Ventricular tachycardia arising from His-bundle.

During tachycardia, His-bundle potentials preceded Purkinje potentials. When the radiofrequency application was performed at a site where Purkinje potentials could be recorded slightly more peripherally than His-bundle potentials, tachycardia temporarily stopped, but was quickly followed by tachycardia with left-axis deviated because of the complication of the left anterior fascicular block.

The efficacy of right ventricular pacing for symptomatic left mid-ventricular obstruction.

The serial changes in intraventricular pressure gradient in the left ventricle and NYHA functional classification in each case. Both the left intraventricular pressure gradient and symptoms improved after right ventricular pacing. In one case, the left intraventricular pressure gradient disappeared immediately after right ventricular pacing, while in the others it disappeared during the chronic phase, more than a year later.

Atrial fibrillation ablation in a patient complicated by persistent left superior vena cava and absent right superior vena cava.

A comparison between the three-dimensional contact mapping created by the Ensite system and that created by contrast-enhanced computed tomography angiography (CTA). Right atrial appendage was not well delineated on CTA.

Antidromic atrioventricular reentrant tachycardia in a patient with Wolff-Parkinson-White syndrome and unapparent preexcitation: A case report.

This is a case of antidromic AVRT in a patient with unapparent preexcitation, and we could successfully diagnose and treat with the careful interpretation of wide QRS tachycardia. We should keep in mind that differentiation between intermittent and unapparent preexcitation is difficult, and some patients with unapparent preexcitation have short refractory periods of those accessory pathways, leading to sudden death.

Fluorescent alpha-cyclodextrin as a chemosensor for halomethanes.

A new fluorescent chemosensor, NBDamine-appended alpha-cyclodextrin, was prepared and showed high selectivity for perhalogenated methanes via multisite interactions between the perhalogenated methane and the cyclodextrin molecule.

A case of accessory pathway between the coronary sinus musculature and the left ventricle.

A 64-year-old female underwent catheter ablation of long R-P' tachycardia. Ventricular pacing exhibited retrograde conduction with an identical atrial activation sequence as during tachycardia because of an accessory pathway (AP) with a long VA conduction. A radiofrequency application within the posterior coronary sinus (CS) could achieve a change of activation pattern from distal-to-proximal to proximal-to-distal within CS proximal to the ablation site, caused by conduction block of CS musculature (CSM) at the proximal site. This phenomenon could explain that this AP was connected between the CSM and the left ventricle, in site far away from the discrete connection between the left atrium and CSM.

A case of repeated occlusion in the common iliac artery due to an unexpected stent deformation.

We report a case experiencing repeated common iliac artery (CIA) occlusion due to an unexpected stent deformation. A 74-year-old man with intermittent claudication had undergone balloon-expandable stenting for the left CIA. Six years after his first stent implantation, his left CIA was totally occluded inside the stent. We performed revascularization for the left CIA and achieved sufficient balloon inflation and balloon-expandable stenting. Then, one and a half years later, his left CIA was re-occluded. CT angiography showed compression by the protruding hyperostotic lumbar vertebral body, such that both stents had become deformed into a crescent shape. We were told that he had been using a powerful massage machine to stretch and relieve his spondylotic back pain. We suspected that the external pressure of the hyperostotic spondylosis and massage might have caused the CIA compression and repeated crush of the stents.

Remarkably enhanced excimer formation of naphthylacetate in cation-charged gamma-cyclodextrin.

[reaction: see text] 6(A),6(D)-Bispyridinio-appended gamma-cyclodextrin effectively enhanced the excimer fluorescence of 2-naphthylacetate. This increase derived from the increase of formation of the 1:2 complex between the cation-charged gamma-cyclodextrin and 2-naphthylacetate by the electrostatic interaction between the host and the guest.

Chiral recognition by fluorescent chemosensors based on N-dansyl-amino acid-modified cyclodextrins.

Four kinds of N-dansyl-amino acid-modified beta-cyclodextrins (beta-CDs) were prepared as fluorescent chemosensors for chiral discrimination. The use of an amino acid as a spacer improved binding affinities and chiral discrimination abilities of the chemosensors. N-dansyl-l-Phe-modified beta-CD showed high d-selectivity for norbornane derivatives and N-dansyl-d-Phe-modified beta-CD showed high l-selectivity for menthol. Microcalorimetric titration results indicate that the chemosensors selectively accommodate the enantiomer that induces the least unfavorable entropy change on making an inclusion complex.

Direct assay for alpha-amylase using fluorophore-modified cyclodextrins.

A simple assay method for alpha-amylase was developed based on fluorophore-modified cyclodextrins (CDs). Four kinds of CD derivatives bearing a 4-amino-7-nitrobenz-2-oxa-1,3-diazole (NBD-amine) moiety were prepared as artificial substrates for the assay method. The fluorescence intensity of all the NBD-amine-modified CDs decreased upon addition of Aspergillus oryzae alpha-amylase, indicating a reduction in hydrophobicity near the NBD-amine moiety induced by hydrolysis of the CD ring. NC4gammaCD, having a gamma-CD and an amino-tetramethylene spacer, was the most sensitive substrate for the alpha-amylase assay. The initial rate of hydrolysis of NC4gammaCD displayed a liner correlation to the concentration of the alpha-amylase. NC4gammaCD was sensitive to the alpha-amylase but was not sensitive to guest compounds that were accommodated by the native CDs.

Template-assisted stereoselective photocyclodimerization of 2-anthracenecarboxylic acid by bispyridinio-appended gamma-cyclodextrin.

[reaction: see text] Four kinds of bispyridinio-appended gamma-cyclodextrin (gamma-CD) were prepared to make a molecular flask for controlling the stereoselectivity of photocyclodimerization of 2-anthracenecarboxylate. When the photocyclodimerization of 2-anthracenecarboxylate was carried out in the presence of A,E-bispyridinio-appended gamma-CD, the relative yield of one of the configurational isomers, the head-to-head/anti-isomer, was increased 1.8-fold compared to the corresponding yield in the presence of unmodified gamma-CD or in the absence of any gamma-CD. The optical yields of the photocyclodimerization reaction products also increased more than 10-fold by the addition of bispyridinio-appended gamma-CD compared with unmodified gamma-CD.

Skeleton-selective fluorescent chemosensor based on cyclodextrin bearing a 4-amino-7-nitrobenz-2-oxa-1,3-diazole moiety.

A new type of fluorescent chemosensor, based on modified cyclodextrins bearing the fluorophore unit NBD-amine, was prepared. One of these new chemosensors, NC0betaCD, is sensitive to adamantane and borneol derivatives, which have a comparatively spherical shape that fits the beta-CD cavity, but is not sensitive to bile acids, which are strongly bound by the native beta-CD. Even in the presence of a bile acid, NC0betaCD can detect 1-adamantanol. Another of this new type of chemosensors, NC0gammaCD, is sensitive to bile acids but not to adamantane derivatives. The response of the new type of chemosensors to a guest was an increase in the fluorescence intensity.

Efficient transport of saccharides through a liquid membrane mediated by a cyclodextrin dimer.

A new efficient system for transporting saccharides through a liquid membrane has been constructed. The transport rates of saccharides were accelerated greatly by the cyclodextrin dimer 2; by contrast, the corresponding cyclodextrin monomer 1 was not effective at mediating saccharide transport. The transport rate of D-ribose through a chloroform liquid membrane was 17 times faster when the cyclodextrin dimer 2 was used as the transporter than when the cyclodextrin monomer 1 was used. Similarly the transport rate of methyl D-galactopyranoside was 16 times faster by 2 than by 1.

Amyloid architecture: complementary assembly of heterogeneous combinations of three or four peptides into amyloid fibrils.

The amyloid fibril is a misfolded and undesirable state for proteins that has been proposed to be a causative agent for a variety of fatal diseases known as amyloid diseases, such as Alzheimer's and prion diseases. However, the fibril has a highly ordered tertiary structure in which numerous beta-strand polypeptide chains align in a regular pattern. Thus, this kind of fibril has the potential to be engineered into proteinaceous materials. Amyloid fibrils of misfolded proteins primarily comprise a single polypeptide species, that is, the self-assembly is homogeneous. We here found that three or four designed peptides can assemble heterogeneously and cooperatively into amyloid fibrils, a process accompanied by a drastic secondary structural transition from alpha helix to beta sheet. Heterogeneous assembly into fibrils is accomplished by complementary electrostatic interactions between three or four peptide species, each of which is not able to self-assemble homogeneously. These findings will lead to a novel way to study the molecular details of amyloid formation and also to design beta-sheet peptidyl materials.

Nucleobase amino acids incorporated into the HIV-1 nucleocapsid protein increased the binding affinity and specificity for a hairpin RNA.

L-alpha-amino acids with a nucleobase in the side chain (nucleobase amino acids; NBAs) were used to enhance the function of RNA-binding proteins that recognize structured RNA. These NBAs were utilized in the three-dimensional structure of the protein to enhance RNA binding affinity and specificity as a result of selective recognition of NBAs by RNA bases. NBA units were incorporated at various positions into the HIV-1 nucleocapsid protein NCp7 (residues 1-55), which contains two CCHC-type (Cys-X(2)-Cys-X(4)-His-X(4)-Cys-type; X=an amino acid residue) zinc knuckle domains. The binding ability was evaluated by using the stem-loop (SL)3 region of HIV-1 Psi-RNA. Visible light absorption measurements revealed that two zinc ions bound strongly and quantitatively to the NBA-NCp7 molecule and to the wild-type NCp7 protein. This result indicates that the incorporation of NBA units composed of L-alpha-amino acids did not influence the formation of the specific structure of NCp7. Binding analysis with fluorescein-labeled SL3 RNA revealed that incorporation of NBA units into the NCp7 protein at appropriate positions increased its RNA binding affinity and specificity. An NBA-NCp7 protein that possessed cytosine and guanine NBA units at positions 13 and 46, respectively, showed a binding affinity for SL3 RNA ninefold higher than that of wild-type NCp7 as a result of the specific and cooperative interaction of the NBA units with RNA bases. These results clearly demonstrate that inclusion of NBA units in the three-dimensional structure of an RNA-binding protein is a useful strategy for enhancing the function of the protein.

Construction of the novel conformationally-restricted peptide library for screening of peptides that control the interaction between nucleobases.

A unique conformationally-restricted peptide library was constructed using a loop structure as a structural scaffold. This library was used for the screening of the amino acid sequences that control the interaction between nucleobase triplets. The peptides have PNAs at the C-terminus as the recognition site and the random amino acid sequence at the N-terminus as the effector for the interaction between PNA and its complementary DNA triplets. From the peptide libraries constructed by the positional scanning method, the sequences that affect the interaction between PNA and complementary DNA were selected. The difference in the characteristic results by using A-T and G-C pairs was presented. This study would also give us some useful information about interaction between peptides and nucleic acids, such as relevances between these biomolecules in a prebiotic era.

Fluorescence resonance energy transfer in a novel cyclodextrin-peptide conjugate for detecting steroid molecules.

A novel cyclodextrin conjugated peptide, 1, having two different fluorophores, coumarin and pyrene, in the side chains has been designed and synthesized. The circular dichroism study reveals that 1 shows typical alpha-helix pattern, and forms intramolecular inclusion complex with coumarin. The fluorescence emission study shows that the peptide exhibits intramolecular fluorescence resonance energy transfer (FRET) without quenching of two fluorophores. We have determined the binding constants of 1 for various biologically important steroid molecules as guests using the guest-responsive variation in the fluorescence emission intensity of coumarin.

Cyclodextrin trimers as receptors for arranging ester and catalyst at optimized location to achieve enhancement of hydrolytic activity.

Two novel trimer receptor molecules (AC and AD trimers) consisting of two alpha-cyclodextrins (alpha-CDs) and one beta-cyclodextrin (beta-CD) have been designed and synthesized in order to make an optimum arrangement between a substrate and a catalyst. In the reaction systems that use trimer receptors as host molecules, the substrate and the catalyst are thought to be accommodated by two alpha-CDs and one beta-CD, respectively. The rate for the hydrolytic reaction of a long-shaped ester was largely increased, when the trimer receptors were used as receptor molecules or molecular flasks, which provided optimum location between the substrate and the catalyst.

Enantioselective ester hydrolysis catalyzed by beta-cyclodextrin conjugated with beta-hairpin peptides.

Designed cyclodextrin-peptide conjugates, which have one or two beta-hairpin peptides, have been synthesized as catalysts for ester hydrolysis. One or two beta-hairpin peptides were located at the primary hydroxyl group side of beta-cyclodextrin so as to arrange two histidine residues that act as a general acid and a general base catalysts and provide the substrate recognition subsite. Kinetic studies revealed that the two-beta-hairpin peptide was more effective than that of the one-beta-hairpin peptide for substrate recognition.