Therapy of paroxysmal pulmonary edema by antifoaming agents

Transwell Insert-Embedded Microfluidic Devices for Time-Lapse Monitoring of Alveolar Epithelium Barrier Function under Various Stimulations

This paper reports a transwell insert-embedded microfluidic device capable of culturing cells at an air-liquid interface (ALI), mimicking the in vivo alveolar epithelium microenvironment. Integration of a commercially available transwell insert makes the device fabrication straightforward and eliminates the tedious device assembly processes. The transwell insert can later be detached from the device for high-resolution imaging of the cells. In the experiments, the cells showing type-I pneumocyte markers are exploited to construct an in vitro alveolar epithelium model, and four culture conditions including conventional liquid/liquid culture (LLC) and air-liquid interface (ALI) cell culture in normal growth medium, and ALI cell culture with inflammatory cytokine (TNF-α) stimulation and ethanol vapor exposure are applied to investigate their effects on the alveolar epithelium barrier function. The barrier permeability is time-lapse monitored using trans-epithelial electrical resistance (TEER) measurement and immunofluorescence staining of the tight junction protein (ZO-1). The results demonstrate the functionalities of the device, and further show the applications and advantages of the constructed in vitro cell models for the lung studies.

Foams and antifoams

Foams and antifoams are two entities with completely different natures. For example, the foams are structures of bubbles in contact, while the antifoams are emulsions containing hydrophobic particles. The interaction between them makes the foam decay faster and in the same time exhausts the antifoam. The mechanism of such an effect is complex of many phenomena taking place in the foam. Thus the antifoams are known as powerful foam suppressors. For these reasons, they are very important from fundamental and practical viewpoints. This paper summarizes the knowledge on antifoams since their very creation till nowadays. In this regard, the review discloses the scientific interpretations on antifoams in chronological order in accord with the literature. Thus, for example it begins with description of the first antifoams (oils) from the 1940s and the pioneering studies of S. Ross and his group. The first physical methods for studying antifoams were presented along with the concepts of spreading and entering coefficients of oils (W. Harkins, 1941, J. Robinson and W. Woods, 1948). The further development of the antifoams (oils+hydrophobic particles) was described by means of the works of R. Kulkarni et al., A. Dippenaar and P. Garrett in the late 1970s and the early 1980s. The theoretical models on the antifoam performance of R. Pelton and P. Garrett, developed in 1980s and 1990s, were presented and analyzed as well in regard with their limits of applicability. Substantial advance on the experimental techniques for studying antifoams has been achieved by introducing different variants of the film trapping technique (FTT) developed by D. Wasan et al., I. Ivanov et al. and T. Tamura et al. in the middle and the late 1990s. An assessment of these techniques was carried out in regard with their capacity for detailed studying the antifoam action within the thin liquid films. Finally, the latest knowledge on the antifoams was achieved due to N. Denkov and his group, who harnessed both the most successful type of FTT and the interferometric thin film setup of Scheludko to conduct innovative experiments on the antifoam's action in the foam films under different conditions. They derived new more detailed understanding on the antifoam's action. For this reason, we must acknowledge the series of works under the supervision of N. Denkov performed between 1996 and 2004 as the lately ones in the field. The present work contains in addition a subchapter devoted to describing alternative methods for design and control of the foam stability. As far as the foaminess and the rate of foam decay depends on the states of the surfactant adsorption layers situated on the bubble surfaces, both foaminess and foam durability can be designed by means of proper choices of surfactants, concentrations and methods of foam generation. Therefore, this paper scrutinized the very mechanism of foam generation whose product is initial foam. Afterwards it was pointed out that the elastic modulus of the foam bubbles is responsible for the further "life" of the already generated foam. A compilation between foaminess and average rate of foam decay named foam production was shown as more successful way to describe the foaming capacity of the frothers. In addition, the properties of tenacious famous under various conditions were exhibited as well. This subchapter does not give any formula for precise design of foams with entailed durability but rather outlines new ways to achieve such recipe.

Adjuvant use of warm butyl alcohol vapor in experimental pulmonary edema

Studies were done to determine if warm n-butyl alcohol vapor might be effective for the destruction of respiratory tract foam bubbles and for alleviation of the arterial hypoxemia accompanying severe acute pulmonary edema. In vitro studies showed that warm butyl alcohol vapors made from 5% and 7% butyl alcohol solutions at 39 degrees C were much more effective in antifoam activity against synthetic foam bubbles than ethyl alcohol vapors, made from 20% and 30% ethyl alcohol at 22 degrees C. Warm butyl alcohol vapor also slowly destroyed in vitro the fine foam bubbles of alveolar lining origin made in rabbit lung post mortem. Evolving lung edema was induced in anesthetized rabbits by aspiration of 1.1 ml/kg of 1.2 molal sorbitol/0.14 molal sodium chloride/0.01 molal hydrochloric acid solution of pH 2.0. After established severe arterial hypoxemia and in the absence of overt foam, inhalation of warm butyl alcohol/H2O vapor-air mixture, made by air humidification from 7% butyl alcohol at 39 degrees C, alleviated promptly the hypoxemia. The improvement was progressive over the first 45 minutes of continued vapor therapy. The lessened hypoxemia occurred without concurrent improvement in the amount of formed lung edema fluid. Control inhalations of warm 100% H2O vapor-air mixture did not improve the hypoxemia. The only noted side effects of warm butyl alcohol vapor treatments were slight hypotension and slight metabolic acidosis which developed very slowly. The results suggest that warm butyl alcohol vapor might prove to be an effective adjuvant agent to lessen critically severe hypoxemia in selective cases of acute pulmonary edema in man.

Alcohol Vapor by Inhalation in the Treatment of Acute Pulmonary Edema

Accepted therapy of pulmonary edema is contraindicated in shock, central nervous system lesions, or pregnancy. Diagnosis of the underlying disease is not always immediately possible. Alcohol inhalation, previously tested in animals, changes surface tension of the foam and has beneficial effects. Clinical experience has revealed prompt relief in over one-half of the acute cases, definite improvement in another 29 per cent. Some cases with subacute edema also exhibited decreased foaming. The absence of contraindications and the possibility of using the method in conjunction with other procedures are favorable elements of alcohol therapy by inhalation.