Impedance measurement during air and He-O2 breathing before and after salbutamol in normal subjects

1990 ◽  
Vol 69 (5) ◽  
pp. 1665-1669
Author(s):  
E. F. Wouters
Keyword(s):  
Impedance Measurement ◽  
Normal Subjects ◽  
Normal Male ◽  
Respiratory Resistance ◽  
Adrenergic Agonist ◽  
Before And After ◽  
The Subject ◽  
Beta Adrenergic Agonist ◽  
Male Subjects ◽  
Inductive Reactance

Total respiratory resistance and reactance from 4 to 52 Hz were determined by the method of forced pseudorandom noise oscillation in 20 normal male subjects before and after inhalation of 0.200 mg salbutamol (albuterol) and before and after the subjects were equilibrated with 80% He-20% O2. During air breathing, there was a statistically significant decrease of resistance values at lower frequencies after inhalation of salbutamol. When the subject was equilibrated with 80% He-20% O2, total respiratory resistance markedly decreased at all frequencies, and a negative frequency dependence of resistance was observed between 8 and 20 Hz. Resistance values further decreased during He-O2 breathing after inhalation of salbutamol. After inhalation of salbutamol, reactance values increased during air and He-O2 breathing. The density-dependent decrease of the real part of impedance can be explained by a decrease of turbulence in the larger airways. The bronchodilating effect of salbutamol was not influenced by a change in the physical properties of the inhaled gas. During He-O2 breathing, reactance values significantly decreased, resulting in an increase of resonant frequency due to a decrease of inductive reactance. It is concluded that an increase in the capacitance of the respiratory system must be supposed to explain the increase in reactance values after inhalation of the beta-adrenergic agonist salbutamol.

The Retention of Lung Secretions during the Night in Normal Subjects

1978 ◽  
Vol 55 (6) ◽  
pp. 523-527 ◽  
Author(s):  
J. R. M. Bateman ◽  
D. Pavia ◽  
S. W. Clarke
Keyword(s):  
Diurnal Variation ◽  
Chronic Bronchitis ◽  
Mucociliary Clearance ◽  
Normal Subjects ◽  
Early Morning ◽  
Normal Male ◽  
Related Phenomenon ◽  
Before And After ◽  
Male Subjects

1. Mucociliary clearance has been measured over a 6 h period by using the radioaerosol technique in seven normal male subjects lying supine, both during the day when awake, and during the night when asleep. 2. The percentage of radioaerosol cleared during the night, when asleep, was significantly less than during the day when awake (P < 0.02). 3. A comparison of radioaerosol clearance before and after the time of onset of sleep demonstrates that reduced clearance occurred during sleep, indicating that this is probably a sleep-related phenomenon and not merely a result of diurnal variation. 4. This finding has important implications for patients with chronic bronchitis or asthma, in whom early morning cough or wheeze may be a predominant feature.

O2 cost of inspiratory and expiratory resistive breathing in humans

1988 ◽  
Vol 65 (6) ◽  
pp. 2518-2523 ◽  
Author(s):  
D. S. Dodd ◽  
J. Yarom ◽  
S. H. Loring ◽  
L. A. Engel
Keyword(s):  
Normal Subjects ◽  
Normal Male ◽  
O2 Uptake ◽  
Pressure Time ◽  
Resistive Breathing ◽  
Before And After ◽  
Expiratory Muscles ◽  
Variable Recruitment ◽  
Equivalent Load ◽  
Male Subjects

In six normal male subjects we compared the O2 cost of resistive breathing (VO2 resp) between equivalent external inspiratory (IRL) and expiratory loads (ERL) studied separately. Each subject performed four pairs of runs matched for tidal volume, breathing frequency, flow rates, lung volume, pressure-time product, and work rate. Basal O2 uptake, measured before and after pairs of loaded runs, was subtracted from that measured during resistive breathing to obtain VO2 resp. For an equivalent load, the VO2 resp during ERL (184 +/- 17 ml O2/min) was nearly twice that obtained during IRL (97 +/- 9 ml O2/min). This twofold difference in efficiency between inspiratory and expiratory resistive breathing may reflect the relatively lower mechanical advantage of the expiratory muscles in overcoming respiratory loads. Variable recruitment of expiratory muscles may explain the large variation of results obtained in studies of respiratory muscle efficiency in normal subjects.

scholarly journals Comparison of the Effects of Intravenous Papaverine Hydrochloride and Oral Pavabid HP Capsulets on Regional Cerebral Blood Flow in Normal Individuals

1983 ◽  
Vol 3 (4) ◽  
pp. 442-447 ◽  
Author(s):  
Lawrence C. McHenry ◽  
David A. Stump ◽  
George Howard ◽  
Thomas T. Novack ◽  
Don H. Bivins ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Regional Cerebral Blood Flow ◽  
Normal Subjects ◽  
Normal Male ◽  
Regional Cerebral Blood ◽  
Normal Individuals ◽  
Left And Right ◽  
Male Subjects ◽  
Papaverine Hydrochloride

A single-blind study was conducted in 13 right-handed normal male subjects to compare the effects of oral and i.v. papaverine on regional cerebral blood flow (rCBF). Six xenon-133 inhalation rCBF measurements were performed on each subject; three tests—baseline, placebo, and drug evaluations—were carried out on each of two separate days. The oral and i.v. drugs were randomized for first-day administration. rCBF, measured as flow gray (FG), increased significantly (p ≤ 0.001) from baseline with both drug forms. Increases of 10.53% and 13.94% (left and right hemispheres, respectively) were demonstrated 90 min after a single 600-mg dose of oral papaverine. Increases of 5.09% and 8.69%, respectively, were recorded immediately after a single 100-mg dose of i. v. papaverine. FG also increased significantly (p ≤ 0.001) for both drug forms when compared to that of placebo. Placebo produced only a slight increase (not significant) with both the oral and i.v. groups. The data show that both oral and i.v. papaverine are equally effective in increasing rCBF in normal subjects.

Effect of Single and Combined Infusions of Angiotensin II and Aldosterone on Colonic Potential Difference, Blood Pressure and Renal Function, in Patients with Adrenal Deficiency

1975 ◽  
Vol 48 (3) ◽  
pp. 219-226
Author(s):  
A. D. Efstratopoulos ◽  
W. S. Peart
Keyword(s):  
Blood Pressure ◽  
Renal Function ◽  
Plasma Concentrations ◽  
Young Male ◽  
Normal Subjects ◽  
Potential Difference ◽  
Normal Male ◽  
Adrenal Deficiency ◽  
Increased Sensitivity ◽  
Male Subjects

1. The effect of single and combined infusions of angiotensin and aldosterone on colonic potential difference, blood pressure and renal function was studied in two normal male subjects and four female patients with adrenal deficiency maintained only on cortisone. 2. Aldosterone had its usual effect on colonic potential difference and it was possible to show that angiotensin had a small but definite effect of its own in the absence of aldosterone. The two hormones produced a summation response when given together. 3. The effects on renal function in two normal young male subjects were similar to those known previously. The response of the patients was different and probably reflected a number of factors, such as age, sex and long-standing adrenal deficiency. 4. Although the numbers were small, both normal subjects and patients showed a significantly greater rise of blood pressure with combined infusions of angiotensin and aldosterone than with angiotensin alone. The plasma concentrations of angiotensin were similar with both types of infusion, and so increased sensitivity to angiotensin in the presence of aldosterone is postulated.

The effect of verapamil and inspired CO2 on the bronchoconstriction provoked by hyperventilation in normal humans

1985 ◽  
Vol 69 (3) ◽  
pp. 361-364 ◽  
Author(s):  
C. H. C. Twort ◽  
J. E. Neild ◽  
I. R. Cameron
Keyword(s):  
Co2 Concentration ◽  
Normal Subjects ◽  
Specific Conductance ◽  
Forced Oscillation Technique ◽  
Respiratory Resistance ◽  
Voluntary Hyperventilation ◽  
Before And After ◽  
Normal Humans ◽  
End Tidal ◽  
Oral Verapamil

1. Two groups of eight normal subjects were investigated in separate studies to demonstrate the effects of changes in end-tidal Pco2, and of pretreatment with the calcium antagonist drug verapamil, on bronchoconstriction provoked by voluntary hyperventilation. 2. Total respiratory resistance (Ros) was measured by the forced oscillation technique before and after 90s voluntary hyperventilation. End-tidal Pco2 during hyperventilation was varied by altering inspired CO2 concentration. When end-tidal Pco2 fell during hyperventilation, there was a rise in Ros. This did not occur if end-tidal Pco2 was controlled at a normal resting level during hyperventilation. 3. Specific conductance (sGaw) was measured before and after 90 s voluntary hyperventilation of air. Subjects were treated with oral verapamil or placebo for 2 1/2 days and the effect of hyperventilation on sGaw was reassessed. Verapamil reduced significantly the fall in sGaw caused by hyperventilation. Placebo had no effect. 4. In normal humans, bronchoconstriction provoked by hyperventilating air at ambient temperature and humidity is mediated by the fall in Pco2, and is also reduced by verapamil.

Effects of nitroglycerin on liquid gastric emptying and antropyloroduodenal motility

1998 ◽  
Vol 275 (5) ◽  
pp. G1173-G1178 ◽  
Author(s):  
W.-M. Sun ◽  
S. Doran ◽  
K. L. Jones ◽  
E. Ooi ◽  
G. Boeckxstaens ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Gastric Emptying ◽  
Pressure Wave ◽  
Normal Subjects ◽  
Nitric Oxide Donor ◽  
Pressure Waves ◽  
The Subject ◽  
And Control ◽  
Male Subjects

The effects of the nitric oxide donor nitroglycerin on gastric emptying and antropyloroduodenal motility were evaluated in nine healthy male subjects (ages 19–36 yr). Antropyloroduodenal pressures were recorded with a manometric assembly that had nine side holes spanning the antrum and proximal duodenum and a pyloric sleeve sensor; gastric emptying was quantified scintigraphically. In each subject, the emptying of 300 ml of 25% glucose labeled with99mTc was assessed on two separate days during intravenous infusion of either nitroglycerin (5 μg/min in 5% dextrose) or 5% dextrose (control). Studies were performed with the subject in the supine position; blood pressure and heart rate were monitored. Nitroglycerin had no significant effect on blood pressure or heart rate. Nitroglycerin slowed gastric emptying ( P < 0.02), and this was associated with greater retention of the drink in the proximal stomach ( P < 0.05). In both nitroglycerin and control studies, ingestion of the drink was associated with an increase in the number of isolated pyloric pressure waves ( P < 0.05) and antral pressure wave sequences ( P < 0.05). Nitroglycerin reduced the number of isolated pyloric pressure waves ( P < 0.05), basal pyloric pressure ( P < 0.05), and the number of antral pressure wave sequences ( P < 0.05), but not the total number of antral pressure waves. The rate of gastric emptying and the number of isolated pyloric pressure waves were inversely related during control ( P = 0.03) and nitroglycerin ( P < 0.05) infusions. We conclude that in normal subjects, 1) gastric emptying of 300 ml of 25% glucose is inversely related to the frequency of phasic pyloric pressure waves, and 2) nitroglycerin in a dose of 5 μg/min inhibits pyloric motility, alters the organization but not the number of antral pressure waves, and slows gastric emptying and intragastric distribution of 25% glucose.

Practical Importance of a Preceding Full Inhalation or Exhalation upon the Measurement of Airway Resistance

1980 ◽  
Vol 58 (3) ◽  
pp. 249-253 ◽  
Author(s):  
T. Higenbottam ◽  
T. J. H. Clark
Keyword(s):  
Airway Resistance ◽  
Practical Importance ◽  
Normal Male ◽  
Indirect Measurements ◽  
Lung Capacity ◽  
Airway Function ◽  
Before And After ◽  
Residual Capacity ◽  
Normal Men ◽  
Male Subjects

1. Airway resistance was measured close to functional residual capacity before and after a full inhalation of total lung capacity, as well as before and after a full exhalation to residual volume. 2. The effects of these volume manoeuvres upon airway resistance (and associated lung volume) were determined in four resting normal male subjects and in six normal men during experimentally induced bronchoconstriction after breathing an air/histamine mist from a Wright's nebulizer. 3. In four men the duration of the effect of a full inhalation upon airway resistance after induced bronchoconstriction was assessed separately. 4. Neither a full inhalation nor a full exhalation altered airway resistance under normal conditions. However, a full inhalation reduced airway resistance in the presence of bronchoconstriction and this effect lasted for a period of 45 s. Even with bronchoconstriction, a full exhalation had no effect on airway resistance. 5. Account must therefore be taken of the potential reduction in airway resistance which may result from a full inhalation, particularly when indirect measurements of airway function which involve a full inhalation, such as forced spirometry, are used to assess airway obstruction.

scholarly journals Direct measurement of the lumped constant for 2-deoxy-[1-14C]glucose in vivo in human skeletal muscle

2000 ◽  
Vol 279 (1) ◽  
pp. E228-E233 ◽  
Author(s):  
Tapio Utriainen ◽  
Stefania Lovisatti ◽  
Sari Mäkimattila ◽  
Alessandra Bertoldo ◽  
Susan Weintraub ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Human Skeletal Muscle ◽  
Insulin Infusion ◽  
Normal Subjects ◽  
Normal Male ◽  
Wide Range ◽  
Lumped Constant ◽  
Male Subjects ◽  
Forearm Vein

The lumped constant (LC) is used to convert the clearance rate of 2-deoxy-d-glucose (2-DGcr) to that of glucose (Glccr). There are currently no data to validate the widely used assumption of an LC of 1.0 for human skeletal muscle. We determined the LC for 2-deoxy-[1-14C]glucose (2-DG) in 18 normal male subjects (age, 29 ± 2 yr; body mass index, 24.8 ± 0.8 kg/m2) after an overnight fast and during physiological (1 mU · kg−1· min−1insulin infusion for 180 min) and supraphysiological (5 mU · kg−1· min−1insulin infusion for 180 min) hyperinsulinemic conditions. Normoglycemia was maintained with the euglycemic clamp technique. The LC was measured directly with the use of a novel triple tracer-based method. [3-3H]glucose, 2-[1-14C]DG, and [12C]mannitol (Man) were injected as a bolus into the brachial artery. The concentrations of [3-3H]glucose and 2-[1-14C]DG (dpm/ml plasma) and of Man (μmol/l) were determined in 50 blood samples withdrawn from the ipsilateral deep forearm vein over 15 min after the bolus injection. The LC was calculated by a formula involving blood flow calculated from Man and the Glccrand 2-DGcr. The LC averaged 1.26 ± 0.08 (range 1.06–1.43), 1.15 ± 0.05 (0.99–1.39), and 1.18 ± 0.05 (0.97–1.37) under fasting conditions and during the 1 and 5 mU · kg−1· min−1insulin infusions (not significant between the different insulin concentrations, mean LC = 1.2, P < 0.01 vs. 1.0). We conclude that, in normal subjects, the LC for 2-DG in human skeletal muscle is constant over a wide range of insulin concentrations and averages 1.2.

Control variables and proprioceptive feedback in fast single-joint movement

1995 ◽  
Vol 73 (2) ◽  
pp. 316-330 ◽  
Author(s):  
M. F Levin ◽  
Y. Lamarre ◽  
A. G. Feldman
Keyword(s):  
Normal Subjects ◽  
Final Position ◽  
Joint Movement ◽  
Control Variables ◽  
Random Test ◽  
Before And After ◽  
The Subject ◽  
Sensorimotor Mechanisms ◽  
Load Perturbations ◽  
Torque Angle

Sensorimotor mechanisms were studied on the basis of kinematic and electromyographic data as well as the static torque developed by the muscles as a function of joint angle. The latter relationship is known as the torque/angle characteristic. Fast single-joint movement may result from a shift in this characteristic and a change in its slope. Such movements were studied at the wrist in 9 normal and 1 deafferented subject. After training to flex the wrist to a target, subjects repeated the same movements but in random test trials movements were opposed by the load generated by linear position feedback to a torque motor. At the end of the loaded trials, the load was suddenly removed. In the second experiment, subjects made wrist movements to the target that were opposed by the load and, on random test trials, the movements were not loaded. In these test trials, the wrist arrived in a static position outside the target zone. In both experiments, subjects were instructed not to correct errors. The final torque/angle characteristics specified in the movements were reconstructed on the basis of the static wrist positions and torques before and after unloading. Normal subjects made movements by shifting the position of the torque/angle characteristic and by increasing its slope. If subjects indeed maintained the same pattern of control variables (descending commands), the same final position of the characteristic would be reproduced from trial to trial regardless of load perturbations. This assumption of equifinality was tested by comparing the final position of the wrist in nonloaded movements with that after removal of the load in loaded movements. Equifinality was observed in normal subjects. Movements in the deafferented subject were also associated with a shift of the torque/angle characteristic and a change in its slope. However, she was unable to consistently reproduce its final position. In spite of muscle coactivation, her maximal stiffness was lower than in normal subjects. In the absence of vision, the subject made movements with the load by increasing the slope of the characteristic instead of by shifting its position far enough. Load perturbation affected her final wrist position (inequifinality), which may reflect the presence of a significant hysteresis of the characteristic as a result of the absence of stretch reflexes. The deficits following deafferentation presumably result from the destruction of biomechanical and sensorimotor mechanisms including the ability of control variables to specify the positional frame of reference for afferent and descending systems.Key words: sensorimotor integration, positional frames of reference, deafferentation, wrist stiffness, equilibrium-point hypothesis.

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