reaction between phosphate and hydroxyl ions. Additional evidence from reusability experiments exhibited that the composite could maintain its good adsorption performance even after three adsorption-desorption cycles. The transformation of BC-LDHs 6 after its usage in phosphate treatment (P-BC-LDHs 6) into a fertilizer was further explored by using seed germination and early growth assays of lettuce through a comparison with phosphate-loaded LDHs (P-LDHs). Lettuce seeds germinated in all P-BC-LDH 6 treatments showed undesirable growth characteristics compared with the controls, while total germination failure was observed under high concentrations of P-LDHs. In the latter experiments, the optimal application rates for plant growth were 2.5% for P-BC-LDHs 6 and 1.0% for P-LDHs. The considerably greater biomass development and length of lettuce were visible in samples delivered from P-BC-LDHs 6 compared to those from P-LDHs. The results obtained suggest that BC-LDHs 6 is a promising adsorbent for phosphate treatment and post-adsorption BC-LDHs 6 has the application potential to serve as a fertilizer for horticultural crop production.

Phosphorus is an indispensable nutrient to sustain the daily life of all living things on Earth. However, the over-enrichment of the aquatic ecosystem with phosphorus leads to eutrophication, which is still a global environmental problem. More stringent regulations have been put in place for the limit of phosphorus discharge to address this problem and resulted in the removal of phosphorus removal becomes exceptionally crucial. Furthermore, phosphorus deposits are a non-renewable resource and forecasted to deplete until 2170, given the current usage and global population growth. Thus, the removal of phosphorus coupled with the recovery and reuse of phosphorus offer the best strategies to meet the future phosphorus demand. Accordingly, adsorption represents a fascinating separation technique for phosphate from water because of the possibility of phosphorus recovery. Moreover, this approach has many advantages, such as efficient, easy operating conditions, low sludge production, and the possibility of regenerating the adsorbent. Numerous attractive low-cost adsorbents have been studied for phosphate removal, one of which is layered double hydroxides (LDH). Unfortunately, a high phosphate adsorption capacity of LDH can generally be achieved by calcination, which increases the preparation cost of LDH. In this study, LDH is functionalized with amorphous zirconium (hydr)oxide to obtain enhanced adsorption capacity and eliminate the high-temperature requirement during the synthesis process. Although different treatment techniques have been developed to eliminate phosphorus contamination, including for wastewater treatment, treated water often fails to meet quality regulations. Amorphous zirconium (hydr)oxide/MgFe layered double hydroxides composites (am-Zr/MgFe-LDH) with different molar ratios (Zr/Fe = 1.5 2) were prepared in two-stage synthesis by the combination of coprecipitation and hydrothermal methods. The synthesis of the composite could eliminate the requirement of high-temperature calcination in the LDH for phosphate adsorption. Moreover, the phosphate adsorption ability of the composite was higher than that of the individual LDH and amorphous zirconium (hydr)oxide. The presence of amorphous zirconium (hydr)oxide increased the phosphate adsorption ability of composite at low pH. The adsorption capacity was increased by decreasing the pH and increasing the temperature (from 290 to 324 K). The bicarbonate (HCO3 ) was the most competitive anion for phosphate adsorption. The pseudo-secondorder model provided the best description of the kinetic adsorption data. Furthermore, the adsorbed phosphate was easily desorbed by 1 N and reused 2 N of NaOH solutions. The results suggest that the am-Zr/MgFe-LDH composite is a promising material for phosphate removal and recovery from wastewater. A Fixed-bed column has been considered an industrially feasible technique for phosphate removal from water. Besides the adsorption capacity, the effectiveness of an adsorbent is also determined by its reusability efficiency. In this study, phosphate removal by a synthesized am-Zr/MgFe-LDH in a fixed-bed column system was examined. The results showed that the increased bed height and phosphate concentration, and reduced flow rate, pH, and adsorbent particle size were found to increase the column adsorption capacity. The optimum adsorption capacity of 25.15 mg-P g^{-1} was obtained at pH 4. The coexistence of seawater ions had a positive effect on the phosphate adsorption capacity of the composite. Nearly complete phosphate desorption, with a desorption efficiency of 91.7%, could be effectively achieved by 0.1 N NaOH for an hour. Moreover, the initial adsorption capacity was maintained at approximately 83% even after eight adsorption-desorption cycles, indicating that the composite is economically feasible. The am-Zr/MgFe-LDH, with its high adsorption capacity and superior reusability, has the potential to be utilized as an adsorbent for phosphorus removal in practical wastewater treatment. The possible adsorption mechanisms of phosphate by am-Zr/MgFe-LDH were investigated via X-ray diffraction (XRD), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), and pH at the point of zero charge (pHPZC) analyses. It was suggested that the high phosphate adsorption capacity of the composite involves three main adsorption mechanisms, which are the electrostatic attraction, inner-sphere complexation, and anion exchange, where the amorphous zirconium (hydr)oxide on the surface of the layered double hydroxides likely increased the number of active binding sites and surface area for adsorption. This study provides insights into the design of am-Zr/MgFe- LDH for phosphorus removal and recovery in a practical system.