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N Shibata

Publications and source records attributed to N Shibata.

At least 289 records · Page 16Linked to original sources
PubMed1989

Structural analysis of phospho-D-mannan-protein complexes isolated from yeast and mold form cells of Candida albicans NIH A-207 serotype A strain.

The immunochemical properties between phospho-D-mannan-protein complexes of yeast (Y) and mycelial (M) forms of Candida albicans NIH A-207 (serotype A) strain were compared. Hydrolysis of the Y-form complex gave a mixture of beta-(1----2)-linked D-mannooligosaccharides consisting mainly of tri- and tetra-ose, whereas the M-form complex gave preponderantly D-mannose. The antiserum against Y-form cells exhibited a lower reactivity with the M-form than with the Y-form complex, whereas the antiserum to M-form cells could not distinguish significantly between both complexes. Moreover, these acid-modified complexes showed lower antibody-precipitating effect than each corresponding intact complex against antisera of Y- and M-form cells. Digestion of the acid-modified Y- and M-form complexes with the Arthrobacter GJM-1 strain alpha-D-mannosidase yielded 35- and 40-% degradation products, respectively. Acetolysis of each modified complex under mild conditions gave the same D-mannohexaose, beta-D-Manp-(1----2)-beta-D-Manp-(1----2)-alpha-D-Manp -(1----2)-alpha-D-Manp- (1----2)-alpha-D-Manp-(1----2)-D-Man. Because the complexes of Y- and M-form cells of C. albicans NIH B-792 (serotype B) strain did not give any hexaose fraction containing beta-(1----2) linkages, the presence of this hexaose can be regarded as one of the dominant characteristics of the serotype-A specificity of C. albicans spp.

Candida albicans↗
PubMed1989

Evaluation of fluorescence polarization immunoassay for determination of cyclosporin in plasma.

The fluorescence polarization immunoassay (FPIA) method for determination of cyclosporin in plasma was evaluated and compared with the high-performance liquid chromatography (HPLC) and the radioimmunoassay (RIA) methods. The coefficients of variation for the within-run and between-run precision were less than 5 and less than 8%, respectively, for samples ranging in concentration from 50 to 600 ng/ml. Recoveries were determined by adding cyclosporin at concentrations from 25 to 1,000 ng/ml to patient plasma; they were, on average, 98.5%. The calibration curve was stable throughout a 10-week study period. There was no clinically significant interference due to hemolysis, icterus, lipemia, or other commonly used drugs. There was considerable variation of the ratio of the FPIA result to the HPLC result, whereas there was a good correlation between the FPIA and the RIA results (r = 0.975, n = 25, y = 1.2x - 36.4), when evaluated using specimens from renal transplant patients receiving cyclosporin orally. It was concluded that the FPIA is an appropriate, rapid method for patient cyclosporin analysis in plasma and serves as a practical alternative to the RIA.

Adolescent↗
PubMed1989

Effects of temperature and endogenous factors in blood on concentrations of cyclosporin in plasma measured by high-performance liquid chromatography.

The effects of temperature, hematocrit (Hct), lipid level in plasma and cyclosporin A (CyA) level in whole blood on the concentration of CyA in plasma measured by high-performance liquid chromatography were studied in vitro. With rise in blood storage temperature before cells were removed, the concentration of CyA in plasma was increased in the temperature range between 10 degrees C and 37 degrees C, but was decreased between 4 degrees C and 10 degrees C. With rise in Hct, the concentration of CyA in plasma was decreased, and it was more markedly decreased at the blood storage temperature of 4 degrees C than at 37 degrees C. A lipid supplementation study showed that the concentration of CyA in plasma was increased with rise in plasma triglyceride level and in plasma cholesterol level at the storage temperature of 4 degrees C but not at 37 degrees C. Studies of the effect of CyA concentration in blood on the CyA distribution in blood demonstrated that the cellular/plasma concentration (C/P) ratio at low levels (less than 200 micrograms/ml) of plasma CyA ranged from 4 to 10 and was about 2 times higher than that at higher concentrations at 4 degrees C, but the ratio was relatively constant at 37 degrees C. The saturation capacity of the cellular fraction for CyA showed considerable individual variations, but there was no difference between the capacities at 4 degrees C and 37 degrees C. The separation of plasma after equilibration at 37 degrees C made it possible to avoid the variations in the distribution of CyA in whole blood associated with changes in Hct, lipid level in plasma and CyA level in whole blood, and to obtain a measurement reflecting the physiologically significant concentration of CyA in plasma.

Chromatography, High Pressure Liquid↗
PubMed1989

[Clinical characteristics of unstable angina in 162 consecutive cases].

We surveyed the clinical characteristics, treatment, and prognosis of 162 patients with unstable angina, who were admitted to our center between 1985 and 1987. There were 112 males and 50 females, with a mean age of 65 years. The clinical characteristics according to the American Heart Association classification were new angina of effort in 21%, changing pattern in 61%, and new angina at rest in 18% of the patients. ECG recordings during attacks of angina were obtained in 70%, and ST elevation was detected in 11%, ST depression in 54%, and T wave abnormality in 5%. Coronary arteriography performed in 42% of the patients revealed single vessel lesion in 21%, two vessel lesion in 10%, three vessel lesion in 5%, and left main trunk lesion in 3% of the patients. Seventy-seven percent of the patients were controlled by medical therapy, including nitrates, calcium antagonists, and, in some cases, beta blockades. Three percent of the patients were controlled with intra aortic balloon pumping in addition to medical therapy. Coronary artery bypass graft surgery (CABG) was performed in 6% of the patients. Since 1987, percutaneous transluminal angioplasty (PTCA) was introduced in our center and PTCA was performed in 9 patients (6%). Restenosis of the dilated portions of the coronary artery was observed and PTCA was again performed in 2 of 9 patients (22%). All patients who received CABG or PTCA survived and have been free from angina or myocardial infarction. Non-fatal myocardial infarction occurred in 10 cases (5.6%) and fatal infarction occurred in one patient (0.6%).

Angina Pectoris↗
PubMed1989

[Clinical effects and plasma concentration levels of aprindine hydrochloride in patients with tachyarrhythmias].

Aprindine hydrochloride (aprindine) was administered orally in 17 Japanese patients with supraventricular or ventricular tachyarrhythmias, and the clinical effects and plasma concentration levels were evaluated. The antiarrhythmic effects were defined using Holter ECG recordings. Aprindine was administered orally with a daily dose of 40 mg for 2 weeks in all cases, and aprindine, 60 mg daily, was administered for the next 2 weeks in patients who did not show sufficient antiarrhythmic effects with 40 mg of the drug. Aprindine was effective in 9 of 17 patients, and the mean plasma concentration level reached 0.6 micrograms/ml 2 weeks after the administration was started. Effective results were seen in 2 of the 4 patients receiving a daily dose of 60 mg, and the mean plasma concentration level reached 1.0 microgram/ml 2 weeks after the administration was started. Transient mild elevations of liver transaminases were observed in one patient and mild transient anemia was observed in another. These abnormal data disappeared although the drug administration was continued. In conclusion, the administration of a relatively small dose of aprindine and, consequently, low plasma concentration levels, are effective for cardiac tachyarrhythmias in Japanese patients.

Administration, Oral↗
PubMed1989

[A case of mitral stenosis with left atrial thrombus arose and reduced in a short-term].

A case of mitral stenosis with left atrial thrombus which rapidly arose and reduced within a month was reported. A 61-year-old female was admitted to our hospital on November 14, 1986 because of a syncopal attack due to ventricular tachycardia. On admission she had typical auscultatory signs of mitral stenosis, mild hepatomegaly and no neurological abnormality. Laboratory findings included coagulation studies were normal, and atrial fibrillation was noted on ECG. Heart catheterization revealed low cardiac output, the mitral orifice area to be 2.4 cm2 and left ventriculography showed mild mitral regurgitation. Ventricular tachycardia was controlled following improvement of heart failure. On two-dimensional echocardiography performed on December 24, left atrial thrombus was revealed which was not detected on December 3. Through the continuous administration of warfarin and aspirin to prevent the thrombus' growth, it markedly reduced in size, from 3 x 2 x 4.5 cm on December 24, 1986 to 1.5 x 1 x 2.5 cm on January 30, 1987 without systemic embolism. Then a mitral valve replacement and a left atrial thrombectomy were performed on February 3, with the removal of a red thrombus, partially organized, measuring 1 x 0.7 x 2.5 cm. This case is unique in its clinical outcome and further investigation is necessary for the management of patients as our case.

Aspirin↗
PubMed1988

Gelsolin is Ca2+-sensitive regulator of actomyosin system in platelet.

Effects of gelsolin on the actomyosin system in platelet have been studied. MgATPase activity of platelet actomyosin is enhanced up to two folds by 200 nM of platelet gelsolin in the presence, but not in the absence of Ca ion. The half maximum enhancement is observed at the concentration of Ca2+ around 10(-5) M. The effect of gelsolin to enhance the ATPase activity of actomyosin is potentiated by tropomyosin, which is a Ca2+-insensitive actomyosin enhancer. The results indicate that gelsolin may control the activity of actomyosin system in platelets.

Actinin↗
PubMed1988

Evidence for the sexual bipotentiality of spermatogonia in the fish, Oryzias latipes.

The origin of the oocyte-like cells (testis-ova) induced by the administration of estradiol in the testis of the fish, Oryzias latipes, was examined by light and electron microscopy. A small number of testis-ova at the zygotene stage was seen on the sixth day after the beginning of treatment with estradiol, and on the 12th day testis-ova at the pachytene and diplotene stages were observed. Ultrastructural observations revealed that the testis-ova at the zygotene stage were organized as cysts and that all testis-ova within a given cyst developed synchronously. The number of these testis-ova in each cyst varied but cysts containing 16-20 or 26-30 testis-ova were most frequently observed. Spermatogonia of O. latipes are classified morphologically into two types: the type A and the type B spermatogonia (Grier, '76 Cell Tissue Res., 168:419-431). Type A spermatogonia, which were separated from each other by Sertoli cells, were of the stem type and type B spermatogonia appeared to divide clonally 9-10 times in each cyst before entering meiosis. The present observations on zygotene testis-ova indicate that the testis-ova originate from type B spermatogonia which have divided clonally four or five times, suggesting that male germ cells remain sexually bipotent through the early stages of development of type B spermatogonia.

Animals↗
PubMed1988

Influence of shock strength and timing on induction of ventricular arrhythmias in dogs.

We delivered strong shocks via electrodes on the left ventricular apex and the right atrium in seven dogs during the T wave of atrial pacing while recordings were made from 56 epicardial electrodes. After shocks that induced arrhythmias were given, the earliest activation occurred in the middle of the ventricles for lower-energy shocks and in the base for higher-energy shocks. For shocks late in the vulnerable period, activation was recorded soon after the shock, whereas for shocks early in the vulnerable period activation was not recorded for a mean of 70 ms (+/- 17 ms SD) after the shock. We also gave 1-J shocks during right and left ventricular pacing. For shocks early in the vulnerable period, activation initiating fibrillation arose in a focal pattern from the paced region. For shocks during the midportion of the vulnerable period, fibrillation arose by two leading circle reentrant loops rotating in opposite directions, one on the left and the other on the right ventricle. For shocks at the end of the vulnerable period, the two reentrant loops fused on the side of the heart opposite the pacing site to again form a single focal activation pattern. Thus the initial activation patterns of arrhythmias initiated by shocks, the time from the shock until earliest postshock activation, and the site of earliest postshock activation are strongly influenced by the coupling interval and strength of the shock.

Animals↗
PubMed1988

Epicardial activation after unsuccessful defibrillation shocks in dogs.

To study defibrillation, shocks were given to seven dogs during electrically induced fibrillation, while recordings were made from 56 epicardial electrodes. Shocks were given via electrodes on the left ventricular apex and the right atrium, creating an uneven shock field with much higher potential gradients in the apex than in the base of the ventricles. For unsuccessful 0.01- to 0.05-J shocks, activation occurred soon after the shock at many sites in both the base and the apex. For 0.1- to 0.5-J shocks, the number of early activation sites was greatly decreased, and the latency from the shock until earliest recorded activation was greatly increased at the apex but not at the base. For 1- to 5-J shocks, one to three early sites were present and confined to the base, with a long latency between the shock and the appearance of these early sites. The latency and location of earliest activation were similar to those after 1- to 5-J shocks given to induce fibrillation during normal paced rhythm. Shocks of 10 J successfully defibrillated. These findings suggest that the shock field can have at least three effects. One, a weak field fails to halt the activation fronts of fibrillation. Two, a stronger field halts but then reinduces fibrillation in a manner similar to that of the same strength field during the vulnerable period of normal rhythm. Three, a still higher field halts fibrillation without reinitiating it. Successful defibrillation requires a shock strong enough to create this third field intensity throughout the ventricles.

Animals↗
PubMed1988

Effects of diltiazem on rheological properties of human blood.

The in vitro effects of diltiazem (DTZ), a coronary vasodilator, deacetyldiltiazem (D-M1), one of the metabolites of DTZ, and pentoxifylline (PTF) which is known to improve erythrocyte deformation, on the viscosity of platelet poor blood were compared. Furthermore the change in the viscosity of whole blood from patients with effort angina after intravenous administration of DTZ was examined ex vivo. The addition of DTZ into platelet poor blood at 37 degrees C caused a rapid reduction in blood viscosity and an enhancement of erythrocyte deformability within 5 min, which then diminished in a time-dependent manner. Similar effects were also found by adding D-M1. On the other hand, the effects of PTF appeared after an incubation period of more than 60 min and were enhanced in a time-dependent manner. These actions of PTF, but not those of DTZ and D-M1, paralleled the increase of erythrocyte adenosine-triphosphate content. DTZ and D-M1, but not PTF, had biphasic effects on the osmotic behavior of erythrocytes. Whole blood viscosity was reduced significantly during the period 5-30 min after intravenous administration of 10 mg of DTZ, which diminished with the elimination of plasma DTZ. In conclusion, the action mechanisms involved in the effect of DTZ and D-M1 on blood rheological properties appeared to be different from that of PTF. These effects of DTZ are clinically significant in improving the flow properties of blood in vascular diseases.

Adenosine Triphosphate↗
PubMed1988

Augmentation of eicosanoids in ischemic heart muscle in dogs: its role in the deterioration of the ischemic lesion.

The dissolution of infarcted myocardium occurs after the infiltration of leukocytes. In the search for a mechanism of the leukocyte infiltration, we measured the production of lipoxygenase metabolites of arachidonic acid in the canine myocardium after ligation of the circumflex branch of the left coronary artery. At least 2 lipoxygenase products, namely 5- and 12-hydroxyeicosatetraenoic acids (HETEs), were augmented in myocardium subjected to ischemia lasting more than 6 hours, with levels of the latter being raised much more than the former. Augmentation of the HETEs in ischemic myocardium appeared to occur prior to any significant infiltration of leukocytes. More than 12 hours after coronary ligation, the infiltration of leukocytes became prominent and an increase in 12-HETE was observed. Calcium content in the infarcted myocardium appeared to be increased several hours before the increase in 12-HETE. These data suggest that the initial increment in 12-HETE may result from it being a product of infarcted myocardium, where Ca2+ is accumulated in the cell, and that the increased HETEs work as a leukocyte chemoattractant in infarcted myocardium. This hypothesis is supported by the independent experiment which showed that cultured cardiomyocytes produced lipoxygenase metabolites of arachidonic acid, including 12-HETEs etc, which exhibited neutrophil-chemoattractant activity when they were challenged by calcium ionophore and/or arachidonic acid. Azelastine-HCl, a lipoxygenase inhibitor, attenuated not only the above production of HETEs from the cardiomyocytes, but also production of HETEs and infiltration of neutrophils in ischemic myocardium, resulting in attenuation of the fibrous scar of infarcted myocardium.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1988

Quantitative precipitin reaction and enzyme-linked immunosorbent assay of mannans of Candida albicans NIH A-207 and NIH B-792 strains compared.

We assessed the difference between results by enzyme-linked immunosorbent assay (EIA) in plastic support wells and the quantitative precipitin reaction (QPR) in glass test tubes for antigenic mannans and antibodies of two representative Candida albicans strains, NIH A-207 and NIH B-792. We investigated each of four mannan subfractions, with different phosphate contents, for their reactivities to the homologous polyclonal rabbit antiserum. Each series of mannan subfractions showed a reactivity proportional to their phosphate content in EIA, in a similar manner as observed in QPR. Moreover, in EIA, the cross-reactivities between the bulk mannans of the two C. albicans strains and the polyclonal antiserum of a Saccharomyces cerevisiae wild-type strain containing specific antibodies to the non-reducing terminal alpha-1,3-linked D-mannopyranose unit resembled those of the same antigen-antibody reactions in QPR. However, the mannan of C. albicans NIH A-207 strains, a weak antigen in the cross-QPR system, reacted fairly strongly in EIA in its high concentration range, indicating that EIA can be used to detect such an epitope in these mannans in concentrations undetectable by QPR. We conclude that EIA is a useful technique for immunochemical assay of yeast mannans and their antibodies on a smaller scale than with QPR.

Candida albicans↗
PubMed1988

Thallium-201 imaging in a patient with mid-ventricular hypertrophic obstructive cardiomyopathy.

Findings specific to mid-ventricular hypertrophic obstructive cardiomyopathy were obtained in a patient by means of 201Tl planar myocardial scintigraphy. Namely, a myocardial band-like image dividing the left ventricle into two chambers was clearly shown. This was identified as hypertrophic muscle with sphincter-like muscular stenosis at the mid portion of the left ventricle.

Adult↗
PubMed1988

Preparation of monoclonal antibodies reactive with beta-1,2-linked oligomannosyl residues in the phosphomannan-protein complex of Candida albicans NIH B-792 strain.

Hybridomas obtained by fusing the spleen cells of BALB/c female mice hyperimmunized with heat-killed yeast-form cells of Candida albicans NIH B-792 strain and a mouse myeloma cell line, P3X63Ag8.653, produced antibodies to beta-1,2-linked oligomannosyl residues in the phosphomannan-protein complex of the parent cells. Most of these monoclonal antibodies were IgM, but about 10% of the hybridomas produced IgG1 immunoglobulins. Ascites fluid from BALB/c mice inoculated with an IgG1-producing hybridoma showed different precipitability with the phosphomannan-protein complexes of three representative C. albicans strains, with NIH B-792 (serotype B) greater than NIH A-207 (serotype A) greater than J-1012 (serotype A, formerly serotype C). In contrast, a rabbit polyclonal antiserum to C. albicans NIH B-792 cells was unable to distinguish these same complexes. This ascites fluid agglutinated the heat-killed cells of three Candida strains, but not those of three others or of Torulopsis glabrata IFO 0622. The other ascites fluids, containing antibodies of the IgM class, agglutinated cells from three C. albicans strains and also C. tropicalis IFO 0587 cells.

Agglutination Tests↗
PubMed1987

Calpain abolishes the effect of filamin on the actomyosin system in platelets.

Platelet filamin was shown to cross-link F-actin and inhibit actomyosin ATPase activity. Filamin was also shown to be degraded by calpain (calcium-activated neutral proteinase; CANP) when the platelet was activated. The consequences of the proteolysis of filamin on the actomyosin system have been investigated. When degraded by calpain in the presence of Ca2+, filamin loses its ability to cross-link F-actin. Under the same conditions, its inhibitory effects on the superprecipitation and ATPase activity of actomyosin are abolished. The result suggests that the degradation of filamin is favorable for contraction of the activated platelets.

Actins↗