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Biomedical subjects

S Miyabo

Publications and source records attributed to S Miyabo.

At least 73 records · Page 4Linked to original sources
PubMed1990

Effects of pretreatment with 2-O-octadecylascorbic acid, a novel free radical scavenger, on reperfusion-induced arrhythmias in isolated perfused rat hearts.

The effects of pretreatment with 2-O-octadecylascorbic acid (CV-3611), a novel liposoluble free radical scavenger, on reperfusion-induced arrhythmias were studied in isolated perfused rat hearts (n = 15 per group). The hearts were subjected to 10 min of coronary artery occlusion and 3 min of reperfusion. Pretreatment with CV-3611 (5 and 20 mg/kg) reduced the incidence of ventricular fibrillation (VF; reversible plus sustained) from its control value of 93% to 47% (p less than 0.05). Furthermore, CV-3611 reduced the incidence of sustained VF in a dose-dependent manner, from 67% in the control group to 13% in the CV-3611, 20 mg/kg treated group (p less than 0.01). CV-3611 (5 and 20 mg/kg) reduced the incidence of ventricular tachycardia (VT) from its control value of 93% to 73%. Pretreatment with ascorbic acid (5 mg/kg) had no effect on VF and VT. The myocardial content of CV-3611 was proportional to the dosage. We concluded that CV-3611 could reduce significantly the susceptibility to reperfusion-induced arrhythmias, especially VF, and that its effect may be due to the elimination of oxygen-derived free radicals by CV-3611 present in the membrane and the capture of lipid radicals, thereby inhibiting lipid peroxidation.

Animals↗
PubMed1990

Bronchial hyperresponsiveness in patients with chronic congestive heart failure.

To investigate the relationship between pulmonary congestion and bronchial responsiveness, we measured bronchial responsiveness to acetylcholine in 51 patients with left heart disorders. The measurement of bronchial responsiveness was performed by inhaling doses of acetylcholine chloride (0.08 to 20 mg/ml) and calculating the PC20-FEV1. The median value for PC20-FEV1 was above 20 mg/ml in the subjects without history of congestive heart failure (n = 18), was 5.29 mg/ml in the subjects with clinical evidence of congestive heart failure in the past days (n = 18; p less than 0.01), and was 5.74 mg/ml in the subjects with clinical evidence of congestive heart failure at the time of study (n = 15; p less than 0.01). The hemodynamic variables by cardiac catheterization and the clinical symptoms were not correlated with the grade of bronchial responsiveness. These results suggest that the bronchial responsiveness was increased in most of the patients with chronic congestive heart failure. We concluded that continuous pulmonary congestion may contribute to the pathogenesis of bronchial hyperresponsiveness.

Acetylcholine↗
PubMed1990

Effect of chronic intracerebroventricular infusion of corticotropin-releasing factor on circadian corticosterone rhythm in the rat.

The effects of chronic (14 day) intracerebroventricular infusion of various amounts of ovine corticotropin-releasing factor (oCRF) on the circadian blood corticosterone rhythm in male rats were examined. Control (saline-infused) rats showed distinct blood corticosterone rhythms over 48 h with nadirs at 0900 h and peaks at 2100 h on days 6-7 and 13-14. oCRF at 3 pmol/h did not affect the circadian corticosterone rhythm on these days. When oCRF was infused at a rate of 12 pmol/h, blood corticosterone was increased throughout the 48 h periods. A significant circadian rhythm remained at days 6-7, but continuous infusion for an additional 7 days disrupted the rhythm. Higher doses of oCRF (48 and 240 pmol/h) obliterated the rhythm during both periods; the disruption was characterized by an increase in corticosterone during the lights-on period without a substantial change in the evening maximum. Thus, the blood corticosterone concentration was eventually confined within a narrow range, not exceeding the normal circadian peak, over a wide dose range of centrally administered CRF. Significant effects of oCRF on body and adrenal weight were observed only at the two highest doses used. These findings may provide some insight into the state of the hypothalamic-pituitary-adrenal axis in animals exposed to chronic stress and in patients with depression.

Adrenal Glands↗
PubMed1990

Interference of immunoglobulins in the radioimmunoassay of human beta-endorphin.

The interference of immunoglobulins in the radioimmunoassay (RIA) of human beta-endorphin was investigated. Human IgM showed no cross-reactivity. Human IgA showed a weak cross-reaction, but the dilution curve of IgA did not show parallelism with the standard curve of beta-endorphin, thus indicating its antigenic difference. The dilution curves of human IgG showed 0.18% displacement with respect to the human beta-endorphin standard curve, with good parallelism. Moreover, five patients with multiple myeloma of the IgG type showed falsely elevated beta-endorphin levels. We investigated the possibility that certain IgGs may be responsible for the displacement of [125I]beta-endorphin in the beta-endorphin kit. The apparent beta-endorphin level of plasma from multiple myeloma patients was markedly decreased after affinity chromatography of the serum on protein A-Sepharose. In another 3 patients with multiple myeloma, we examined IgG interference by measuring the beta-endorphin levels in their lyophilized IgG diluted with saline. The results demonstrated high values of 20.2, 25.5 and 21.2 pmol/l respectively, also showing good parallelism. These immunological parallels to human beta-endorphin verify that a part of the amino acid sequence of human IgG is similar to that of human beta-endorphin. Consequently, in the measurement of beta-endorphin with polyclonal antibody, the results may sometimes be spuriously high due to cross-reaction with IgG, e.g., in patients with IgG myeloma. To avoid IgG interference, a specific monoclonal antibody to synthetic beta-endorphin should be used rather than polyclonal antibodies.

Blood Chemical Analysis↗
PubMed1990

[Quantitative evaluation of right ventricular overload in cor pulmonale using 201T1 myocardial SPECT].

In patients with right ventricular overload, the free wall of the right ventricle is often visualized by 201T1 myocardial scintigraphy. To determine quantitatively the discriminant and characteristics of cor pulmonale, 201T1 myocardial perfusion single photon emission computed tomography (SPECT) was performed in 16 patients with chronic obstructive pulmonary disease (COPD) and seven with restrictive pulmonary disease (RPD). We selected one section of the short-axis image of SPECT in which the right ventricle was most clearly visualized, and defined the T1-score as the ratio of the sum of counts in the region of interest (ROI) at the anterior, mid and posterior regions of the right ventricular free wall to the sum of counts in the ROI at the posterior, lateral, anterior walls of the left ventricle, and the anterior and posterior regions of the interventricular septum. Correlation of the T1-score with mean pulmonary arterial pressure (mPAP), systolic pulmonary arterial pressure (sPAP), and total pulmonary vascular resistance (TPR), as obtained by right cardiac catheterization, arterial oxygen tension (PaO2), and arterial carbon dioxide tension (PaCO2) were evaluated. The results were as follows: 1. In the patients with COPD, the T1-score correlated positively with mPAP (r = 0.71, p less than 0.005), TPR ( r = 0.69, p less than 0.005), and PaCO2 (r = 0.63, p less than 0.01), and it correlated inversely with PaO2 (r = -0.58, p less than 0.05). However, there was no significant correlation between the T1-score and mPAP, TPR, PaCO2, and PaO2 in the patients with RPD.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

[Noncontact and noninvasive microwave biological measurements].

Without contact probes, the signals of small human body surface movements were obtained with microwave Doppler sensors using a two-phase interferometric method. The signals were then compared with mechanocardiographic records routinely obtained by contact transducers. Furthermore, this system was applied to patients wearing clothes. The study subjects consisted of 20 cardiac patients and 10 normal controls. 1. The microwave signals obtained in the cervical and precordial regions were similar to those of the mechanocardiographic recordings, such as the carotid pulse and jugular venous pulse tracings and the apexcardiogram. There was a significant correlation between left ventricular ejection time (LVET) obtained by microwave Doppler sensors and that by the carotid pulse tracing (r = 0.95). 2. The signals of the microwave Doppler sensor were obtained from the patients wearing clothes. The heart beat components were distinguished from respiratory motion and patients' movements using band-pass filters. These results suggest that this method is capable of evaluating cardiac function noninvasively and thus has a distinct advantage in the field of non-contact measurements.

Heart Function Tests↗
PubMed1990

[A case of miliary tuberculosis associated with acute respiratory failure during pregnancy].

A case of miliary tuberculosis associated with acute respiratory failure during pregnancy was reported. A 39-year-old, 29-week pregnant woman was admitted to our hospital with complaints of nonproductive cough and fever on June 12. On admission, her temperature was 38.2 degrees C; pulse rate was 90/min., and blood pressure was 120/76 mmHg. Physical examination revealed moist rales at right lung basis. Chest X-ray showed small nodular infiltrates in right lower lung field. Laboratory data revealed positive CRP, accelerated ESR and increased level of alpha 2-globulin. The number of T-cells was markedly decreased (14/mm3). The PPD skin test was negative, and the sputum smears for acid-fast bacilli were negative. Suspected of bacterial or viral pneumonia, the patient was treated with antibiotics (CPM, EM and CAZ), which had no effects for her. On June 16, the Chest X-ray showed infiltrates throughout bilateral lung fields, and the patient became increasingly dyspneic. On June 18, the results of arterial blood gas, analysis under room air were: PaO2 26.7 Torr, PaCO2 29.0 Torr, pH 7.505. Because of severe hypoxemia, she was intubated and placed on a volume-cycled respirator. Hydrocortisone (1000 mg, daily) was added to treatment because ARDS was suspected. Since the smears of tracheobronchial secretions showed acid-fast bacilli on June 24, she was diagnosed to have miliary tuberculosis. Then the intensive therapy with antituberculosis drugs (isoniazid 400 mg, rifampicin 450 mg, and streptomycin 1g, daily) was started. The non specific antibiotics were discontinued; hydrocortisone was tapered and stopped. The next week, she became afebrile and hypoxemia steadily improved.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1989

Normoreninemic hypoaldosteronism in a case of isolated ACTH deficiency.

This paper documents the rare and hitherto unreported association between isolated ACTH deficiency and normoreninemic hypoaldosteronism in a 63-year-old woman. Baseline plasma aldosterone and 18-hydroxycorticosterone were extremely low. Both steroids did not respond to exogenous angiotensin II infusion, whereas they were increased in parallel to ACTH stimulation. Thus, acquired dysfunction or congenital dysgenesis of the zona glomerulosa was suspected. The upright posture-furosemide test showed a subnormal but definite plasma aldosterone response coupled with a normal increase in plasma renin activity, indicating that there may be a yet unidentified mechanism(s) underlying the postural increase of aldosterone.

17-Hydroxycorticosteroids↗
PubMed1989

Effectiveness of long-acting nifedipine in pheochromocytoma.

In the present study, we report a case of pheochromocytoma whose high blood pressure was well controlled by single-agent therapy with long-acting nifedipine, in spite of the failure of the combination of labetalol and prazosin in lowering blood pressure satisfactorily. A 48 year old female was first noted to have hypertension (160/100 mmHg) at 45 years of age. Hypertension was not controlled by conventional antihypertensive drugs. She was admitted to Fukui Prefectural Hospital in September, 1985. Her blood pressure on admission was 210/110 mmHg. Extraction of the left adrenal gland containing a pheochromocytoma (30 x 37 x 10 mm) was performed in November, 1985. Her hypertension and abnormally high plasma noradrenaline (NA) concentration (1,760 pg/ml, normal value 40-350 pg/ml) were sustained even after operation. Combination therapy with labetalol (400 mg/day) and prazosin (6 mg/day) was unsatisfactory, and the addition of long-acting nifedipine (40 mg/day) produced a marked decrease in blood pressure. Furthermore, single therapy with long-acting nifedipine was effective. No reduction of urinary NA excretion was observed in our patient during long-acting nifedipine therapy, suggesting that the decrease in blood pressure was not caused by suppression of NA release from pheochromocytoma tissue.

Adrenal Gland Neoplasms↗
PubMed1989

[Assessment of the left atrial myxoma with gated blood pool SPECT].

A left atrial myxoma with 4 cm diameter was studied with ECG gated Tc-99m blood pool SPECT. The long axial images showed the myxoma to protrude through the mitral valve (MV) during diastole and to come back into the atrium in systole. No significant atrial dilatation due to the MV obstruction was detected. The ejection fraction calculated from the SPECT images was 10% lower than that of the conventional method viewed from LAO 45 degrees. Nuclear medicine gave an additional information for the assessment of the hemodynamics.

Aged↗
PubMed1988

The effects of physical exercise on plasma lipoprotein and apolipoprotein metabolism in elderly men.

The present study was undertaken to evaluate the effects of physical exercise on plasma lipoprotein and apolipoprotein metabolism in elderly men. We measured plasma concentrations of lipids, lipoproteins, and apolipoproteins (apo) in 12 elderly runners (OR), 12 elderly sedentary controls, 16 young runners (YR), and 15 young sedentary controls. Although there were no significant differences in plasma levels of cholesterol (Ch), triglyceride, and phospholipid between two old groups and between two young groups, OR and YR had decreased levels of VLDL-Ch (42% and 59% of respective control) and LDL-Ch (90%, 94%), and increased levels of HDL-Ch (133%, 112%), apo A-I (109%, 101%), and apo A-II (109%, 105%). These data indicate that physical exercise may have favorable effects on plasma concentrations of lipoproteins and apolipoproteins in OR as well as in YR, and affect HDL-lipids, HDL-proteins, and ratio of HDL-proteins/HDL-lipids.

Adult↗
PubMed1988

Sarcoidosis with multiple calcification.

Sarcoidosis, having a twenty-nine years of clinical course, associated with multiple calcified deposits in neck, mediastinum, liver, spleen, kidney, abdominal lymphnodes and lung was reported. Calcified opacity, which was firstly detected during initial two years on plain chest and abdominal x-ray films, increased in calcified mass insidiously. Though, the examination on this admission failed to reveal pathogenesis of multiple calcification, immunological derangement seemed to initiate and promote the calcification.

Calcinosis↗