多様な構造のTiO[2]膜の作製および光触媒特性に関する研究

京都大学0048新制・課程博士博士(エネルギー科学)甲第18612号エネ博第308号新制||エネ||63(附属図書館)31512京都大学大学院エネルギー科学研究科エネルギー応用科学専攻(主査)教授 平藤 哲司, 教授 馬渕 守, 教授 土井 俊哉学位規則第4条第1項該当Doctor of Energy ScienceKyoto UniversityDGA

Subchronic oral toxicity of silver nanoparticles

<p>Abstract</p> <p>Background</p> <p>The antibacterial effect of silver nanoparticles has resulted in their extensive application in health, electronic, consumer, medicinal, pesticide, and home products; however, silver nanoparticles remain a controversial area of research with respect to their toxicity in biological and ecological systems.</p> <p>Results</p> <p>This study tested the oral toxicity of silver nanoparticles (56 nm) over a period of 13 weeks (90 days) in F344 rats following Organization for Economic Cooperation and Development (OECD) test guideline 408 and Good Laboratory Practices (GLP). Five-week-old rats, weighing about 99 g for the males and 92 g for the females, were divided into four 4 groups (10 rats in each group): vehicle control, low-dose (30 mg/kg), middle-dose (125 mg/kg), and high-dose (500 mg/kg). After 90 days of exposure, clinical chemistry, hematology, histopathology, and silver distribution were studied. There was a significant decrease (P < 0.05) in the body weight of male rats after 4 weeks of exposure, although there were no significant changes in food or water consumption during the study period. Significant dose-dependent changes were found in alkaline phosphatase and cholesterol for the male and female rats, indicating that exposure to more than 125 mg/kg of silver nanoparticles may result in slight liver damage. Histopathologic examination revealed a higher incidence of bile-duct hyperplasia, with or without necrosis, fibrosis, and/or pigmentation, in treated animals. There was also a dose-dependent accumulation of silver in all tissues examined. A gender-related difference in the accumulation of silver was noted in the kidneys, with a twofold increase in female kidneys compared to male kidneys.</p> <p>Conclusions</p> <p>The target organ for the silver nanoparticles was found to be the liver in both the male and female rats. A NOAEL (no observable adverse effect level) of 30 mg/kg and LOAEL (lowest observable adverse effect level) of 125 mg/kg are suggested from the present study.</p

In-stent restenosis-prone coronary plaque composition: A retrospective virtual histology-intravascular ultrasound study

  Background: The mechanism of in-stent restenosis (ISR) is multifactorial, which includes biological, mechanical and technical factors. This study hypothesized that increased inflammatory reaction, which is known to be an important atherosclerotic process, at a culprit lesion may lead to higher restenosis rates. Methods: The study population consisted of 241 patients who had undergone percutaneous coronary intervention with virtual histology-intravascular ultrasound (VH-IVUS) and a 9-month follow-up coronary angiography. Compared herein is the coronary plaque composition between patients with ISR and those without ISR. Results: Patients with ISR (n = 27) were likely to be older (66.2 ± 9.5 years vs. 58.7 ± 11.7 years, p = 0.002) and have higher levels of high-sensitivity C-reactive protein (hs-CRP, 1.60 ± 3.59 mg/dL vs. 0.31 ± 0.76 mg/dL, p &lt; 0.001) than those without ISR (n = 214). VH-IVUS examination showed that percent necrotic core volume (14.3 ± 8.7% vs. 19.5 ± 9.1%, p = 0.005) was higher in those without ISR than those with ISR. Multivariate analysis revealed that hs-CRP (odds ratio [OR] 3.334, 95% con­fidence interval [CI] 1.158–9.596, p = 0.026) and age (OR 3.557, 95% CI 1.242–10.192, p = 0.018) were associated with ISR. Conclusions: This study suggests that ISR is not associated with baseline coronary plaque composition but is associated with old age and increased expression of the inflammatory marker of hs-CRP. (Cardiol J 2018; 25, 1: 7–13

Subchronic inhalation toxicity of gold nanoparticles

<p>Abstract</p> <p>Background</p> <p>Gold nanoparticles are widely used in consumer products, including cosmetics, food packaging, beverages, toothpaste, automobiles, and lubricants. With this increase in consumer products containing gold nanoparticles, the potential for worker exposure to gold nanoparticles will also increase. Only a few studies have produced data on the <it>in vivo </it>toxicology of gold nanoparticles, meaning that the absorption, distribution, metabolism, and excretion (ADME) of gold nanoparticles remain unclear.</p> <p>Results</p> <p>The toxicity of gold nanoparticles was studied in Sprague Dawley rats by inhalation. Seven-week-old rats, weighing approximately 200 g (males) and 145 g (females), were divided into 4 groups (10 rats in each group): fresh-air control, low-dose (2.36 × 10⁴particle/cm³, 0.04 μg/m³), middle-dose (2.36 × 10⁵particle/cm³, 0.38 μg/m³), and high-dose (1.85 × 10⁶particle/cm³, 20.02 μg/m³). The animals were exposed to gold nanoparticles (average diameter 4-5 nm) for 6 hours/day, 5 days/week, for 90-days in a whole-body inhalation chamber. In addition to mortality and clinical observations, body weight, food consumption, and lung function were recorded weekly. At the end of the study, the rats were subjected to a full necropsy, blood samples were collected for hematology and clinical chemistry tests, and organ weights were measured. Cellular differential counts and cytotoxicity measurements, such as albumin, lactate dehydrogenase (LDH), and total protein were also monitored in a cellular bronchoalveolar lavage (BAL) fluid. Among lung function test measurements, tidal volume and minute volume showed a tendency to decrease comparing control and dose groups during the 90-days of exposure. Although no statistically significant differences were found in cellular differential counts, histopathologic examination showed minimal alveoli, an inflammatory infiltrate with a mixed cell type, and increased macrophages in the high-dose rats. Tissue distribution of gold nanoparticles showed a dose-dependent accumulation of gold in only lungs and kidneys with a gender-related difference in gold nanoparticles content in kidneys.</p> <p>Conclusions</p> <p>Lungs were the only organ in which there were dose-related changes in both male and female rats. Changes observed in lung histopathology and function in high-dose animals indicate that the highest concentration (20 μg/m³) is a LOAEL and the middle concentration (0.38 μg/m³) is a NOAEL for this study.</p

Comparison of angiographic patterns of in-stent restenosis between sirolimus-and paclitaxel-eluting stent

Abstract Background: Angiographic pattern of in-stent restenosis (ISR) after drug-eluting stent (DES) implantation was known to be different to that after bare metal stent (BMS) implantation. But the different angiographic patterns of ISR and its prognosis between sirolimus-eluting stent (SES) and paclitaxel-eluting stent (PES) has not been properly addressed in large scale studies. Results: In angiographic ISR pattern, diffuse ISR was more common in PES implantation (SES vs PES; 23.7% vs 48.7%, p = 0.001) mainly because of higher incidence of diffuse intrastent ISR (8.2% vs 33.8%, p b 0.001, respectively) whereas focal ISR was more common in SES implantation (76.3% vs 51.3%, p = 0.001, respectively) mainly because of higher incidence of focal margin ISR (27.8% vs 2.5%, p b 0.001, respectively). Among 177 ISR lesions, clinically driven target lesion revascularization (TLR) was performed in 53.6% in SES implantation and 56.3% in PES implantation ( p = 0.725). Conclusion: Angiographic pattern of ISR differed after SES and PES implantation, but their subsequent TLR rate was similar to both types of DES

The Mildly Elevated Serum Bilirubin Level is Negatively Associated with the Incidence of End Stage Renal Disease in Patients with IgA Nephropathy

Oxidative stress plays various roles in the development and progression of IgA nephropathy, while bilirubin is known as a potent antioxidant. We therefore hypothesized that serum bilirubin would be associated with renal prognosis in IgA nephropathy. The study subjects comprised 1,458 adult patients with primary IgA nephropathy in Korea. We grouped patients according to the following quartile levels of bilirubin: <0.4 mg/dL (Q1), 0.4-0.5 mg/dL (Q2), 0.6-0.7 mg/dL (Q3), and >0.8 mg/dL (Q4). The outcome data were obtained from the Korean Registry of end-stage renal disease (ESRD). Eighty patients (5.5%) contracted ESRD during a mean follow-up period of 44.9 months. The ESRD incidences were 10.7% in Q1, 8.2% in Q2, 2.8% in Q3, and 2.8% in Q4 (p<0.001). The relative risk of ESRD compared to that in Q1 was 0.307 (95% confidence interval [CI], 0.126-0.751) in Q3 and 0.315 (95% CI, 0.130-0.765) in Q4. The differences of ESRD incidence were greater in subgroups of males and of patients aged 35 yr or more, with serum albumin 4.0 g/dL or more, with normotension, with eGFR 60 mL/min/1.73 m2 or more, and with proteinuria less then 3+ by dipstick test. In conclusion, higher bilirubin level was negatively associated with ESRD incidence in IgA nephropathy

Fabrication of three-dimensional titania building blocks on glass substrate from Mono-dispersed titanium glycolate spheres and their photocatalystic properties

Mono-dispersed titanium glycolate sphere powders were successfully synthesized through a homogeneous nucleation and growth process. The obtained titanium glycolate sphere powders showed a fine size distribution and shape. On calcination, the titanium glycolate spheres lost chemically bound organic compounds, and changed to anatase (500°C) and rutile (900°C) titania spheres. Titania films fabricated with the synthesized titanium glycolate spheres exhibited marked photocatalytic activity and effective reusability. The fabricated films were characterized by X-ray diffraction, scanning electron microscopy, and thermogravimetric and differential thermal analyses

Detection of Gamma-Irradiation Effect on DNA and Protein Using Magnetic Sensor and Cyclic Voltammetry

In this study, a magnetic sensor utilizing Planar Hall Resistance (PHR) and cyclic Voltammetry (CV) for detecting the radiation effect was fabricated. Specifically, we applied in parallel a PHR sensor and CV device to monitor the irradiation effect on DNA and protein respectively. Through parallel measurements, we demonstrated that the PHR sensor and CV are sensitive enough to measure irradiation effect. The PHR voltage decreased by magnetic nanobead labeled DNA was slightly recovered after gamma ray irradiation. The behavior of cdk inhibitor protein p21 having a sandwich structure of Au/protein G/Ab/Ag/Ab was checked by monitoring the cyclic Voltammetry signal in analyzing the gamma ray irradiation effect