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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.

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.

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.

Thermotropic liquid crystalline (LC) hyperbranch oligoesters (molecular weight of ca. 8 kDa) composed of rigid biodegradable segments, oligo{4-hydroxycinnamic acid (4HCA)}, plus a multifunctional biomolecule, cholic acid (CA), were prepared. Semiempirical calculations for the most stable conformation of the model compound CA derivatives with four arms of 4HCA tetramer showed that every arm can adopt an almost parallel orientation and that the CA unit can form a crankshaft architecture and function as a four-way junction of a branch point. Oligo(4HCA-co-CA)s successfully form molecularly oriented fibers with a high orientation degree by spinning viscous LC melts. Scanning electron microscopy demonstrated that mouse fibroblasts oriented uniaxially along the fiber longitudinal axis. Moreover, confocal fluorescence scanning microscopy showed that the RFP-stained cytoskeleton of these fibroblasts oriented highly.

Oligopeptides were conjugated to the thermoresponsive polymer poly(N-vinylbutyramide) (PNVIBA) by the graft polymerization of the corresponding N-carboxyamino acid anhydrides from the amino side groups of P(NVIBA-co-vinylamine)s. The P{NVIBA-graft-l-aspartic acid (LAA)} with random-coiled graft chains showed a quick coil−globule transition accompanied by an endotherm due to chain dehydration across its low critical solution temperature (LCST) upon heating. In contrast, the P{NVIBA-graft-l-glutamic acid (LGA)}s with α-helical graft chains showed a slow transition accompanied by not only an endotherm but also an exotherm. A circular dichroism (CD) study indicated that the oligoLGA grafts changed their conformation accompanying the coil−globule transition of the PNVIBA backbone but recovered the α-helix at just above the exothermic temperature. 1H nuclear magnetic resonance (1H NMR) indicated that the proton signals from the PNVIBA backbones and oligoLGA grafts were clearly detected just above the LCST, but ...

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.

症例は51歳,男性で,平成15年10月,労作時息切れのため受けた心臓超音波検査で大動脈弁閉鎖不全症が4年前に比べて進行していたため,手術目的で当科入院となった.小児期より数回の骨折歴あり,身長は146.0cm,体重は49.0kgで青色強膜を認めたので,骨形成不全症と診断されていた.血液・凝固系に明らかな異常はなかった.心臓超音波検査では,大動脈弁左冠尖の逸脱が逆流の主たる原因で,バルサルバ洞は軽度拡大していた.大動脈弁置換術(SJM25mm)を施行した.胸骨および軟部組織は通常に比べ脆弱な印象であった.大動脈弁は全体に菲薄化した弁尖で,病理組織学的所見(Elastica-Masson染色)では,弁尖および左室心筋で弾性線維肥厚が著明であった.術後経過は良好であった.骨形成不全症に心・血管疾患の合併することは希であるが,手術による死亡率が約30%と高い.術後21ヵ月目に心不全で死亡した例の報告もあり,今後注意深い観察を必要とする.

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.

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.

ABA-type triblock copolymers, poly{(γ-benzyl l-aspartate) (BLA)-block-ethylene oxide (EO)-block-BLA}, with a controlled chain length were prepared. The copolymer film (ca. 0.01 mm thickness) was immersed into the water to create a thin, self-sustainable hydrogel membrane (0.01−0.02 mm thickness) that was largely deformable and tough in its equilibrated water-swollen state (water content: 58−83 wt %). Crossed-polarizing microscopy confirmed that the water-swollen membrane had a framework of giant crystalline domains 10 μm−4 mm in size; as far as we know, crystalline domains large enough to observe by an optical microscope in the hydrogels have never been reported. During the water-swelling process, the triblock copolymers showed an α-helix−β-strand transformation of their PBLA blocks and long-range structural formation, which may have reinforced the hydrogel thin membrane, thus increasing its toughness.

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)-γ-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.

Porous poly(N-isopropylacrylarfide) (PNI-PAAm) hydrogels were successfully prepared in the presence of nanosized silica particles with network morphology and subsequent silica extraction by HF treatment. The nanosized pores induced very rapid deswelling of the hydrogels, accompanied by volume phase transitions from swelling to deswelling states at approximately 30 °C. Deswelling, which was analyzed by a quick change in temperature of the aqueous media from 20 to 40 °C, was facilitated by increased silica particle content. The deswelling rate constant of the hydrogel prepared using silica nanoparticles with a network morphology (NT gel) was about 1 900-fold greater than that of nonporous hydrogels and 13-fold larger than that of porous hydrogels perforated using spherical silica nanoparticles (SP gel). The releasing rate of the low-molecular weight chromophore from the NT gel was higher than that from the SP gel. In the chromophore-labeled macromolecules, the network morphology was effective for increasing the releasing rate based on the transfer inside the hydrogel, as well as for increasing the amount released based on the surface pore morphology.

Solvent-sensitive Nanospheres Prepared by the Self-organization of Polymerizing Hydrophilic Graft Chain Copolymers

Successful ATRP Syntheses of Amphiphilic Block Copolymers Poly(styrene- block - N , N -dimethylacrylamide) and Their Self-assembly

疎水性のメソゲン基の近傍に親水性のアクリル酸を共重合により存在させると, スメクチックA (SmA) 相の層構造秩序が増大し, 等方化温度が上がる現象が見られた. 乾燥状態で配向した繊維を水中に浸すことにより分子配向した液晶性ヒドロゲルを初めて作製した. 本ヒドロゲルは含水率の変化によりSmA相からスメクチックI (SmI) 相へ構造転移を示し, 続く延伸処理において逆のSmI-SmA構造転移を示した. さらに, 加熱時には40℃付近で同様のSmI-SmA液晶相転移を示した. そこで, 配向ヒドロゲルの片端を固定し, ゆっくりと昇温すると, 相転移温度付近で収縮挙動を示した. 構造と運動機能との相関を調べたところ, 液晶相転移とそのメカニクスには強い相関があることが見いだされた. 以上により, 液晶-液晶転移が等方化温度よりも低いことを利用し, 水中でかつ体温領域で運動性を示すアクチュエーターを作製することができた.

Background 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. Methods and Results Rheologic examinations were done in 197 patients using a vacuum-suction glass tube viscometer after CABG surgery was completed. Shear stress and shear rate were calculated from the geometry of the graft, blood flow in the graft and blood viscosity. Of 197 patients, 177 underwent LITA grafting to the left anterior descending artery (LAD) and 160 had SVG anastomosis to coronary arteries. Mean wall shear stress in the LITA grafts to the LAD (13.8±1.0 dyne/cm2) was nearly 4-6-fold larger than that in the SVG grafts. Mean shear rate (559.1±57.0 s-1) of LITA-LAD grafts was approximately 2-3-fold higher than that of SVG. Conclusion These results suggest that high wall shear stress and shear rate play an important role in the higher patency rate of LITA grafts. (Circ J 2005; 69: 700 - 706)

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.

Background 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. Methods and Results Of 101 patients with AF undergoing PV-cryo, the 71 in SR at discharge were grouped according to whether they maintained or lost SR (group SR, n=61, and group AF, n=10) after an average of 2.3 years. Atrial fibrillation present at discharge (n=30) persisted during follow up. Comparisons were made to identify preoperative predictive factors, including transthoracic and transesophageal echocardiographic parameters. Of patients discharged from the hospital with SR, 92% (46 of 50) of those with AF duration of 3 years or less were in group SR, as were 92% (23 of 25) of those with left atrial dimension of 50 mm or less, and 93% (37 of 40) of those with average peak left atrial appendage outflow velocities (LAA-V) of at least 30 cm/s. Of 25 patients in group SR who had no paroxysmal AF and did not require antiarrhythmic drugs, all had LAA-V over 20 cm/s. Patients in group AF all had LAA-V under 40 cm/s. Conclusions Left atrial appendage outflow velocities was the best predictor of whether SR was maintained long-term after PV-cryo. (Circ J 2005; 69: 446 - 451)

Freeze−thawed poly(vinyl alcohol) hydrogels were structurally oriented by uniaxial mechanical drawing up to 1−5 times their original length, and the orientation was fixed by successive chemical cro...

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.

The hydrogel of poly(11-(4‘-cyanobiphenyloxy)undecyl acrylate-co-acrylic acid), poly(11CBA-co-AA), which was comprised of the hydrophobic cross-linking junction zone with the liquid crystalline nature and the hydrated amorphous domain, showed a smectic mesophase transition at 40 °C in the body temperature range. X-ray diffraction study suggests the water transfer from the main chain domain of the liquid crystalline junction zone to the amorphous domain through the smectic transition. The oriented hydrogel fiber showed a drastic shrinkage through this transition, keeping the orientation. Moreover, the mesomorphic behavior of LCG depended on the aqueous milieu. Thus, the present LCG physically cross-linked by the mesomorphic junction could be considered to be an open system of new actuators controllable in the change in the aqueous milieu at ambient conditions.

The compound 4-hydroxycinnamic acid (4HCA), a naatural biomonomer, is polymerized by melt polycondensation to yield a liquid-crystalline biopolymer (P4HCA) with UV reactivity. L929 cells were successuflly incubated on P4HCA films at 37°C.

ABA triblock copolymers comprised of poly(β-benzyl-l-aspartate) (PBLA) as an A segment and poly(ethylene oxide) (PEO) as the B segment were precisely synthesized by a ring-opening polymerization of the N-carboxyanhydride of BLA initiated from amines at both terminals of the PEO chain. The copolymers have a number-average molecular weight (Mn) of 1.5 × 104−3.6 × 104 and a monodisperse molecular weight distribution in the range 1.04−1.07. The copolymer films casted from a dichloromethane solution were flexible and elastic despite their low Mn. The film formed a hierarchical structure, i.e., the chains adopted an α-helix−72 helix−α-helix conformation and was highly crystallized, forming a long-range ordering structure which resulted in a rodlike construct arranged like ripples, as confirmed by Fourier transformed infrared spectroscopy, X-ray diffraction, and atomic force microscopy. Differential scanning calorimetry confirmed that the film showed a melting endotherm of the PEO segment at 313−326 K depending ...

Thermosensitive biopolymers with an amphipathic structure were synthesized through the propyl esterification of the carboxyl groups of poly γ-glutamic acid) (γ-PGA). The clouding temperature on heating was controlled by the addition of different amounts of NaCl and by the degree of esterification. The clearing temperature on cooling was independent of the aqueous milieu, presumably because of the strong multiple hydrogen bonds between the polymer chains formed in the collapsed state. The hydrogel of γ-PGA propylate crosslinked by a chemical reaction with hexamethylene diisocyanate also showed pH-responsive and thermoresponsive shrinking, but the volume recovery was incomplete during the cooling process. A Fourier transform infrared/ attenuated total reflection study showed that the incomplete volume recovery might be associated with the amide hydrogen bonding being strengthened by the chemical crosslinkage. The addition of urea made the volume change complete.

Background 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. Methods and Results Seventy-seven patients with AF undergoing PV-cryo were recruited and divided into 2 groups based on whether they were able to maintain SR at discharge. The duration of AF (AF-D), left atrial dimension (LAd), and the average of the peak left atrial appendage outflow velocities (LAA-V) before surgery were determined for both groups. Group SR consisted of 54 patients (70%), and group AF consisted of 23 patients (30%). All patients with an AF-D ≤3 years, LAd 40 cm/s were in group SR and all those with an AF-D >10 years and LAd ≥65 mm were in group AF. Only 71% of patients with a LAA-V ≤20 cm/s were in group AF. Conclusions Restoration of AF to SR by PV-cryo can be predicted from a knowledge of the AF-D, LAd and LAA-V. (Circ J 2004; 68: 999 - 1003)

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.

Physically crosslinked sacran gels were prepared, and the degree of swelling in pure water and in 0.9 wt % NaCl solution was measured. The sacran gel showed anomalous swelling with a degree of swel...

Nanoparticles with projection coronas were prepared by the one-step dispersion terpolymerization of styrene, acrylonitrile, and poly(ethylene glycol) monomethacrylate in ethanol-water solution, and their morphologies were controlled. When the mole composition of acrylonitrile to the total monomers CAN was 0.49-0.66, electron microscopy showed that the nanoparticles were spherical and had a number of projections on the surface. A CAN of more than 0.66 yielded no nanospheres, and a CAN smaller than 0.49 yielded projection-free nanospheres. The morphology of the nanospheres could be controlled by changing the reaction conditions, and some conditions yielded a regular arrangement of uniform projections on the surface similar to that seen in some coronaviruses. X-ray and spectroscopic studies suggested that the projections might be formed as a result of the nonequilibrated swelling of acrylonitrile and poly(ethylene glycol) domains on the surface.

Copolymers composed of 5-acryloyloxypentyl cholesterate (Ch5A) and acrylic acid (AA), poly(Ch5A-co-AA)s, were prepared changing their molar ratio, and their mesomorphic behaviors were investigated. Wide- and small-angle X-ray diffraction studies showed that poly(Ch5A-co-AA)s with a Ch5A mole fraction, F, of 0.20 and larger showed the smectic A phase in which side chains are arranged perpendicularly to the main-chain axis forming bilayers. The structural ordering and the clearing temperature, Tc, increased with decreasing F. The copolymers with F of around 0.10 exhibited a mesophase showing extremely high Tc and longer periodic spacing than the SmA phase. The copolymers of F = 0.05 and higher were not dissolved in water but swelled to form hydrogels with mesomorphic properties, presumably due to the physical cross-linking of hydrophobic aggregates of Ch5A side chains. The relationship between the uncommon thermotropic behavior and the mesomorphic structure formed by the specific interaction of chiral Ch5A ...

The complexation of bile acids with various solvated polycations was studied. A one-to-one complex was precipitated when an aqueous solution of cholic acid sodium salt (CA) was mixed with aqueous solutions of 3,3-ionene and grew to form crystals with needle-like morphology, 3 millimeters in length. Hydrogen bonding of hydroxyls at the steroid face and the spacing between cationic sites of polycations were crucial for the formation of the giant needle.

Poly(aramid silicone) (PAS) multiblock copolymers were synthesized by the low-temperature solution polycondensation of isophthaloyl dichloride (IPC) and two diamines, diamino poly(dimethyl siloxane) (PDMS; number-average molecular weight = 1680) and 3,4'-diaminodiphenylether (3,4'-DAPE), in tetrahydrofuran/dimethylacetamide (2/1 v/v). Two synthetic methods for the control of the PAS sequence were used: a one-step synthesis that presumably gave PAS with a random sequence and the polymerization of 3,4'-DAPE with a presynthesized dimer, IPC-PDMS-IPC (two-step synthesis), that presumably gave PAS with an alternating sequence of 3,4'-DAPE and PDMS segments. In a 1 H NMR study of the amide protons of the 3,4'-DAPE component in PAS, the relative length of the 3,4'-DAPE segment of randomly sequenced PAS to that of ideally sequenced PAS could be estimated. The glass-transition temperatures of the 3,4'-DAPE and PDMS segments of random PAS were 152-234 and -104 to - 117 °C, respectively, whereas the alternating PAS sequences showed no glass transition for the 3,4'-DAPE segments. A tensile test indicated that randomly sequenced PAS behaved like a rubber-toughened material at lower PDMS contents and like a thermoplastic elastomer at higher PDMS contents, whereas the alternately sequenced PAS behaved like a very soft rubber, showing a high value of elongation at the breaking point.

Porous poly(N-isopropylacrylamide) hydrogels were prepared by the free-radical polymerization of its monomer and a suitable crosslinker in the presence of spherical silica particles of different sizes (74 and 1600 nm) and by the subsequent acid extraction of silica. The yields were 81–83%, and the yields were not affected by the silica content. Scanning electron microscopy observations revealed the porous structure of the hydrogels. Porous and nonporous hydrogels showed volume phase transitions from swelling states to deswelling states at approximately 30 °C, as analyzed by the ratio of the diameter of cylinder-shaped hydrogels to that of the glass tube used for the hydrogel preparation at the corresponding temperature. Deswelling, which was analyzed by rapid changes in the temperature of the aqueous media from 20 to 40 °C, was facilitated by decreased silica particle size and increased silica content. The deswelling rate constant of the hydrogel prepared with 74-nm silica at 10 v/v % (silica/solvent) was more than 1500 times greater than that of conventional hydrogels. Swelling was similarly analyzed through changes in the temperature from 40 to 20 °C and was independent of the pore structure. The deswelling–swelling cycle was repeatable with reasonable reproducibility. Moreover, the mechanical strength of the porous hydrogels was significantly maintained compared with that of conventional nonporous hydrogels. This method produced thermoresponsive hydrogels of suitable mechanical strength and remarkable deswelling properties. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4228–4235, 2002

Free radical polymerization of N-isopropylacrylamide (NIPAAm) and crosslinker solutions, which were fulfilled in silica particles with an interpenetrated and nanometer-sized porous structure (a diameter of 3 mm and mean pore sizes of 15, 30, and 50 nm), fabricated hybrids of organic hydrogels and inorganic silica. Differential scanning calorimetric analyses of the hybrids revealed that silica components affected the thermoresponsive properties of polyNIPAAm hydrogels. Porous polyNIPAAm hydrogels were prepared by the subsequent acid treatment of the hybrids to remove silica. Transmission Fourier transformed infrared spectra indicated the selective extraction of silica. Scanning electron microscopic observation of the hydrogels confirmed the porous structure. The deswelling rate of porous hydrogels was 7 times larger than that of conventional hydrogels and increased with increasing the pore size of silica used. However, the swelling was not affected by the pore formation. The thermoresponsiveness of porous polyNIPAAm hydrogels could be regulated by the pore size. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3542–3547, 2002

We have detected second-order nonlinear optical response from an amphoteric mega-saccharides named sacran under a needle/ring electrode stimulus by using an optical second harmonic generation (SHG) microscope. SHG was observed from sacran in the neighborhood of the negatively biased needle electrode below -4.5 V with respect to the outer ring electrode. From the incident light polarization dependence of SHG, this sacran was suggested to be oriented toward the electrode needle. SHG of the sacran polymer was judged to be induced by sacran aggregates with net positive charge.

The water-soluble copolymers having pendant terthiophene, poly(AA3T-co-AA), were synthesized by radical copolymerization of [(2,2':5',2-terthiophen-5- yl)methyl acrylate] (AA3T) and acrylic acid (AA), and their molecular structures and thermal behaviors were studied. X-ray diffraction study showed that the copolymers containing a certain amount of AA3T can form the crystals with monolayer structure, while incorporation of too many AA units into the copolymers disrupted this structure. Possible mechanism of self-doping on heating was discussed in terms of interaction between AA3T unit with AA unit in the copolymers.

Background & Aims : Although aortic valve replacement (AVR) is the only effective treatment for patients with aortic stenosis (AS), it is generally recognized that the surgical risk increases with age.Methods : We examined the outcome of surgical management for AS in patients above 70 years of age in comparison with younger ones to determine whether age was a risk factor.Results : We obtained relatively good results in 3-and 5-year mortality (17% and 25%) in the elder group which were not significantly different from the younger group (5% and 13%). Perioperative factors were not significantly different between the two group. Elderly patients had significantly smaller body surface areas (BSAs) (1.43 ± 0.15 vs. 1.53 ± 0.16m2) and smaller valves (20.5 ± 1.8 vs. 22.0±2.0mm). The age was significantly correlated with the BSA (correlation coefficient=-0.433, p

Background: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.Methods and Results:A total of 199 consecutive patients who underwent isolated CABG were retrospectively examined and classified according to the presence (n=95) or absence (n=104) of postoperative AF. On univariate analysis mean postoperative BS (P

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.