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Biomedical subjects

H Bachofen

Publications and source records attributed to H Bachofen.

At least 37 records · Page 2Linked to original sources
PubMed1992

[Chronic asthmatic bronchitis].

Many patients with chronic obstructive pulmonary disease (COPD) episodically or continuously have asthmatic signs with a degree of reversibility in response to bronchodilators. In such cases, the diagnosis 'chronic asthmatic bronchitis' is often used, although the cause-effect relationship between COPD and asthmatic manifestations is not established. Hence, the 'chronic asthmatic bronchitis' is not a pathogenetic diagnosis, but rather a working diagnosis which implies a specific treatment of the reversible component of chronic airway obstruction. Certainly, the most important measure to avoid a rapid progression of COPD is the elimination of damaging agents by inhalation (smoking). In addition, it was a widely accepted belief that these patients require a continuous inhalation therapy with beta-agonists or anticholinergics. However, there is new evidence, indicating that a continuous treatment might accelerate the decline in ventilatory function and that a better long-term outcome might be achieved by on-demand inhalations.

Aged↗
PubMed1991

[Why is the lung dry?].

The extremely thin blood-gas barrier, the high blood perfusion rate and the deformability of the lung required for ventilation call for safety measures in order to keep the peripheral airspaces dry. The protective factors are provided in part by the particular structural organization of the lung, in part by physiological safeguards. Amongst the structural safety factors the extremely low permeability of the alveolar epithelial cell layer, the effective drainage system of interstitial spaces, and the loose connective tissue layers which surround vessels and bronchi, and which can act as transient fluid reservoirs, should be mentioned. The physiologic safety factors include the low hemodynamic pressures in the pulmonary vessels, the high colloid-osmotic pressure of blood, the decrease in perimicrovascular colloid-osmotic pressure on increased transcapillary fluid filtration, the interstitial pressure gradient between peripheral and central parts of the lung, and the minimal mechanical forces acting on the fine lung parenchyma owing to the low surface tensions provided by alveolar surfactant. Whether the active pumping mechanism improving reabsorption of edema fluid is also operative under normal conditions has not yet been clarified.

Blood Pressure↗
PubMed1990

[Respiration physical therapy?].

This review assesses the role of physical modalities - chest physical therapy, breathing exercises, breathing training, and physical exercises - in the treatment of patients with pulmonary diseases. Controlled studies suggest that "routine" exercises yield a disappointing effort-benefit ratio, but that individually adapted programs may improve the well-being and functional ability of selected patients.

Breathing Exercises↗
PubMed1989

A captive bubble method reproduces the in situ behavior of lung surfactant monolayers.

We tested a new captive bubble surface tensiometer with films adsorbed from aqueous suspensions of rabbit lung surfactant and a bovine lung surfactant lipid extract and with films of dipalmitoyl-sn-3-glycerophosphorylcholine (DPPC) spread from solvents. The lack of tubes penetrating the bubble surface eliminated potential leakage pathways for the surface film, which was compressed by increasing external pressure. Surface tensions and areas were calculated directly from bubble shapes without the need of pressure measurements. After only one to two compressions, the rabbit surfactant films exhibited the low surface tension, collapse rates, and compressibilities characteristic of the alveolar surface in situ and approached the behavior of spread DPPC films. The bubble "clicking" phenomenon described earlier by Pattle (Proc. R. Soc. Lond. B Biol. Sci. 148: 217-240, 1958) was also reproduced, but only with the bovine extract, which did not perform as well as the rabbit surfactant in surface tests. These findings suggest that surfactant apoprotein SP-A, which was probably present in the rabbit but not the bovine preparations, enhances both adsorption and stability of pulmonary surfactant monolayers.

Animals↗
PubMed1988

Ultrastructural aspects of pulmonary edema.

The alveolar septa are designed for gas exchange as well as for the exchange of water and solutes. The organization of the tissue elements and the ultrastructural architecture of the alveolar septa minimize the interference between gas and liquid exchange even when excess water begins to accumulate in the septal interstices and the alveoli. Larger amounts of alveolar edema fluid, however, profoundly alter both function and structure of the lung parenchyma. As to the routes of abnormal fluid movement, the ultrastructural findings are not always conclusive, though in some types of permeability edema frank anatomic disruptions of the endothelial and epithelial barriers can be observed. On the other hand, in hemodynamic edema the permeability barriers appear to be intact. However, experiments involving macromolecular tracers and the presence of numerous red blood cells in the interstitial and alveolar spaces indicate that transient separations of cell junctions have taken place.

Acute Disease↗
PubMed1988

Low plasma concentrations of ionized calcium in patients with asthma.

It has been suggested that calcium homeostasis is abnormal in the vascular smooth muscle of hypertensive patients and in the bronchial smooth muscle in asthmatics. We have found the mean baseline concentration of plasma ionized calcium to be significantly lower both in 12 asthmatics with exercise-induced asthma (EIA) [1.16 +/- 0.01 (SE) mmol/l, P less than 0.001] and in 20 asthmatics without EIA (1.16 +/- 0.01; P less than 0.001) compared with 42 healthy subjects (1.24 +/- 0.01). The mean concentrations of plasma ionized calcium were not significantly different in asthmatics with and without EIA when measured either before treadmill exercise, during the last seconds of this exercise, or 10 or 20 min after exercise but were significantly lower than in another seven healthy subjects who undertook the same exercise protocol. Total plasma calcium concentrations in the three exercising groups were not significantly different at any point in time. The results suggest that in bronchial asthma an alteration of calcium metabolism may be important, but they also suggest that there is no simple relationship between the plasma ionized calcium concentration and acute exercise-induced bronchoconstriction.

Asthma↗
PubMed1987

Relations among alveolar surface tension, surface area, volume, and recoil pressure.

For pulmonary structure-function analysis excised rabbit lungs were fixed by vascular perfusion at six points on the pressure-volume (P-V) curve, i.e. at 40, 80, and 100% of total lung capacity (TLC) on inflation, at 80 and 40% TLC on deflation, and at 80% TLC on reinflation. Before fixation alveolar surface tensions (gamma) were measured in individual alveoli over the entire P-V loop, using an improved microdroplet method. A maximal gamma of approximately 30 mN/m was measured at TLC, which decreased during lung deflation to about 1 mN/m at 40% TLC. Surface tensions were considerably higher on the inflation limb starting from zero pressure than on the deflation limb (gamma-V hysteresis). In contrast, the corresponding alveolar surface area-volume (SA-V) relationship did not form a complete hysteresis over the entire volume range. There was a considerable difference in SA between lungs inflated to 40% TLC (1.49 +/- 0.11 m2) and lungs deflated to 40% TLC (2.19 +/- 0.21 m2), but at 80% TLC the values of SA were essentially the same regardless of the volume history. The data indicate that the gamma-SA hysteresis is only in part accountable for the P-V hysteresis and that the determinative factors of alveolar geometry change with lung volume. At low lung volumes airspace dimensions appear to be governed by an interplay between surface and tissue forces. At higher lung volumes the tissue forces become predominant.

Animals↗
PubMed1986

Effect of dietary caffeine on airway reactivity in asthma.

The potential influence of dietary caffeine on bronchoprovocation challenges with carbachol was examined in 7 patients with asymptomatic asthma. In a double-blind fashion placebo or caffeine (6 mg/kg body weight; equivalent to approximately 4 cups of coffee) solved in orange juice was administered, and carbachol challenges were performed. The average peak serum concentration achieved 60 min after dosing was 7.6 +/- SD 2.1 mg/l. These caffeine levels did not produce any appreciable attenuation of the bronchoconstrictor response to carbachol inhalations. It thus appears that dietary caffeine is barely a cause of erroneous interpretations of bronchoprovocation challenges with carbachol.

Administration, Oral↗
PubMed1985

[Bronchial reactions to carbachol inhalation in patients with a suspected diagnosis of cough due to asthma].

In 50 patients with persistent cough suspected to be of asthmatic origin and in 16 healthy subjects, the bronchoconstrictor response to carbachol inhalation was determined by the method of Orehek. Data analysis yielded the following results: on average, the bronchial reactivity of patients was significantly higher than that of normal subjects (p less than 0.005), in healthy subjects, the spectrum of airway responsiveness showed a log-normal distribution, the patients' bronchial reactivities also showed a log-normal distribution, but with larger variance than in healthy subjects, both distributions overlapped to a considerable extent. These distribution patterns, and the difficulties in estimating the probability of errors, call for a cautious interpretation of the results of provocation testing in patients with chronic cough. Increased airway reactivity is an additional sign, rather than proof, of the asthmatic origin of chronic cough.

Adult↗
PubMed1985

Alveolar surface tensions in excised rabbit lungs: effect of temperature.

In excised, perfused rabbit lungs the alveolar surface tension was measured in individual alveoli over the entire P-V loop at different temperatures (22 and 37 degrees C), using an improved microdroplet method. Additional in vitro experiments are reassuring that the microdroplets do not affect the properties of the alveolar surface film. The in situ measurements show that the alveolar surface tension and the surface tension to volume relation are essentially the same at 22 and 37 degrees C. A maximal surface tension of about 30 mN X m-1 was measured at TLC, and there is a substantial surface tension to volume hysteresis, which amounts to almost 10 mN X m-1 in the middle volume range of a complete pressure volume cycle of the lung. However, with respect to the absolute values of alveolar surface tension, and the shape and width of the hysteresis, these directly obtained results are different from previous findings.

Animals↗
PubMed1985

Effects of the calcium antagonist tiapamil on pulmonary gas exchange in patients with chronic obstructive pulmonary disease who receive salbutamol.

Patients with chronic obstructive pulmonary disease (COPD) and cardiovascular diseases are frequently given combination therapy with a beta 2-agonist and a calcium antagonist. Each drug is known to increase ventilation-perfusion inequalities. It was our aim to define the effects of their combination on lung function and on pulmonary gas exchange in eight subjects with COPD but partially reversible airway obstruction. Sixty minutes after placebo or 450 mg tiapamil, subjects inhaled 0.2 mg salbutamol. There was no significant effect of tiapamil on specific airway conductance and the forced expiratory volume in 1 second before or after the inhalation of salbutamol. Blood was drawn 30, 55, 80, and 100 minutes after placebo or tiapamil dosing. After placebo the mean (+/- SD) arterial oxygen tension (Pao2) fell from 67.1 +/- 7.3 to 64.4 +/- 5.5 mm Hg and the mean alveolar-arterial oxygen tension difference (AaDo2) rose from 34.6 +/- 8.4 to 40.5 +/- 6.8 mm Hg. After tiapamil the mean Pao2 fell from 68.7 +/- 7.3 to 66.4 +/- 5.8 mm Hg and the mean AaDo2 rose from 35.1 +/- 6.8 to 38.7 +/- 7.4 mm Hg. The changes in Pao2 were not significant. The increase in AaDo2 after placebo was significant, but that after tiapamil was not. We conclude that the combination of the calcium antagonist tiapamil and the bronchodilator salbutamol is safe with respect to lung function in COPD. There is no evidence that tiapamil increases beta 2-agonist-induced impairment in pulmonary gas exchange.

Adult↗
PubMed1985

Lung fixation by airway instillation: effects on capillary hematocrit.

Instillation of glutaraldehyde into the airways of collapsed lungs is a widely used fixation procedure for analysis of pulmonary structure-function relations. In order to better define the effect of this fixation method on the pulmonary microvasculature, a morphometric analysis was made in rat lungs fixed under different conditions. In one group of animals the lungs were allowed to collapse; then the circulation was suddenly interrupted with a sling placed in the coronary sulcus before instillation of the fixative. In a second group the same procedure was carried out with the exception that the lungs were kept inflated at the time of circulatory arrest. In third group the standard technique was used, i.e., the collapsed lungs were instilled before circulatory arrest. The results show that important parameters of alveolar and septal dimensions, and in particular the capillary surfaces and volumes, are alike regardless of the procedure of fixation. However, in lungs fixed by the standard technique a higher capillary hematocrit (approximately 33%) and a decreased harmonic mean thickness of the plasma barrier were found. This artificial hemoconcentration in the microvasculature resulted in a substantial morphometric overestimate of the diffusing capacity of the lung.

Animals↗
PubMed1984

[Asthma and pregnancy].

Asthma during pregnancy threatens both mother and child. The pregnancy may worsen the asthma, and the asthma may endanger fetal oxygenation. However, by appropriate medical management, which requires careful consideration of the risk-benefit ratio of antiasthmatic drugs, the risk for mother and child can be minimized.

Asthma↗
PubMed1983

[Inhalation of beta-stimulators: comparison of the effects of 6 different inhalation devices].

The efficacy of salbutamol inhalations with six different aerosol devices has been evaluated. In four crossover experiments 38 patients with stable asthmatic airway diseases inhaled salbutamol with a pressurized metered-dose inhaler, with a powder inhaler, with two different jet nebulizers, an ultrasonic nebulizer, and an IPPB device. The bronchodilator response was assessed by measurements of FEV1 and specific airway conductance before and after the inhalations.

Adult↗