Search PubMed⌕ Search

Biomedical subjects

A Wanner

Publications and source records attributed to A Wanner.

At least 181 records · Page 10Linked to original sources
PubMed1977

Study of the pulmonary circulation in a canine asthma model.

Measurements of respiratory mechanics, gas exchange, and pulmonary hemodynamics were made before and serially for 2 hours after inhalation challenge with Ascaris suum extract in dogs with natural sensitivity to this antigen. Nine of 14 dogs randomly exposed to an inspired oxygen fraction of 0.21 or 0.60 to 0.70, responded to the challenge with bronchospasm reflected by a transient decrease of mean specific respiratory system conductance to 50 per cent of baseline after 5 to 15 min. This was accompanied by a decrease in alveolar ventilation in all and acidosis in some animals. No changes were observed in transmural pulmonary arterial pressure, cardiac output, pulmonary vascular resistance, and pulmonary blood volume in all 9 dogs who responded with bronchospasm, whether or not arterial hypoxemia was allowed to develop. In contrast, a significant increase in pulmonary vascular resistance occurred in control dogs in whom comparable degrees of arterial hypoxemia were produced by 10 per cent oxygen breathing or mechanical bronchial obstruction by placing beads in lobar and segmental airways. No changes in any parameter measured occurred in the 5 dogs who did not develop bronchospasm after antigen challenge. The results indicated that moderately severe, antigen-induced bronchospasm in anesthetized dogs has no effect on the pulmonary circulation even when associated with arterial hypoxemia. Because nonuniformity of alveolar hypoxia allowing redistribution of blood flow is probably not responsible for this failure to develop increases in pulmonary vascular resistance in induced asthma, it is suggested that the elaboration of chemical mediators may have interfered with the hypoxic pulmonary vasoconstrictor response.

Acidosis↗
PubMed1977

Acute effects of an aerosol hair spray on tracheal mucociliary transport.

The acute effects of a commercially available aerosol hair spray preparation and a Freon propellant on various pulmonary function tests and tracheal mucociliary transport were studied in 12 normal nonsmokers. Tracheal mucous velocity was estimated by a roentgenographic method. In 7 subjects exposed to hair spray by directing the aerosol to the hair for 20 sec, no significant changes occurred in any of the various pulmonary function parameters, whereas mean tracheal mucous velocity decreased by 57 per cent (P less than 0.001) 1 hour after exposure. This effect was transient and could no longer be demonstrated after 3 hours. No significant changes in tracheal mucous velocity or pulmonary function tests were observed in the 5 control subjects exposed to the Freon propellant alone. These observations suggest that acute exposure to aerosol hair spray produces a transient impairment of a pulmonary defense mechanism, and that measurements of mucociliary transport is a more sensitive indicator of this type of airway irritation than conventional pulmonary function tests.

Adult↗
PubMed1976

Effect of beta-adrenergic agonists aerosolized by freon propellant on tracheal mucous velocity and cardiac output.

The present study was designed to assess the effects of two beta-adrenergic agonists, isoproterenol sulfate and carbuterol hydrochloride, and aerosolized Freon propellant (a mixture of Freon II, Freon 12, and Freon 114) on tracheal mucous velocity and cardiac output in anesthetized dogs. Five groups of ten animals each received the following dosages of aerosols: Freon, 20 puffs; isoproterenol, four puffs; carbuterol, four puffs; isoproterenol, 20 puffs; and carbuterol, 20 puffs. The puff was delivered by a standard metered aerosol; each puff of isoproterenol spray contained 75 mug of isoproterenol sulfate, and each puff of carbuterol spray contained 100 mug of carbuterol hydrochloride. Tracheal mucous velocity was not changed by receiving Freon, but administration of both isoproterenol and carbuterol caused a significant increase in this measurement, with peak increases ranging from 74 to 111 percent above control values. The duration of action for four and 20 puffs of isoproterenol and for four puffs of carbuterol was two hours. Twenty puffs of carbuterol increased tracheal mucous velocity for three hours. Administration of carbuterol effected a slightly larger increase in cardiac output than isoproterenol. The duration of action for the increased cardiac output was shorter than the duration of action for the increased tracheal mucous velocity. These studies indicate that beta-adrenergic agonists may have an important role in improving mucous transport in patients with chronic obstructive pulmonary disease in whom mucociliary clearance is depressed.

Adrenergic beta-Agonists↗
PubMed1975

["Small airway disease". A short review].

Recent research aimed at detection of early chronic obstructive lung disease has resulted in the concept of "small airway disease". The physiologic abnormalities associated with this entity, which is characterized by structural changes in peripheral airways, are too slight to be detected by conventional pulmonary function tests. A number of more sensitive methods have been found helpful in the recognition of small airway disease which, among other conditions, appears to be present in asymptomatic young smokers. Although final evidence of the suggested relationship between small airway disease and clinically manifest chronic obstructive lung disease is still lacking, this hypothesis is intriguing since it relates to a chronic disease in a potentially reversible stage.

Airway Obstruction↗
PubMed1975

Tracheal mucous transport in Beagles after long-term exposure to 1 ppm sulfur dioxide.

Tracheal mucous velocity was determined in eight purebred beagle dogs exposed intermittently to 1 ppm sulfur dioxide for 12 months. Three control dogs were also studied. Teflon disks filmed at constant speed through a bronchofiberscope served as indicators of mucous motion. An average of 16 disks were analyzed in each dog. Although there was no significant difference in average velocity for controls and the SO-2-exposed animals, the frequency distribution curve of individual disk velocities in SO-2-exposed dogs revealed significant slowing. No significant differences in mechanics of breathing and gas exchange were found between the two groups. It appears that long-term exposure to low levels of SO-2 produces an impairment of mucociliary activity as one of the first signs of pulmonary dysfunction.

Animals↗
PubMed1975

Effects of lung inflation on pulmonary arterial blood volume in intact dogs.

The isolated effects of alterations of lung inflation and transmural pulmonary arterial pressure (pressure difference between intravascular and pleural pressure) on pulmonary arterial blood volume (Vpa) were investigated in anesthetized intact dogs. Using transvenous phrenic nerve stimulation, changes in transmural pulmonary arterial pressure (Ptm) at a fixed transpulmonary pressure (Ptp) were produced by the Mueller maneuver, and increases in Ptp at relatively constant Ptm by a quasi-Valsalva maneuver. Also, both Ptm and Ptp were allowed to change during open airway lung inflation. Vpa was determined during these three maneuvers by multiplying pulmonary blood flow by pulmonary arterial mean transit time obtained by an ether plethysmographic method. During open airway lung inflation, mean (plus or minus SD) Ptp increased by 7.2 (plus or minus 3.7) cmH2O and Ptm by 4.3 (plus or minus 3.4) cmH2O for a mean increase in Vpa by 26.2 (plus or minus 10.7) ml. A pulmonary arterial compliance term (Delta Vpa/Delta Ptm) calculated from the Mueller maneuver was 3.9 ml/cmH2O and an interdependence term (Delta Vpa/Delta Ptp) calculated from the quasi-Valsalva maneuver was 2.5 ml/cmH2O for a 19% increase in lung volume, and 1.2 ml/cmH2O for an increase in lung volume from 19% to 35%. These findings indicate that in normal anesthetized dogs near FRC for a given change in Ptp and Ptm the latter results in a greater increase of Vpa.

Animals↗
PubMed1975

Tracheal mucous transport in experimental canine asthma.

Tracheal mucous velocity (TMV) was measured in experimental canine asthma. All 10 sensitive dogs exposed to an aerosol of Ascaris suum extract showed a decrease in TMV to about one-third of base-line values within 45 min whereas only half of them (reactors) responded with bronchospasm as measured by a significant reduction in specific respiratory system conductance (SGrs). Mean TMV remained decreased at the end of the 2-h observation period when mean SGrs had returned to base-line values in the reactors. Neither TMV nor SGrs changed in nonsensitive animals who inhaled ragweed antigen. Aerosols of acetylcholine and histamine increased TMV thereby excluding these mediators as responsible for the impairment of mucous transport in asthma. Nebulization of A. suum antigen together with a selective antagonist of slow reacting substance of anaphylaxis (srs-a) produced a marked increase of TMV in all dogs regardless of whether or not bronchospasm was elicited. This suggests that the observed decrease in TMV may be related to the release of SRS-A during the immunologic reaction.

Animals↗
PubMed1975

Tracheal mucociliary transport in patients with cystic fibrosis and its stimulation by terbutaline.

Tracheal mucous velocity was measured by observing the motion of teflon discs across the tracheal mucosa through a fiberoptic bronchoscope. The average rate of movement in 14 adult patients with cystic fibrosis was 2.6 mm per min plus or minus 3.3 SD, compared with 20.1 mm per min plus or minus 6.3 in 20 normal subjects of the same age (P less than 0.001). This failure of mucociliary transport may play a role in the pathogenesis of the pulmonary disease in cystic fibrosis. Administration of a beta-adrenergic agent, terbutaline, increased the average mucous velocity in the patients with cystic fibrosis (to 5.5 mm per min plus or minus 3.6 SD, P less than 0.001) but not in control subjects. This observation has potential therapeutic significance.

Adolescent↗
PubMed1974

Relationship between frequency dependence of lung compliance and distribution of ventilation.

The previously demonstrated empirical association between frequency dependence of lung compliance and distribution of ventilation, the latter determined by the N(2) washout technique, was confirmed by establishing a mathematical link between the two tests. By assuming a two-compartment system with known compliances and making corrections for Pendelluft and common dead space mixing effects, the ratio of dynamic to static compliance (C(dyn)/C(st)) for any respiratory frequency can be calculated from the compartmental analysis of the N(2) washout at a single respiratory frequency. By using these equations, a good correlation was found between calculated and measured C(dyn)/C(st) in dogs with artificially induced bronchial obstruction and in young smokers or young nonsmokers after carbachol inhalation. A two-compartment N(2) washout was demonstrated in 10 young healthy smokers at one or two respiratory frequencies whereas all 10 normal controls showed a single exponential curve. These findings indicate that the non-invasive N(2) washout test is capable of predicting C(dyn)/C(st) and at the same time gives a direct measure of gas distribution. Further, it appears to be a highly sensitive method for the detection of "small airway disease."

Adult↗