Preparation of silver-decorated Soluplus® nanoparticles and antibacterial activity towards S. epidermidis biofilms as characterized by STEM-CL spectroscopy.

Biofilm infections present a serious problem because antibacterial drugs are not effective against mature biofilms or biofilms formed by drug-resistant bacteria. To address this issue, we developed a drug delivery system based on metal-decorated polymeric particles. Polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (Soluplus®) is an amphiphilic polymer used in biomedical formulations, while silver nanoparticles are widely acknowledged to have high antibacterial activity. We prepared silver-decorated Soluplus® micelle nanoparticles with high antibacterial activity using the emulsion solvent diffusion method. Decoration of Soluplus® micelles with silver nanoparticles was found to increase their antibacterial activity. Scanning transmission electron microscopy-cathodoluminescence (STEM-CL) spectroscopy allows imaging of the spatial distribution of labeled targets and the chemical identification of materials. However, STEM-CL spectroscopy of fragile polymer materials is challenging. We optimized the STEM-CL spectroscopy technique to determine the distribution of silver nanoparticles in Soluplus® micelles. Additionally, the surface plasmon properties of the silver nanoparticles were successfully characterized without deactivation. The developed silver-decorated Soluplus® nanoparticles were effective against biofilm infections and have the potential to be applied for other biofilm-related diseases. Additionally, the optimized STEM-CL spectroscopy technique is expected to contribute to the analysis and imaging of fragile polymer materials, as well as other soft materials such as cells and tissues.

Comparison of platinum photodeposition processes on two types of titanium dioxide photocatalysts.

The photodeposition method is useful for the preparation of metal-loaded photocatalysts, by which the metal precursors are adsorbed on the photocatalyst surface and reduced by photoexcited electrons to typically form metallic nanoparticles. In the present study, the photodeposition process of Pt nanoparticles was investigated on anatase and rutile TiO2 photocatalysts. It was found that on the anatase surface, only some of the Pt4+ precursors were first adsorbed in an adsorption equilibrium and reduced to form a smaller number of initial metal species; then, they functioned as electron receivers to reduce the remaining precursors on their metallic surfaces and become larger particles. In contrast, the rutile surface can adsorb most of the precursors and quickly reduce them upon photoirradiation to form nanoparticles, giving a larger number of small nanoparticles. As a result, the Pt-loaded rutile photocatalyst exhibited higher activity in hydrogen evolution from an aqueous methanol solution than the Pt-loaded anatase photocatalyst.

The First Case of TEMPI Syndrome in Japan.

TEMPI syndrome, a disease entity comprising telangiectasia, erythrocytosis with high erythropoietin, monoclonal gammopathy, perinephric fluid collection, and intrapulmonary shunting, was first described by Sykes et al. in 2011. To our knowledge, only 15 cases have been reported worldwide, none of which were in Japan. We herein report a 47-year-old man who had intractable ascites for 2 and a half years and was referred to our department for a peritoneovenous shunt. In addition to ascites, he had telangiectasia, high erythropoietin, monoclonal gammopathy, and perinephric fluid collection. Thus, this is the first case of TEMPI syndrome in Japan.

Optimization of ionic liquid-incorporated PLGA nanoparticles for treatment of biofilm infections.

Ionic liquids (ILs) containing imidazolium cations have a number of useful properties, such as high permeability to cells, high antimicrobial activity, and good biocompatibility. With the aid of ILs, transdermal delivery, solubilization of poorly soluble drugs were developed and therapeutic effects were improved. In this work, 1­butyl­3­methylimidazolium hexafluorophosphate-incorporated, chitosan-modified, submicron-sized poly(dl­lactide­co­glycolide) (PLGA) nanoparticles (NPs) were prepared using the emulsion solvent diffusion method for the treatment of biofilm infections. Prepared IL-incorporated PLGA NPs using surfactants such as Tween-80 and poloxamer-188 showed a high antibacterial activity to the bacterial cells under the biofilm. Additionally, antibacterial mechanism of IL-incorporated PLGA NPs was revealed by annular dark field scanning transmission electron microscopy combined a simple sample pretreatment method. We established a drug delivery system using IL-incorporated PLGA NPs to enhance the potential of polymeric nanocarriers for treating biofilm infections.

Robust Binding between Carbon Nitride Nanosheets and a Binuclear Ruthenium(II) Complex Enabling Durable, Selective CO2 Reduction under Visible Light in Aqueous Solution.

Carbon nitride nanosheets (NS-C3 N4 ) were found to undergo robust binding with a binuclear ruthenium(II) complex (RuRu') even in basic aqueous solution. A hybrid material consisting of NS-C3 N4 (further modified with nanoparticulate Ag) and RuRu' promoted the photocatalytic reduction of CO2 to formate in aqueous media, in conjunction with high selectivity (approximately 98 %) and a good turnover number (>2000 with respect to the loaded Ru complex). These represent the highest values yet reported for a powder-based photocatalytic system during CO2 reduction under visible light in an aqueous environment. We also assessed the desorption of RuRu' from the Ag/C3 N4 surface, a factor that can contribute to a loss of activity. It was determined that desorption is not induced by salt additives, pH changes, or photoirradiation, which partly explains the high photocatalytic performance of this material.

Effective nitrogen doping into TiO2 (N-TiO2) for visible light response photocatalysis.

The thickness-controlled TiO2 thin films are fabricated by the pulsed laser deposition (PLD) method. These samples function as photocatalysts under UV light irradiation and the reaction rate depends on the TiO2 thickness, i.e., with an increase of thickness, it increases to the maximum, followed by decreasing to be constant. Such variation of the reaction rate is fundamentally explained by the competitive production and annihilation processes of photogenerated electrons and holes in TiO2 films, and the optimum TiO2 thickness is estimated to be ca. 10nm. We also tried to dope nitrogen into the effective depth region (ca. 10nm) of TiO2 by an ion implantation technique. The nitrogen doped TiO2 enhanced photocatalytic activity under visible-light irradiation. XANES and XPS analyses indicated two types of chemical state of nitrogen, one photo-catalytically active N substituting the O sites and the other inactive NOx (1⩽x⩽2) species. In the valence band XPS spectrum of the high active sample, the additional electronic states were observed just above the valence band edge of a TiO2. The electronic state would be originated from the substituting nitrogen and be responsible for the band gap narrowing, i.e., visible light response of TiO2 photocatalysts.

Generation of gaseous sulfur-containing compounds in tumour tissue and suppression of gas diffusion as an antitumour treatment.

BACKGROUND AND AIMS: The mechanisms of cancer cell growth and metastasis are still not entirely understood, especially from the viewpoint of chemical reactions in tumours. Glycolytic metabolism is markedly accelerated in cancer cells, causing the accumulation of glucose (a reducing sugar) and methionine (an amino acid), which can non-enzymatically react and form carcinogenic substances. There is speculation that this reaction produces gaseous sulfur-containing compounds in tumour tissue. The aims of this study were to clarify the products in tumour and to investigate their effect on tumour proliferation. METHODS: Products formed in the reaction between glucose and methionine or its metabolites were analysed in vitro using gas chromatography. Flatus samples from patients with colon cancer and exhaled air samples from patients with lung cancer were analysed using near-edge x-ray fine adsorption structure spectroscopy and compared with those from healthy individuals. The tumour proliferation rates of mice into which HT29 human colon cancer cells had been implanted were compared with those of mice in which the cancer cells were surrounded by sodium hyaluronate gel to prevent diffusion of gaseous material into the healthy cells. RESULTS: Gaseous sulfur-containing compounds such as methanethiol and hydrogen sulfide were produced when glucose was allowed to react with methionine or its metabolites homocysteine or cysteine. Near-edge x-ray fine adsorption structure spectroscopy showed that the concentrations of sulfur-containing compounds in the samples of flatus from patients with colon cancer and in the samples of exhaled air from patients with lung cancer were significantly higher than in those from healthy individuals. Animal experiments showed that preventing the diffusion of sulfur-containing compounds had a pronounced antitumour effect. CONCLUSIONS: Gaseous sulfur-containing compounds are the main products in tumours and preventing the diffusion of these compounds reduces the tumour proliferation rate, which suggests the possibility of a new approach to cancer treatment.

[Toward regional combined NST approached from convalescent hospital].

In these days, organization of nutrition support team (NST) is gradually spreading out in Japan. But, its action is frequently limited within acute hospitals. In order to realize an ideal nutritional care of chronic phase (convalescent hospital, nursing home and home care), we are required to set up a regional combined NST. We organized a society named EIYOU NETWORK SHOUNAN (EN-S) as a study group of NST, treatment for swallowing disorder and care after percutaneous endoscopic gastrostomy (PEG). EN-S takes a regional active part of these study groups at Kanagawa prefecture. We held a seminar about the nutritional care after PEG and a conference about the regional combined NST. According to the questionnaire at the conference, most participants were expected to making a regional combined NST to come true. The convalescent hospital is located in between acute hospital and home care. And that position has a profitable opportunity to achieve a regional partnership, if actively make the effort to organize.

Late results of gelatin-resorcin-formalin glue-aided repair in acute type A aortic dissection.

Gelatin-resorcin-formalin (GRF) glue has been used to obliterate the false lumen of dissected aortas, resulting in reduced mortality. However, because of the cytotoxicity of formalin, the application of GRF remains controversial. In this study, a total of 138 consecutive patients with acute type A dissection since 1995, who underwent emergency graft replacement, were reviewed. The mean age was 65.5 years. The hospital mortality rate was 6.5%. In-hospital re-exploration rate and patency rate of the false lumen were 6.5% and 24.7%, respectively. The actuarial survival rates were 81.5% after 5 years and 54.8% after 10 years. Reoperation-free rates were 87.9% after 5 years and 72.3% after 10 years. Tissue necrosis or aneurismal degeneration was not demonstrated at reoperation. In conclusion, GRF glue demonstrats excellent tissue adhesion and hemostasis capability, and contributes to improve surgical results.

Validity of a limited ascending and hemiarch replacement for acute type A aortic dissection.

BACKGROUND: The extent of arch repair at emergency surgery for acute type A dissection is controversial. This study was designed to evaluate the rationale of tear-oriented conservative ascending/hemiarch replacement, comparing it against total arch replacement. METHODS: A total of 134 consecutive patients with acute type A dissection who underwent emergency surgery between 1995 and 2005 were reviewed. RESULTS: The median age was 68 years (range, 19 to 90); the patients were 62 men and 72 women. The extent of aortic resection included the ascending aorta and hemiarch in 105 patients (group AH) and the total aortic arch in 29 patients (group TA). The hospital mortality rates in groups AH and TA were 6.7% and 6.9%, respectively. The actuarial survival rates were 77.4% (AH) and 80.8% (TA) after 5 years, and 63.5% (AH) and 80.8% (TA) after 10 years. The freedom rates from reoperation were 91.3% (AH) and 88.0% (TA) after 5 years, and 60.9% (AH) and 76.6% (TA) after 10 years. Multivariate analysis indicated that predictors of reoperation were Marfan syndrome and aortic valve regurgitation. CONCLUSIONS: Limited ascending/hemiarch replacement did not increase the risk of reoperation and would not compromise late results.

Emergency surgery for acute type a aortic dissection in octogenarians.

BACKGROUND: Emergency surgery for acute type A dissection is associated with a high mortality rate in aged patients. This study was designed to explore perioperative risk factors and prognosis in octogenarians with acute type A aortic dissection. METHODS: Twenty-four octogenarians, of 134 consecutive patients with acute type A dissection between 1995 and 2005 who underwent emergency surgery, were reviewed. The median age was 82 years (80 to 90); the patients were 10 men and 14 women. All 24 patients underwent conservative tear-oriented surgery under deep hypothermic circulatory arrest with cerebral perfusion; the procedures were 23 ascending aortic replacements and one entire arch replacement. RESULTS: The hospital mortality rate was 13% (3 of 24 patients), without statistical significance compared with 6% in patients younger than 80 years. The late mortality rate was 38% (9 of 24 patients), with significance compared with 9% in the other patients. Five- and 10-year survivals ware 55% and 42%, respectively, compared with 83% and 73%, respectively (p = 0.0013), in the other patients. Univariate and multivariate analysis demonstrated that age 80 or greater was not an independent risk factor of hospital death. Risk factors of late death in younger-aged patients were pneumonia and reoperation. CONCLUSIONS: Emergency surgery for octogenarians with acute type A aortic dissection was successfully performed using a conservative intimal tear-oriented procedure, resulting in satisfactory early and late survival. Aggressive surgical treatment is mandatory for improving the outcome of this medical emergency in octogenarians.

High-resolution photoelectron spectroscopy of Heusler-type Fe(2)VAl alloy.

The electronic structure of Heusler-type Fe(2)VAl has been studied by high-resolution photoelectron spectroscopy with the excitation photon energy hnu ranging from 21.2 eV (the He I laboratory light source) to 904 eV (the soft X-ray synchrotron light source) for clean surfaces prepared by scraping or fracturing polycrystalline and single crystalline specimens. Photoelectron spectra recorded for the fractured surfaces show a 10 eV-wide valence band with fine structures and a clear decrease in the intensity towards the Fermi level E(F), while a high intensity at E(F) and no fine structures are observed for the scraped surface. Comparison with the theoretical density of states (DOS) indicates that the vacuum ultraviolet photoelectron spectra emphasize the transition-metal 3d bands but the soft X-ray photoelectron spectra agree remarkably well with the DOS including the fine structures and the pseudogap at E(F). The present results suggest that the electronic structure of Fe(2)VAl is highly sensitive to possible strain and defects induced by scraping. Bulk electronic structures of Fe(2)VAl are discussed in relation to the reported fascinating transport properties.

Experiences of Postcardiotomy Assist: Pneumatic Ventricular Assist Device or Venoarterial Bypass with Percutaneous Cardiopulmonary Support.

From October 1982 to the present, 16 patients have been supported by a pneumatic ventricular assist device (VAD). Since April 1990, we have introduced a venoarterial bypass (VAB) with percutaneous cardiopulmonary support (PCPS) system. This PCPS system was used in 12 patients. The long-term survival rate of PCPS cases (41%) was much better than that of VAD cases (19%). The main cause of death in VAD cases was multiple organ failure (MOF). Although VAB was initiated more recently than VAD, the duration on support was longer in the VAD group than in the VAB group. Because of the longer support duration and the presence of many patients with MOF, coagulopathy deteriorated more readily in the VAD group than in the VAB group. In the case of postcardiotomy cardiopulmonary bypass weaning or low-output syndrome (LOS), the VAB with PCPS system should be applied first under intraaortic balloon pumping assist because of its simplicity and low cost. Thereafter, VAD should be applied in cases refractory to VAB support.