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T Hayano

Publications and source records attributed to T Hayano.

At least 19 recordsLinked to original sources
PubMed2001

Solution NMR structure of the myosin phosphatase inhibitor protein CPI-17 shows phosphorylation-induced conformational changes responsible for activation.

Contractility of vascular smooth muscle depends on phosphorylation of myosin light chains, and is modulated by hormonal control of myosin phosphatase activity. Signaling pathways activate kinases such as PKC or Rho-dependent kinases that phosphorylate the myosin phosphatase inhibitor protein called CPI-17. Phosphorylation of CPI-17 at Thr38 enhances its inhibitory potency 1000-fold, creating a molecular on/off switch for regulating contraction. We report the solution NMR structure of the CPI-17 inhibitory domain (residues 35-120), which retains the signature biological properties of the full-length protein. The final ensemble of 20 sets of NMR coordinates overlaid onto their mean structure with r.m.s.d. values of 0.84(+/-0.22) A for the backbone atoms. The protein forms a novel four-helix, V-shaped bundle comprised of a central anti-parallel helix pair (B/C helices) flanked by two large spiral loops formed by the N and C termini that are held together by another anti-parallel helix pair (A/D helices) stabilized by intercalated aromatic and aliphatic side-chains. Chemical shift perturbations indicated that phosphorylation of Thr38 induces a conformational change involving displacement of helix A, without significant movement of the other three helices. This conformational change seems to flex one arm of the molecule, thereby exposing new surfaces of the helix A and the nearby phosphorylation loop to form specific interactions with the catalytic site of the phosphatase. This phosphorylation-dependent conformational change offers new structural insights toward understanding the specificity of CPI-17 for myosin phosphatase and its function as a molecular switch.

Algorithms↗
PubMed2000

Fast folding of Escherichia coli cyclophilin A: a hypothesis of a unique hydrophobic core with a phenylalanine cluster.

Escherichia coli cyclophilin A, a 164 residue globular protein, shows fast and slow phases of refolding kinetics from the urea-induced unfolded state at pH 7.0. Given that the slow phases are independent of the denaturant concentration and may be rate-limited by cis/trans isomerizations of prolyl peptide bonds, the fast phase represents the true folding reaction. The extrapolation of the fast-phase rate constant to 0 M urea indicates that the folding reaction of cyclophilin A is extraordinarily fast and has about 700 s(-1) of the rate constant. Interrupted refolding experiments showed that the protein molecules formed in the fast phase had already been fully folded to the native state. This finding overthrows the accepted view that the fast folding is observed only in small proteins of fewer than 100 amino acid residues. Examination of the X-ray structure of cyclophilin A has shown that this protein has only one unique hydrophobic core (phenylalanine cluster) formed by evolutionarily conserved phenylalanine residues, and suggests that this architecture of the molecule may be responsible for the fast folding behavior.

Amino Acid Sequence↗
PubMed2000

Double ventricular response by a single ventricular extrastimulus to the inner loop of reentry in a patient without apparent heart disease.

In a patient without apparent heart disease, a ventricular extrastimulus delivered from the left ventricular apex where the electrogram was recorded 30 ms after the onset of the QRS complex during VT advanced the second QRS complex, but not the first QRS complex. The morphology of the second QRS complex was the same as that of VT. The postpacing interval was the same as the cycle length of the VT. These findings indicated that the site of stimulation was at the inner loop of the reentry circuit of the VT. A ventricular extrastimulus with a shorter coupling interval advanced the first and second QRS complexes, indicating that the ventricle was activated by antidromic and orthodromic activation from the extrastimulus. Radiofrequency ablation at that site of stimulation terminated the VT and no further VT could be induced.

Aged↗
PubMed1999

Interferon-alpha elevates pulmonary blood pressure in sheep--the role of thromboxane cascade.

We tested the effect of interferon-alpha on lung function to examine whether interferon-alpha causes some pathophysiological change in the lung. We prepared awake sheep with chronic lung lymph fistula, and measured the pulmonary hemodynamics, lung fluid balance and concentrations of prostanoid products. At 1 h after intravenous interferon-alpha administration (18 x 10(6) I.U.), pulmonary arterial pressure and pulmonary vascular resistance were significantly increased compared to the baseline values. The levels of thromboxane B2 in both plasma and lung lymph were increased concomitant with early elevation on pulmonary arterial pressure. In addition, OKY-046 [sodium-3[4-(1-imidazolylmethyl)phenyl]-2-propenoic acid] (10 mg kg(-1)), a selective thromboxane synthase inhibitor, significantly prevented the interferon-alpha-induced pulmonary hypertension and thromboxane B2 production. While no evidence of increased pulmonary vascular leakage was observed. These findings suggest that a single infusion of interferon-alpha stimulates a thromboxane cascade and causes transient pulmonary hypertension. However, interferon-alpha itself or increased thromboxane A2 might not affect the pulmonary vascular permeability in sheep.

6-Ketoprostaglandin F1 alpha↗
PubMed1999

Effects of proline mutations on the folding of staphylococcal nuclease.

Effects of proline isomerizations on the equilibrium unfolding and kinetic refolding of staphylococcal nuclease were studied by circular dichroism in the peptide region (225 nm) and fluorescence spectra of a tryptophan residue. For this purpose, four single mutants (P11A, P31A, P42A, and P56A) and four multiple mutants (P11A/P47T/P117G, P11A/P31A/P47T/P117G, P11A/P31A/P42A/P47T/P117G, and P11A/P31A/P42A/P47T/P56A/P117G) were constructed. These mutants, together with the single and double mutants for Pro47 and Pro117 constructed in our previous study, cover all six proline sites of the nuclease. The P11A, P31A, and P42A mutations did not change the stability of the protein remarkably, while the P56A mutation increased protein stability to a small extent by 0.5 kcal/mol. The refolding kinetics of the protein were, however, affected remarkably by three of the mutations, namely, P11A, P31A, and P56A. Most notably, the amplitude of the slow phase of the triphasic refolding kinetics of the nuclease observed by stopped-flow circular dichroism decreased by increasing the number of the proline mutations; the slow phase disappeared completely in the proline-free mutant (P11A/P31A/P42A/P47T/P56A/P117G). The kinetic refolding reactions of the wild-type protein assessed in the presence of Escherichia coli cyclophilin A showed that the slow phase was accelerated by cyclophilin, indicating that the slow phase was rate-limited by cis-trans isomerization of the proline residues. Although the fast and middle phases of the refolding kinetics were not affected by cyclophilin, the amplitude of the middle phase decreased when the number of the proline mutations increased; the percent amplitudes for the wild-type protein and the proline-free mutants were 43 and 13%, respectively. In addition to these three phases detected with stopped-flow circular dichroism, a very fast phase of refolding was observed with stopped-flow fluorescence, which had a shorter dead time (3.6 ms) than the stopped-flow circular dichroism. The following conclusions were drawn. (1) The effects of the P11A, P31A, and P56A mutations on the refolding kinetics indicate that the isomerizations of the three proline residues are rate-limiting, suggesting that the structures around these residues (Pro11, Pro31, and Pro56) may be organized at an early stage of refolding. (2) The fast phase corresponds to the refolding of the native proline isomer, and the middle phase whose amplitude has decreased when the number of proline mutations was increased may correspond to the slow refolding of non-native proline isomers. The occurrence of the fast- and slow-refolding reactions together with the slow phase rate-limited by the proline isomerization suggests that there are parallel folding pathways for the native and non-native proline isomers. (3) The middle phase did not completely disappear in the proline-free mutant. This suggests that the slow-folding isomer is produced not only by the proline isomerizations but also by another conformational event that is not related to the prolines. (4) The very fast phase detected with the fluorescent measurements suggests that there is an intermediate at a very early stage of kinetic refolding.

Amino Acid Substitution↗
PubMed1999

Paradoxical effects of pirenzepine on parasympathetic activity in chronic heart failure and control.

We studied the effect of intravenous pirenzepine (3 mg) in normal subjects (n=15, 43+/-16 years old) and in patients with chronic heart failure (n=15, 61+/-12 years old) to assess the effect of low-dose pirenzepine on vagal activity. R-R intervals and the standard deviations, low-frequency power (LF: ln ms2, 0.04-0.15 Hz), high-frequency power (HF: ln ms2, 0.15-0.40 Hz) and the ratio of low- to high-frequency power (LF/HF ratio) were measured 10 min before and after pirenzepine using a Holter analysis system. Pirenzepine was found to cause a significant increase in the R-R interval from 903+/-112 to 956+/-129 ms in the control group (P<0.0001) and from 927+/-141 to 958+/-168 ms in patients with chronic heart failure (P<0.01). Pirenzepine also increased HF significantly from 4.29+/-0.32 to 5.16+/-0.38 ln ms2 in the control group (P<0.0001) and from 4.04+/-0.16 to 4.48+/-0.24 ln ms2 in the chronic heart failure group (P<0.05). Pirenzepine did not significantly alter the LF/HF ratio in either group. We emphasize that pirenzepine appears to have a vagoinimetic effect in patients with chronic heart failure and that it may be useful for augmenting vagal control of the heart in some patients with chronic heart failure.

Adult↗
PubMed1999

A 21-aminosteroid, U-74006F, attenuates endotoxin-induced lung injury in awake sheep.

The purpose of the present study was to examine the efficacy of U-74006F, a 21-aminosteroid, on lung dysfunction induced by endotoxaemia in awake sheep with lung lymph fistula and haemodynamic monitoring. We measured pulmonary haemodynamics, lung lymph balance, circulating leucocyte count, arterial blood gas tensions, and levels of thromboxane (Tx) B2 and 6-keto-prostaglandin (PG) F1 alpha in plasma and lung lymph. We performed two experiments. In experiment 1 (n = 6), we intravenously infused Escherichia coli lipopolysaccharide endotoxin (1 microgram/kg) over 30 min and observed the parameters over 5 h. In experiment 2 (n = 6), we pretreated sheep with an intravenous bolus of U-74006F (2 mg/kg) 30 min before the infusion of endotoxin in the same manner of experiment 1, and continuously infused U-74006F (0.5 mg/kg per h) over 5 h after the bolus during the experiment. The U-74006F significantly suppressed the early pulmonary hypertension, the late increase in pulmonary permeability and the elevations of TxB2 and 6-keto-PGF1 alpha levels in plasma and lung lymph during the early period following endotoxaemia, although the compound did not change the time course of leucocytopenia and hypoxaemia. These findings suggest that the administration of U-74006F attenuates the lung dysfunction induced by endotoxaemia in awake sheep.

6-Ketoprostaglandin F1 alpha↗
PubMed1999

Ultrastructural studies on the formation and distribution of lipid droplets in the lung capillary endothelial cells in patients with sarcoidosis.

BACKGROUND AND AIM OF THE WORK: We previously reported the presence of definite morphological alterations in the capillary endothelium of sarcoid lung. The aim of this study was to examine ultrastructural changes and distribution of lipid droplets in the endothelium of lung capillaries of patients with sarcoidosis. METHODS: Tissue specimens were obtained by transbronchial lung biopsy or open lung biopsy from 16 patients with sarcoidosis and 13 controls. Biopsies were evaluated by electron microscopy following lead citrate and uranyl acetate staining. RESULTS: Typical lipid droplets were observed in pulmonary capillaries of 11 out of 16 sarcoid patients (69%); the droplet frequency was higher in sarcoid patients than in control specimens. Lipid droplets were characterized by biphasic density: most droplets contained eccentrically located vacuoles (saturated fatty acids) others were characterized by low density areas (unsaturated fatty acids). Biphasic droplets were covered by large lysosomal granules and were mainly distributed in the endothelium and pericytes. Interestingly, in the latter, vacuoles increased in size while small amounts of lysosomal granules were detectable. CONCLUSION: Our findings suggest that biphasic droplets increase in number in pulmonary capillaries of patients with sarcoidosis with a characteristic distribution pattern from the endothelium to pericytes.

Adult↗
PubMed1999

Assessment of right artrial mapping and P wave-triggered signal-average in patients with paroxysmal atrial fibrillation.

To assess right atrial mapping and P wave-triggered signal-averaged electrocardiogram (ECG) in patients with paroxysmal atrial fibrillation (PAF), this study examined right atrial electrograms using atrial mapping and parameters by P wave-triggered signal-averaged ECG in 39 patients without sick sinus syndrome. Subjects were divided into those with PAF (n = 13; 60+/-13 years old) and a control group (n = 26; 49+/-19 years old). The total number of abnormal right atrial electrograms per patient was significantly greater in the PAF group (3.2+/-1.9) than in the control group (1.1+/-0.9; P < .001). The longest duration of right atrial electrogram in the PAF group tended to be greater than that in the control group (P = .06). The filtered P wave duration was significantly longer in the PAF group than in the control group (144+/-21 vs 125+/-14 ms [P < .002]). The values of the root mean square of P wave-triggered signal-averaged ECG 15 ms from the onset (RMSi 15) and 20 ms from the offset (RMSe 20) were significantly lower in the PAF group (1.1+/-0.4 microV, 1.4+/-0.5 microV) than in the control group (1.9+/-1.1 microV [P < .02], 2.1+/-0.9 microV [P < .01]). The total number of right atrial electrograms in patients with RMSi 15 of < or =1.5 microV was significantly greater than in patients with RMSi 15 of >1.5 microV (2.2+/-1.8 vs 1.3+/-1.3 [P < .05]). Thus, the total number of abnormal right atrial electrograms per patient, the total filtered P wave duration, RMSi 15, and RMSe 20 may be good indices of PAF in patients without sick sinus syndrome. RMSi 15 may reflect the total number of the abnormal right atrial electrograms per patient.

Atrial Fibrillation↗
PubMed1998

Molecular evolution of the domain structures of protein disulfide isomerases.

Protein disulfide isomerase (PDI) is an enzyme that promotes protein folding by catalyzing disulfide bridge isomerization. PDI and its relatives form a diverse protein family whose members are characterized by thioredoxin-like (TX) domains in the primary structures. The family was classified into four classes by the number and the relative positions of the TX domains. To investigate the evolution of the domain structures, we aligned the amino acid sequences of the TX domains, and the molecular phylogeny was examined by the NJ and ML methods. We found that all of the current members of the PDI family have evolved from an ancestral enzyme, which has two TX domains in the primary structure. The diverse domain structures of the members have been generated through domain duplications and deletions.

Evolution, Molecular↗
PubMed1998

Churg-Strauss syndrome (allergic granulomatous angitis) presenting with ileus caused by ischemic ileal ulcer.

We report a rare case of Churg-Strauss syndrome (CSS) in a 41-year-old Japanese man with a history of middle-age onset of bronchial asthma who had severe abdominal pain. He presented with ileus caused by an annular ulcer of the ileum, attributable to mucosal ischemia resulting from necrotizing vasculitis of the mesenteric artery. He also had marked hypereosinophilia (51.5%), elevated serum IgE levels (34040 IU/ml), and generalized enlargement of the superficial cervical lymph nodes, containing eosinophilic granulomas. A stenotic lesion caused by an annular ulcer in the ileum was found and resected by laparotomy. Microscopic examination of the resected specimen revealed luminal narrowing or occlusion of small arteries in the ulcer base, subserosa, and mesenterium resulting from marked fibrotic intimal thickening with fragmentation or lack of the internal elastic lamina. These findings were diagnosed as vasculitis, scar stage. The postoperative course was uneventful, with the patient receiving a maintenance dose of prednisolone (10-15 mg/day) for 7 years subsequently. We must carefully diagnose and treat patients with middle-age onset asthma, because the symptom may be a lung manifestation of CSS, in which various organs including gastrointestinal tract are involved as a result of systemic necrotizing vasculitis.

Adult↗
PubMed1998

Inflammatory cytokines in BAL fluid and pulmonary hemodynamics in high-altitude pulmonary edema.

To evaluate the pathogenesis of high-altitude pulmonary edema (HAPE), we performed bronchoalveolar lavage (BAL) and pulmonary hemodynamic studies in seven patients with HAPE at its early stage. We measured cell counts, biochemical contents, and concentrations of pro-inflammatory cytokines including interleukin (IL)-1, IL-6, IL-8 and tumor necrosis factor (TNF)-alpha and of anti-inflammatory cytokines including IL-1 receptor antagonist (ra) and IL-10 in the BAL fluid (BALF). All patients showed increased counts for total cells, alveolar macrophages, neutrophils and lymphocytes, and markedly elevated concentrations of proteins, lactate dehydrogenase, IL-1beta, IL-6, IL-8, TNF-alpha and IL-1ra. The levels of IL-1alpha and IL-10 were not increased. Patients also showed pulmonary hypertension with normal wedge pressure. Both the driving pressure obtained as pulmonary arterial pressure minus wedge pressure and the PaO2 under room air were significantly correlated with the concentrations of IL-6 and TNF-alpha in the BALF. These findings suggest that the inflammatory cytokines play a role at the early stage of HAPE and might be related to pulmonary hypertension.

Adult↗
PubMed1998

Isolation of anti-glutathione antibodies from a phage display library.

We have isolated anti-glutathione antibodies from a human synthetic phage antibody scFv library (Nissim,A., Hoogenboom,H.R., Tomlinson,I.M., Flynn,G., Midgley,C., Lane,D. and Winter,G., 1994, EMBO J., 13, 692-698). Glutathione (GSH) conjugates with carrier proteins, such as bovine serum albumin (BSA), keyhole limpet hemocyanin (KLH) and human lysozyme (LZM), were used as antigens. After four cycles of panning and affinity chromatography, clones that recognized GSH-conjugated proteins, but not BSA, KLH or LZM, were isolated. The isolated phage antibodies and the soluble scFv fragments were characterized by immunoblotting, and the nucleotide sequences of the VH segments of selected clones were determined. The binding of several isolates to GSH-BSA was competitively inhibited by GSH in an ELISA. These observations have demonstrated that antibodies against GSH, a tripeptide, can be isolated from the library. We constructed the tertiary models of several scFv fragments and discussed the mechanism of antigen binding sites.

Antibodies, Viral↗
PubMed1998

Pharmacokinetic evaluation of amphotericin B in lung tissue: lung lymph distribution after intravenous injection and airspace distribution after aerosolization and inhalation of amphotericin B.

We have studied the pharmacokinetics of amphotericin B (AmB) in lung lymph circulation and bronchial-wash fluid after intravenous infusion and inhalation, respectively. For two experiments with awake sheep, we used lung lymph fistulas and tracheotomy. In experiment 1, AmB concentrations in plasma and lung lymph after intravenous infusion of AmB (1 mg/kg of body weight) over 1.5 h were measured. The mean peak in plasma level was 756.0 +/- 188.8 ng/ml at 3 h after the start of infusion, and the level then decreased gradually to 194.8 +/- 28.9 ng/ml at 24 h. The stable and maximal levels in lung lymph last 5 to 9 h after the start of AmB infusion. The concentrations in lung lymph after 9 h were slightly higher than those in plasma. Thus, the lung lymph-to-plasma ratio of AmB concentrations increased gradually during infusion, and the ratio was more than 1.0 after the end of infusion, suggesting that AmB could be easily moved from plasma to pulmonary interstitium and/or lung lymph circulation. In another experiment, 5 or 30 mg of aerosol AmB was inhaled, and the concentration of AmB in the bronchial-wash fluid was determined by bronchoalveolar lavage. The peak AmB concentration in the fluid was observed at 0.5 h. After that, AmB was slowly eliminated over 24 h. The area under the concentration-time curve for 30 mg of inhaled AmB was higher than that for 5 mg, but maximum concentrations of AmB in serum for 5 and 30 mg were almost similar. These observations identify the pharmacokinetic characteristics of AmB in the lung and may provide a new insight into the strategy for clinical treatment of fungal pneumonia.

Administration, Inhalation↗
PubMed1998

[Radiofrequency catheter ablation therapy in elderly patients with supraventricular tachycardia].

138 patients with Wolf-Parkinson-White (WPW) syndrome (n = 96), atrioventricular nodal reentrant tachycardia (AVNRT; n = 27) and the other supraventricular tachycardia (n = 15), were divided into two groups, a control group (less than 65 years old; n = 108) and an elderly group (more than 66 years old; n = 30). We then estimated the success rate and safety of radiofrequency ablation for supraventricular tachycardia in elderly patients. For WPW syndrome, there were 76 (97%) successes and 9 (13%) recurrences in the control group (n = 78). In the elderly group of WPW patients, the number of successes was 18 (100%) and the number of recurrences one (63%). In 27 patients with AVNRT, the number of successes was 26 (96%) and there were no recurrences. In 15 patients with some other supraventricular tachycardia, there were 11 patients (73%) successes and one recurrence (11%). Major complications consisted of cardiac tamponade in 2 patients, dissecting aneurysm in one patient and cerebral embolism in one patients. All major complications occurred in patients with WPW syndrome. The cause of the complications, except the cerebral embolism was manipulation of the electrical or ablation catheter. Three of four patients with major complications belonged to the control group. It is possible that radiofrequency catheter ablation for supraventricular tachycardia in elderly patients is safe and highly effective. However, it is still invasive therapy. Ablation on a left accessory pathway by the transaortic valve approach especially needs meticulous care.

Aged↗
PubMed1997

Stabilized analogs of thymopentin. 1. 4,5-Ketomethylene pseudopeptides.

The pentapeptide, thymopentin (Arg1-Lys2-Asp3-Val4-Tyr5) is known for its activity as an immunomodulating drug, but with limited half-life in plasma. In this first paper of a series of three studies, the synthesis of analogs stabilized at the peptide bond between the C-terminal amino acids via insertion of a ketomethylene moiety is described. N-Blocked pseudopeptides containing Val(k)Phe, Ala(k)Phe, and Val(k)Val units were prepared and attached to chloromethyl Merrifield resin via the carboxy terminal. Removal of the N-BOC group by trifluoroacetic acid was followed by sequential coupling with N-BOC dipeptides of aspartic acid to yield resin-bound N-BOC pseudotetrapeptides. Removal of N-BOC and coupling with N-BOC-r-N-tosylarginine followed by total cleavage of blocking groups and resin by HF afforded the target pseudopentapeptides. The analogs were found to compete favorably with thymopentin for binding to CEM cells, but binding was reduced by about 20-30% on average. All analogs showed significant enhancement of half-life versus thymopentin in mouse serum, but most showed only modest improvement in human serum. Insertion of proline or norleucine at position 2 in the chain caused a substantial increase in half-life (3-4-fold), while N-methylnorleucine conferred complete stability in the analogs.

Adjuvants, Immunologic↗