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Yamauchi S, Kim H, Shinomoto S. Elemental spiking neuron model for reproducing diverse firing patterns and predicting precise firing times. Front Comput Neurosci 2011; 5:42. [PMID: 22203798 PMCID: PMC3215233 DOI: 10.3389/fncom.2011.00042] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Accepted: 09/14/2011] [Indexed: 12/02/2022] Open
Abstract
In simulating realistic neuronal circuitry composed of diverse types of neurons, we need an elemental spiking neuron model that is capable of not only quantitatively reproducing spike times of biological neurons given in vivo-like fluctuating inputs, but also qualitatively representing a variety of firing responses to transient current inputs. Simplistic models based on leaky integrate-and-fire mechanisms have demonstrated the ability to adapt to biological neurons. In particular, the multi-timescale adaptive threshold (MAT) model reproduces and predicts precise spike times of regular-spiking, intrinsic-bursting, and fast-spiking neurons, under any fluctuating current; however, this model is incapable of reproducing such specific firing responses as inhibitory rebound spiking and resonate spiking. In this paper, we augment the MAT model by adding a voltage dependency term to the adaptive threshold so that the model can exhibit the full variety of firing responses to various transient current pulses while maintaining the high adaptability inherent in the original MAT model. Furthermore, with this addition, our model is actually able to better predict spike times. Despite the augmentation, the model has only four free parameters and is implementable in an efficient algorithm for large-scale simulation due to its linearity, serving as an element neuron model in the simulation of realistic neuronal circuitry.
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Shinozaki S, Ito T, Kikuta H, Sumiyoshi T, Shibata M, Mibiki Y, Oosawa N, Sato Y, Yamauchi S, Endo T. Passive-Fixation Lead Implantation into Interventricular Septum. An Easy and Safety Method. J Arrhythm 2011. [DOI: 10.4020/jhrs.27.pj2_058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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78
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Masuda T, Akiyama J, Fujimoto A, Yamauchi S, Maekawa T, Sone Y. Antioxidation reaction mechanism studies of phenolic lignans, identification of antioxidation products of secoisolariciresinol from lipid oxidation. Food Chem 2010. [DOI: 10.1016/j.foodchem.2010.04.065] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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79
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Shimada T, Nakanishi T, Toyama A, Yamauchi S, Kanzaki A, Fujiwake H, Sato TA, Ikegawa M. Potential Implications for Monitoring Serum Bile Acid Profiles in Circulation with Serum Proteome for Carbon Tetrachloride-Induced Liver Injury/Regeneration Model in Mice. J Proteome Res 2010; 9:4490-500. [DOI: 10.1021/pr1002388] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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80
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Yamauchi S, Kim H, Shinomoto S. Dynamical behavior of multi-timescale adaptive threshold model. Neurosci Res 2010. [DOI: 10.1016/j.neures.2010.07.1924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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81
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Kawai N, Ikematsu H, Hirotsu N, Maeda T, Kawashima T, Tanaka O, Yamauchi S, Kawamura K, Matsuura S, Nishimura M, Iwaki N, Kashiwagi S. Clinical effectiveness of oseltamivir and zanamivir for treatment of influenza A virus subtype H1N1 with the H274Y mutation: a Japanese, multicenter study of the 2007-2008 and 2008-2009 influenza seasons. Clin Infect Dis 2009; 49:1828-35. [PMID: 19911968 DOI: 10.1086/648424] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Influenza A virus subtype H1N1 with the H274Y mutation emerged and spread worldwide. However, the clinical effectiveness of the neuraminidase inhibitors, oseltamivir and zanamivir, has not been adequately reevaluated. METHODS Data from 164 patients with H1N1 virus infection and 59 patients with H3N2 virus infection during the 2008-2009 influenza season and 68 patients with H1N1 virus infection during the 2007-2008 influenza season who received a neuraminidase inhibitor were analyzed. The duration of fever (body temperature 37.5 degrees C) after the first dose of oseltamivir or zanamivir and from onset of symptoms was calculated from patient reports. The influenza virus was isolated, and its subtype was determined by hemagglutinin inhibition assay and polymerase chain reaction. The H274Y neuraminidase mutation status was determined by sequencing the neuraminidase segment. RESULTS Of 68 patients with H1N1 virus infection during the 2007-2008 season, 41 were treated with oseltamivir, and 27 were treated with zanamivir. During the 2008-2009 season, 77 patients with H1N1 virus infection were treated with oseltamivir, and 87 were treated with zanamivir; 31 and 28 patients with H3N2 virus infection were treated with oseltamivir and zanamivir, respectively. All 49 analyzed H1N1 virus isolates obtained during the 2008-2009 season, but none of the isolates obtained during the 2007-2008 season, contained the H274Y mutation. The mean +/- standard deviation duration of fever after the start of oseltamivir therapy was significantly longer for patients with H1N1 virus infection (49.1+/-30.2 h) than it was for patients with H3N2 virus infection (33.7+/-20.1 h; P < .01) during the 2008-2009 season and patients with H1N1 virus infection during the 2007-2008 season (32.0+/-18.9 h; P < .001). The duration of fever was significantly longer after the first dose of oseltamivir than it was after the first dose of zanamivir for patients with H1N1 virus infection during the 2008-2009 season (P <.001). The duration of fever from onset of H1N1 virus infection was significantly longer for children 15 years of age during 2008-2009 (70.6+/-34.5 h) than it was for such children during 2007-2008 (48.4+/-21.2). CONCLUSION The effectiveness of oseltamivir, but not that of zanamivir, decreased significantly for H1N1 virus infection during the 2008-2009 season.
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Fukui K, Nomura A, Ogasawara T, Kawamura T, Yamauchi S, Watanabe K, Taniguchi S, Daitoku K, Suzuki Y, Fukuda I. [Surgical treatment of aortic root disease]. KYOBU GEKA. THE JAPANESE JOURNAL OF THORACIC SURGERY 2009; 62:958-963. [PMID: 19827548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We reviewed aortic root disease and operative procedures. Between January 1982 and December 2008, aortic root operation was performed for 58 patients with various aortic root disease. We chose Bentall type operations in extensive root destructive cases and urgent or reoperative cases. Overall in-hospital mortality was 8.6% (5/58). Four patients (7.5% of survivors) died during the period of followup. Actuarial survival at 15 years was 92%. Freedom from cardiovascular event at 10 and 15 years was 81% and 27%, respectively. Of 5 reoperations in 5 patients, only 1 was required due to complications of the initial Bentall type operation. The Bentall type operations resulted in a durable result. Although, in Marfan syndrome, freedom from cardiovascular event was lower than that in non-Marfan syndrome, actuarial survival rate was equal with non-Marfan syndrome. Close observation is necessary for detecting cardiovascular event, especially in Marfan syndrome.
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Nishio A, Yoshimura M, Yamauchi S, Masamura S, Kawakami T, Goto T, Mitsuhashi Y, Ohata K. Anomalous origin of the anterior choroidal artery. Interv Neuroradiol 2009; 15:73-6. [PMID: 20465932 DOI: 10.1177/159101990901500111] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Accepted: 07/28/2008] [Indexed: 11/16/2022] Open
Abstract
SUMMARY We describe a very rare case of anomalous origin of the anterior choroidal artery. In our case the anterior choroidal artery arises from the internal carotid artery proximal to the posterior communicating artery.
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Yamauchi S, Suzuki Y, Daitoku K, Minakawa M, Fukui K, Fukuda I. [Interrupted aortic arch type B survived after single stage repair and continuous hemodiafiltration; report of a case]. KYOBU GEKA. THE JAPANESE JOURNAL OF THORACIC SURGERY 2008; 61:1161-1164. [PMID: 19068708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A 14-day-old, 2,042 g neonate with interrupted aortic arch (IAA) type B was admitted to our hospital because of respiratory failure. Although alprostadil and alprostadil alfadex were used to keep the ductus arteriosus open, her congestive heart failure became worse and anuria and metabolic acidosis started to appear. We performed single-stage repair for her at 14 days old. Continuous hemodiafiltration (CHDF) was initiated immediately after the operation and peritoneal dialysis was started after paralytic ileus improved. CHDF improved her renal function and she was discharged at postoperative day 84. We conclude that CHDF is effective for neonates with acute renal failure although circulation management is rather difficult.
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Tarasov VF, Saiful ISM, Ohba Y, Takahashi K, Yamauchi S. Electron paramagnetic resonance of the excited states of the three-spins-1/2 ZnTPP-3-NOPy complex. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2008; 69:1327-1330. [PMID: 17996490 DOI: 10.1016/j.saa.2007.09.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2007] [Accepted: 09/17/2007] [Indexed: 05/25/2023]
Abstract
EPR spectra of the excited quartet and doublet molecular states of (tetraphenylporphinato)zinc(II) covalently bounded to 3-(N-nitronyl-notroxide) pyridine stable radical are modeled in terms of the spin-Hamiltonian given by the sum of the contributions from the radical and triplet moieties, and the interaction between them. The later is represented by anisotropic point dipolar and isotropic exchange electron spin-spin interactions. It is shown that the high field (W-band) EPR spectra depend on energy separation between the electronic doublet (D) and quartet (Q) states. This dependence was utilized to estimate the upper limit of the intensity of exchange interaction between the radical and porphyrin moieties.
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86
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Watanabe K, Daitoku K, Suzuki Y, Kawamura T, Yamauchi S, Minakawa M, Fukui K, Fukuda I. [Palliative right ventricular outflow reconstruction in tetralogy of Fallot with pulmonary atresia and aberrant right subclavian artery; report of a case]. KYOBU GEKA. THE JAPANESE JOURNAL OF THORACIC SURGERY 2008; 61:403-406. [PMID: 18464488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A 1-month-old girl weighting 3.1 kg was diagnosed as tetralogy of Fallot (TOF) with pulmonary artery atresia (PA) and aberrant right subclavian artery. Before the operation, pulmonary blood flow from a ducus arteriosus was maintained by lipo prostaglandin E1 (PGE1). The patient underwent palliative right ventricular outflow tract reconstruction (pRVOTR) because the proximal aberrant right subclavian artery was stenotic and the ductus arteriosus and branch of the left pulmonary artery were so close. Postoperative course was uneventful and pulmonary artery showed good growth. The pRVOTR as 1st procedure is a useful method for hypoplastic pulmonary artery to get equal and good growth. Although there are controversies about the size of right ventricular outflow tract (RVOT), 5 or 6 mm diameter of RVOT is recommended for the operative repair of hypoplastic left heart syndrome. We concluded that the pRVOTR should be one of the options as 1st palliative procedure for TOF with PA and diminutive pulmonary artery.
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Kawai N, Ikematsu H, Iwaki N, Maeda T, Kanazawa H, Kawashima T, Tanaka O, Yamauchi S, Kawamura K, Nagai T, Horii S, Hirotsu N, Kashiwagi S. A comparison of the effectiveness of zanamivir and oseltamivir for the treatment of influenza A and B. J Infect 2007; 56:51-7. [PMID: 17936910 DOI: 10.1016/j.jinf.2007.09.002] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2007] [Revised: 09/04/2007] [Accepted: 09/06/2007] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To compare the effectiveness of zanamivir with oseltamivir for influenza A and B. METHODS 1113 patients with influenza A or B were enrolled in the 2006-2007 influenza season. The duration of fever (temperature, >or=37.5 degrees C) and the percentage of patients afebrile at 24 and 48 h after the first dose of zanamivir or oseltamivir were calculated. Virus persistence after zanamivir therapy was also evaluated. RESULTS There were marginally significant differences between the duration of fever after the first dose of zanamivir (31.8+/-18.4h) and oseltamivir (35.5+/-23.9h) for influenza A (p<0.05). The duration of fever after starting zanamivir therapy (35.8+/-22.4h) was significantly shorter than that of oseltamivir (52.7+/-31.3h) for influenza B (p<0.001). There were no significant differences between influenza A and B in the percentage of patients afebrile at 24 or 48 h after the first inhalation of zanamivir. The reisolation rate after zanamivir therapy showed marginally significant differences between influenza A and B (<0.05). By multiple regression analysis, therapy (zanamivir or oseltamivir) was the major determinant affecting the duration of fever for influenza B. CONCLUSION Zanamivir therapy is more effective than oseltamivir for the treatment of influenza B infection.
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88
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Nakato T, Yamauchi S. Enantioselective synthesis of the tetrahydrofuran lignans (-)- and (+)-magnolone. JOURNAL OF NATURAL PRODUCTS 2007; 70:1588-92. [PMID: 17887723 DOI: 10.1021/np070300v] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The optically pure trisubstituted 7'-oxotetrahydrofuran lignans (-)- and (+)-magnolone ( 1) were synthesized by employing stereoselective S N1 intramolecular cyclization as a key reaction. The absolute configuration of naturally occurring (-)-magnolone was determined as (7 S,8 R,8' S).
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89
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Mitsuhashi Y, Nishio A, Kawahara S, Ichinose T, Yamauchi S, Naruse H, Matsuoka Y, Ohata K, Hara M. Morphologic evaluation of the caudal end of the inferior petrosal sinus using 3D rotational venography. AJNR Am J Neuroradiol 2007; 28:1179-84. [PMID: 17569984 PMCID: PMC8134147 DOI: 10.3174/ajnr.a0489] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2006] [Accepted: 09/29/2006] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE The inferior petrosal sinus (IPS) is the main transvenous access route used to examine or treat lesions involving the cavernous sinus. To carry out these procedures successfully, one must have a detailed knowledge of the anatomy of the venous system around the junction of the IPS and the internal jugular vein (IJV). MATERIALS AND METHODS Eighty-three sides in 63 patients (26 men, 37 women; mean, 56.5 years of age) were examined by using 3D rotational venography (3DRV). RESULT The drainage patterns of the IPS could be classified into the following 6 types, with emphasis on the level of IPS-IJV junction: type A, the IPS drains into the jugular bulb in 1/83 sides (1.2%); type B, the IPS drains into the IJV at the level of the extracranial opening of the hypoglossal canal in 29/83 sides (34.9%); type C, the IPS drains into the lower extracranial IJV in 31/83 sides (37.3%); type D, the IPS forms a plexus and has multiple junctions to the IJV near the jugular foramen in 5/83 sides (6.0%); type E, the IPS drains directly into the vertebral venous plexus (VVP) with no connection to the IJV in 3/83 sides (3.6%); and type F, the IPS is absent in 14/83 sides (16.9%). Each type is also characterized by the way of anastomosis with the VVP. CONCLUSION This classification seemed to be rational from the embryologic viewpoint, and it may be useful in establishing treatment strategies that involve endovascular manipulation via the IPS.
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Akiyama K, Yamauchi S, Nakato T, Maruyama M, Sugahara T, Kishida T. Antifungal activity of tetra-substituted tetrahydrofuran lignan, (-)-virgatusin, and its structure-activity relationship. Biosci Biotechnol Biochem 2007; 71:1028-35. [PMID: 17420596 DOI: 10.1271/bbb.60696] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Antifungal activities of the optically pure (>99%ee) (-)- and (+)-virgatusin, a tetra-substituted tetrahydrofuran lignan, were tested. (-)-Virgatusin, which is a natural product, showed highest antifungal activity against Colletotrichum lagenarium. Research on its structure-activity relationship was also performed. It was shown that two methoxy groups on 9 and 9' positions and a 3,4-methylenedioxyphenyl group on the 7 position of virgatusin were essential for high fungal growth inhibition. The part on 7'-phenyl group was not essential for activity. The 7'-(4-methoxyphenyl) derivative showed higher activity than that of (-)-virgatusin.
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91
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Yamauchi S, Sugahara T, Akiyama K, Maruyama M, Kishida T. Determination of the stereochemistry of the tetrahydropyran sesquineolignans morinols A and B. JOURNAL OF NATURAL PRODUCTS 2007; 70:549-56. [PMID: 17302455 DOI: 10.1021/np060461j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The 7',8'-stereochemistry of the tetrahydropyran sesquineolignans morinols A and B was determined as threo via synthetic studies and by comparison of NMR data of 7',8'-threo-morinol and 7',8'-erythro-morinol. This study also confirmed that the biosynthetic process produces enantiomeric mixtures of morinols A and B. This was ascertained by comparing the specific rotations of synthesized morinols A and B with those of naturally occurring morinols A and B.
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92
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Hirao H, Yamauchi S, Ishibashi F, Ishibashi F. Synthesis of Amino Tetrahydrofuran Lignan viaan N, O-Heterocyclic Compound as an Intermediate. Biosci Biotechnol Biochem 2007; 71:741-5. [PMID: 17341840 DOI: 10.1271/bbb.60575] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Tetrahydrofuran aminolignans bearing an amino group at the 8 position were synthesized via an N,O-heterocyclic compound that had been obtained by silylnitronate cycloaddition.
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93
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Maruyama M, Yamauchi S, Akiyama K, Sugahara T, Kishida T, Koba Y. Antibacterial activity of a virgatusin-related compound. Biosci Biotechnol Biochem 2007; 71:677-80. [PMID: 17341839 DOI: 10.1271/bbb.60429] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The relationship between antibacterial activity of tetra-substituted tetrahydrofuran lignans (1-4) and their absolute configurations was tested. Only compound 4 among two virgatusins and two related compounds exhibited growth inhibitory activity against the Gram-positive bacteria Bacillus subtilis, Staphylococcus aureus and Listeria denitrificans. Compound 4 affected the growth of B. subtilis in a bactericidic manner, and its ability to dissipate the cytoplasmic membrane potential was investigated using the fluorescence probe 3,3'-dipropylthiadicarbocyanine iodide. These results suggested that compound 4 damages cells by causing the loss of the proton motive force and disruption of the cellular integrity of the membrane, leading to cell death. In addition, it was shown that the antibacterial activity of a lignan was closely related to its absolute configuration and functional groups.
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Fukui K, Kanazawa J, Kawamura T, Yamauchi S, Watanabe K, Taniguchi S, Daitoku K, Minakawa M, Suzuki Y, Fukuda I. [Left ventricular-right atrial communication resulting from infective endocarditis]. KYOBU GEKA. THE JAPANESE JOURNAL OF THORACIC SURGERY 2007; 60:213-6. [PMID: 17352139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
We report a rare case of acquired left ventricular-right atrial communication resulting from infective endocarditis. A 57-year-old male with aortic regurgitation due to infective endocarditis was referred to our hospital because of severe congestive heart failure. Preoperative transthoracic echocardiography showed aortic, mitral and tricuspid severe regurgitations. Intraoperative transesophageal echocardiography revealed left ventricular-right atrial shunt. The fistula was located at the atrioventricular membranous septum. The communication site from the left view was below the commissure between the right coronary cusp and non-coronary cusp, and from the right view was just above the tricuspid annulus of the septal leaflet. The fistula was closed directly with mattress suture and aortic valve replacement and both mitral and tricuspid ring annuloplasty were carried out simultaneously. The postoperative course was uneventful. It is important to inspect shunts carefully in echocardiography of infective endocarditis with massive regurgitations.
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95
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Yamauchi S, Sugahara T, Nakashima Y, Okada A, Akiyama K, Kishida T, Maruyama M, Masuda T. Radical and superoxide scavenging activities of matairesinol and oxidized matairesinol. Biosci Biotechnol Biochem 2006; 70:1934-40. [PMID: 16926506 DOI: 10.1271/bbb.60096] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The radical and superoxide scavenging activities of oxidized matairesinols were examined. It could be assumed that the free benzylic position was important for higher radical scavenging activity. The different level of activity was observed between 7'-oxomatairesinol (Mat 2) and 7-oxomatairesinol (Mat 3). The activity of 8-hydroxymatairesinol was lower than that of matairesinol (Mat 1). The superoxide scavenging activity of the oxidized matairesinols was also demonstrated for the first time. It is assumed that the pKa value of phenol in the oxidized matairesinols affected this activity.
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Saiful ISM, Heinze P, Ohba Y, Yamauchi S, Yamamoto M, Tohda Y, Tani K. Interplanar interactions in the excited triplet states of carbazole dimers by means of time-resolved EPR spectroscopy. Mol Phys 2006. [DOI: 10.1080/00268970600638606] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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97
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Mori S, Iwamoto S, Yamauchi S. Synthesis of a glandular secretion of the civet cat, (2S,6S)-(6-methyltetrahydropyran-2-yl)acetic acid and its enantiomer, by using the yeast-reduction product and recovered substrate from yeast reduction. Biosci Biotechnol Biochem 2006; 70:712-7. [PMID: 16556990 DOI: 10.1271/bbb.70.712] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A glandular secretion of the civet cat, (2S,6S)-(6-methyltetrahydropyran-2-yl)acetic acid 1 and its enantiomer, were synthesized from the yeast-reduction product and recovered substrate from yeast reduction.
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Yamauchi S, Hayashi Y, Nakashima Y, Kirikihira T, Yamada K, Masuda T. Effect of benzylic oxygen on the antioxidant activity of phenolic lignans. JOURNAL OF NATURAL PRODUCTS 2005; 68:1459-70. [PMID: 16252908 DOI: 10.1021/np050089s] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
It has been clarified in the present investigation that a high degree of oxidation at the benzylic position of phenolic lignans bearing a 4-hydroxy-3-methoxybenzyl group reduces their antioxidant activity and that the antioxidant activity of the bis(4-hydroxy-3-methoxybenzyl)tetrahydrofuran lignan 2 is higher than that of the corresponding gamma-butyrolactone lignan 1. This was demonstrated by comparing the antioxidant activities of compounds 1 and 2 with those of the (benzyl)(hydroxybenzyl)tetrahydrofurans 3 and 4, the bis(hydroxybenzyl)tetrahydrofurans 7 and 8, the (benzoyl)(benzyl)tetrahydrofuran 6, and the dibenzoyltetrahydrofuran 9. The activity level of compound 2 was approximately the same potency as that of the tetrahydronaphthalene-tetrahydrofuran 5. These compounds possess either a 4-hydroxy-3-methoxybenzyl group or a 4-hydroxy-3-methoxybenzoyl group as the benzyl or benzoyl group. An examination of radical scavenging activity showed differences of activity between diastereomers. To make this comparison possible, compounds 1-9 were synthesized using new synthetic routes for several of these lignans. In this investigation, stereoisomers of the (benzyl)(hydroxybenzyl)tetrahydrofurans 3 and 4 and liovils 7 and 8 were synthesized for the first time.
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Yamauchi S, Okazaki M, Akiyama K, Sugahara T, Kishida T, Kashiwagi T. First enantioselective synthesis of (–)- and (+)-virgatusin, tetra-substituted tetrahydrofuran lignan. Org Biomol Chem 2005; 3:1670-5. [PMID: 15858648 DOI: 10.1039/b501151e] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The first highly enantioselective syntheses of tetra-substituted tetrahydrofuran lignan, (-)- and (+)-virgatusin, were achieved. Hemiacetal was stereoselectively obtained from Evans's syn-aldol product as a single isomer. This hemiacetal was converted to (-)-virgatusin via hydrogenolysis. (+)-Virgatusin was also synthesized through the same process. The enantiomeric excess of the both enantiomers was determined as more than 99% ee.
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100
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Yamauchi S, Mori S, Hirai Y, Kinoshita Y. Syntheses of (+)- and (-)-dihydropinidine and (+)- and (-)-epidihydropinidine by using yeast reduction of methyl (2-oxocyclohexyl)acetate. Biosci Biotechnol Biochem 2004; 68:676-84. [PMID: 15056903 DOI: 10.1271/bbb.68.676] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
(+) and (-)-Dihydropinidine and (+)- and (-)-epidihydropinidine were synthesized from hydroxy esters 1 and 2 which had been prepared by yeast reduction of methyl (2-oxocyclohexyl)acetate. The enantiomeric excess at the C-1 positions of 1 and 2 were both determined as more than 99% ee.
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