In JoVE (1)

Other Publications (66)

Articles by Tatsuo Kaneko in JoVE

Other articles by Tatsuo Kaneko on PubMed

Unidirectional Atrio-atrial Conduction After Surgical Isolation of the Posterior Part of the Left Atrium and Pulmonary Veins for Atrial Fibrillation: Simple Postsurgical Procedure Electrophysiological Evaluation

Pacing and Clinical Electrophysiology : PACE. Jun, 2004  |  Pubmed ID: 15189540

A 66-year-old woman underwent mitral valve replacement and surgical isolation of the posterior part of the left atrium for persistent AF. During sinus rhythm an isolated atrial rhythm was recorded from the isolated posterior left atrium using an esophageal electrode catheter. After the intravenous administration of adenosine triphosphate sinus rhythm was suppressed and 1:1 conduction from the posterior left atrium to the rest of the atrium was recorded. Unidirectional atrio-atrial conduction was revealed by a simple electrophysiological evaluation

Shear-induced Mesophase Organization of Polyanionic Rigid Rods in Aqueous Solution

Langmuir : the ACS Journal of Surfaces and Colloids. Jul, 2004  |  Pubmed ID: 15248745

IgG Responses to Intranasal Immunization with Cholera-toxin-immobilized Polymeric Nanospheres in Mice

Journal of Biomaterials Science. Polymer Edition. 2004  |  Pubmed ID: 15264666

IgG responses to antigen-nanosphere hybrids were studied in mice. Cholera toxin (CT) was covalently immobilized onto the surface of polymeric nanospheres (NS) with a nanophase-separated structure consisting of a polystyrene core and a poly(methacrylic acid) graft corona. Reaction conditions favoring the dehydroxide condensation reaction of the amino group of the CT with the carboxyl group of NS effectively immobilized CT onto their surface. When CT-immobilized nanospheres (CT-NS) were suspended in aqueous solution and administrated to mice either intranasally or intramuscularly, serum IgG titers elevated with increasing time and reached a maximum level at 8 weeks after immunization. On the other hand, intranasal administration of CT alone induced an even higher serum IgG titer than that of CT-NS at 4 weeks. However, the titer gradually decreased thereafter. Thus, polymeric NS may be an effective substrate to covalently immobilize antigen on their surface, steadily inducing a high level of IgG production in response to the intranasal administration.

Preparation and Thermosensitivity of Naturally Occurring Polypeptide Poly(gamma-glutamic Acid) Derivatives Modified by Propyl Groups

Macromolecular Bioscience. Apr, 2004  |  Pubmed ID: 15468231

Poly(gamma-glutamic acid) (gamma-PGA) is a biosynthetic polymer, and the carboxyl groups are able to undergo a chemical modification. In this study, poly(alpha-propyl gamma-glutamate) (gamma-PGA propylate) was synthesized by the esterification of these carboxyl groups to yield a thermosensitive and biodegradable polymer. In aqueous solution, the gamma-PGA propylate can impart thermosensitivity by controlling the hydrophobic-hydrophilic balance of the gamma-PGA polymeric chains.

Factors Predicting Success in Cryoablation of the Pulmonary Veins in Patients with Chronic Atrial Fibrillation

Circulation Journal : Official Journal of the Japanese Circulation Society. Nov, 2004  |  Pubmed ID: 15502379

This study was designed to investigate the factors predicting maintenance of sinus rhythm (SR) in patients with chronic atrial fibrillation (AF) undergoing cryoablation of the pulmonary veins (PV-cryo) during cardiac surgery.

Adhesion Behavior of Peritoneal Cells on the Surface of Self-assembled Triblock Copolymer Hydrogels

Biomacromolecules. Nov-Dec, 2004  |  Pubmed ID: 15530062

Adhesion behavior of cells to the surface of physical hydrogel membranes prepared by water-induced self-organization of precisely synthesized ABA-triblock copolymers comprised of poly(beta-benzyl L-aspartate) (PBLA) as A segment and poly(ethylene oxide) (PEO, molecular weight = 20 000) as the B segment were investigated. The cast film from the methylenechloride solution of these copolymers swelled in water very rapidly forming hydrogels (100-400% water content of total weight). The content of PBLA affected the strength, the hydrophobicity, and the amount of water involved in the hydrogel surface. During the early stage of cultivation with murine peritoneal cells, cell adhesion on the hydrogels of PEO and PBLA with 18 (20K18) and 25 (20K25) monomeric units was not observed, while adhesion on the hydrogels of PEO and PBLA with 32 (20K32) and 55 (20K55) monomeric units was successful, suggesting more than 12 mol % in PBLA content is necessary for adhesion of these cells. Although cell spreading on the hydrogels of 20K18, 20K25, and 20K32 was not sufficient, the hydrogel of 20K55 allowed cell adhesion and spreading to be bipolar with leading edge whose raffling is active with pseudopodium and lamellipodium as well as PBLA homopolymer, suggesting active motility of these cells. Remarkably, prolonged incubation restored adhesiveness onto the films at 20K18 in contrast to adhesion with 20K25 despite low hydrophobicity. It is conceivable that adaptation of proteins and chemical changes to the surface during the culture period may participate in these phenomena. Mechanical properties and interaction between cell and these copolymer hydrogels could be controlled by composition of block segments, and optimization for implants could also be attainable.

Biatrial Epicardial Pacing Prevents Atrial Fibrillation and Confers Hemodynamic Benefits After Coronary Artery Bypass Surgery

Pacing and Clinical Electrophysiology : PACE. Jan, 2005  |  Pubmed ID: 15683483

Biatrial pacing (BIP) can be more effective than standard right atrial pacing (RAP) in preventing atrial fibrillation (AF) after coronary artery bypass graft surgery (CABG). However, the mechanisms and hemodynamic benefits of BIP have not been studied in detail. This study examined the efficacy and hemodynamic benefits conferred by overdrive epicardial BIP in preventing post-CABG AF. After undergoing CABG, 72 patients (mean age = 66 +/- 12 years, 48 men) were randomly assigned to triggered BIP (BIP-AAT; n = 50) versus single RAP (RAP-AAI; n = 22). The hemodynamic effects of BIP were measured by right heart catheterization and echocardiography. The patients were monitored for 8.8 +/- 2.4 days after CABG to detect episodes of AF. The incidence of AF was significantly lower in the BIP-AAT group (22.0%) than in the RAP-AAI group (59.1%, P < 0.01). Cardiac output was significantly higher and pulmonary artery wedge pressure (PAWP) significantly lower during BIP-AAT than during RAP-AAI. The E-wave (65.2 +/- 37.8 vs 57.8 +/- 37.8 cm/s, P < 0.05) was significantly higher during BIP-AAT, and the interval between atrial pacing spike and the end of A-wave (241 +/- 18.4 vs 286 +/- 17.2 ms, P < 0.001) was significantly shorter during BIP-AAT than during RAP-AAI. Triggered BIP was well tolerated and significantly reduced the incidence of post-CABG AF compared to single-site RAP. The hemodynamic improvements conferred by BIP-AAT were due to a shortening of the inter-atrial conduction delay and greater contribution of left atrial contraction. These hemodynamic benefits may play a role in lowering intra-atrial pressure and in preventing AF.

Long-term Results of Cryoablation with a New Cryoprobe to Eliminate Chronic Atrial Fibrillation Associated with Mitral Valve Disease

Pacing and Clinical Electrophysiology : PACE. Jan, 2005  |  Pubmed ID: 15683531

The purpose of this study was to examine the performance of a new cryoprobe in the treatment of chronic atrial fibrillation (AF) associated with mitral valve disease. The study included 66 patients undergoing mitral valve replacement. The mean AF duration was 9.0 +/- 9.0 years and mean left atrial (LA) was diameter 57 +/- 10 mm. Cryoablation (-60 degrees C) was applied to four pulmonary vein (PV) orifices over 2-3 minute. The spherical tip (2-cm in diameter) of the cryoprobe is capable of ablating the left atrium near the PV, as well as the PV ostium with a single cryoablation. After cryoablation, mitral valve surgery or a combined surgical procedure were performed in 66 patients. There were no intraoperative complications. Sinus rhythm was restored in 60 patients (91%) immediately after the operation. Recurrent AF was treated with antiarrhythmic drugs and/or direct current cardioversion in 43 patients (72%). At discharge, 48 patients (72%) were in sinus rhythm. During a mean follow-up period of 31 +/- 16 months, 40 patients (61%) were in sinus rhythm with (29) or without antiarrhythmic drugs (11). In patients in sinus rhythm at the end of the follow-up period, the duration of preoperative AF duration was significantly shorter (P < 0.05) and the preoperative LA diameter and cardiothoracic ratio were significantly smaller than in patients who were in AF (both for P < 0.005). Using this new cryoprobe, sinus rhythm was restored and maintained in 61% of patients with chronic AF and mitral valve disease with a 12-15 minute cryoablation procedure.

Potent Activation of Antigen-specific T Cells by Antigen-loaded Nanospheres

Immunology Letters. Apr, 2005  |  Pubmed ID: 15790517

Polystyrene nanospheres (NS) were found to be efficiently taken up by murine antigen-presenting cells (APC), especially bone marrow-derived dendritic cells (DC), in vitro and in vivo. The efficiency of NS uptake was not affected by the maturation state of DC. Both immature and mature DC had similar ability to take up NS in a dose- and time-dependent manner. Uptake and intracellular localization of NS was clearly demonstrated by confocal laser microscopy, using NS with fluorescence. DC could efficiently take up ovalbumin (OVA), when loaded on the surface of NS (OVA-NS). Consequently, OVA-NS-pulsed DC activated antigen-specific interferon (IFN)-gamma-producing T cells much more strongly than OVA-pulsed DC in vitro. These results suggest that NS can be used as an efficient antigen delivery system to DC for a variety of vaccines, such as an anti-human immunodeficiency virus type 1 vaccine.

Left Atrial Appendage Outflow Velocity is Superior to Conventional Criteria for Predicting of Maintenance of Sinus Rhythm After Simple Cryoablation of Pulmonary Vein Orifices

Circulation Journal : Official Journal of the Japanese Circulation Society. Apr, 2005  |  Pubmed ID: 15791040

We sought to identify factors favoring long-term restoration of sinus rhythm (SR) in patients with atrial fibrillation (AF) who underwent a simple cryoablation of pulmonary vein orifices (PV-cryo) as part of their cardiac surgery.

Enhanced Effects of Lithocholic Acid Incorporation into Liquid-crystalline Biopolymer Poly(coumaric Acid) on Structural Ordering and Cell Adhesion

Biomaterials. Nov, 2005  |  Pubmed ID: 15913768

A novel thermotropic liquid-crystalline biocopolymer, poly{trans-4-hydroxycinnamic acid (4HCA: trans-coumaric acid)-co-lithocholic acid (LCA)}, was synthesized by a thermal polycondensation of 4HCA and LCA. When the LCA composition of P(4HCA-co-LCA) was 0, 5, 7, 23, 27, and 45 mol%, the copolymers showed a nematic liquid-crystalline phase. The melting point of the copolymers was 120-250 degrees C depending on the LCA composition, and showed a maximum at 7 mol%. Wide angle X-ray diffraction (WAXD) analyses showed a typical diffraction pattern of a hexagonal arrangement for 0, 7, 23, and 27 mol% LCA composition, which were cooled from a nematic melt. The other polymers showed no distinct diffraction. In particular, the copolymer of 7 mol% LCA composition showed four distinct diffractions corresponding to spacings with a reciprocal ratio of 1, radical3, 2, and radical7, indicating the highest structural ordering of all copolymers prepared here. The results of the cell adhesion and static contact angle tests suggest that the 7 mol% LCA composition copolymer had the highest hydrophobicity and cell adhesion ability, which was easily controlled by altering in feed. We conclude that the structural ordering may have a significant correlation with cell adhesion activity.

Comparison of the Rheologic Parameters in Left Internal Thoracic Artery Grafts with Those in Saphenous Vein Grafts

Circulation Journal : Official Journal of the Japanese Circulation Society. Jun, 2005  |  Pubmed ID: 15914949

Left internal thoracic artery (LITA) grafts have superior patency to saphenous vein grafts (SVG). Because shear stress augments the release of nitric oxide throughout the LITA endothelium, shear stress and shear rate in coronary artery bypass grafts (CABG) may play an important role in the higher patency, so the aim of the present study was to evaluate and compare the rheologic parameters in CABG using LITA and SVG.

In Vitro Enzymatic Degradation of Nanoparticles Prepared from Hydrophobically-modified Poly(gamma-glutamic Acid)

Macromolecular Bioscience. Jul, 2005  |  Pubmed ID: 15991216

Amphiphilic poly(gamma-glutamic acid) (gamma-PGA) was prepared by the introduction of L-phenylalanine ethylester (L-PAE) as a side chain. This gamma-PGA-graft-L-PAE formed monodispersed nanoparticles in water. The particle size of the gamma-PGA nanoparticles could be controlled by the degree of L-PAE grafting. The hydrolytic degradation and enzymatic degradation by gamma-glutamyl transpeptidase (gamma-GTP) of these gamma-PGA nanoparticles was studied by gel permeation chromatography (GPC) and scanning electron microscopy (SEM). The hydrolysis ratio of gamma-PGA was found to decrease upon increasing the hydrophilicity of the gamma-PGA. The degradation of the gamma-PGA backbone by gamma-GTP resulted in a dramatic change in nanoparticle morphology. With increasing time, the gamma-PGA nanoparticles reduced in size and finally disappeared completely.Time-course of the changes in the morphology of the gamma-PGA nanoparticles following incubation with gamma-glutamyl transpeptidase.

Self-assembling Bionanoparticles of Poly(epsilon-lysine) Bearing Cholesterol As a Biomesogen

Biomacromolecules. Jul-Aug, 2005  |  Pubmed ID: 16004486

Preparation and Characterization of Biodegradable Nanoparticles Based on Poly(gamma-glutamic Acid) with L-phenylalanine As a Protein Carrier

Journal of Controlled Release : Official Journal of the Controlled Release Society. Nov, 2005  |  Pubmed ID: 16125267

The objective of the present study was to prepare nanoparticles composed of poly(gamma-glutamic acid) (gamma-PGA) and l-phenylalanine ethylester (l-PAE) in order to evaluate the possibility of using these nanoparticles as protein carriers. Novel amphiphilic graft copolymers composed of gamma-PGA as the hydrophilic backbone and l-PAE as the hydrophobic segment were successfully synthesized by grafting l-PAE to gamma-PGA using water-soluble carbodiimide (WSC). Due to their amphiphilic properties, the gamma-PGA-graft-l-PAE copolymers were able to form nanoparticles. The size of the gamma-PGA nanoparticles was measured by photon correlation spectroscopy (PCS) and showed a monodispersed size distribution with a mean diameter ranging from 150 to 200 nm. The solvents selected to prepare the gamma-PGA nanoparticles by a precipitation and dialysis method affected the particle size distribution. To evaluate the feasibility of vehicles for these proteins, we prepared protein-loaded gamma-PGA nanoparticles by surface immobilization and encapsulation methods. Ovalbumin (OVA) was used as a model protein and was immobilized onto the gamma-PGA nanoparticles or encapsulated into the inner core of these nanoparticles. Moreover, these OVA-encapsulated gamma-PGA nanoparticles could be preserved by freeze-drying process. The results of cytotoxicity tests showed that the gamma-PGA and gamma-PGA nanoparticles did not cause any relevant cell damage. It is expected that biodegradable gamma-PGA nanoparticles can immobilize proteins, peptides, plasmid DNA and drugs onto their surfaces and/or into the nanoparticles. These nanoparticles are potentially useful in pharmaceutical and biomedical applications.

Acute Myocardial Infarction and Ischemia in the Left Anterior Descending Artery Territory in a Patient with Single Coronary Artery

International Heart Journal. Jul, 2005  |  Pubmed ID: 16157963

This report describes a 77-year-old woman with a single coronary artery who suffered an acute anterior wall myocardial infarction. The single coronary artery arose from the right coronary artery through the transverse trunk, and there were no other cardiovascular anomalies. Coronary angiography did not reveal significant coronary artery stenosis in the left anterior descending artery. The patient was treated medically in the acute phase. She developed typical angina and evidence of myocardial ischemia, and underwent successful coronary artery bypass grafting in the chronic phase with anterior chest pain.

Reversible Thermoresponsive Aggregation/deaggregation of Water-dispersed Polymeric Nanospheres Exhibiting Structural Transformation

Langmuir : the ACS Journal of Surfaces and Colloids. Oct, 2005  |  Pubmed ID: 16207054

Crystalline polymeric nanospheres composed of poly{stearyl methacrylate (SMA)-co-poly(ethylene glycol) monomethacrylate (PEGm)}s were prepared by the dispersion radical polymerization of SMA and PEGm in an ethanol/water solution. Scanning electron microscopy showed that the nanospheres were highly spherical, and had a narrow size distribution. Electron spectroscopy for chemical analysis and X-ray diffraction studies of the nanospheres suggested a core-corona-type structure; the hydrophilic PEGm corona accumulated on the nanosphere surface, while the hydrophobic SMA core formed a layered structure. Heat treatment caused a melting of the SMA layers, but successive cooling allowed it to re-form. Accompanying this reversible order-disorder transition, the nanospheres also showed a reversible aggregation/deaggregation behavior in their water-dispersion state.

Rapid Deswelling of Semi-IPNs with Nanosized Tracts in Response to PH and Temperature

Journal of Controlled Release : Official Journal of the Controlled Release Society. Jan, 2006  |  Pubmed ID: 16310274

Porous linear-polymer penetrating networks (semi-IPNs) were prepared by the radical polymerization of acrylic acid (AAc) inside porous poly(N-isopropylacrylamide) hydrogels with "nano-sized tract networks (nano-tracts)." The deswelling behavior was investigated by measuring the time course of the swelling ratio change of the semi-IPNs just after the temperature or pH was changed. Although the incorporation of PAAc linear chains into the PNIPAAm hydrogel networks should facilitate deswelling, nonporous semi-IPNs showed only a slow thermoresponse under low pH conditions, and a slow pH-response under a high temperature. On the other hand, the porous semi-IPNs showed a rapid deswelling in response to either a change in pH or temperature, regardless of the environment, presumably due to the nano-tracts through which the water was rapidly released from the hydrogel without any interference by network shrinking. The novel network design of these nano-tracted semi-IPNs may be useful for high performance, dual molecule-release functions.

Hydrolytic and Enzymatic Degradation of Nanoparticles Based on Amphiphilic Poly(gamma-glutamic Acid)-graft-L-phenylalanine Copolymers

Biomacromolecules. Jan, 2006  |  Pubmed ID: 16398528

Amphiphilic graft copolymers consisting of poly(gamma-glutamic acid) (gamma-PGA) as the hydrophilic backbone and L-phenylalanine ethylester (L-PAE) as the hydrophobic side chain were synthesized by grafting L-PAE to gamma-PGA. The nanoparticles were prepared by a precipitation method, and about 200 nm-sized nanoparticles were obtained due to their amphiphilic properties. The hydrolytic and enzymatic degradation of these gamma-PGA nanoparticles was studied by gel permeation chromatography (GPC), scanning electron microscopy (SEM), dynamic light scattering (DLS) and (1)H NMR measurements. The hydrolysis ratio of gamma-PGA and these hydrophobic derivatives was found to decrease upon increasing the hydrophobicity of the gamma-PGA derivates. The pH had an effect on the hydrolytic degradation of the polymer. The hydrolysis of the polymer could be accelerated by alkaline conditions. The degradation of the gamma-PGA backbone by gamma-glutamyl transpeptidase (gamma-GTP) resulted in a dramatic change in nanoparticle morphology. With increasing time, the gamma-PGA nanoparticles began to decrease in size and finally disappeared completely. Moreover, the gamma-PGA nanoparticles were degraded by four different enzymes (Pronase E, protease, cathepsin B and lipase) with different degradation patterns. The enzymatic degradation of the nanoparticles occurred via the hydrolysis of gamma-PGA as the main chain and L-PAE as the side chain. In the case of the enzymatic degradation of gamma-PGA nanoparticles with Pronase E, the size of the nanoparticles increased during the initial degradation stage and decreased gradually when the degradation time was extended. Nanoparticles composed of biodegradable amphiphilic gamma-PGA with reactive function groups can undergo further modification and are expected to have a variety of potential pharmaceutical and biomedical applications, such as drug and vaccine carriers.

One-step Advanced Preparation of Surface-functional Peptide Nanospheres by the Polymerization of L-phenylalanine N-carboxyanhydride with Dual Initiators

Langmuir : the ACS Journal of Surfaces and Colloids. Feb, 2006  |  Pubmed ID: 16460051

Surface-grafted peptide nanospheres consisting of hydrophobic poly(L-phenylalanine) with hydrophilic poly(ethylene glycol) (PEG) grafts were successfully prepared by the one-step polymerization of L-phenylalanine N-carboxyanhydride with the dual initiators of hydrophobic n-butylamine and hydrophilic NH2-monoterminated PEG (NH2-PEG). The monodispersed peptide nanospheres were stably self-assembled during polymerization in a mixture of water/dimethyl sulfoxide to create a colloidal solution, but only aggregated in water or organic solvents. When n-butylamine or NH2-PEG was used as a solitary initiator, the peptide nanospheres were not formed. The peptide nanospheres showed high dispersion-stability in water, and their diameter was approximately 300 nm. Furthermore, the peptide nanospheres were well-redispersed in water, retaining the same diameter and monodispersity even after lyophilization. Peptide nanospheres with the functional carboxylic acid on their graft layer were also successfully prepared by the one-step preparation method. This one-step preparation method of surface-grafted peptide nanospheres will be useful as an advanced technology to develop biodegradable functional nanospheres.

Multifunctional Conjugation of Proteins On/into Bio-nanoparticles Prepared by Amphiphilic Poly(gamma-glutamic Acid)

Journal of Biomaterials Science. Polymer Edition. 2006  |  Pubmed ID: 17024878

The present study focuses on nanoparticles composed of amphiphilic poly(gamma-glutamic acid) (gamma-PGA) as potential protein carriers. Amphiphilic graft co-polymers composed of y-PGA as the hydrophilic backbone and L-phenylalanine ethylester (L-PAE) as the hydrophobic segment were synthesized by grafting L-PAE to y-PGA using water-soluble carbodiimide (WSC). Due to their amphiphilic properties, the gamma-PGA-graft-L-PAE co-polymer formed monodispersed nanoparticles in water. The particle size of the nanoparticles composed of gamma-PGA-graft-L-PAE (gamma-PGA nanoparticles) was about 200 nm and showed a highly negative zeta potential. To evaluate their potential applications as multifunctional protein carrier, we prepared protein-entrapped gamma-PGA nanoparticles by encapsulation, covalent immobilization or physical adsorption methods. For this purpose, 11 different proteins with various molecular weights and isoelectric points (pI values) were used as model proteins. The encapsulation of the protein into the nanoparticles was observed for all tested proteins. The amount of protein covalently immobilized or adsorbed onto the nanoparticles showed different tends based on the molecular weight and pI of each protein. Positively charged proteins could be adsorbed onto the negatively charged nanoparticles by electrostatic interaction. Moreover, it was found that enzyme-encapsulated nanoparticles showed higher enzymatic activity than surface-immobilized nanoparticles. These results indicated that the enzymatic activity of the enzyme-entrapped nanoparticles was significantly affected by the conjugation method, and that encapsulation was the optimal method for the conjugation of proteins and nanoparticles. It is expected that the y-PGA nanoparticle will have great potential as multifunctional carriers in pharmaceutical and biomedical applications, such as drug and vaccine delivery systems.

Effects of Thermoresponsive Coacervation on the Hydrolytic Degradation of Amphipathic Poly(gamma-glutamate)s

Macromolecular Bioscience. Nov, 2006  |  Pubmed ID: 17099867

Hydrolytic properties of thermoresponsive biopolymers with amphiphilic structures, gamma-PGA-P, were investigated. Hydrolysis was monitored in terms of molecular weight changes using GPC and spectroscopic measurements. The hydrolytic degradation of gamma-PGA-P was controlled by a change in the degree of propyl group conversion, reaction temperature, and/or reaction pH. The degradation was classified as the rapid elimination of propyl side chains and the moderate cleavage of peptide linkages in the backbone. Furthermore, hydrophobic environments established by the thermoresponsive coacervation of gamma-PGA-P60 solutions inhibited hydrolytic degradation reactions. Inversely, hydrolytic degradations increased coacervation temperatures. Kinetic studies of hydrolytic reactions suggest that the degradation rate of gamma-PGA-P60 solutions can be controlled by their thermoresponsivity. The hydrolysis reported here represents the first degradation rate controlled by thermoresponsive coacervation.

Rapid and Precise Release from Nano-tracted Poly(N-isopropylacrylamide) Hydrogels Containing Linear Poly(acrylic Acid)

Macromolecular Bioscience. Nov, 2006  |  Pubmed ID: 17099869

We investigated the rapid and precise molecular release from hydrogels in response to dual stimuli. To achieve precise on/off drug release using thermoresponsive poly(N-isopropylacrylamide) hydrogels, we prepared nano-structured semi-IPNs, which consisted of thermosensitive PNIPAAm networks penetrated by pH-responsive poly(acrylic acid) (PAAc) linear chains and perforated to create nano-tracts as a molecular pathway. The present nano-tracted semi-IPNs show a rapid deswelling response to both temperature and pH. Model drug releases were investigated when simultaneous changes in temperature and pH were applied. We observed that the cationic drug was rapidly released and then abruptly discontinued from the nano-tracted semi-IPNs in response to the dual stimuli, and clear release and stopping cycles were repeatedly observed on successive steps. Moreover, the release rates and amount of drug released were controllable by the deswelling speed of the gels and the PAAc content inside the gels. This novel release system using the nano-tracted semi-IPNs may be useful for the high performance, pulsed release of molecules.

Environmentally Degradable, High-performance Thermoplastics from Phenolic Phytomonomers

Nature Materials. Dec, 2006  |  Pubmed ID: 17128261

Aliphatic polyesters, such as poly(lactic acid), which degrade by hydrolysis, from naturally occurring molecules form the main components of biodegradable plastics. However, these polyesters have become substitutes for only a small percentage of the currently used plastic materials because of their poor thermal and mechanical properties. Polymers that degrade into natural molecules and have a performance closer to that of engineering plastics would be highly desirable. Although the use of a high-strength filler such as a bacterial cellulose or modified lignin greatly increases the plastic properties, it is the matrix polymer that determines the intrinsic properties of the composite. The introduction of an aromatic component into the thermoplastic polymer backbone is an efficient method to intrinsically improve the material performance. Here, we report the preparation of environmentally degradable, liquid crystalline, wholly aromatic polyesters. The polyesters were derived from polymerizable plant-derived chemicals--in other words, 'phytomonomers' that are widely present as lignin biosynthetic precursors. The mechanical performance of these materials surpasses that of current biodegradable plastics, with a mechanical strength, sigma, of 63 MPa, a Young's modulus, E, of 16 GPa, and a maximum softening temperature of 169 degrees C. On light irradiation, their mechanical properties improved further and the rate of hydrolysis accelerated.

Particulation of Hyperbranched Aromatic Biopolyesters Self-organized by Solvent Transformation in Ionic Liquids

Langmuir : the ACS Journal of Surfaces and Colloids. Mar, 2007  |  Pubmed ID: 17309286

Hyperbranched copolymers were prepared by the heat transesterification of 4-hydroxycinnamic acid (4HCA) and 3,4-dihydroxycinnamic acid (DHCA) with a high 4HCA composition dissolved in trifluoroacetic acid (TFA). The nanoparticles were formed after two homogeneous copolymer solutions were mixed in DMF and TFA, which are both good solvents for the copolymer P(4HCA-co-DHCA). We confirmed that the driving force for particulation was solvent interactions that produce ion pairs, which elevate the polarity of the solvent too much to solubilize the copolymers.

High-performance Functional Ecopolymers Based on Flora and Fauna

Chemical Record (New York, N.Y.). 2007  |  Pubmed ID: 17663444

Liquid crystalline (LC) polymers of rigid monomers based on flora and fauna were prepared by in-bulk polymerization. Para-coumaric (p-coumaric) acid [4-hydroxycinnamic acid (4HCA)] and its derivatives were selected as phytomonomers and bile acids were selected as biomonomers. The 4HCA homopolymer showed a thermotropic LC phase only in a state of low molecular weight. The copolymers of 4HCA with bile acids such as lithocholic acid (LCA) and cholic acid (CA) showed excellent cell compatibilities but low molecular weights. However, P(4HCA-co-CA)s allowed LC spinning to create molecularly oriented biofibers, presumably due to the chain entanglement that occurs during in-bulk chain propagation into hyperbranching architecture. P[4HCA-co-3,4-dihydroxycinnamic acid (DHCA)]s showed high molecular weight, high mechanical strength, high Young's modulus, and high softening temperature, which may be achieved through the entanglement by in-bulk formation of hyperbranching, rigid structures. P(4HCA-co-DHCA)s showed a smooth hydrolysis, in-soil degradation, and photo-tunable hydrolysis. Thus, P(4HCA-co-DHCA)s might be applied as an environmentally degradable plastic with extremely high performance.

Aortic Root Replacement with a Mechanical Valve and Prosthetic Conduit for the Complicated Degeneration of the Ascending Aorta Resulting from Infective Endocarditis

Annals of Thoracic and Cardiovascular Surgery : Official Journal of the Association of Thoracic and Cardiovascular Surgeons of Asia. Oct, 2007  |  Pubmed ID: 17954997

A 28-year-old man with infective endocarditis of the aortic valve underwent a course of antibiotic therapy, but developed severe aortic root deformity requiring aortic root replacement with a mechanical composite valve conduit. Of note, this patient had undergone a previous aortic valve operation for bicuspid valve stenosis, and indurations and fragility of the aortic root caused by the preceding operation may have contributed to subsequent aortic root deformity during the course of infective endocarditis of the aortic valve. Over the 7-year follow-up period, the patient showed no signs of recurrent infection or new cardiac events. For younger patients with endocarditis, the use of a mechanical valve and prosthetic conduit with sufficient surgical debridement and appropriate antibiotic therapy appears to be a safe and effective treatment strategy.

Synthesis and Properties of Coumaric Acid Derivative Homo-polymers

Journal of Biomaterials Science. Polymer Edition. 2008  |  Pubmed ID: 18177555

Poly(4-hydroxycinnamic acid) (P4HCA), poly(3-hydroxycinnamic acid) (P3HCA), poly(3-methoxy-4-hydroxycinnamic acid) (PMHCA) and poly(3,4-dihydroxycinnamic acid) (PDHCA) were synthesized by the thermal poly-condensation of the corresponding monomers, which are lignin precursors, coumaric acid derivatives consisting of cinnamoyl groups and different position and number of OH groups. The solubility of the homo-polymers in organic solvents decreased in the order of P3HCA > PDHCA > P4HCA > PMHCA. The wide angle X-ray diffraction (WAXD) results indicated that P4HCA or PMHCA with p-OH group had higher crystallinity, in contrast to P3HCA or PDHCA with m-OH group which had lower crystallinity. Crossed-polarizing microscopy suggested that P4HCA had the nematic liquid crystal properties at 220 degrees C and PDHCA showed birefringence properties at 200 degrees C. In cell-adhesion tests, PDHCA showed the highest cell adhesion (ca. 70%), whereas P3HCA, P4HCA and PMHCA had 50, 18 and 10% cell adhesion, respectively. The coumaric acid derivative homo-polymers can be useful as cell adhesion controllable thermotropic polymers for biomedical and environmental fields.

[Pseudo-aneurysm of the Left Ventricle]

Kyobu Geka. The Japanese Journal of Thoracic Surgery. Aug, 2009  |  Pubmed ID: 19780239

Cyanobacterial Megamolecule Sacran Efficiently Forms LC Gels with Very Heavy Metal Ions

Langmuir : the ACS Journal of Surfaces and Colloids. Aug, 2009  |  Pubmed ID: 20050044

We extracted the megamolecular polysaccharide sacran, which contains carboxylate and sulfate groups, from the jellylike extracellular matrix (ECM) of the cyanobacterium Aphanothece sacrum, which has mineral adsorption bioactivity. We investigated the gelation properties of sacran binding with various heavy metal ions. The sacran chain adsorbed heavier metal ions such as indium, rare earth metals, and lead ions more efficiently to form gel beads. In addition, trivalent metal ions adsorbed onto the sacran chains more efficiently than did divalent ions. The investigation of the metal ion binding ratio on sacran chains demonstrated that sacran adsorbed gadolinium trivalent ions more efficiently than indium trivalent ions. Gel bead formation may be closely correlated to the liquid-crystalline organization of sacran.

Unusual Swelling of HPC in Toluene Forming a Microspherical Domain Structure That Causes Christiansen Scattering Coloration

Langmuir : the ACS Journal of Surfaces and Colloids. Feb, 2010  |  Pubmed ID: 19731958

The unusual swelling behavior of hydroxypropyl cellulose (HPC) by toluene is described. At temperatures as high as 100 degrees C, toluene molecules can enter the HPC film up to the weight fraction of 55%; however, they are segregated from the HPC matrix and form microspherical domains. The size of the spherical domain is approximately 4.5 microm in diameter on average. Such an unusual swelling behavior is due to the amphiphilic nature of the HPC; HPC polymers rearrange to contact their hydrophobic group with toluene and confine the toluene molecules in spherical domains. Because of the similarity in refractive indices of the toluene microspherical phase and the HPC continuum phase, the swollen film shows a beautiful scattering color that is called the Christiansen filter effect.

Cyanobacterial Polysaccharide Gels with Efficient Rare-earth-metal Sorption

Biomacromolecules. Jul, 2010  |  Pubmed ID: 20560613

The cyanobacterial polysaccharide sacran, which contains carboxylate and sulfate groups, was extracted from Aphanothece sacrum , and the metal sorption behavior of sacran was investigated. Heterogels, where the sacran chains were trapped by polyvinyl alcohol networks, were prepared and immersed in NdCl3 solutions to shrink and cloud due to Nd binding. These heterogels had the ability to sorb excessive amounts of Nd ions, more than the stoichiometric ratio of 1:3 (sacran anion/Nd). Furthermore, the sacran-containing gels sorbed Nd ions under highly acidic conditions below pH 2 more efficiently than alginate-containing gels. We speculated that the strong Nd condensation effect of the sulfate groups in sacran under the acidic conditions may enhance the Nd sorption to the carboxylate groups.

[Total Aortic Arch Replacement for Aortic Aneurysm in a 91-year-old Man: Report of a Case]

Kyobu Geka. The Japanese Journal of Thoracic Surgery. Sep, 2010  |  Pubmed ID: 20845701

A 91-year-old man was transferred to our hospital because of severe chest pain. Chest computed tomography (CT) scan showed impending rupture of the true aneurysm of the aortic arch. The patient underwent emergent graft replacement of the total aortic arch. He was extubated on the 1st postoperative day, and received continuous hemodiafiltration (CHDF) for oliguria. However, he recovered from oliguria and renal dysfunction. He discharged at the 67th postoperative day.

Gelation Behavior by the Lanthanoid Adsorption of the Cyanobacterial Extracellular Polysaccharide

Biomacromolecules. Nov, 2010  |  Pubmed ID: 20923217

The self-organization behavior of an extracellular polysaccharide (sacran) extracted from the cyanobacterium Aphanothece sacrum in response to lanthanoid ion adsorption was investigated. Consequently, cryogenic TEM images revealed that sacran could be cross-linked by Nd(3+) trivalent ions and formed a fibrous nanostructural network containing water. Furthermore, sacran adsorbed trivalent metal ions at a 3:1 ratio, which was the theoretical ionic adsorption and showed more efficient adsorption than alginate based on electric conductivity titration. The critical gelation concentrations, Cg, where sacran formed tough gels upon metal ion binding were estimated. The Cg for trivalent metal ions was lower than that for divalent ions, and the Cg for lanthanoid ions was particularly low at 10(-3) to 10(-4) M, changing every four elemental numbers. The extracellular matrix of Aphanothece sacrum, sacran, may adsorb metal ions to create fibrous nanostructures that reinforce the jelly matrix.

Influence of Prosthetic Heart Valve Sound on a Patient's Quality of Life

Annals of Thoracic and Cardiovascular Surgery : Official Journal of the Association of Thoracic and Cardiovascular Surgeons of Asia. Dec, 2010  |  Pubmed ID: 21263422

To elucidate the effects of prosthetic valve sound on a patient's quality of life (QOL).

[Simultaneous Coronary Artery Bypass Grafting and the Ascending Aorta to Bifemoral Bypass]

Kyobu Geka. The Japanese Journal of Thoracic Surgery. Dec, 2011  |  Pubmed ID: 22242287

Coronary artery disease and arteriosclerosis obliterans (ASO) frequently coexist. Concomitant revascularization procedures may be required because harvest of the internal thoracic artery (ITA) in patients with ASO carries a risk of leg ischemia. This study reports our experience with combined coronary and femoral revascularization using the ascending aorta to bifemoral bypass.

Anti-inflammatory Effects of Sacran, a Novel Polysaccharide from Aphanothece Sacrum, on 2,4,6-trinitrochlorobenzene-induced Allergic Dermatitis in Vivo

Annals of Allergy, Asthma & Immunology : Official Publication of the American College of Allergy, Asthma, & Immunology. Feb, 2012  |  Pubmed ID: 22289731

Sacran is a newly discovered sulfated polysaccharide extracted from an algae, Aphanothece sacrum, grown in a river of the Kyushu region in Japan.

[Thoracic Endovascular Stent Graft for Late Pseudoaneurysm Formation After Patch Aortoplasty; Report of a Case]

Kyobu Geka. The Japanese Journal of Thoracic Surgery. Feb, 2012  |  Pubmed ID: 22314173

We report a case of a 51-year-old man presenting with pseudoaneurysm associated with a knitted Dacron patch used to repair coarctation of the aorta. At the age of 15 years, he underwent patch angioplasty for coarctation of the aorta. However the computed tomography( CT) scan, taken after 36 years, demonstrated pseudoaneurysm of the thoracic aorta at the anastmotic site. He was treated by endovascular stent graft using Gore-TAG 3115. His postoperative course was uneventful. Follow-up CT scan demonstrated no recurrence of pseudoaneurysm.

[Successful Surgical Case of DeBakey III B Dissecting Aortic Aneurysm Associated with Right-sided Aortic Arch]

Kyobu Geka. The Japanese Journal of Thoracic Surgery. Mar, 2012  |  Pubmed ID: 22374597

A 66-year-old man was admitted to our institute for surgical treatment of chronic dissecting aortic arch aneurysm with right-sided aortic arch which occurred 2 months previously. The size of the aortic arch aneurysm was larger than 6 cm. Total arch replacement using open stent grafting was performed through median sternotomy. The postoperative condition was well, and the patient was discharged without any complications.

Anti-allergic Effects of Vernonia Amygdalina Leaf Extracts in Hapten-induced Atopic Dermatitis-like Disease in Mice

Allergology International : Official Journal of the Japanese Society of Allergology. Dec, 2012  |  Pubmed ID: 22918214

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by pruritic and eczematous skin lesions. In this study, AD-like disease was induced in NC/Nga mice so as to evaluate the anti-allergic effects of Vernonia amygdalina leaf extracts (VAM).

Photoshrinkage in Polysaccharide Gels with Trivalent Metal Ions

Biomacromolecules. Dec, 2012  |  Pubmed ID: 23121693

The giant anionic polysaccharide "sacran", which is composed of 6-deoxyhexoses, pentoses, uronic acids as well as hexoses, showed hydrophobization and insolubilization phenomena in response to ultraviolet light irradiation. The sacran solution became turbid, and microparticles were formed by photoirradiation. To visualize the results of this photoreaction, anionic polysaccharide gels cross-linked by metal cations were used. As a result, we observed that sacran-gels with trivalent metal ions gradually contracted depending on the photoirradiation energy. In contrast, alginate gels used as a comparison degraded instead of contracting. This photoshrinkage of the sacran gels may be attributed to the hydrophobization of uronic acid based on photodecarboxylation. We propose that sacran-metal ion gels can function as effective, photoresponsive gels.

Anionic Complexes of MWCNT with Supergiant Cyanobacterial Polyanions

Biopolymers. Jan, 2013  |  Pubmed ID: 23097225

Multi-walled carbon nanotubes (MWCNTs) were well dispersed in an aqueous solution of the cyanobacterial polysaccharide, sacran, with an ultra-high molecular weight >10 million g/mol. MWCNTs powder was put into aqueous solutions of various polysaccharides including sacran and was dispersed under sonication. As a result of the turbidity measurement of the supernatant, it was found that sacran showed the highest MWCNT-dispersion efficiency of all the polysaccharides used here. Cryogenic transmission electron microscopic (Cryo-TEM) studies directly demonstrated the existence of MWCNTs in the supernatant, and high-resolution TEM observation revealed that MWCNTs covered by sacran chains made their efficient dispersion in water. Raman spectroscopy demonstrated the existence of MWCNT in dried sample from supernatant and the interaction between MWCNT and sacran. The ζ-potential measurement of the dispersion indicated the negative surface charges of the sacran/MWCNT complexes. Then the MWCNT complexes were able to fabricate by ionic interaction; electrophoresis of the anionic complex formed the sacran/MWCNT gels on the anode while the droplet of sacran/MWCNT dispersion formed gel beads in the presence of the lanthanoid cations.

Ionic State and Chain Conformation for Aqueous Solutions of Supergiant Cyanobacterial Polysaccharide

Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics. Apr, 2013  |  Pubmed ID: 23679443

We have investigated the electric conductivity, dielectric relaxation behavior, and viscosity for the aqueous solution of cyanobacterial megamolecules, molecular weight =1.6×10(7) g/mol, named sacran. Sacran is an anionic polyelectrolyte which has carboxylate and sulfate groups on the saccharide chain. The electric conductivity and the zero shear viscosity demonstrated three crossover concentrations at 0.004, 0.02, and 0.1 wt%. The viscosity was found to be scaled as ~c(1.5), ~c(0.5), ~c(1.5), and ~c(3.0) with increasing the sacran concentration. At 0.1 wt%, the sacran chain formed a weak gel which exhibits macroscopic liquid crystal domains including Schlieren texture. Therefore, these crossover concentrations are considered to be the overlap concentration, entanglement concentration, and gelation concentration (or critical polyelectrolyte concentration), respectively. Dielectric relaxation analysis exhibited the fact that sacran has two types of counterions with different counterion-polyion interaction, i.e., strongly bound and loosely bound counterions. The dielectric parameters such as relaxation time or relaxation strength are sensitive to both the entanglement concentration and the gelation concentration, but not the overlap concentration. The number density of bound counterions calculated from the relaxation strength revealed that the counterion is condensed on the sacran chain with raising the sacran concentrations. The decrease in the charge density of the sacran chain reduces the repulsive force between the chains and this would cause the helix transformation or gelation behavior. The chain conformation of sacran in pure water and the gelation mechanism are discussed in relation with the behavior of polyelectrolytes and liquid crystals.

Microbial Monomers Custom-synthesized to Build True Bio-derived Aromatic Polymers

Applied Microbiology and Biotechnology. Oct, 2013  |  Pubmed ID: 23949992

Aromatic polymers include novel and extant functional materials although none has been produced from biotic building blocks derived from primary biomass glucose. Here we screened microbial aromatic metabolites, engineered bacterial metabolism and fermented the aromatic lactic acid derivative β-phenyllactic acid (PhLA). We expressed the Wickerhamia fluorescens gene (pprA) encoding a phenylpyruvate reductase in Escherichia coli strains producing high levels of phenylalanine, and fermented optically pure (>99.9 %) D-PhLA. Replacing pprA with bacterial ldhA encoding lactate dehydrogenase generated L-PhLA, indicating that the produced enzymes converted phenylpyruvate, which is an intermediate of phenylalanine synthesis, to these chiral PhLAs. Glucose was converted under optimized fermentation conditions to yield 29 g/l D-PhLA, which was purified from fermentation broth. The product satisfied the laboratory-scale chemical synthesis of poly(D-PhLA) with M w 28,000 and allowed initial physiochemical characterization. Poly(D-PhLA) absorbed near ultraviolet light, and has the same potential as all other biomass-derived aromatic bioplastics of phenylated derivatives of poly(lactic acid). This approach to screening and fermenting aromatic monomers from glucose exploits a new era of bio-based aromatic polymer design and will contribute to petroleum conservation and carbon dioxide fixation.

Hyperbranched Polycoumarates with Photofunctional Multiple Shape Memory

Angewandte Chemie (International Ed. in English). Oct, 2013  |  Pubmed ID: 24038918

In good shape: The films of hyperbranched polycoumarate derivatives can undergo a reversible [2+2] cycloaddition under irradiation of UV light and behave like photomechanical elastomers. From a predetermined original shape A the photonically and thermally memorized shapes B and C were obtained. The original shape was recovered by photoirradiation (see picture; Tg =glass transition temperature).

Long-term Outcome of the Carpentier-edwards Pericardial Valve in the Aortic Position in Japanese Patients

Circulation Journal : Official Journal of the Japanese Circulation Society. 2014  |  Pubmed ID: 24621565

 According to the Japanese Circulation Society guidelines, a bioprosthesis is recommended for aortic valve replacement (AVR) in patients aged ≥65 years who have no risk factors for thromboembolism. There are few data, however, regarding the actual durability of bioprosthetic valves in Japanese patients. The purpose of this study was to assess the long-term durability of Carpentier-Edwards pericardial (CEP) valves in Japanese AVR patients, and to assess the risk factors for reoperation due to structural valve deterioration (SVD).

Thoracoabdominal Aortic Aneurysm Repair in a Patient with a Left Ventricular Assist Device

The Annals of Thoracic Surgery. May, 2014  |  Pubmed ID: 24792264

We report a case of thoracoabdominal aneurysm repair in a 44-year-old man with end-stage heart failure requiring an extracorporeal left ventricular assist device (LVAD). At the age of 31 years, the patient experienced type B acute aortic dissection, which gradually dilated to a maximum dimension of 66 mm at the diaphragm. The aneurysm prevented the patient from meeting heart transplantation criteria. For this reason and because of an increased risk of rupture, we undertook surgical repair of the aneurysm. This report constitutes the first such published case, and we describe the management of the LVAD in the perioperative period.

[Successful Excision of a Left Ventricular Fibroma in an Adult Patient; Report of a Case]

Kyobu Geka. The Japanese Journal of Thoracic Surgery. Jul, 2014  |  Pubmed ID: 25137330

A 55-year-old man was referred with a diagnosis of a left ventricular thrombus. Echocardiography revealed that he had a thrombus in the free wall of the left ventricle. Under cardiopulmonary bypass, we removed the intramural tumor. After the removal, the defect was repaired by Dor operation. Pathological examination revealed the tumor was a cardiac fibroma. He is doing well without any troubles 3 years after the operation.

[Graft Replacement Under Percutaneous Cardiopulmonary System for Traumatic Aortic Rupture with Multiple Injuries]

Kyobu Geka. The Japanese Journal of Thoracic Surgery. Sep, 2014  |  Pubmed ID: 25201365

We report a case of traumatic aortic rupture with multiple injuries. A 20-year-old man was transferred to our hospital. He was suffering from traumatic thoracic aortic rupture with multiple injuries (femoral fracture, pelvis fracture and so 4th) due to a traffic accident. Enhanced computed tomography revealed leakage from the aortic isthmus and hematoma in the surrounding area. Emergency operation was performed. The left 4th intercostal thoracotomy was performed and a lacerated foramen was observed across the lesser curvature of the aortic isthmus. The affected site was replaced by a prosthetic graft under percutaneous cardiopulmonary system. He was treated with open fixation of the right femur 11 days after the 1st operation. The postoperative recovery was generally uneventful and he was discharged on the 51st hospital day.

Aortoiliac Aneurysm with Congenital Right Pelvic Kidney

Heart and Vessels. May, 2015  |  Pubmed ID: 24531628

The association of congenital pelvic kidney with abdominal aortoiliac aneurysm is an extremely rare clinical finding. Previous reports have described various methods of aneurysm repair with successful preservation of the function of pelvic kidney. However, to our knowledge, reconstruction of more than two renal arteries has not been established. We report a case of abdominal aortic aneurysm complicated by congenital right pelvic kidney in a 72-year-old man. Computed tomography (CT) revealed an abdominal aortic aneurysm with a maximum diameter of 54 mm and a right common iliac aneurysm of 45 mm. In addition, he had a congenital right pelvic kidney and CT angiography identified three right pelvic renal arteries. The upper artery originated from the bifurcation of the terminal aorta and the lower two originated from the right common iliac artery. Three-dimensional CT was helpful for the accurate planning of the operation. Open surgical repair of the aortoiliac aneurysm with a Dacron bifurcated graft replacement was decided and reimplantation of all three right pelvic kidney arteries to the right limb of the graft was also performed. For renal preservation, the right pelvic kidney arteries were perfused with cold Ringer's lactate using a rapid infusion pump and coronary perfusion cannula. The patient's postoperative course was uneventful, and worsening of renal function was not observed. The perfusion of renal arteries with cold Ringer's solution was thought to be a simple and appropriate procedure for renal protection.

Postoperative Hyperglycemia and Atrial Fibrillation After Coronary Artery Bypass Graft Surgery

Circulation Journal : Official Journal of the Japanese Circulation Society. 2015  |  Pubmed ID: 25392072

Postoperative atrial fibrillation (AF) is a common complication following coronary artery bypass grafting (CABG). We investigated the risk factors for postoperative AF and analyzed the relationship between blood sugar concentration (BS) and AF after CABG.

[Valve Replacement for Tricuspid Valve Regurgitation Due to Pacemaker Lead Adherence;Report of Two Cases]

Kyobu Geka. The Japanese Journal of Thoracic Surgery. Feb, 2015  |  Pubmed ID: 25743352

We experienced tricuspid valve regurgitation (TR) due to pacemaker lead adherence in an 81-year-old woman and in a 68-year-old woman, who both had right heart failure. The cause of TR was deformation of the tricuspid valve by pacemaker leads. Because of strong adherence between the lead and the leaflet or the tendinous cord, lead extraction and valve replacement were performed. The living lead was preserved by fixation at the septum wall outside the valve cuff in 1 patient. In the other patient, the epicardial lead was used for implantation because it was easier compared to intravenous lead implantation. The heart failure and TR improved after the operation in both patients.

[Infectious Endocarditis Complicated with Preoperative Infectious Intracranial Aneurysm;report of a Case]

Kyobu Geka. The Japanese Journal of Thoracic Surgery. Feb, 2015  |  Pubmed ID: 25743362

A 44-year-old man was admitted with the diagnosis of active infective endocarditis( IE) due to Streptococcus mitis, complicated with infectious intracranial aneurysm. Preoperative echocardiography showed mobile vegetation on the mitral leaflet, size of which was 20 mm. The magnetic resonance imaging( MRI) demonstrated that the size of aneurysm was increasing, and infectious intracranial aneurysm was treated surgically. Twenty one days after the operation, the mitral valve plasty was performed. He was discharged on foot without any neurological findings. The duration between the brain surgery and the cardiac surgery was thought to be important to prevent the new neurological complication.

[Restenosis Following Descending Aortic Replacement for Coarctation of the Aorta; Report of a Case]

Kyobu Geka. The Japanese Journal of Thoracic Surgery. Mar, 2015  |  Pubmed ID: 25743559

We report a case of a 44-year-old man with restenosis of coarctation of aorta (CoA). He had a history of descending aortic replacement for CoA using a graft 14 mm in diameter at 29 years ago. He had reoperation because of pressure gradient of 61 mmHg across the graft and intermittent claudication. Reoperation was done under unilateral lung ventilation with lung collapsed, through 3th and 5th interspace thoracotomy. Left lung adhesion was carefully released with an ultrasonically vibrating scalpel. After full heparinization, femoro-femoral bypass was started and descending aorta was clamped. The old graft was excised, and descending aortic replacement was done with a new graft of 26 mm in a diameter. His postoperative course was uneventful. The intermittent claudication disappeared.

Long-term Durability of Pericardial Valves in the Aortic Position in Younger Patients: when Does Reoperation Become Necessary?

Journal of Cardiac Surgery. May, 2015  |  Pubmed ID: 25786674

We sought to assess the long-term durability of pericardial valves in patients at age <65 years undergoing aortic valve replacement (AVR), and to determine the timing of redo operations due to structural valve deterioration (SVD).

Twenty-year Outcome of Aortic Valve Replacement with St. Jude Medical Mechanical Valves in Japanese Patients

Circulation Journal : Official Journal of the Japanese Circulation Society. 2015  |  Pubmed ID: 26346033

Bioprostheses have become increasingly popular for aortic valve replacement (AVR) in recent years, but mechanical valves are still the standard choice, especially for younger patients. The aim of this study was to assess the very long-term outcomes in Japanese patients who underwent AVR with St. Jude Medical (SJM) mechanical valves.

(1)H NMR and FT-IR Dataset Based Structural Investigation of Poly(amic Acid)s and Polyimides from 4,4'-diaminostilbene

Data in Brief. Jun, 2016  |  Pubmed ID: 26933669

Structural investigation of polymers by various available analytical methods is important in order to correlate the structure with polymer properties for which understanding of polymer structure is very important factor. The data presented here in this article shows the (1)H NMR spectra used for the characterization of prepared poly(amic acid)s (PAAs). It is often difficult to assigns the peak in NMR of polymers due to its complexity. Data presented here helps in assigning the proton peak in complex NMR of PAAs prepared from aromatic diamines. Further functionality in polymer chains can be confirmed by FT-IR spectra. Change in functionality during some reaction or process can be monitored by disappearance or appearance of peaks in FT-IR. The complete imidization of PAAs to Polyimides (PIs) is difficult to analyze because of the chemical stability i.e. insolubility of PIs in most of the solvent therefore the completion of imidization process was confirmed using FTIR.

Milliscale Self-Integration of Megamolecule Biopolymers on a Drying Gas-Aqueous Liquid Crystalline Interface

Biomacromolecules. Jun, 2016  |  Pubmed ID: 27077450

A drying environment is always a proposition faced by dynamic living organisms using water, which are driven by biopolymer-based micro- and macrostructures. Here, we introduce a drying process for aqueous liquid crystalline (LC) solutions composed of biopolymer with extremely high molecular weight components such as polysaccharides, cytoskeletal proteins, and DNA. On controlling the mobility of the LC microdomain, the solutions showed milliscale self-integration starting from the unstable gas-LC interface during drying. In particular, we first identified giant rod-like microdomains (∼1 μm diameter and more than 20 μm length) of the mega-molecular polysaccharide, sacran, which is remarkably larger than other polysaccharides. These microdomains led to the formation of a single milliscale macrodomain on the interface. In addition, the dried polymer films on a solid substrate also revealed that such integration depends on the size of the microdomain. We envision that this simple drying method will be useful not only for understanding the biopolymer hierarchization at the macroscale level but also for preparation of surfaces with direction controllability, as seen in living organisms, for use in various fields such as diffusion, mechanics, and photonics.

Physically Crosslinked-sacran Hydrogel Films for Wound Dressing Application

International Journal of Biological Macromolecules. Aug, 2016  |  Pubmed ID: 27151668

The thin hydrogel films consisting of water-swollen polymer networks can potentially be applied for biomedical fields. Recently, natural polysaccharides have great attentions to be developed as wound healing and protection. In the present study, we newly prepared and characterized a physically crosslinked-hydrogel film composed of a novel megamolecular polysaccharide sacran for wound dressing application. We successfully fabricated a physically crosslinked-sacran hydrogel film by a solvent-casting method. The thickness of a sacran hydrogel film was lower than that of a sodium alginate (Na-alginate) film. Importantly, the swollen ratio of a sacran hydrogel film in water at 24h was 19-fold, compared to initial weight. Meanwhile, a Na-alginate hydrogel film was completely broken apart after rehydration. Moreover, a sacran hydrogel film did not show any cytotoxicity on NIH3T3 cells, a murine fibroblast cell line. The in vivo skin hydration study revealed that a sacran hydrogel film significantly increased the moisture content on hairless mice skin and considerably improved wound healing ability, compared to control (non-treated), probably due to not only the moisturing effect but also the anti-inflammatory effect of sacran. These results suggest that sacran has the potential properties as a basic biomaterial in a hydrogel film for wound dressing application.

Bacterial Fermentation Platform for Producing Artificial Aromatic Amines

Scientific Reports. May, 2016  |  Pubmed ID: 27167511

Aromatic amines containing an aminobenzene or an aniline moiety comprise versatile natural and artificial compounds including bioactive molecules and resources for advanced materials. However, a bio-production platform has not been implemented. Here we constructed a bacterial platform for para-substituted aminobenzene relatives of aromatic amines via enzymes in an alternate shikimate pathway predicted in a Pseudomonad bacterium. Optimization of the metabolic pathway in Escherichia coli cells converted biomass glucose to 4-aminophenylalanine with high efficiency (4.4 g L(-1) in fed-batch cultivation). We designed and produced artificial pathways that mimicked the fungal Ehrlich pathway in E. coli and converted 4-aminophenylalanine into 4-aminophenylethanol and 4-aminophenylacetate at 90% molar yields. Combining these conversion systems or fungal phenylalanine decarboxylases, the 4-aminophenylalanine-producing platform fermented glucose to 4-aminophenylethanol, 4-aminophenylacetate, and 4-phenylethylamine. This original bacterial platform for producing artificial aromatic amines highlights their potential as heteroatoms containing bio-based materials that can replace those derived from petroleum.

Highly Transparent and Flexible Bio-based Polyimide/TiO2 and ZrO2 Hybrid Films with Tunable Refractive Index, Abbe Number, and Memory Properties

Nanoscale. Jul, 2016  |  Pubmed ID: 27297905

The novel bio-based polyimide (4ATA-PI) and the corresponding PI hybrids of TiO2 or ZrO2 with excellent optical properties and thermal stability have been prepared successfully. The highly transparent 4ATA-PI containing carboxylic acid groups in the backbone could provide reaction sites for organic-inorganic bonding to obtain homogeneous hybrid films. These PI hybrid films showed a tunable refractive index (1.60-1.81 for 4ATA-PI/TiO2 and 1.60-1.80 for 4ATA-PI/ZrO2), and the 4ATA-PI/ZrO2 hybrid films revealed a higher optical transparency and Abbe's number than those of the 4ATA-PI/TiO2 system due to a larger band gap of ZrO2. By introducing TiO2 and ZrO2 as the electron acceptor into the 4ATA-PI system, the hybrid materials have a lower LUMO energy level which could facilitate and stabilize the charge transfer complex. Therefore, memory devices derived from these PI hybrid films exhibited tunable memory properties from DRAM, SRAM, to WORM with a different TiO2 or ZrO2 content from 0 wt% to 50 wt% with a high ON/OFF ratio (10(8)). In addition, the different energy levels of TiO2 and ZrO2 revealed specifically unique memory characteristics, implying the potential application of the prepared 4ATA-PI/TiO2 and 4ATA-PI/ZrO2 hybrid films in highly transparent memory devices.

Starr-Edwards Caged-ball Aortic Valve: Preserved Function 40 Years After Implantation

Journal of Cardiac Surgery. Sep, 2016  |  Pubmed ID: 27443237

Enhancing Effect of γ-cyclodextrin on Wound Dressing Properties of Sacran Hydrogel Film

International Journal of Biological Macromolecules. Jan, 2017  |  Pubmed ID: 27720964

A wound dressing is one of the essential approaches for preventing further harm to cutaneous wounds as well as promoting wound healing. Therefore, to achieve ideal wound healing, the development of advanced dressing materials is necessary. Recently, we revealed that a novel megamolecular polysaccharide, sacran, has potential properties as a biomaterial in a physically cross-linked hydrogel film (HGF) for wound dressing application. In this study, to enhance the wound-healing properties of sacran hydrogel film (Sac-HGF) further, we fabricated and characterized novel Sac-HGFs containing cyclodextrins (CyDs). The sacran/α-CyD film (Sac/α-CyD-HGF) and sacran/γ-CyD HGF (Sac/γ-CyD-HGF), but not sacran/β-CyD HGF (Sac/β-CyD-HGF), were well prepared without surface roughness. Powder X-ray diffraction (XRD) patterns of the Sac/γ-CyD-HGFs showed a totally amorphous state compared to that shown by Sac/α-CyD-HGFs. Furthermore, the addition of γ-CyD to Sac-HGFs significantly increased the swelling ratio, porosity, and moisture content of the HGFs, compared to those of the Sac-HGF without CyDs. The Sac/γ-CyD-HGFs were not cytotoxic against NIH3T3 cells, a murine fibroblast cell line. Notably, the Sac/γ-CyD-HGFs significantly improved wound healing in mice, compared to that achieved with the Sac-HGF without γ-CyD. These results suggest that γ-CyD has the potential to promote the wound healing ability of Sac-HGF.

Optical Second-harmonic Images of Sacran Megamolecule Aggregates

Journal of the Optical Society of America. A, Optics, Image Science, and Vision. Feb, 2017  |  Pubmed ID: 28157840

We have detected a second-order nonlinear optical response from aggregates of the ampholytic megamolecular polysaccharide sacran extracted from cyanobacterial biomaterials by using optical second-harmonic-generation (SHG) microscopy. The SHG images of sacran cotton-like lump, fibers, and cast films showed SHG intensity microspots of several tens of micrometers in size. The dependence of the SHG spot intensity on an excitation light polarization angle was observed to illustrate sacran molecular orientation in these microdomains. We also observed SHG signals around a special region of the cast film edges of sacran. These results show that sacran megamolecules aggregate in several different ways.

Enhancement of Curcumin Wound Healing Ability by Complexation with 2-hydroxypropyl-γ-cyclodextrin in Sacran Hydrogel Film

International Journal of Biological Macromolecules. May, 2017  |  Pubmed ID: 28161536

Curcumin is one of promising agents to accelerate the wound-healing process. However, the efficacy of curcumin is limited due to its poor water solubility and stability. To enhance the properties of curcumin, 2-hydroxypropyl-γ-cyclodextrin (HP-γ-CyD) can be used through complexation. Recently, we revealed that sacran has the potential to form a hydrogel film (HGF) as a wound dressing material. Therefore, in the present study, we investigated the wound healing ability of curcumin/HP-γ-CyD (Cur/HP-γ-CyD) complex in sacran-based HGF (Sac-HGF). We prepared the Cur/HP-γ-CyD complex in Sac-HGF without surface roughness. Additionally, the amorphous form in the Cur/HP-γ-CyD complex in Sac-HGF were observed. In contrast, the curcumin in Sac-HGF and curcumin/HP-γ-CyD physical mixture in Sac-HGF formed inhomogeneous films due to crystallization of curcumin. Furthermore, HP-γ-CyD played an important role to increase the elastic modulus of the Sac-HGF with high re-swelling ability. The Cur/HP-γ-CyD complex in Sac-HGF maintained antioxidant properties of curcumin. Curcumin was gradually released from the HP-γ-CyD complex in Sac-HGF. Notably, the Cur/HP-γ-CyD complex in Sac-HGF provided the highest wound healing ability in hairless mice. These results suggest that the Cur/HP-γ-CyD complex in Sac-HGF has the potential for use as a new transdermal therapeutic system to promote the wound-healing process.

Drying-Induced Self-Similar Assembly of Megamolecular Polysaccharides Through Nano and Submicron Layering

Langmuir : the ACS Journal of Surfaces and Colloids. Feb, 2017  |  Pubmed ID: 28190355

We propose a self-similar assembly to generate planar orientation of megamolecular polysaccharides on the nanometer scale and submicron scale. Evaporating the aqueous liquid crystalline (LC) solution on a planar air-LC interface induces polymer layering by self-assembly and rational action of macroscopic capillary forces between the layers. To clarify the mechanisms of nanometer- and submicron-scale layering, the polymer films are investigated by electron microscopy.

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