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Biomedical subjects

W Hida

Publications and source records attributed to W Hida.

At least 127 records · Page 7Linked to original sources
PubMed1983

The effect of adrenergic and cholinergic drugs on methacholine- and histamine-induced bronchoconstriction in monkeys.

The effect of adrenergic and cholinergic drugs on bronchial contraction of monkeys was studied using bronchoconstriction induced by aerosol challenge with methacholine and histamine. Under the anesthesia with ketamine hydrochloride, changes in the total respiratory resistance were continuously measured in monkeys to estimate the bronchial response to both histamine and methacholine. Isoprenaline decreased bronchial susceptibility to aerosol challenge with both methacholine and histamine. Isoprenaline was also potent in antagonizing the bronchoconstriction induced by methacholine and histamine. Atropine decreased bronchial susceptibility to aerosol challenge with methacholine and also partially with histamine. Atropine also antagonized the bronchoconstriction induced by methacholine, but not by histamine. Phentolamine had neither inhibitory effects on the aerosol challenge with methacholine and histamine, nor produced an antagonistic effect on bronchoconstriction induced with methacholine and histamine.

Animals↗
PubMed1982

Lobe weight gain and vascular, alveolar, and peribronchial interstitial fluid pressures.

Interstitial fluid movements in acute pulmonary edema were studied by recording interstitial fluid pressure [Px (f)] relative to pleural pressure (atmospheric), together with lobe weight gain or loss (delta W). Px (f) was measured by wicks inserted between lobar bronchus and artery while alveolar pressure (PA) was fixed at either 5 or 20 cmH2O. When vascular pressure (Pvas) was raised abruptly from -5 to +25 cmH2O by air inflation for 60 min, Px (f) became abruptly less negative, then remained stable. However, during vascular inflation with plasma, delta W began a steady increase, but plotted against delta W, Px(f) became less negative in several phases. After an immediate rise due to interdependence effects following vascular distension, Px (f) remained almost unchanged for 4-7 min as delta W increased 15-80% of initial lobe weight (Wi), representing a transport lag between leakage and measuring sites and suggesting that interstitial edema was not homogeneous. Next, Px (f) increased progressively as weight increased a further 70-200% of Wi and finally slowed its rise near zero pressure. When Pvas was lowered, Px (f) became abruptly more negative, again by interdependence; however, as delta W then decreased 20-50% of Wi over 30 min, Px (f) did not change consistently. It was possible to relate the rate of weight gain occurring between 2 and 5 min after Pvas was raised to two pressure gradients, Pvas - Px (f) and Pvas - PA, and to relate the time lag to filtration rate and Pvas - Px (f).

Animals↗
PubMed1981

Effect of ventilatory frequency on regional transpulmonary pressure in normal adults.

The relation between the ventilatory frequency and the elastic (delta Pel) or resistive (delta Prs) components of changes of the regional pleural pressure (delta PL) was studied at functional residual capacity (FRC) in six normal adults. The regional delta PL was measured simultaneously at three levels in the esophagus using a three-balloon-catheter system. Elastic components of regional delta PL normalized by overall tidal volume (delta Pel/delta V) increased with frequency at all three balloon positions; the percentages of delta Pel/delta V at 60 breaths/min to those at zero frequency were 107, 119, and 157% in the upper, middle, and lower balloon, respectively. The resistive component of regional delta PL normalized by overall air flow (delta Prs/delta V) did not show significant dependence on frequency at any of the three positions and was almost the same everywhere. It is suggested that the increase of local delta Pel with frequency might reflect mainly the frequency dependence of local dynamic compliance (Cdyn) and that the change of the local Cdyn with frequency might be larger in dependent than in upper lung.

Adult↗
PubMed1981

Direct-writing recorder of the dose-response curves of the airway to methacholine. Clinical application.

We report a new device for examining the bronchial hyperresponsiveness by directly writing the dose-response curve of respiratory resistance (Rrs) during the continuous inhalation of the methacholine in stepwise incremental concentrations. Respiratory resistance was measured by the forced oscillation method. We found that the Rrs began to increase at a certain threshold concentration of methacholine (bronchial sensitivity) and that it has a curvilinear slope (bronchial reactivity). Subsequent inhalation of the bronchodilator drug returned the Rrs to the control level. Thus, we were able to examine bronchohyperresponsiveness in the patterns of the cumulative dose-response curves of methacholine. All normal subjects were nonresponders; while all of the asthmatic subjects, 63 percent (10) of the 16 patients with chronic bronchitis and 50 percent (7) of the 14 patients with acute bronchitis were responders. The dose-response curves were reproducible. Our device may be clinically applicable for examinations of bronchial hyperresponsiveness and for screening tests.

Adult↗
PubMed1981

Direct graphical recordings of the cumulative dose-response curves of the airway to methacholine in normal, bronchitic and asthmatic subjects.

We studied bronchial responsiveness to methacholine in 10 normal subjects, in 60 patients with bronchial asthma and in 30 patients with bronchitis using a new device, with which we were able to obtain the dose-response curve of respiratory resistance (Rrs) continuously and graphically by the 3 Hz oscillation method during inhalation of methacholine. All normal subjects were non-responders, while all of the bronchial asthma cases, 63% of the chronic bronchitis cases and 50% of the acute bronchitis cases were responders. Among responders we found a very poor correlation between the initial respiratory conductance (Grs.cont) and the bronchial sensitivity (defined as the reverse of the cumulative dose until Rrs starts to increase); yet we found a good correlation between Grs.cont and the bronchial reactivity (defined as the slope of the decreasing rate of Grs). Metaproterenol and atropine decreased the bronchial sensitivity and reactivity in 28 asthmatic patients. We concluded that for clinical purposes the new method was very useful for assessing bronchial responsiveness to inhalation challenge because of its simplicity of operation as well as the quantitative differentiation between bronchial sensitivity and reactivity. Our results suggest that the bronchial response system to methacholine is explainable by a model of multiple dose-response curves without any parallel shift.

Adult↗
PubMed1980

Bronchial response to methacholine and histamine in monkeys with beta adrenergic blockade.

The possibility has been investigated that propranolol administration could alter bronchial reactivity to methacholine and histamine in monkeys (Macaca fuscata and Macaca fascicularis). The impedance of the total respiratory system was measured by the forced 3-HZ oscillation method through an endotracheal tube. Methacholine and histamine dose-dependently increased the impedance in monkeys irrespective of the route of administration (inhalation of aerosol or intravenous injection). Propranolol treatment increased the bronchial response to intravenously injected methacholine and caused no significant change in the bronchial response to aerosolized methacholine. No marked difference was observed in the bronchial response to histamine due to treatment with propranolol regardless of whether administered by intravenous injection or aerosol challenge.

Adrenergic beta-Antagonists↗
PubMed1979

Inflection points of lung pressure-volume curves using a three-balloon-catheter system.

We measured the pressure-volume curves (PV curves) of the lung simultaneously at three levels in the esophagus below the tracheal bifurcation using the three-short-balloon-catheter system in 11 normal seated men and compared the inflection points (IP's) of three PV curves with the closing volume (CV) on the single-breath nitrogen washout curve. The mean pressure gradient from the top of the uppermost balloon to the top of the lowermost balloon (10 cm apart) was 0.58 +/- 0.06 cmH2O/cm at 60% total lung capacity (TLC). The IP was dependent on depth within the esophagus; i.e., the lung volume at IP (VIP) of the uppermost balloon was the smallest and the transpulmonary pressure (Ptp) at IP (PIP) of that balloon was the largest of the three IP's. VIP's were significantly larger than CV's and the mean absolute difference between the VIP of the uppermost balloon and the closing capacity (CC) was 0.9 liter. These results suggest that IP may not exactly reflect airway closure.

Adult↗
PubMed1979

Influence of metoprolol on hemodynamics and respiratory function in asthmatic patients.

Studies of metoprolol in asthmatic patients showed beta 1-selective blocking properties on the adrenergic receptor. Metoprolol in a dose of 40 mg given orally to 9 asthmatic patients significantly decreased the pulse rate at 60 and 120 minutes and the systolic blood pressure at 120 minutes but did not cause any increase of respiratory impedance, measured by the forced oscillation technique. A double-blind test was carried out to compare the effects of metoprolol and inactive placebo on the respiratory response to isoproterenol in 24 asthmatic patients. In the metoprolol group, systolic blood pressure decreased significantly and pulse rate at rest also tended to decrease. There was no significant difference between the metoprolol and placebo groups in the respiratory response to an isoproterenol aerosol.

Asthma↗
PubMed1977

Influence of body position on dynamic compliance in young subjects.

We studied the effect of a postural change from the erect to the supine position on the unevenness of pulmonary ventilation in six normal subjects. Static pressure-volume curves had a similar shape in both positions but the supine curves were shifted such that all transpulmonary pressures were 5-8 cmH2O lower. Dynamic compliance (Cdyn) was measured in seated and supine postures at functional residual capacity (FRC) and also while the seated subjects maintained end-expiratory lung volume at the level of supine FRC. Frequency dependence of Cdyn increased relative to that measured in the seated position at FRC when the subject remained seated but decreased his lung volume, or when he assumed the supine posture. There was no significant difference between Cdyn measured in the supine posture and in the seated at supine FRC. We conclude that the increased frequency dependence seen in the supine posture is largely attributed to the associated decrease of lung volume rather than to position per se.

Adult↗
PubMed1976

The maximum expiratory flow rate and volume dependent respiratory resistance in small airway obstruction.

In 8 healthy subjects (group A) and 4 subjects with respiratory symptoms (group B), the lung pressure-volume curve (P-V curve), maximum expiratory flow-volume curve (MEFVC) and respiratory resistance (Rrs) at all vital capacities were measured. To avoid laryngeal artifact on a mouth pressure, an intratracheal catheter was used for measurement of Rrs which was obtained with 3 cycles/sec oscillatory forced pressure. Group B did not show a different elastic recoil from group A. In comparison of the maximum expiratory flow (Vmax) at 80, 70, 60 and 50% of the total lung capacity (TLC). Vmax of group B showed lower values than that of group A. Rrs was almost the same in both groups from 70% TLC upwards, but Rrs of group B was higher than that of group A from 65%TLC downwards. Since the lung elastic recoil pressures (Pst (1)) in the two groups were not different and Rrs's were different significantly only at low lung volumes, the decrease in Vmax of group B was supposed to be due to the increased Rrs which might reflect small airway obstruction.

Adult↗
PubMedDate not supplied

CO2 response for the brain stem artery blood flow velocity in man.

We examined changes in the blood flow velocity of brain stem artery (BSA) and middle cerebral artery (MCA) in response to hypercapnic, normocapnic and hypocapnic hyperventilation in seven awake subjects with a transcranial Doppler to determine if there are differences in blood flow control in regional brain perfused by these respective arteries, and to separate the effects of CO2 and ventilation itself on blood flow velocity during CO2 loading. During hypercapnic hyperventilation, BSA flow velocity increased linearly with an increase in end-tidal partial pressure of CO2 (PETCO2). During hypocapnic hyperventilation, BSA flow velocity decreased linearly with decrease in PETCO2, but did not change during normocapnic hyperventilation. The mean CO2 reactivity of BSA was 2.8%/mmHg. The responses of MCA to these hyperventilations and CO2 reactivity were similar to those of BSA. These findings suggest that CO2 rather than ventilation per se is the important stimulus to changes in brain blood flow velocity and that the CO2 responses of brain arteries are not affected by differences in vascular beds.

Adult↗
PubMedDate not supplied

Effect of local vibration on ventilatory response to hypercapnia in normal subjects.

We studied the effects of local high frequency mechanical vibration on ventilatory (VE) and occlusion pressure (P0.1) responses to CO2 rebreathing in twelve normal subjects. Three kinds of vibration procedures were employed: a) sustained vibration over the tendon of the quadriceps femoris near the knee, b) sustained vibration of the right 2nd or 3rd parasternal intercostal spaces and c) 'in-phase' chest wall vibration applied during inspiration on the right 2nd or 3rd parasternal intercostal spaces and during expiration on the right 9th or 10th intercostal spaces anterior to the midaxillary line. The slopes of VE response to hypercapnia (delta VE/delta PETCO2) were 2.05 +/- 0.26 (mean +/- SE), 2.48 +/- 0.24, 2.82 +/- 0.32 and 3.35 +/- 0.38 l.min-1/mmHg in the control state, during tendon vibration of quadriceps femoris, sustained chest wall vibration and 'in-phase' chest wall vibration, respectively. This sequential increase in slopes was significant compared to the control values. The effect of vibration on the P0.1 response to hypercapnia was similar to that of VE. We conclude that local mechanical vibration facilitates responsiveness to hypercapnia.

Adult↗