Biomedical subjects

Y Miyahara

Publications and source records attributed to Y Miyahara.

At least 37 records · Page 2Linked to original sources

PubMed2000

Cardiac function in dialysis patients evaluated by Doppler echocardiography and its relation to intradialytic hypotension: a new index combining systolic and diastolic function.

AIM, PATIENTS AND METHODS: Cardiac function of 40 patients on maintenance dialysis was examined using a new Doppler index combining systolic and diastolic function. Immediately before dialysis, ultrasonic pulsed Doppler was used to measure right and left ventricular inflow and outflow waveforms. The sum of the isovolumetric contraction time (ICT) and isovolumetric relaxation time (IRT) was calculated by subtracting the ejection time from the interval between the end of an inflow waveform and the start of the next inflow waveform. The new index was obtained by dividing the sum of the two isovolumetric times by the ejection time. Cardiac function was evaluated in dialysis patients and healthy controls using new indices of the right and left heart systems. RESULT: Indices of the right and left heart systems in dialysis patients were significantly higher than those in healthy controls. With respect to hypotension during dialysis, patients were divided into two groups, a group with decreased blood pressure (group A: 27 patients) and a group with normal blood pressure (group B: 13 patients). Only the left heart system index in group A was significantly higher. There were no significant differences in other M-mode Doppler indices between the two groups. CONCLUSION: The new index was a more sensitive evaluator of cardiac function and predictor of hypotension during dialysis compared to standard echocardiographic indices.

Adult↗

PubMed2000

Sesamin and episesamin induce apoptosis in human lymphoid leukemia Molt 4B cells.

The exposure of human lymphoid leukemia Molt 4B cells to sesamin and episesamin which were isolated from unroasted sesame seed oil and identified by MS, and 1H and 13C-NMR, led to both growth inhibition and the induction of programmed cell death (apoptosis). Morphological change showing apoptotic bodies was observed in the Molt 4B cells treated with sesamin and episesamin. The fragmentations by sesamin and episesamin of DNA to oligonucleosomal-sized fragments that are characteristics of apoptosis were observed to be concentration-dependent, respectively. Moreover, the amount of the DNA fragments in the sesamin-treated cells was increased from 2 days, while that in the episesamin-treated cells was elevated at 3 days after addition of the compounds. These findings suggest that growth inhibitions by sesamin and episesamin of Molt 4B cells result from the induction of apoptosis in the cells.

Antineoplastic Agents↗

PubMed1999

Serial changes in negative T wave on electrocardiogram in acute pulmonary thromboembolism.

A negative T wave is frequently observed in precordial ECG leads in patients with acute pulmonary thromboembolism. We investigated the clinical significance of negative T wave in 15 patients with acute pulmonary thromboembolism who were treated with thrombolytic agents by measuring the mean pulmonary artery pressure and ratio of right to left ventricular end-diastolic diameter using echocardiography and ECG. The study included only patients with massive acute pulmonary thromboembolism of a mean age of 65+/-9.7 years (+/-SD). A negative T wave was observed on admission in 10 patients but was later detected in 14 of the 15 patients. The mean amplitude of the negative T wave increased within 1 week then decreased after thrombolytic treatment. The peak negative amplitude of the T wave was observed from 1 to 7 days (mean, 2.6+/-1.8 days) and disappeared afterwards. During this period, improvements in both the mean pulmonary artery pressure (37.8+/-11.2 to 19.1+/-6.7 mmHg) and the ratio of right to left ventricular end-diastolic diameter (0.97+/-0.16 to 0.51+/-0.13) were noted in all patients. Our results suggest that an increase in the amplitude of negative T wave in precordial leads after thrombolytic therapy in patients with massive acute pulmonary thromboembolism reflects improvement in cardiopulmonary hemodynamics.

Aged↗

PubMed1999

Histamine H1 receptor and reactivity of the nasal mucosa in sensitized guinea pigs.

OBJECTIVE: Nasal Hypersensitivity to histamine is higher in allergic patients than that in normal control, suggesting that affinity and/or density of H1 receptors in nasal mucosa may be increased in patients with allergic rhinitis. The purpose in this study is to examine the correlation between the hyperresponsiveness and number of histamine H1 receptors in guinea pig nasal mucosa. METHODS: Guinea pigs were sensitized by DNP-Ascaris antigen. To block histamine H1 receptors, ketotifen was used and the number of receptors was counted by receptor binding assay technique. These data were compared with nasal airway volume (VOL) assessed by acoustic rhinometry of the same animals to know whether the number of H1 receptors is correlated to the nasal responsiveness to the antigen, or not. Eighty animals were divided into five groups which are composed of nonsensitized and sensitized group pretreated with saline, 0.1, 1.0 and 10 mg/kg of ketotifen, respectively. RESULTS: The number of H1 receptors (Bmax) was significantly increased in sensitized group compared with that in control. It decreased dose dependently by pretreatment of ketotifen. The percent change of VOL showed - 31.1 +/- 4.1% at 10 min and - 42.9 +/- 4.1% at 30 min after antigen challenge in sensitized animals. This was dose dependently inhibited by ketotifen. There was a highly inverse correlation between VOL and Bmax (r = -0.708, P< 0.0001). CONCLUSION: These results suggest that sensitization increases the number of histamine H1 receptor, and that increased number of H1 receptor in nasal mucosa in sensitized guinea pigs may be one of the causes of nasal hyperresponsiveness to antigen.

Administration, Oral↗

PubMed1999

Simultaneous assessment of right ventricular function and hypertrophy by Tc-99m MIBI.

PURPOSE: Tc-99m MIBI allows the simultaneous performance of cardiac blood pool scintigraphy and myocardial SPECT. The authors performed studies to determine whether right ventricular function and hypertrophy can be evaluated simultaneously using Tc-99m MIBI in patients with right heart disease. METHODS: Using right heart catheterization, several parameters of pulmonary circulation were measured, including right ventricular ejection fraction, in 23 patients with chronic pulmonary disease and pulmonary vascular disease. Within 1 week, right heart blood pool scintigraphy was performed using the first-pass method using Tc-99m MIBI. The right ventricular ejection fraction calculated from right heart blood pool scintigraphy was compared with that measured using right heart catheterization. Myocardial SPECT was performed 1 hour after right heart blood pool scintigraphy. On the short axis images, which allowed optimal visualization of the right ventricle, the right and left ventricular free walls were established as regions of interest. Myocardial wall counts were determined. The right ventricular uptake: left ventricular uptake ratio was calculated to study the relation of that ratio to mean pulmonary artery pressure and total pulmonary resistance. RESULTS: A significant correlation was observed between the right ventricular ejection fraction calculated on right heart catheterization and that calculated on right heart blood pool scintigraphy. The right ventricular uptake:left ventricular uptake ratio correlated positively with pulmonary artery pressure and total pulmonary resistance. CONCLUSION: These results suggest that Tc-99m MIBI allows simultaneous noninvasive evaluation of cardiac function and structure, which previously was considered impossible in patients with right heart disease.

Female↗

PubMed1999

EMG activity of the muscles of the neck and forelimbs during different forms of locomotion.

We recorded the electromyographic (EMG) activity of 7 skeletal muscles in the forequarters and 1 in the hindquarters of 6 Thoroughbred horses during overground walking, swimming in a circular pool, and walking and trotting in a water treadmill. Bipolar fine wire electrodes were inserted into the muscles and the EMG signals were recorded using a telemetric system. The splenius exhibited tonic EMG activity during swimming. The brachiocephalicus showed its highest intensity during swimming followed by the walk and trot in the water treadmill and then walking overground. The triceps brachii caput longum had a similar activity pattern to the brachiocephalicus. The brachialis showed only weak EMG activity in all 3 types of locomotion. The extensor digitorum communis had higher intensity of EMG activity in the walk in the water treadmill than in other kinds of locomotion. The flexor digitorum profundus exhibited the most intense EMG activity during swimming. These results indicated that swimming evoked strong EMG activity in the antigravity muscles in spite of reduced gravitational force. Walking in the water treadmill may require more intensified EMG activity of the forelimb than the trot in the same treadmill.

Animals↗

PubMed1999

A possible role of immunoglobulin E in patients with hyperthyroid Graves' disease.

To investigate the possible participation of immunoglobulin E (IgE) in the autoimmune process of Graves' disease, incidence of elevation of serum IgE level, TSH receptor antibody (TRAb), and thyroid status were studied in 66 patients with hyperthyroid Graves' disease, 54 patients with Hashimoto's thyroiditis, 19 patients with bronchial asthma, and 15 patients with pollen allergy. In hyperthyroid Graves' patients, elevation of serum IgE levels (> or = 170 U/mL) was found in 19 of 66 patients (29%), 11 of whom had hereditary and/or allergic conditions. Elevations of serum IgE levels were found in 63% of patients with bronchial asthma and in 40% of patients with pollen allergy. Mean values of serum IgE were the same in patients with hyperthyroid Graves' disease and with bronchial asthma. During methimazole treatment TRAb decreased without fluctuation of IgE levels in both groups. The decrease in TRAb was significantly greater in patients with normal IgE than in patients with IgE elevation. After prednisone administration, reduction in TRAb was greater in patients with normal IgE than that in patients with IgE elevation. High incidence of IgE elevation in hyperthyroid Graves' disease and slower reduction in TRAb in association with IgE elevation suggest a difference in the autoimmune processes in Graves' disease with and without elevation of IgE.

Adolescent↗

PubMed1999

A case in which stent insertion is considered to have triggered contrast medium-induced coronary vasospasm.

A Gianturco-Roubin II (GR-II) stent was inserted in a 75-year-old man who developed restenosis of the right coronary artery (RCA) after percutaneous transluminal coronary angioplasty (PTCA). Although the vessel became partially occluded after 7 months, it was redilated by PTCA. Follow-up angiography of the RCA and left coronary artery (LCA) was performed 3 months later. Chest pain with bradycardia and hypotension occurred immediately after this examination, and ST elevation appeared in ECG leads II, III, and aVF. Repeat angiography of the RCA confirmed complete occlusion due to a spasm at a site proximal to the GR-II stent. The spasm was resolved by intracoronary infusion of isosorbide dinitrate (ISDN), and PTCA was carried out for extensive recurrent restenosis of the RCA; however, vascular dissection developed at the distal end of the GR-II stent. Therefore, a Palmaz-Schatz (P-S) stent was placed such that its proximal end overlapped the distal end of the GR-II stent. Follow-up angiography 3 months later showed no restenosis, but an episode of vasospasm similar to the previous one occurred immediately after left ventriculography. The RCA was completely occluded proximal to the GR-II stent because of spasm. Although this spasm was gradually relieved by intracoronary infusion of ISDN, marked spasm was also observed distal to the P-S stent; complete relief was achieved by infusion of additional ISDN.

Aged↗

PubMed1999

Bone marrow-derived dendritic cells incorporate and process hydrophobized polysaccharide/oncoprotein complex as antigen presenting cells.

We have previously shown that a novel hydrophobized polysaccharide/oncoprotein complex vaccine can induce immune responses against the HER2/neu/c-erbB2 (HER2) expressing tumors. Bone marrow-derived dendritic cells (DCs), as antigen presenting cells (APCs), are the first candidates for presentation of tumor antigens. The aim of this study was to see whether DCs are able to elicit antigen specific host immune responses by stimulating the proliferation of T cells after exposure to cholesteryl group bearing pullulan (CHP) and HER2 protein complex. Vaccination by CHP-HER2 complex was as effective as cholesteryl group bearing mannan (CHM) and HER2 complex on which we reported previously. Immunization of mice with HER2 expressing CMS17HE tumor cells generated both CD4+ T cells and CD8+ T cells reactive with CHP-HER2 complex pretreated DCs. In addition, immunization with either CHP-HER2 complex or HER2 protein alone could also generate both CD4+ T cells and CD8+ T cells specifically reactive with CHP-HER2 complex pretreated DCs. The complete rejection of tumors occurred when immunization with CHP-HER2 complex pretreated DCs was started 10 days after tumor inoculation. Therefore, bone marrow-derived DCs pretreated with hydrophobized polysaccharide/oncoprotein complex are a powerful tool for enhancing the effectiveness of oncoprotein for anti-tumor vaccination, opening new options for immune cell therapy.

Animals↗

PubMed1999

[Extra-intestinal complications of ulcerative colitis: arteriovenous thrombosis/embolism].

Thromboembolic episode is a well known extraintestinal complications of ulcerative colitis, but it is a rare complication in clinically. In the literature there are some interesting observations concerning the factors, may play a major role both in the pathogenesis and in the hypercoagulability in ulcerative colitis. However the exact mechanism of hypercoagulability in patients with ulcerative colitis is still unknown. We reviewed the incidence, the activity and severity of the basic disease, the pathogenesis, the treatment, the prognosis of thromboembolic phenomena in patients with ulcerative colitis.

Anticoagulants↗

PubMed1998

Design of a local bump feedback system for a variably polarizing undulator.

A local bump feedback system is under construction to correct the orbit distortion caused by the magnetic field errors of a double-array undulator used to generate linear and circular polarization of light for a soft X-ray beamline. The local bump orbit is created by steering coils several turns long and four sets of steering magnets. The kick angle of the long steering coils and the steering magnets is determined according to the motion of the undulator and by detecting the beam position.

Journal Article↗

PubMed1998

Proposal of a high-field superconducting wiggler for a slow positron source at SPring-8.

A low-energy positron beam is a unique probe of materials. In high-energy electron and positron storage rings it is possible to generate intense synchrotron radiation with a photon energy of 1-3 MeV by installing a high-field (8-10 T) superconducting wiggler. High-energy photons are converted to low-energy positrons by using a suitable target-moderator system. For an 8 GeV electron storage ring at a beam current of 100 mA, final yields are estimated to be about 10(8)-10(10) slow-e(+) s(-1) or larger depending on the moderation efficiency, with the size of the positron source 10(1)-10(2) cm(2). In the present work a wiggler magnetic system of 10 T is proposed. The main parameters of the superconducting wiggler are presented.

Journal Article↗

PubMed1998

Soft X-ray beamline specialized for actinides and radioactive materials equipped with a variably polarizing undulator.

This report presents the design of an undulator beamline at SPring-8 to be used for soft X-ray spectroscopy focused on radioactive materials. Photoemission spectroscopy experiments are carried out in a radioisotope (RI)-controlled area where actinide compounds as well as unsealed radioactive materials are usable. Intrusion of the radioactive materials into the electron storage ring or to the outside of the evacuated beamline components can be avoided by a specially devised RI protection/inspection mechanism. The combination of a variably polarizing undulator and a varied-line-spacing plane-grating monochromator provides linearly or circularly polarized soft X-rays with a high resolving power in the energy range 0.28-1.5 keV. The beamline will become operational in December 1997.

Journal Article↗

PubMed1998

Six-year survival after excision of cardiac malignant lymphoma.

We report a patient with a postoperative survival period of 6 years after the surgical excision of a cardiac malignant lymphoma. A 35-year-old woman underwent total excision of the tumor arising from the left ventricular outflow tract. After the operation, she was treated with chemotherapy for 6 months. She has been doing well thereafter without any medication. To date there is no evidence of recurrence.

Adult↗

PubMed1998

Nasal passage patency in patients with allergic rhinitis measured by acoustic rhinometry: nasal responses after allergen and histamine provocation.

We investigated nasal passage patency after allergen and histamine provocation in patients with allergic rhinitis by acoustic rhinometry. In total, 75 outpatients with allergic rhinitis were studied. The threshold of nasal hypersensitivity to histamine was measured by the 10 microliters instillation of serial 10-fold dilution in the ipsilateral nasal cavity. Nasal provocation testing to specific antigen was applied to the anterior part of inferior turbinate in bilateral sides in sitting position. Measurement of nasal patency by acoustic rhinometry was repeated three times in each nasal cavity. The minimal cross-sectional area and total volume of nasal cavity were measured in an individual subject. The minimal cross-sectional area and total volume in the histamine challenged-side significantly decreased on the 10(-2), 10(-1), 10(-0) of end point, and up to 30 min after challenge with the threshold dose, but not in the unchallenged side. This means acoustic reflection technique is sensitive at least 100-fold in comparison with classical method like findings by anterior rhinoscopy and symptom scores. Nasal passage patency after bilateral allergen provocation showed predominant in the unilateral side, suggesting the cross over-reflex effects. It was concluded that acoustic rhinometry is one of the highly quantitative and sensitive method which can observe the change of nasal congestion.

Adolescent↗

PubMed1998

An elevation of stem cell factor in patients with hyperthyroid Graves' disease.

Graves' disease is an autoimmune disorder characterized by the presence of antibodies against thyrotropin receptor (TRAb). Stem cell factor (SCF), derived from bone marrow, is known to promote lymphohematopoiesis. To investigate the relation between the alteration in plasma levels of SCF, thyroid hormone status, and TRAb measured by thyrotropin binding inhibition (TBI), 13 untreated, 21 treated, and 4 relapsed hyperthyroid Graves' disease patients, 21 patients with Hashimoto's thyroiditis, 6 patients with subacute thyroiditis, and 11 control subjects were examined. In untreated hyperthyroid Graves' disease patients, serum levels of thyroxine (T4) and triiodothyronine decreased rapidly by methimazole treatment, and TBI decreased progressively, but variably. Simultaneously, the elevated plasma levels of SCF decreased gradually and progressively. The plasma levels of SCF correlated curvilinearly with the serum levels of T4. In 4 patients with relapsed hyperthyroid Graves' disease, TBI was marginally positive in 3 patients and negative in 1, but plasma levels of SCF were elevated significantly in all 4 patients. In patients with subacute thyroiditis and Hashimoto's thyroiditis with or without T4 replacement, plasma levels of SCF did not differ from that of controls. These findings indicate that the elevation of plasma levels of SCF relates to the longstanding thyrotoxic state and that short-term thyrotoxicosis does not significantly affect plasma levels of SCF. It remains to be determined whether the elevation in plasma levels of SCF is induced by excess thyroid hormone, reflecting the hypermetabolic state, or whether the elevation of plasma levels of SCF contributes to stimulation of lymphocytes producing TRAb.

Acute Disease↗

PubMed1998

Two cases of adult varicella accompanied by hepatic dysfunction.

Varicella is a typical acute exanthematous viral infection caused by varicella-zoster virus (VZV). In recently years, as far as hepatic dysfunction caused by viruses other than the hepatitis virus is concerned, there have been a few reports on hepatic dysfunction accompanying varicella following organ transplantation of Europe and America and another report on an immunocompromized adult following treatment for Systemic lupus erythematosis (SLE) in Japan. Nonetheless, we searched the MEDLINE and J MEDICINE listing the publications between 1986 and 1996 and found one report on healthy adults with varicella accompanied by hepatic dysfunction in Europe and America and two reports in Japan. Only Noguchi et al. dealt with the findings of liver biopsy. We examined two healthy adults with varicella and mild-to-moderate hepatic dysfunction, and referred to the results of their liver biopsies. The present paper discusses this issue, citing some references.

Adult↗

PubMed1998

Astemizole-induced torsades de pointes in a patient with vasospastic angina.

Astemizole (Hismanal), an antihistamine agent, has been reported to be associated with ventricular arrhythmias. In this paper we present a case of QT prolongation and torsades de pointes (TdP) in a 77-year-old woman who had been taking astemizole (10 mg/day) for 6 months because of allergic skin disease. At the time of admission, the serum concentration of astemizole and its metabolites was markedly elevated at 15.85 ng/ml, approximately 3 times the normal level. The patient was also taking cimetidine, a known inhibitor of cytochrome P-450 enzymatic activity, and during her admission was diagnosed as having vasospastic angina. To the best of our knowledge, this is the first report of astemizole-induced QT prolongation and TdP in Japan.

Aged↗