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N Ohashi

Publications and source records attributed to N Ohashi.

At least 73 records · Page 4Linked to original sources
PubMed1999

Cerebroprotective properties of SM-20220, a potent Na(+)/H(+) exchange inhibitor, in transient cerebral ischemia in rats.

The aim of this study was to investigate the contribution of the Na(+)/H(+) exchanger to cerebral ischemia using SM-20220 (N-(aminoiminomethyl)-1-methyl-1H-indole-2-carboxamide methanesulfonate), a newly synthesized compound. In in vitro experiments, we evaluated the inhibitory effect of SM-20220 on the Na(+)/H(+) exchanger in cultured neurons and glial cells. The IC(50) of SM-20220 in neurons and glial cells was 5 nM and 20 nM, respectively. To examine the in vivo effects of SM-20220 on brain injury, we used a transient middle cerebral artery occlusion model in rats. SM-20220 given intravenously 1 h after occlusion significantly reduced the extent of cerebral edema, Na(+) content and infarcted area in a dose-dependent manner. The results of the present study suggest that the Na(+)/H(+) exchanger is involved in the aggravation of brain edema and infarction, and its inhibitor may exert protective effects on post-ischemic brain damage.

Amides↗
PubMed1999

A Na+-H+ exchange inhibitor (SM-20550) protects from microvascular deterioration and myocardial injury after reperfusion.

Na+-H+ exchange inhibitors may reduce myocardial damage after reperfusion. However, their effects on microvascular deterioration are not known. We examined the potency of a novel Na+-H+ exchange inhibitor, SM-20550 [ N-(Aminoiminomethyl)-1,4-dimethyl-1H-indole-2-carboxamide methanesulfonate], and its effects on microvascular damage after reperfusion. In an in vitro study, the Na+-H+ exchange inhibiting activity of SM-20550 was about 10 times greater than that of ethylisopropyl amiloride. In in vivo experiments, we occluded the left circumflex coronary artery in 29 dogs for 2 h and then reperfused for 5 h. SM-20550 was administered either before ischemia (n = 11) or before reperfusion (n = 7). Another 11 dogs served as controls. We found that SM-20550 not only improved coronary vasodilator responses to acetylcholine and adenosine after reperfusion, but also reduced infarct size (P < 0.01). Intramyocardial bleeding, which should reflect microvascular damage, was not found in dogs with SM-20550 treatment. Infarct size was correlated inversely with collateral blood flow in control (both, P < 0.01) but not in SM-20550-treated animals. Furthermore, SM-20550 significantly suppressed ventricular fibrillation during both ischemia and reperfusion. These results suggest that protective effects of Na+-H+ exchange inhibitors on reperfused myocardium are due at least in part to microvascular protection.

Acetylcholine↗
PubMed1999

Multiple p44 genes encoding major outer membrane proteins are expressed in the human granulocytic ehrlichiosis agent.

Human granulocytic ehrlichiosis (HGE) is caused by infection with an obligatory intracellular bacterium, the HGE agent. We previously cloned a gene encoding HGE agent 44-kDa major outer membrane protein and designated it p44. In this study, we (i) identified five different mRNAs that are transcribed from p44-homologous genes in the HGE agent cultivated in HL-60 cells; (ii) cloned genes corresponding to the mRNAs from the genomic DNA of the HGE agent; (iii) showed that the genes being expressed were not clustered in the HGE agent genome; (iv) estimated that a minimum copy number of the p44-homologous genes in the genome is 18; (v) detected two different P44-homologous proteins expressed by the HGE agent; and (vi) demonstrated existence of antibodies specific to the two proteins in sera from patients with HGE. These findings showed that p44 multigenes have several active expression sites and the expression is regulated at transcriptional level, suggesting a potentially unique mechanism for generating the diversity in major antigenic outer membrane proteins of the HGE agent. Characterization of p44-homologous genes expressed by the HGE agent in a tissue culture would assist in understanding a role of the p44 multigene family in pathogenesis and immune response in HGE.

Amino Acid Sequence↗
PubMed1999

Anti-monocyte chemoattractant protein-1/monocyte chemotactic and activating factor antibody inhibits neointimal hyperplasia in injured rat carotid arteries.

Monocyte chemoattractant protein-1 (MCP-1)/monocyte chemotactic and activating factor (MCAF) has been suggested to promote atherogenesis. The effects of in vivo neutralization of MCP-1 in a rat model were examined in an effort to clarify the role of MCP-1 in the development of neointimal hyperplasia. Competitive polymerase chain reaction analysis revealed maximum MCP-1 mRNA expression at 4 hours after carotid arterial injury. Increased immunoreactivities of MCP-1 were also detected at 2 and 8 hours after injury. Either anti-MCP-1 antibody or nonimmunized goat IgG (10 mg/kg) was then administered every 12 hours to rats that had undergone carotid arterial injury. Treatment with 3 consecutive doses of anti-MCP-1 antibody within 24 hours (experiment 1) and every 12 hours for 5 days (experiment 2) significantly inhibited neointimal hyperplasia at day 14, resulting in a 27.8% reduction of the mean intima/media ratio (P<0.05) in experiment 1 and a 43.6% reduction (P<0.01) in experiment 2. This effect was still apparent at day 56 (55.6% inhibition; P<0.05). The number of vascular smooth muscle cells in the neointima at day 4 was significantly reduced by anti-MCP-1 treatment, demonstrating the important role of MCP-1 in early neointimal lesion formation. However, recombinant MCP-1 did not stimulate chemotaxis of vascular smooth muscle cells in an in vitro migration assay. These results suggest that MCP-1 promotes neointimal hyperplasia in early neointimal lesion formation and that neutralization of MCP-1 before, and immediately after, arterial injury may be effective in preventing restenosis after angioplasty. Further studies are needed to clarify the mechanism underlying the promotion of neointimal hyperplasia by MCP-1.

Animals↗
PubMed1999

Global Analysis of a-, b-, and c-Type Transitions Involving Tunneling Components of K = 0 and 1 States of the Methanol Dimer.

Spectral data on K = 0 and 1 levels of the methanol dimer available from previous and present Fourier transform microwave measurements have been interpreted globally, using a group-theoretically derived effective Hamiltonian and corresponding tunneling matrix elements to describe the splittings arising from a large number of tunneling motions. In the present work, 302 new measurements (40 K = 1-1 and 262 K = 1-0 transitions) were added to the previous data set to give a total of 584 assigned transitions with J </= 6. As a result of the rather complete K = 0, 1 data set for J </= 4, the lone-pair exchange tunneling splittings were obtained experimentally. Matrix element expansions in J(J + 1) used in the previous K = 0 formalism were modified to apply to K > 0, essentially by making a number of real coefficients complex, as required by the generalized internal-axis-method tunneling formalism. To reduce the number of adjustable parameters to an acceptable level in both the K = 0 and K = 1 effective Hamiltonians (used in separate K = 0 and K = 1 least-squares fits), a rather large number of assumptions concerning probably negligible parameters had to be made. The present fitting results should thus be considered as providing assurance of the group-theoretical line assignments as well as a nearly quantitative global interpretation of the tunneling splittings, even though they do not yet unambiguously determine the relative contributions from all 25 group-theoretically inequivalent tunneling motions in this complex, nor do they permit quantitative extrapolation to higher K levels. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Near-Infrared Diode-Laser Spectroscopy of the CCO Radical in the Ã(010)3Delta-;X(010)3Pi(b) Band.

The Ã(010)3Delta-;X(010)3Pi(b) band spectrum of the CCO radical has been studied in the region from 11,808 to 11,919 cm-1 by near-infrared diode-laser spectroscopy. A least-squares fit has been made using only part of the observed Ã(010)3Delta-;X(010)3Pi(b) band transitions to obtain molecular constants for the Ã(010)3Delta state, removing transitions with upper levels of irregular behavior. The spin-orbit parameter and the subband origin determined in the present analysis have been discussed in relation to higher order contributions to the Renner-Teller effect. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Apoptosis in congestive heart failure induced by viral myocarditis in mice.

It has recently been speculated that progressive deterioration of left ventricular function in chronic heart failure is due to the ongoing loss of viable cardiac myocytes. However, as there is little direct evidence of significant apoptosis contributing to the pathogenesis in cardiac myocytes in vivo, the significance of apoptosis in heart failure remains to be clarified. We investigated the role of apoptosis in heart failure induced by encephalomyocarditis virus myocarditis. DBA/2 mice were inoculated with the virus (day 0), then killed, and their hearts were extracted 3 to 28 days later. Internucleosomal DNA fragmentation, chromatin binding dye staining, and in situ terminal transferase deoxyuridine triphosphate (dUTP) end-labeling were used to detect apoptosis. Internucleosomal DNA fragmentation (DNA ladder) was clearly demonstrated on days 5 to 14 in the virus-infected hearts when myocardial necrosis and infiltration of mononuclear cells were prominent in the hearts. Apoptotic cells demonstrated morphological changes typical of apoptosis (condensation of chromatin and nuclear fragmentation). Both Fas antigen and Fas ligand immunoreactivity were detected in the infiltrating mononuclear cells. The in situ terminal transferase dUTP end-labeling method demonstrated condensed nuclei of infiltrating mononuclear cells on day 7. However, nuclei of cardiac myocytes surrounded by the cellular infiltration were absent. The main source of apoptotic cells in the heart in mice with viral myocarditis appeared to be the infiltrating mononuclear cells.

Animals↗
PubMed1999

Effects of troglitazone on fat distribution in the treatment of male type 2 diabetes.

We investigated the efficacy of additional administration of 400 mg troglitazone (+T), which became available as a treatment for type 2 diabetes following the demonstration of its ability to reduce insulin resistance, in combination with diet (D + T) or sulfonylurea (S + T) therapy. Body fat area as determined by computed tomographic (CT) scanning at the umbilical level, as well as several clinical and biochemical parameters of glycemic control and lipid metabolism, were compared before and after 3 months of additional treatment with troglitazone. The body mass index (BMI) tended to increase in both groups (22.7 +/- 0.6 v 23.2 +/- 0.6 kg/m2 in D + T, nonsignificant [NS]; 22.2 +/- 0.5 v 22.3 +/- 0.5 kg/m2 in S + T, NS), while it tended to decrease in the control group (only diet therapy, 23.6 +/- 0.6 v 23.1 +/- 0.8 kg/m2, NS). Mean blood pressure ([BP] 96 +/- 3 v 89 +/- 4 mm Hg, P < .05) decreased significantly in the D + T group. Changes in the glycemic and lipid profile and leptin did not reach statistical significance. The D + T group showed a significant decline in immunoreactive insulin ([IRI] 12.4 +/- 1.2 v 8.0 +/- 1.0 microU/mL, P < .05), reflecting markedly reduced insulin resistance, as well as a significant increase in plasma insulin-like growth factor-1 ([IGF-1] 175.7 +/- 14.2 v 189.8 +/- 12.6 ng/mL, P < .05). A slight weight gain was associated with a tendency for subcutaneous fat to increase, while visceral fat decreased in both troglitazone-treated groups. The decrease in the visceral to subcutaneous fat ratio (V/S ratio) was statistically significant in the D + T group (1.09 +/- 0.11 v 0.94 +/- 0.09, P < .05), while the V/S ratio in the control group did not change. A notable finding of this study is the difference in the response to troglitazone between subcutaneous and visceral adipose tissue. It is suggested that troglitazone may exert beneficial effects by reducing visceral fat.

Adipose Tissue↗
PubMed1999

Determination of TA-0201, a novel orally active non-peptide endothelin antagonist, in rat plasma and tissues by a liquid chromatography--electrospray ionization--tandem mass spectrometry system.

N-[6-[2-[(5-bromo-2-pyrimidinyl)oxy]ethoxy]-5-(4-methylphenyl)-4-pyrimid inyl]-4-(2-hydroxy-1, 1-dimethylethyl) benzenesulfonamide sodium salt (TA-0201) is a novel orally active non-peptide antagonist for endothelin (ET) receptors. A sensitive and simultaneous determination method of TA-0201 and its major metabolites by liquid chromatography tandem mass spectrometry (LC--MS/MS) in a selected reaction monitoring mode using [2H6]TA-0201 as the internal standard was developed, and the plasma and tissue concentrations of TA-0201 and its major metabolites were determined in a pharmacokinetic study. The lower limit of determination of plasma TA-0201 concentrations by this method was 0.1 ng/0.5 ml, and the between- and within-run accuracy and precision were both less than 5.1%, in the calibration curve range of 0.1-50 ng/0.5 ml. This method was applied to determine the concentrations of TA-0201 and its metabolites in plasma and various target tissues, i.e. the heart, lung and kidney, after oral administration of TA-0201 (0.1 mg/kg(-1)) to male rats. TA-0201 and its major metabolite of a carboxylic acid form were detected in plasma and all the tissues 24 h after administration, their tissue concentrations being higher than those in plasma and still detectable at 72 h. Thus, this method could successfully be applied to study pharmacokinetic properties of TA-0201 in rats.

Administration, Oral↗
PubMed1999

Induction of gamma-glutamylcysteine synthetase gene expression by platinum drugs in peripheral mononuclear cells of lung cancer patients.

BACKGROUND: To investigate in vivo the roles of gamma-glutamylcysteine synthetase (gamma-GCS), multidrug resistance-associated protein (MRP), human canalicular multispecific organic anion transporter (cMOAT) and DNA topoisomerase I (topo I) in relation to platinum drug resistance, we monitored the changes of the steady-state levels of the mRNAs for these factors in peripheral mononuclear cells (PMN) after completing platinum drug administration. PATIENTS AND METHODS: PMN from 46 subjects were studied. We obtained PMN from 14 previously untreated lung cancer patients and 14 normal volunteers to measure the baseline gene expression levels. We then obtained PMN from 18 patients with previously untreated advanced lung cancer before and after they received platinum drug treatment. We analyzed the gene expression levels by using the quantitative reverse transcription polymerase chain reaction (RT-PCR). RESULTS: There were no differences in the baseline expression levels between normal volunteers and lung cancer patients in any of the genes. After platinum drug administration, the heavy subunit of gamma-GCS (gamma-GCSh) expression level increased 2.5-fold within 24 hours and the increase persisted for a month, whereas the light subunit of gamma-GCS (gamma-GCSl) expression level did not show an early response but had increased after a month. By contrast, the MRP, cMOAT and topo I expression levels were similar before, during and after chemotherapy. CONCLUSIONS: These results suggest that the gene expression levels of both subunits of gamma-GCS play an important in vivo role in platinum drug resistance.

Adenocarcinoma↗
PubMed1999

Twin-to-twin transfusion syndrome with hydrops: a retrospective analysis of ten cases.

We retrospectively studied 10 cases of twin-to-twin transfusion syndrome (TTTS) with fetal hydrops. TTTS was diagnosed sonographically between the 17-31 weeks of gestation. All twins were delivered by emergency cesarean section because of cardiac decompensation of one or both fetuses. The mean (+/-SD) age at diagnosis was 26.1 +/- 4.5 and the mean age at delivery was 28.8 +/- 2.0 weeks. Gestational age at birth was similar in survivors and nonsurvivors. However, surviving infants were diagnosed later in gestation (23.6 +/- 4.8 vs. 28.7 +/- 1.9 weeks; p < 0.01); and gestational age at appearance of hydrops were later in survivors (26.1 +/- 3.2 vs. 29.2 +/- 2.4 weeks; p < 0.05). Overall survival rate was 50% (10 of 20 infants). All survivors were delivered within 3 days after the appearance of fetal hydropic changes. Extrauterine treatment in earlier stages of TTTS might improve the outcome. Nevertheless, more aggressive intrauterine treatment should be considered in the most severe cases of TTTS developing before 24-25 weeks' gestation.

Cesarean Section↗
PubMed1999

Ehrlichia chaffeensis and E. sennetsu, but not the human granulocytic ehrlichiosis agent, colocalize with transferrin receptor and up-regulate transferrin receptor mRNA by activating iron-responsive protein 1.

Ehrlichia chaffeensis and E. sennetsu are genetically divergent obligatory intracellular bacteria of human monocytes and macrophages, and the human granulocytic ehrlichiosis (HGE) agent is an obligatory intracellular bacterium of granulocytes. Infection with both E. chaffeensis and E. sennetsu, but not HGE agent, in the acute monocytic leukemia cell line THP-1 almost completely inhibited by treatment with deferoxamine, a cell-permeable iron chelator. Transferrin receptors (TfRs) accumulated on both E. chaffeensis and E. sennetsu, but not HGE agent, inclusions in THP-1 cells or the cells of the promyelocytic leukemia cell line HL-60. Reverse transcription-PCR showed an increase in the level of TfR mRNA 6 h postinfection which peaked at 24 h postinfection with both E. chaffeensis and E. sennetsu infection in THP-1 or HL-60 cells. In contrast, HGE agent in THP-1 or HL-60 cells induced no increase in TfR mRNA levels. Heat treatment of E. chaffeensis or the addition of monodansylcadaverine, a transglutaminase inhibitor, 3 h prior to infection inhibited the up-regulation of TfR mRNA. The addition of oxytetracycline 6 h after E. chaffeensis infection caused a decrease in TfR mRNA which returned to the basal level by 24 h postinfection. These results indicate that both internalization and continuous proliferation of ehrlichial organisms or the production of ehrlichial proteins are required for the up-regulation of TfR mRNA. Results of electrophoretic mobility shift assays showed that both E. chaffeensis and E. sennetsu infection increased the binding activity of iron-responsive protein 1 (IRP-1) to the iron-responsive element at 6 h postinfection and remained elevated at 24 h postinfection. However, HGE agent infection had no effect on IRP-1 binding activity. This result suggests that activation of IRP-1 and subsequent stabilization of TfR mRNA comprise the mechanism of TfR mRNA up-regulation by E. chaffeensis and E. sennetsu infection.

Base Sequence↗
PubMed1999

Western and dot blotting analyses of Ehrlichia chaffeensis indirect fluorescent-antibody assay-positive and -negative human sera by using native and recombinant E. chaffeensis and E. canis antigens.

Human monocytic ehrlichiosis is an emerging infectious disease caused by Ehrlichia chaffeensis, a gram-negative obligatory intracellular bacterium closely related to E. canis. The immunoreactive recombinant fusion proteins rP28 and rP30 have become available after cloning and expressing of the 28- and 30-kDa major outer membrane protein genes of E. chaffeensis and E. canis, respectively. Western immunoblotting was performed to analyze the antibody responses of the 37 E. chaffeensis indirect fluorescent-antibody assay (IFA)-positive and 20 IFA-negative serum specimens with purified whole organisms, rP28, and rP30. All IFA-negative sera were negative with purified whole organisms, rP28, or rP30 by Western immunoblot analysis (100% relative diagnostic specificity). Of 37 IFA-positive sera, 34 sera reacted with any native proteins of E. chaffeensis ranging from 44 to 110 kDa, and 30 sera reacted with 44- to 110-kDa native E. canis antigens. The 28-kDa E. chaffeensis and 30-kDa E. canis native proteins were recognized by 25 IFA-positive sera. Fifteen IFA-positive sera reacted with rP28 by Western blot analysis, whereas 34 IFA-positive sera reacted with rP30 (92% relative diagnostic specificity), indicating that rP30 is more sensitive than rP28 for detecting the antibodies in IFA-positive sera. These 34 IFA-positive sera were positive by the dot blot assay with rP30, distinguishing them from IFA-negative sera. Except for three rP30-negative but IFA-positive specimens that instead showed an E. ewingii infection-like profile by Western immunoblotting, the results of Western and dot blot assays with rP30 matched 100% with the IFA test results. Densitometric analysis of dot blot reactions showed a positive correlation between the dot density and the IFA titer. These results suggest that rP30 antigen would provide a simple, consistent, and rapid serodiagnosis for human monocytic ehrlichiosis.

Animals↗
PubMed1999

Synthesis and biological activity of N-(aminoiminomethyl)-1H-indole carboxamide derivatives as Na+/H+ exchanger inhibitors.

A series of N-(aminoiminomethyl)-1H-indole carboxamide derivatives were synthesized and their inhibitory potencies against the Na+/H+ exchanger were measured. Variation of the carbonylguanidine group at the 2- to 7-position of the indole ring system showed that a substitution at the 2-position improved the Na+/H+ exchanger inhibitory activity the most in vitro. This led to the synthesis and evaluation of an extensive series of N-(aminoiminomethyl)-1H-indole-2-carboxamide derivatives. Derivatives having an alkyl or substituted alkyl group at the 1-position of the indole ring system showed higher levels of in vitro activities. N-(aminoiminomethyl)- 1-(2-phenylethyl)-1H-indole-2-carboxamide (49) had the strongest activity.

Animals↗
PubMed1999

Apical hypertrophic cardiomyopathy and hepatitis C virus infection.

The familial form of hypertrophic cardiomyopathy (HCM) is attributed to mutations in the genes for contractile proteins, but the etiology of non-familial form remains unknown. This study was designed to examine the clinical features, histopathologic changes, and hepatitis C virus (HCV) genomes in patients with HCM associated with HCV infection. Anti-HCV antibody was present in the sera of 9 of 65 patients (13.8%) with HCM versus 2.41% in a control population of voluntary blood donors in Japan, a statistically significant difference (p<0.0001). Among these 9 patients, 6 had ace-of-spades-shaped deformities of the left ventricle with apical hypertrophy. Myocardial fibrosis was found in all patients, and mild cellular infiltration was observed in 5 patients. Type 1b HCV RNA was present in the sera of 5 of the 9 patients. The copy number of HCV was 5.5x10(3)-8.6x10(5) genomes/ml serum, and multiple clones of HCV were detected in the sera of each patient by an analysis of the hypervariable regions using fluorescent single-strand conformation polymorphism. Positive strands of HCV were found in the hearts of 5 patients, and negative strands in the hearts of 2 patients. A high prevalence of HCV infection was found in patients with HCM, particularly of the apical variety, suggesting that HCV is an important causal agent in the pathogenesis of the disease.

Adolescent↗
PubMed1999

[Study on antibiotics susceptibility and mechanism of carbapenem-resistance in clinical isolates of Pseudomonas aeruginosa].

The susceptibility of 260 strains of Pseudomonas aeruginosa to several antibiotics and the mechanism of resistance to carbapenems were investigated. The number of strains of P. aeruginosa moderately resistant or resistant to ofloxacin, ceftazidime and imipenem (IPM) were 76 (29.2%), 31 (11.9%) and 30 (11.5%), respectively. There was no clear relationship between the drug resistance of P. aeruginosa and serum type. Fourteen strains (46.6%) out of 30 IPM-resistant strains were susceptible to meropenem (MEPM). Twenty seven (90.0%) IPM-resistant strains showed cross resistant to panipenem (PAPM), and 12 strains (44.4%) out of the 27 strains showed high susceptibility to MEPM. P. aeruginosa becomes resistant to IPM and PAPM only by the decrease in the outer membrane permeability of these carbapenems. In contrast, P. aeruginosa becomes equally resistant to MEPM by concurrent occurrence of the increase in the efflux of the antibiotics and the decrease in the outer membrane permeability of the antibiotics. The possibility that both mechanisms are taken place concurrently in P. aeruginosa is considered to be low, and it was also supported by the results of the present study.

Anti-Infective Agents↗