Prevalence of congenital coronary artery anomalies of korean men detected by coronary computed tomography.

BACKGROUND AND OBJECTIVES: It has been demonstrated that the anomalous origin of coronary arteries (AOCA) are generally asymptomatic and rare diseases. However, some cases can cause severe life threatening events. To detect these anomalies, coronary angiographies and autopsies were used to detect coronary artery anomalies, but these procedures have limitations because of their invasiveness. The new device, Multidetector Computed Tomography (MDCT), now replaces the method of choice for detecting coronary anomalies. The prevalence of these anomalies in Korea has not been studied yet. This present analysis attempted to determine the prevalence of AOCA in Korean men by MDCT. SUBJECTS AND METHODS: 1582 Korean male police officers underwent coronary MDCT for their health screening voluntarily. After reconstruction of CT images, we could confirm coronary artery anomalies. RESULTS: The prevalence of AOCA in Korean men was 1.14% (18 out of 1582 cases). The most common abnormality (11 cases, 0.70%) was the origin of the coronary artery. Anomalies of the coronary artery end point were observed in 5 cases (0.32%). The anomalous location of coronary ostium on the aortic root was observed in 1 case (0.06%). An anomalous collateral vessel was observed in 1 case (0.06%). CONCLUSION: The prevalence of coronary artery anomalies in Korean men was 1.14%. Coronary CT is a safe and noninvasive modality for detecting coronary anomalies.

A case of balanced type double aortic arch diagnosed incidentally by transthoracic echocardiography in an asymptomatic adult patient.

A 36-year-old male patient with no remarkable medical history was admitted to our hospital for a health check up. On chest radiography, bilateral aortic notches at the level of aortic arch were shown suggesting aortic arch anomaly without any clinical symptoms. Two aortic arches were almost same-in-size on suprasternal view of transthoracic echocardiography. In addition, multidetector computed tomography showed balanced type double aortic arch forming a complete vascular ring which encircled the trachea and esophagus. The trachea was slightly compressed by the vascular ring whereas the esophagus was intact. Nevertheless, the pulmonary function test was normal. The patient was discharged from hospital with instructions for periodic follow-up.

Conjugated polymers and an iron complex as electrocatalytic materials for an enzyme-based biofuel cell.

Poly-5,2':5',2''-terthiophen-3'-carboxylic acid (polyTTCA) and poly-Fe(III)-[N,N'-bis[4-(5,2':5',2''-terthien-3'-yl)salicyliden]-1,2-ethanediamine] (polyFeTSED) were synthesized and electrochemically polymerized on an Au surface for use as mediators and catalysts for a biofuel cell. The atomic force microscopy (AFM) images of (a) the TTCA homopolymer (polyTTCA) and (b) the TTCA-FeTSED copolymer (poly(TTCA-FeTSED)) layers show a nanoparticle structure. The enzymes (glucose oxidase (GOx) or horseradish peroxidase (HRP)) were immobilized onto the conducting polymer layer through covalent bond formation, which allowed for direct electron transfer processes of the enzymes. A quartz crystal microbalance (QCM) revealed that the surface coverages of GOx and HRP were 4.21 x 10(-12)M and 9.65 x 10(-12)M, respectively. The anode with immobilized GOx and the cathode with immobilized HRP were used as model enzyme systems in biofuel cells for glucose and H(2)O(2) detection, respectively. The biofuel cell composed of the GOx/polyTTCA/Au and the HRP/poly(TTCA-FeTSED)/Au electrodes was assembled and examined for cell performance. The copolymer of polyFeTSED complex with polyTTCA revealed a catalytic activity for the electrochemical reduction of H(2)O(2) and resulted in approximately a sevenfold increase in the power density of the biofuel cell over that of polyTTCA itself. Moreover, the conjugated polymers extend the biofuel cell lifetime to 4 months through the stabilization of immobilized enzymes. The biofuel cell operated in a solution containing glucose and anode-produced H(2)O(2) generated an open-circuit voltage of approximately 366.0 mV, while the maximum electrical power density extracted from the cell was 5.12 microW cm(-2) at an external optimal load of 25.0 k Omega.

Water sensor for a nonaqueous solvent with poly(1,5-diaminonapthalene) nanofibers.

A water sensor for a nonaqueous solvent was fabricated using poly(1,5-diaminonapthalene (DAN) nanofibers, which were prepared through a catalytic chemical polymerization of the DAN monomer using Fe(III) salt as the catalyst. Poly(1,5-DAN) nanofibers were characterized by atomic force microscope (AFM), transmission electron microscope (TEM), scanning electron microscope (SEM), and UV-vis spectroscopy. The electrochemical properties of poly(1,5-DAN) nanofibers were investigated using cyclic voltammetry (CV). The electrochemical activity of poly(1,5-DAN) nanofibers was utilized for water sensing. The fabrication of water sensor was followed by placing one drop (about 2 microL) of 0.01% poly(1,5-DAN) nanofibers solution in the gap between two split gold electrodes (PBSA) and completely dried. The response of the water sensor in an acetonitrile solution was evaluated under optimized conditions. The linear dynamic range was from 0.05 to 20%, and the detection limit was determined to be 0.01%. The response of this sensor was shown to be comparable to that obtained with the Karl Fischer titration method.

An all-solid-state reference electrode based on the layer-by-layer polymer coating.

A solid-state reference electrode (SSRE) was fabricated by layering a silicone rubber (SR) film containing KCl on an AgCl surface, then a perfluorinated ionomer film, and finally a polyurethane-based membrane containing an ionophore, a lipophilic ionic additive, and a plasticizer, respectively. The addition of SiCl4 to the polyurethane-based membrane layer enhanced the strength of the membrane in an aqueous solution. The morphologies of the membranes were studied separately by SEM. The fabrication of the Ag/AgCl electrode through this layer-by-layer polymer coating improved the electrode stability enormously. In addition, the potential drift of the SSRE according to the pH of the medium was minimized by introducing a H+-ion-selective ionophore (tridodecylamine; TDDA) into the outmost polymer membrane. The cyclic voltammetric and potentiometric responses using the SSRE and a conventional reference electrode, respectively, were consistent. The SSRE exhibited little potential variation even in the case of the addition of very high concentrations of various salts, such as Na salicylate, LiCl, KCl, CaCl2, MgCl2, KNO3, NaCl, and NaHCO3. The practicability of the proposed SSRE was tested for the determination of blood pH and pCO2 in a flow cell system. The SSRE fabricated in the present study was stable over two years.

Lipid-bonded conducting polymer layers for a model biomembrane: application to superoxide biosensors.

Model biomembranes composed of poly-DATT/DGS/POPA and poly-DATT/DGS/CL were separately prepared on gold electrodes. A monolayer of 1,2-dioleoyl-sn-glycero-3-succinate (DGS) was covalently bonded onto electrochemically grown poly-(3,4-diamiono-2,2:5,2-terthiophene) (DATT) layers (thickness of approximately 300 nm; particle size of approximately 50 to 70 nm). The numbers of unit molecules of the poly-DATT layer and of the DGS immobilized onto the poly-DATT layers were 1.53 x 10(-7) and 1.56 x 10(-9) mol cm(-2), respectively, using a quartz crystal microbalance technique. The lipid bilayers of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphate (POPA) and cardiolipin (CL) were formed onto the poly-DATT/DGS layer using the Langmuir-Blodgett technique. The surface characterizations of each step were investigated by SEM, AFM, and XPS analyses. Cytochrome c (cyt c) was immobilized onto these model biomembranes through the charge interaction between the positive charges of cyt c and the negative charges of phosphate groups in CL or POPA lipids. At the POPA- and CL-modified biomembranes, the formal potentials of the redox couple of the immobilized cyt c were 0.22 and 0.23 V (vs Ag/AgCl), respectively. The redox reaction of the immobilized cyt c at the POPA- and CL-modified biomembranes was quasireversible, and the electron-transfer rate constants were 0.121 s(-1) and 0.133 s(-1), respectively. The applicability of these cyt c immobilized bioimitation membranes as the biosensors was tested for the determination of superoxide.

Functionalized conducting polymer as an enzyme-immobilizing substrate: an amperometric glutamate microbiosensor for in vivo measurements.

The functionalized conducting polymer (CP) of 5, 2':5', 2' '-terthiophene-3'-carboxylic acid on a platinum microelectrode was prepared through the electropolymerization process using cyclic voltammetry and was used as a substrate for the immobilization of enzymes. The nanoparticles of the CP were obtained at a high scan rate in the cyclic voltammetric experiment. A needle-type amperometric glutamate microbiosensor based on the covalent immobilization of glutamate oxidase (GlOx) onto the CP layer was fabricated for in vivo measurements. The surfaces of the CP/Pt and GlOx/CP/Pt were characterized by QCM, ESCA, and AFM. The biosensor efficiently detected glutamate through the oxidation of enzymatically generated H2O2 at approximately +0.45 V versus Ag/AgCl. Various experimental parameters, such as pH, temperature, and the applied potential in the detection step were optimized. The interference effects from other biological compounds were examined, and ascorbate and dopamine interferences were observed, which were completely minimized by coimmobilizing ascorbate oxidase and by coating the sensor surface with a cationic polymer, polyethyleneimine. A linear calibration plot for glutamate was obtained between 0.2 and 100 microM with a detection limit of 0.1 +/- 0.03 microM. The proposed glutamate microbiosensor was successfully used for in vivo monitoring of the extracellular glutamate released by cocaine stimulation.

Selective binding of NH4 + by redox-active crown ethers: application to a NH4 + sensor.

Two redox-active crown ethers, (1,1'- bi-2-naphthyl)-23-crown-6 incorporating 9,10-anthraquinone (BNAQ) and 1,4-benzoquinone (BNBQ), were synthesized and employed in the selective binding of NH(4)(+) over K(+). Their applications to NH(4)(+) detection were studied by cyclic voltammetry and amperometry in aqueous media. The results showed that the magnitude of the quinone redox peak decreased linearly as the concentration of NH(4)(+) increased, indicating the formation of BNAQ-NH(4)(+) and BNBQ-NH(4)(+) complexes. Formation constants of BNAQ-NH(4)(+) and BNBQ-NH(4)(+) complexes were determined to be 4.3 x 10(3) and 4.0 x 10(3) M(-1), respectively, which were 2 orders of the magnitude greater than those of BNAQ-K(+) and BNBQ-K(+) complexes. The (1)H NMR titration method carried out in DMSO-d(6) showed that both complexes possessed 1:1 stoichiometry, and association constants were determined to be 648 +/- 35 and 600 +/- 47 M(-1) for BNAQ-NH(4)(+) and BNBQ-NH(4)(+), respectively. Interference effects from other alkali and alkaline earth metal ions in the analysis of NH(4)(+) were also investigated. The BNAQ-modified sensor showed a linear response from 1.0 microM to 1.0 mM for NH(4)(+), and the detection limit was determined to be 0.9 +/- 0.03 microM.