[Diagnosis and treatment of a liver abscess with contrast-enhanced ultrasound]. / Peripherer Leberabszess: Darstellung und Behandlung mit Hilfe des Ultraschall- kontrastmittels SonoVue.

We report on a patient with pyogenic liver abscess. Using a ultrasound contrast agent improves the characterization of pyogenic hepatic abscesses and facilitates repetitive therapeutic punctures. The use of ultrasound contrast agents opens new aspects in the diagnosis of liver abscesses and gives additional confidence in diagnostic and therapeutic procedures.

Structures of surfactant films: a scanning force microscopy study.

The alveolar lining layer is thought to consist of a continuous duplex layer, i.e., an aqueous hypophase covered by a thin surfactant film which is a monolayer with dipalmitoyl-phosphatidylcholine (DPPC) as its most important component. Findings obtained by electron microscopy and results from in vitro experiments suggest, however, that the structure and hence the structure-function relations of surfactant films are more complex. In order to better define their structures films of surfactants were studied by scanning force microscopy. Four different surfactants were spread on a Langmuir-Wilhelmy balance, and then transferred onto a solid mica plate by the Langmuir-Blodgett technique, under various states of film compression. Imaging of the films by scanning force microscopy was performed in the contact (repulsive) mode in air. The scanning force micrographs revealed that surfactant films are not homogeneous, but rather undergo phase transitions depending on the surface pressures. Even at comparable surface pressures different surfactants show quite different surface patterns. Differences in surface structure can even be observed in films containing surfactant proteins (SP)-B and SP-C. These observations give further evidence that the widely accepted hypothesis of a regular monolayer of phospholipids governing the surface tension probably does not hold true, but that the structure-function relationship of surface active surfactant films is even more complex than hitherto thought.

Ultrastructure of the aqueous lining layer in hamster airways: is there a two-phase system?

For particle retention and clearance, the structure and surface properties of the airway lining layer are important. Due to difficulties of its preservation, structural analysis has been hampered, and, hence, the existence of two distinct and continuous phases and how much osmiophilic material is available are unclear. It was the objective of this study to investigate the ultrastructure of the aqueous lining layer in the intrathoracic conducting airways of hamsters. By means of transmission electron microscopy, we investigated the ultrastructure of the airway lining layer in hamsters whose lungs have been fixed by the application of fixative dissolved in nonpolar fluorocarbon, either by instillation via the trachea or injection into the gas exchange parenchyma, together with intravascular perfusion of aqueous fixatives. The results were compared to lungs fixed by intravascular perfusion only. In twelve hamsters, the airway lining layer was found to consist of an aqueous phase and was coated by an osmiophilic film that follows fairly closely the upper-extending contours of cilia protruding from epithelial cells. Substantially less osmiophilic material was preserved in extrapulmonary airways and when nonaqueous fixative was injected. We found that the aqueous lining layer of the intrathoracic airways in hamsters essentially surrounds and covers the cilia, the microvilli, and any other structures like macrophages or deposited particles contained in it and is coated by an osmiophilic film of variable thickness. In healthy animals, a gel phase is expected to be very thin, not clearly separated from the periciliary fluid, and located just beneath the osmiophilic film.

Influence of bilirubin on surface tension properties of lung surfactant.

AIM: To investigate the influence of bilirubin on the surface tension activity of a porcine derived (Curosurf) and synthetic (Exosurf) surfactant. METHODS: The captive bubble surfactometer at phospholipid doses of 0.5 mg/ml (low dose) and 1 mg/ml (high dose) in solutions of increasing bilirubin concentrations (0.25, 0.5, and 1.0 mg/ml) was used. RESULTS: Curosurf (without bilirubin) showed a higher surface f1p4ion activity than Exosurf, as shown by area compression of 30 (SD 0.6)% compared with 76(1.4)% at low surfactant dose and 25 (0.9)% compared with 85 (0.5)% at high dose (P < 0.01). Bilirubin showed negligible surface activity at the concentrations studied. At low phospholipid dose (0.5 mg/ml Curosurf), bilirubin increased film area compression of lipid extract surfactant from 30 (0.6)% to 55 (1.6)%, 59 (0.1)%, and 68 (0.5)% at the three studied bilirubin concentrations, respectively (P < 0.01). At high phospholipid dose (1 mg/ml Curosurf), bilirubin had the same adverse, although less pronounced, effect on film area compression of porcine lipid extract surfactant (25 (0.9)% vs 26 (0.9)%, 39 (1.3)%, and 44 (1.1)%, respectively) (P < 0.01). Using synthetic surfactant (Exosurf), with a much lower original surface activity, bilirubin did not further inhibit its surface tension properties at any of the phospholipid doses studied. CONCLUSION: These results indicate that in vitro bilirubin impairs the surface tension activity of porcine lipid extract surfactant, but does not affect synthetic surfactant activity.