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Biomedical subjects

T Takishima

Publications and source records attributed to T Takishima.

At least 325 records · Page 18Linked to original sources
PubMed1988

Dependence of instantaneous transfer function on regional ischemic myocardial volume.

To obtain the instantaneous left ventricular transfer function curve (instantaneous TFC) under conditions of regional ischemia, sinusoidal accelerations ranging from 30 to 150 Hz were applied to a small area of the epicardium of cross-circulated isovolumic canine left ventricle, and the contralateral acceleration was measured under control and during regional coronary occlusion (n = 11). The TFC is the ratio of the output to input acceleration amplitudes. The instantaneous TFC was characterized as a single-peaked configuration under control coronary perfusion. However, TFCs progressively changed from a single-peaked to a double-peaked configuration during regional ischemia. To quantify this change in instantaneous TFC, we defined an index D as the mean squared difference of TFC during ischemia from TFC during control. Index D was linearly related to the percent mass of the ischemic region at 40 minutes after onset of ischemia. We conclude that 1) transfer function curves are sensitive measures of myocardial heterogeneity and 2) the fractional ischemic weight of the ventricle is a major factor in determination of the deformation in instantaneous TFC at the later stages of regional ischemia.

Animals↗
PubMed1988

Airway mucosal permeability in chronic bronchitics and bronchial asthmatics with hypersecretion.

To determine airway mucosal permeability, radiolabeled albumin in sputum was examined on the basis of a 2-h period of sputum collection for as long as 8h after intravenous administration of 131I-labeled human serum albumin. This technique was applied to 12 patients with bronchial asthma associated with hypersecretion or chronic bronchitis. Group A consisted of 6 asthmatics (2 females and 4 males, 56.0 +/- 6.4 yr of age, mean +/- SEM); Group B consisted of 6 bronchitics (3 females and 3 males, 53.8 +/- 6.5 yr of age). Between Groups A and B, there was no significant difference in sputum volume per day or in obstructive impairment. Radiolabeled albumin concentration (cpm/ml) was obtained from radiocount of each sputum sample and then divided by serum concentration at the time of each sampling (2, 4, 6, and 8 h after administration). Group B showed large values compared with those in Group A. In Group A, the ratios were 2.0 +/- 0.8, 2.5 +/- 0.5, 2.2 +/- 0.2, and 1.5 +/- 0.4% (mean +/- SEM) at 2, 4, 6, and 8 h after the administration, respectively, whereas in Group B, the ratios were 3.0 +/- 0.6, 7.0 +/- 1.8, 7.2 +/- 1.8, and 7.4 +/- 2.4%, respectively. The differences between Groups A and B were statistically significant (two-way analysis of variance). These findings suggest that an increase in airway mucosal permeability is due to mucosal epithelial damage by chronic inflammation in bronchitics and not to the underlying abnormality of asthma.

Asthma↗
PubMed1988

Serial distribution of bronchoconstriction in normal subjects. Methacholine versus histamine.

We compared the relative sites of airway responses to methacholine and histamine aerosols in normal subjects by simultaneous assessment of respiratory resistance (Rrs) and anatomic dead space (VD). Methacholine (12.5 mg/ml) or histamine (12.5 mg/ml) was continuously inhaled during tidal breathing until a nearly twofold increase in Rrs was observed. Large airway response was determined by VD, and overall airway response was determined by Rrs. Small airways response was inferred from Rrs when the change in VD was slight. Inhalation of methacholine and histamine increased Rrs with decreased VD, but the decrease in VD was significantly greater with methacholine than with histamine for an equivalent change in Rrs (p less than 0.01). Inhalation of atropine (5 mg/ml) decreased Rrs with a simultaneous increase in VD. After inhalation of atropine, time required for a twofold increase in Rrs by histamine inhalation was prolonged, and histamine did little decrease VD. These results suggest that the predominant site of cholinergically mediated constriction is the large airways, and that histamine constricts the large airways in part via a cholinergic reflex mechanism and constricts the small airways via its direct action in normal subjects.

Adult↗
PubMed1988

Nonadrenergic bronchodilation in normal subjects.

To investigate whether bronchial C-fiber stimulation induced by capsaicin inhalation evokes nonadrenergic inhibitory (NAI) system bronchodilation, we studied partial and maximal expiratory flow-volume (PEFV and MEFV) curves in 5 normal subjects after inhalation of oxitropium bromide and propranolol. PGF2 alpha (1 mg/ml inhaled for 5 min) was administered to induce bronchoconstriction. Then aerosolized capsaicin was inhaled (2.4 x 10(-9) mol) to stimulate bronchial C-fibers. PGF2 alpha produced significant bronchoconstriction; FEV1 and flow during a PEFV curve at 30% forced vital capacity (V30p) decreased over a 15-min period. Capsaicin induced significant bronchodilation; V30p increased for 2 to 6 min (0.001 less than p less than 0.02), and FEV1 increased for 2 to 4 min (p less than 0.05) when compared with saline-ethanol (vehicle of capsaicin) inhalation. After treatment with the ganglionic blocking agent hexamethonium, the significant bronchodilator response disappeared. These results suggest that the NAI system has a distinct bronchodilator action in human subjects in vivo, and that the bronchial C-fiber receptors may be involved in the reflex pathway for NAI system bronchodilation in humans.

Adult↗
PubMed1988

Role of CO2 responsiveness and breathing efficiency in determining exercise capacity of patients with chronic airway obstruction.

We examined the role of CO2 responsiveness and breathing efficiency in limiting exercise capacity in 15 patients with chronic airway obstruction (FEV1 = 0.88 +/- 0.25 L, mean +/- SD). Responses of minute ventilation and P0.1 (mouth pressure 0.1 s after the onset of occluded inspiration) to hypercapnia (delta VE/delta PCO2, delta P0.1/delta PCO2) were measured by rebreathing, and the ratio of the two (delta VE/delta P0.1) was defined as an index of breathing efficiency during hyperventilation. Exercise capacity was measured as symptom-limited, maximal oxygen consumption (VO2max/BW) in an incremental treadmill test and also as the 12-min walking distance (TMD). All patients discontinued the treadmill test because of dyspnea, and the exercise capacity correlated with the degree of airway obstruction, although there was a wide variability among patients with comparable FEV1. There were no significant correlations between the responses to CO2 and exercise capacity. However, there was a significant correlation between delta VE/delta P0.1 and VO2max/BW (r = 0.87, p less than 0.001) or TMD (r = 0.78, p less than 0.001), and these correlations remained significant even when the relational effects of FEV1 were taken out. These results support the hypothesis that airway obstruction and breathing efficiency are important, but that CO2 responsiveness is not a major factor in determining the exercise capacity of patients with chronic airway obstruction.

Aged↗
PubMed1988

Chemical properties of bronchorrhea sputum in bronchial asthma.

Bronchorrhea, defined as watery sputum of 100 ml or more per day, was seen in 18 of 207 patients (8.7 percent) with bronchial asthma during attack. Fifteen bronchorrhea sputum samples were chemically examined using ten parameters: dry weight, albumin, IgA, pH, Na+, Cl-, K+, prostaglandins E and F and histamine, and compared with eight saliva samples and 17 mucoid sputum samples. Bronchorrhea sputum differed from saliva in its chemical parameters. Bronchorrhea sputum exhibited parameter values intermediate between those of saliva and mucoid sputum, except for the two following parameters. The pH of bronchorrhea sputum was significantly lower than that of mucoid sputum and histamine concentration, expressed as weight per dry weight of sample, was significantly higher in bronchorrhea than in mucoid sputum. Administration of corticosteroid or an histamine H1-blocker to five to nine asthmatic patients with associated bronchorrhea sputum during asthmatic attacks, significantly reduced the volume of bronchorrhea sputum, whereas anticholinergics and H2-blocker did not alter the sputum volume.

Administration, Topical↗
PubMed1988

Load dependency of end-systolic pressure-volume relations in isolated, ejecting canine hearts.

If characteristic muscle properties such as myocardial viscosity and/or shortening deactivation influence left ventricular ejection in the whole heart, the slope of the left ventricular end-systolic pressure-volume relation should be a function of both the contractile state and the loading mode. Thus, the load dependence of the end-systolic pressure-volume relation was examined using isolated, perfused canine hearts ejecting saline into a hydraulic loading system. The instantaneous left ventricular volume was measured with a plethysmograph. Under constant coronary flow and heart rate, two regression lines for end-systolic pressure-volume relations in two sets of loading modes were obtained: (1) Preload (left ventricular end-diastolic pressure; 4-15 mmHg) changes under fixed afterload impedance (preload changes); (2) Afterload impedance (peripheral resistance; 1.9-9.6 x 10(3) dyn sec cm-5) changes under fixed left ventricular end-diastolic volume (afterload changes). The slope of the end-systolic pressure-volume relation with afterload changes was steeper than that with preload changes (6.3 +/- 0.7 vs 4.8 +/- 0.6 mmHg/ml, p less than 0.05). Accordingly, under constant coronary flow, the slope of the end-systolic pressure-volume relation depended on loading conditions within the physiological range of afterload impedance and preload. This finding supports our hypothesis and implies that the slope change is of limited value as a contractile index in the ejecting heart.

Animals↗
PubMed1988

Does diffuse intimal thickening in human coronary artery act as a diffusion barrier to endothelium-derived relaxing factor?

We investigated the effect of intimal thickness in human coronary artery on the endothelium-dependent relaxation. Histamine (in the presence of cimetidine), substance P and A23187 potently relaxed arterial rings with intima thinner than 200 microns. However, those relaxations diminished progressively in the artery with intimal thickness of 200-400 microns, and disappeared at the thickness greater than 400 microns. These results suggest that diffuse intimal thickening greater than 200 microns may inhibit the diffusion of endothelium-derived relaxing factor.

Biological Factors↗
PubMed1988

The receptor mechanisms for histamine actions in proximal portion differ from those in distal portion in human coronary artery.

While most distal human coronary arteries markedly relaxed in response to histamine, nearly half the proximal ones contracted only. Thus, we investigated the receptor mechanisms for those heterogeneous histamine actions. After a combination of cimetidine-treatment and endothelial removal, but neither one alone, proximal and distal rings contracted to histamine to the same degree. It is suggested that histamine hypercontractility in proximal human coronary artery is due to a lack of both direct (H2-receptor) and endothelial-mediated (H1-receptor) relaxant actions.

Cimetidine↗
PubMed1988

The effect of sustained stellate ganglion stimulation on left ventricular contractility in the dog.

Although a progressive reduction in left ventricular contractility during sustained left stellate ganglion stimulation has been well documented, there have been no reports on the contractile state after nerve stimulation. Left ventricular contractility after cessation of 60 min of electrical (10 V. 10 Hz. 1 msec) left stellate ganglion stimulation has been assessed in open chest dogs. Before and 15 min after stimulation, left ventricular contractility was evaluated by the end-systolic pressure-segment length relationship using ultrasonic crystals during a stepwise aortic constriction to increase left ventricular afterload. Restimulation of the left stellate ganglion was also performed 15 min after cessation of the first stimulation. After sustained left stellate ganglion stimulation, the end-systolic points shifted to the right from the control and the slope of multiple pressure-segment length coordinates significantly decreased (102.5 +/- 16.1 to 76.5 +/- 10.2 mmHg/mm, mean +/- S.E., p less than 0.05, n = 5), indicating a depression of left ventricular contractility. Increased left ventricular dP/dt max and norepinephrine level in the coronary sinus gradually returned to near base line during 60 min of stimulation. These reduced responses lasted for at least 15 min after cessation of stimulation. The myocardial norepinephrine content was reduced to 0.59 +/- 0.08 (mean +/- S.E.) ng/mg wet tissue from 0.90 +/- 0.15 of the control level (p less than 0.05). These data suggested that left ventricular contractility decreased after sustained cardiac sympathetic nerve stimulation, probably due to norepinephrine reduction in the myocardium.

Animals↗
PubMed1988

The production of tumor necrosis factor-alpha by rat basophilic leukemia cells with triggering IgE receptor.

We evaluated cytotoxic factor released from rat basophilic leukemia cells (RBL) sensitized with anti-ovalbumin (OVA) mouse serum after incubation with OVA. The cytotoxic activity of this factor was completely blocked by anti-mouse tumor necrosis factor-alpha (mTNF-alpha) specific antibody. Therefore, we concluded that by triggering the IgE receptor, RBL could produce and release TNF-alpha.

Animals↗
PubMed1988

Partitioning of large and small airway resistance in human measured by an anterograde catheter with a tip micromanometer.

We measured lateral pressure in airways 3 mm in internal diameter in three normal subjects using an anterograde catheter with a tip micromanometer. The pressure was used to partition total pulmonary resistance into a large airway resistance component between the mouth and the pressure sensor and a small airway resistance component between the pressure sensor and alveoli. Large airway resistance and small airway resistance during inspiration were 2.3 +/- 0.4 and 0.9 +/- 0.2 cmH2O/liter/sec (mean +/- S.E.), respectively, and small airway resistance was 29% of the total pulmonary resistance. We suggest that the present technique may be useful for determining the localization of airway resistance in human subjects.

Adult↗
PubMed1988

Home sleep monitor for detecting apnea episodes by nasal flow and tracheal sound recordings.

We have developed a portable home sleep monitoring system using nasal airflow (NA), tracheal sound recordings (TSR), and electrocardiogram (ECG). NA was recorded by two thermisters. TSR was recorded by a microphone attached to the skin overlying the cervical trachea. Three kinds of signals were recorded with a cassette recorder. Thirty-seven outpatients who had sleep complaints were monitored during sleep at home using this recorder. Attachment of the pickups was performed by the patients themselves. Recordings were played back and analyzed by a personal computer to evaluate apnea episodes from TSR and R-R intervals beat by beat. This home monitoring system had labor-saving and cost-saving benefits and seemed to be a satisfactory technique for screening.

Ambulatory Care↗
PubMed1988

Effect of sleep position on obstructive sleep apnea.

In order to examine the effect of sleep position on sleep apnea episodes, seven male patients diagnosed as having obstructive sleep apnea syndrome without any organic complication of the upper airway were studied while lying in a supine or lateral position during an all-night polysomnographic study. Apnea index, apnea time/total sleep time (%) and the number of episodes per hour in which oxyhemoglobin saturation dropped below 85% decreased significantly from 51.0 +/- 8.6 (mean +/- S.D.) events/hr, 40.4 +/- 5.8% and 36.2 +/- 9.8 episodes/hr during sleep in supine position to 27.6 +/- 9.1 events/hr, 19.4 +/- 6.0% and 12.9 +/- 5.3 episodes/hr during sleep in lateral position, respectively. Lowest oxyhemoglobin saturation increased significantly from 70.7 +/- 2.6% to 78.0 +/- 2.4%. Thus, sleep in the lateral position may be a simple treatment before essential treatment for patients with obstructive sleep apnea syndrome.

Adult↗
PubMed1988

Bronchoalveolar lavage during inhalation provocation test in a case of farmer's lung disease.

Bronchoalveolar lavage (BAL) was performed in order to reveal inflammatory immune processes during inhalation provocation test in a patient with farmer's lung disease. Three hours after inhalation challenge the patient showed dyspnea and an increase in body temperature to 38.9 degrees C, restrictive and obstructive impairment, and a decrease in peripheral lymphocytes from, 2.8 x 10(3)/mm3 to 1.8 x 10(3)/mm3, although peripheral granulocytes increased from 4.4 x 10(3)/mm3 to 10.3 x 10(3)/mm. BAL fluid at that time showed increases in lymphocytes, granulocytes and macrophage, as well as proteins and complements, compared with that before the inhalation test. These findings indicate that with inhalation challenge in a patient with farmer's lung disease, inflammation increases vascular permeability while protein loss is followed by an increase in lymphocytes, granulocytes and macrophage; the lymphocytes migrate to the lung from peripheral blood.

Aged↗
PubMed1988

Viscoelastic properties of bronchorrhoea sputum in bronchial asthmatics.

Dynamic viscoelastic properties of 13 bronchorrhoea sputum samples from asthmatics with bronchorrhoea, defined as the production of watery sputum of 100 ml or more per day during asthmatic attacks, were examined and then compared with 7 saliva and 12 mucoid sputum samples obtained from patients during remission. Dynamic viscosity (eta') and elasticity (G') of bronchorrhoea sputum increased rapidly with time up to 2 hours after collection and slowly thereafter, whereas eta' and G' of saliva and mucoid sputum remained unchanged up to 6 hours after collection. Then, eta' and G' of saliva, bronchorrhoea and mucoid sputum samples were measured between 2 to 4 hours after expectoration. Bronchorrhoea sputum samples showed significantly larger values at frequencies of both 0.1 and 1.0 rad/sec than did saliva samples and also significantly smaller values than did mucoid sputum samples. Thus, bronchorrhoea sputum differed in dynamic viscoelastic properties from saliva, indicating that it does not result from hypersalivation. Based on data of viscoelastic changes with time, it can be assumed that the viscoelasticity of bronchorrhoea sputum in the airways is considerably less than the optimal range reported previously for mucociliary velocity, suggesting the possibility of impaired mucociliary transport.

Adult↗